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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2016	Mar. 10, 2017	Jun. 30, 2016
Document Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Trading Symbol	NK
Entity Registrant Name	NANTKWEST, INC.
Entity Central Index Key	0001326110
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		82,296,621
Entity Public Float			$ 185.4

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 8,083	$ 175,908
Due from related parties	1,089	217
Prepaid expenses and other current assets	5,135	3,105
Marketable securities	190,838	118,310
Total current assets	205,145	297,540
Marketable securities, noncurrent	87,571	55,135
Property, plant and equipment, net	18,906	5,523
Intangible assets, net	5,086	7,292
Other assets	788	1,359
Total assets	317,496	366,849
Current liabilities:
Accounts payable	4,045	2,085
Accrued expenses	5,864	2,575
Due to related parties	1,753	1,352
Other current liabilities	891	136
Total current liabilities	12,553	6,148
Build-to-suit liability, less current portion	5,651	2,468
Financing obligation, less current portion	2,025	0
Deferred rent	2,426	845
Deferred revenue	187	228
Deferred tax liability	996	1,165
Other liabilities	240	0
Total liabilities	24,078	10,854
Commitments and contingencies (Note 7)
Stockholders’ equity
Common stock	8	8
Additional paid-in capital	680,757	606,555
Accumulated other comprehensive loss	(284)	(192)
Accumulated deficit	(387,063)	(250,376)
Total stockholders’ equity	293,418	355,995
Total liabilities and stockholders’ equity	$ 317,496	$ 366,849

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015	Jul. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001			$ 0.0001
Common stock, shares authorized	500,000,000	500,000,000		100,000,000
Common stock, shares issued	81,983,937	81,311,686	9,531,200
Common stock, shares outstanding	81,983,937	81,311,686

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Revenue	$ 44	$ 236	$ 641
Operating expenses:
Research and development	29,153	11,434	1,595
Selling, general and administrative	95,391	227,678	4,621
Total operating expenses	124,544	239,112	6,216
Loss from operations	(124,500)	(238,876)	(5,575)
Other income (expense):
Investment income, net	3,097	2,988	20
Change in fair value of warrant liability	0	(1,366)	(158)
Interest expense	(66)	0	(471)
Other income, net	88	77	0
Total other income (expense)	3,119	1,699	(609)
Loss before income taxes	(121,381)	(237,177)	(6,184)
Income tax (benefit) expense, net	(572)	(301)	1
Net loss	$ (120,809)	$ (236,876)	$ (6,185)
Net loss per share:
Basic and diluted	$ (1.47)	$ (3.31)	$ (0.75)
Weighted average number of shares during the period:
Basic and diluted	81,979,005	71,519,609	8,246,028

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (120,809)	$ (236,876)	$ (6,185)
Other comprehensive loss, net of income taxes:
Net unrealized gain (loss) on available-for-sale securities	5	(192)	0
Reclassification of net realized gains on available-for-sale securities included in net loss	(97)	0	0
Total other comprehensive loss	(92)	(192)	0
Comprehensive loss	$ (120,901)	$ (237,068)	$ (6,185)

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Accredited Investors	Initial Public Offering	Private Placement	Brink Biologics Inc Spinout	Series B Convertible Preferred Stock	Series B Convertible Preferred Stock Accredited Investors	Series B Convertible Preferred Stock Initial Public Offering	Series B Convertible Preferred Stock Private Placement	Series B Convertible Preferred Stock Brink Biologics Inc Spinout	Common Class A	Common Class A Accredited Investors	Common Class A Initial Public Offering	Common Class A Private Placement	Common Class A Brink Biologics Inc Spinout	Series C convertible preferred stock	Series C convertible preferred stock Accredited Investors	Series C convertible preferred stock Initial Public Offering	Series C convertible preferred stock Private Placement	Series C convertible preferred stock Brink Biologics Inc Spinout	Common Class B	Common Class B Accredited Investors	Common Class B Initial Public Offering	Common Class B Private Placement	Common Class B Brink Biologics Inc Spinout	Common Stock	Common Stock Accredited Investors	Common Stock Initial Public Offering	Common Stock Private Placement	Common Stock Brink Biologics Inc Spinout	Additional Paid-in Capital	Additional Paid-in Capital Accredited Investors	Additional Paid-in Capital Initial Public Offering	Additional Paid-in Capital Private Placement	Additional Paid-in Capital Brink Biologics Inc Spinout	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Accredited Investors	Accumulated Other Comprehensive Income (Loss) Initial Public Offering	Accumulated Other Comprehensive Income (Loss) Private Placement	Accumulated Other Comprehensive Income (Loss) Brink Biologics Inc Spinout	Accumulated Deficit	Accumulated Deficit Accredited Investors	Accumulated Deficit Initial Public Offering	Accumulated Deficit Private Placement	Accumulated Deficit Brink Biologics Inc Spinout
Beginning Balance, Shares at Dec. 31, 2013						1,851					1,158,382					0					1,681,099					0
Beginning Balance at Dec. 31, 2013	$ (3,755)					$ 0					$ 1					$ 0					$ 1					$ 0					$ 3,631					$ 0					$ (7,388)
Exercise of Class B common stock	1,185					$ 0					$ 0					$ 0					$ 0					$ 0					1,185					0					0
Exercise of Class B common stock, Shares						0					0					0					5,851,152					0
Stock-based compensation expense	562					$ 0					$ 0					$ 0					$ 0					$ 0					562					0					0
Issuance of convertible preferred stock less issuance costs	6,701					$ 0					$ 0					$ 0					$ 0					$ 0					6,701					0					0
Issuance of Series C convertible preferred stock less issuance costs, Shares						0					0					5,754,984					0					0
Conversion of debt and payables to Class A common stock	1,339					$ 0					$ 0					$ 0					$ 0					$ 0					1,339					0					0
Conversion of debt and payables to Class A common stock, Shares						0					1,522,799					0					0					0
Issuance of restricted stock	227					$ 0					$ 0					$ 0					$ 0					$ 0					227					0					0
Issuance of restricted stock, Shares						0					129,605					0					0					0
Issuance of stock to placement agent, Shares						0					3,087,324					0					763,151					0
Issuance of common stock less issuance costs	57,337					$ 0					$ 3					$ 0					$ 0					$ 0					57,334					0					0
Issuance of common stock less issuance costs, Shares						0					30,809,800					0					0					0
Conversion of Preferred B and C convertible preferred stock and Class B common stock	0					$ 0					$ 2					$ 0					$ (1)					$ 0					(1)					0					0
Conversion of Preferred B and C convertible preferred stock and Class B common stock, Shares						(1,851)					23,553,284					(5,754,984)					(8,295,402)
Exercise of stock options	180					$ 0					$ 0					$ 0					$ 0					$ 0					180					0					0
Exercise of stock options, Shares						0					833,173					0					0					0
Net loss	(6,185)					$ 0					$ 0					$ 0					$ 0					$ 0					0					0					(6,185)
Ending Balance, Shares at Dec. 31, 2014						0					61,094,367					0					0					0
Ending Balance at Dec. 31, 2014	57,591					$ 0					$ 6					$ 0					$ 0					$ 0					71,158					0					(13,573)
Stock-based compensation expense	211,221					$ 0					$ 0					$ 0					$ 0					$ 0					211,221					0					0
Vesting of restricted stock units						0					0					0					0					485,150
Net share settlement for RSU vesting and option exercises	(2,415)					$ 0					$ 0					$ 0					$ 0					$ 0					(2,415)					0					0
Net share settlement for RSU vesting and option exercises, Shares						0					0					0					0					(96,612)
Warrants issued in conjunction with Inex Bio purchase	5,170					$ 0					$ 0					$ 0					$ 0					$ 0					5,170					0					0
Exercise of warrants	7,348					$ 0					$ 0					$ 0					$ 0					$ 0					7,348					0					0
Exercise of warrants, Shares						0					4,106,492					0					0					570,609
Repurchase of common stock	$ (4,798)					$ 0					$ 0					$ 0					$ 0					$ 0					(4,798)					0					0
Repurchase of common stock, Shares	0					0					(249,952)					0					0					0
Reclassification of warrant liability due to exercise	$ 1,543					$ 0					$ 0					$ 0					$ 0					$ 0					1,543					0					0
Conversion to Class A common stock	0					$ 0					$ (7)					$ 0					$ 0					$ 7					0					0					0
Conversion to Class A common stock, Shares						0					(65,900,303)					0					0					65,900,303
Stockholders Equity Note Spinoff Transaction					$ 73					$ 0					$ 0					$ 0					$ 0					$ 0					$ 0					$ 0					$ 73
Issuance of common stock less issuance costs		$ 77,977	$ 221,475	$ 17,000			$ 0	$ 0	$ 0			$ 0	$ 0	$ 0			$ 0	$ 0	$ 0			$ 0	$ 0	$ 0			$ 0	$ 1	$ 0			$ 77,977	$ 221,474	$ 17,000			$ 0	$ 0	$ 0			$ 0	$ 0	$ 0
Issuance of common stock less issuance costs, Shares							0	0	0			0	0	0			0	0	0			0	0	0			4,063,333	9,531,200	680,000
Exercise of stock options	878					$ 0					$ 1					$ 0					$ 0					$ 0					877					0					0
Exercise of stock options, Shares						0					949,396					0					0					177,703
Other comprehensive loss	(192)					$ 0					$ 0					$ 0					$ 0					$ 0					0					(192)					0
Net loss	(236,876)					$ 0					$ 0					$ 0					$ 0					$ 0					0					0					(236,876)
Ending Balance, Shares at Dec. 31, 2015						0					0					0					0					81,311,686
Ending Balance at Dec. 31, 2015	355,995					$ 0					$ 0					$ 0					$ 0					$ 8					606,555					(192)					(250,376)
Stock-based compensation expense	73,852					$ 0					$ 0					$ 0					$ 0					$ 0					73,852					0					0
Vesting of restricted stock units						0					0					0					0					537,982
Net share settlement for RSU vesting and option exercises	(1,106)					$ 0					$ 0					$ 0					$ 0					$ 0					(1,106)					0					0
Net share settlement for RSU vesting and option exercises, Shares						0					0					0					0					(154,127)
Exercise of warrants	52					$ 0					$ 0					$ 0					$ 0					$ 0					52					0					0
Exercise of warrants, Shares						0					0					0					0					47,457
Change in accounting principle - ASU 2016-09 forfeiture	0					$ 0					$ 0					$ 0					$ 0					$ 0					31					0					(31)
Repurchase of common stock	$ (15,847)					$ 0					$ 0					$ 0					$ 0					$ 0					0					0					(15,847)
Repurchase of common stock, Shares	(2,157,944)					0					0					0					0					(2,157,944)
Exercise of stock options	$ 1,373					$ 0					$ 0					$ 0					$ 0					$ 0					1,373					0					0
Exercise of stock options, Shares						0					0					0					0					2,398,883
Other comprehensive loss	(92)					$ 0					$ 0					$ 0					$ 0					$ 0					0					(92)					0
Net loss	(120,809)					$ 0					$ 0					$ 0					$ 0					$ 0					0					0					(120,809)
Ending Balance, Shares at Dec. 31, 2016						0					0					0					0					81,983,937
Ending Balance at Dec. 31, 2016	$ 293,418					$ 0					$ 0					$ 0					$ 0					$ 8					$ 680,757					$ (284)					$ (387,063)

Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Stock issuance costs	$ 28,000
Initial Public Offering
Stock issuance costs	$ 16,800,000
Series C convertible preferred stock
Stock issuance costs		$ 800,000
Common Class A
Stock issuance costs		$ 200,000

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net loss	$ (120,809)	$ (236,876)	$ (6,185)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,607	1,472	36
Amortization of finance issuance costs	0	0	60
Stock-based compensation expense	73,852	211,221	789
Deferred income tax benefit	(575)	(302)	0
Change in value of warrant liability	0	1,366	158
Amortization of debt discount	0	0	377
Forgiveness of note receivable from related party	0	0	115
Bad debt expense	0	0	25
Non-cash interest items, net	(573)	72	0
Loss incurred by Inex Bio	0	56	0
Loss on disposal of assets	18	0	0
Amortization of net premiums on marketable securities	2,182	38	0
Gain on sales of marketable securities	(137)	(2,501)	0
Gain on settlement of note payable	0	(133)	0
Changes in operating assets and liabilities:
Accounts receivable, prepaid and other current assets	(1,458)	(3,231)	80
Other assets	153	(1,194)	(160)
Accounts payable	888	627	(347)
Accrued expenses and other liabilities	2,127	1,991	(314)
Due to related parties	378	1,352	0
Deferred rent and revenue	1,754	737	(52)
Net cash used in operating activities	(38,593)	(25,305)	(5,418)
Investing activities:
Purchases of property, plant and equipment	(6,560)	(2,241)	(235)
Purchase of Inex Bio Inc., net of cash acquired	0	(1,818)	0
Purchases of marketable securities	(272,999)	(198,068)	0
Sales/maturities of marketable securities	165,887	26,903	0
Net cash used in investing activities	(113,672)	(175,224)	(235)
Financing activities:
Proceeds from equity offerings, net of issuance costs	0	316,452	63,118
Repayments of notes payable	0	(132)	(53)
Proceeds from exercise of Class B common stock	0	0	1,162
Principal payments of financing obligations	(32)	0	0
Proceeds from exercise of stock options	1,373	878	180
Proceeds from exercise of warrants	52	7,348	0
Repurchase of common stock	(15,847)	(4,798)	0
Net share settlement for RSU vesting and option exercises	(1,106)	(2,415)	0
Net cash (used in) provided by financing activities	(15,560)	317,333	64,407
Net increase (decrease) in cash and cash equivalents	(167,825)	116,804	58,754
Cash and cash equivalents, beginning of period	175,908	59,104	350
Cash and cash equivalents, end of period	8,083	175,908	59,104
Cash paid during the period for:
Interest	66	0	52
Income taxes	2	1	1
Supplemental disclosure of non-cash investing and financing activities:
Conversion of debt and payables into common stock	0	0	1,339
Conversion of debt into Series C preferred stock	0	0	1,000
Change in par value from $0.001 to $0.0001	0	0	1
Conversion of accounts payable against note receivable related party	0	0	23
Cashless exercise of stock options and warrants	456	1,543	0
Lease incentive with a related party	849	0	0
Estimated fair value of buildings under build-to-suit leases	5,139	2,740	0
Property, plant and equipment purchases included in accounts payable and accrued expenses	2,753	457	0
Unrealized gain (loss) on marketable securities	(102)	(182)	0
Inex Bio Inc
Supplemental disclosure of non-cash investing and financing activities:
Issuance of warrants in Inex Bio, Inc. acquisition	$ 0	$ 5,170	$ 0

Consolidated Statements of Cash Flows (Parenthetical)	Dec. 31, 2014 $ / shares
Common stock, par value	$ 0.0001
Previously Reported
Common stock, par value	$ 0.001

Description of Business and Basis of Presentation	12 Months Ended
Description of Business and Basis of Presentation	Dec. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business and Basis of Presentation	1. Description of Business and Basis of Presentation Organization NantKwest, Inc. (the Company) was incorporated in Illinois on October 7, 2002 under the name ZelleRx Corporation. On January 22, 2010, the Company changed its name to Conkwest, Inc., and on July 10, 2015, the Company changed its name to NantKwest, Inc. In March 2014, the Company redomesticated from the State of Illinois to the State of Delaware and the Illinois Company ceased to exist. The Company is a pioneering clinical-stage immunotherapy biotechnology company headquartered in San Diego, California with certain operations in Culver City and El Segundo, California and Woburn, Massachusetts. The Company is focused on harnessing the power of the innate immune system by using the natural killer cell to treat cancer, infectious diseases and inflammatory diseases. A critical aspect of our strategy is to invest significantly in expanding our aNK platform and the development of our product candidates. The Company holds the exclusive right to commercialize activated natural killer (aNK) cells, a commercially viable natural killer cell-line, and a variety of genetically modified derivatives capable of killing cancer and virally infected cells. The Company owns corresponding U.S. and foreign composition and methods-of-use patents and applications covering the clinical use of aNK cells as a therapeutic to treat a spectrum of clinical conditions. The Company also licensed exclusive commercial rights to a portfolio of CD16 bearing aNK cells along with the corresponding U.S. and foreign composition and methods-of-use patents and applications covering the non-clinical use in laboratory testing of monoclonal antibodies, as well as clinical use as a therapeutic to treat cancers in combination with antibody products. The Company has licensed or sub-licensed its cell lines and intellectual property to numerous pharmaceutical and biotechnology companies for such non-clinical uses. The Company retains exclusive worldwide rights to clinical and research data, intellectual property and know-how developed with the Company’s aNK cells, as well as the only clinical grade master cell bank. Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, Inex Bio, Inc., and have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). All intercompany amounts have been eliminated. The Company applies the variable interest model under Accounting Standards Codification (ASC) Topic 810, Consolidation, to any entity in which the Company holds an equity investment or to which the Company has the power to direct the entity's most significant economic activities and the ability to participate in the entity's economics. If the entity is within the scope of the model, and meets the definition of a variable interest entity (VIE), the Company considers whether it must consolidate the VIE or provide additional disclosures regarding the Company's involvement with the VIE. If the Company determines that it is the primary beneficiary of the VIE, the Company will consolidate the VIE. This analysis is performed at the initial investment in the entity or upon any reconsideration event. Domicile Change In March 2014, the Company entered into a definitive merger and share exchange agreement pursuant to which the Company redomesticated from the State of Illinois to the State of Delaware and the Illinois Company ceased to exist (the Redomestication). In connection with the Redomestication, the holders of Class A and Class B common stock received one share of Class A and Class B common stock of the Delaware Company, respectively, in exchange for fifteen shares of the Illinois Company. The holders of Series B preferred stock received one share of Series B preferred stock of the Delaware Company in exchange for one share of the Illinois Company. The holders of any options, warrants or other securities are subject to adjustment based on the ratio of 1 for 15. All share numbers and per share prices in the accompanying consolidated financial statements have been adjusted to reflect the 1 for 15 exchange. Initial Public Offering In July 2015, the Company completed an initial public offering (IPO) of its common stock. In connection with its IPO, the Company issued and sold 9,531,200 shares of its common stock, at a price to the public of $25 per share. The Company’s shares of common stock began trading on the NASDAQ Global Market on July 28, 2015. As a result of the IPO, the Company received approximately $221.5 million in net proceeds, after deducting underwriting discounts, commissions and offering expenses of $16.8 million. Liquidity As of December 31, 2016, the Company had an accumulated deficit of approximately $387.1 million. The Company also had negative cash flow from operations of approximately $38.6 million during the year ended December 31, 2016. The Company expects that it will likely need additional capital to further fund development of, and seek regulatory approvals for, its product candidates, and begin to commercialize any approved products. The Company is currently focused primarily on the development of immunotherapeutic treatments for cancers and debilitating viral infections using targeted cancer killing cell lines, and believes such activities will result in the Company’s continued incurrence of significant research and development and other expenses related to those programs. If the clinical trials for any of the Company’s product candidates fail or produce unsuccessful results and those product candidates do not gain regulatory approval, or if any of the Company’s product candidates, if approved, fails to achieve market acceptance, the Company may never become profitable. Even if the Company achieves profitability in the future, it may not be able to sustain profitability in subsequent periods. The Company intends to cover its future operating expenses through cash and cash equivalents, marketable securities, and through a combination of equity offerings, debt financings, government or other third-party funding, marketing and distribution arrangements and other collaborations, strategic alliances and licensing arrangements. Additional financing may not be available to the Company when needed and, if available, financing may not be obtained on terms favorable to the Company or its stockholders. While the Company expects its existing cash and cash equivalents and marketable securities will enable it to fund operations and capital expenditure requirements for at least the next twelve months, it may not have sufficient funds to reach commercialization. Failure to obtain adequate financing when needed may require the Company to delay, reduce, limit or terminate some or all of its development programs or future commercialization efforts or grant rights to develop and market product candidates that the Company might otherwise prefer to develop and market itself, which could adversely affect the Company’s ability to operate as a going concern. If the Company raises additional funds from the issuance of equity securities, substantial dilution to existing stockholders may result. If the Company raises additional funds by incurring debt financing, the terms of the debt may involve significant cash payment obligations, as well as covenants and specific financial ratios that may restrict the Company’s ability to operate its business. Forward Stock Split On July 10, 2015, the Company effected a 1.8515-for-1 forward stock split of its outstanding common stock. All applicable share data, per share amounts and related information in the consolidated financial statements and notes thereto have been adjusted retroactively to give effect to the 1.8515-for-1 forward stock split.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Use of Estimates

The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to the valuation of warrants, stock-based compensation, the valuation allowance for deferred tax assets, preclinical and clinical trial accruals, and the valuation of build-to-suit lease assets. The Company bases its estimates on historical experience and on various other market-specific and relevant assumptions that it believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Risks and Uncertainties

Contingencies

The Company records accruals for loss contingencies to the extent that the Company concludes it is probable that a liability has been incurred and the amount of the related loss can be reasonably estimated. The Company evaluates, on a quarterly basis, developments in legal proceedings and other matters that could cause a change in the potential amount of the liability recorded or of the range of potential losses disclosed.

Cash, Cash Equivalents and Marketable Securities

The Company invests its excess funds in investment grade short- to intermediate-term corporate debt securities, commercial paper, government sponsored securities and foreign government bonds and classifies these investments as available-for-sale. The Company considers all highly liquid investments purchased with original maturities of three months or less to be cash equivalents and all investments purchased with original maturities of greater than three months as marketable securities. Marketable securities with original maturities of 12 months or less are classified as short-term and marketable securities with original maturities greater than 12 months are classified as long-term. All marketable securities are reported at fair value and any unrealized gains and losses are reported as a component of accumulated other comprehensive income (loss), net of tax, in the consolidated statement of stockholders’ equity (deficit), with the exception of unrealized losses believed to be other-than-temporary, which are recorded within other income (expense) in the current period. Realized gains and losses are included in other income (expense) in the consolidated statements of operations. Realized gains and losses from the sale of the securities and the amounts, net of tax, reclassified out of accumulated other comprehensive income, if any, are determined on a specific identification basis.

The Company periodically evaluates whether declines in fair values of its investments below their book value are other-than-temporary. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss, as well as the Company’s ability and intent to hold the investment until a forecasted recovery occurs. Additionally, the Company assesses whether it has plans to sell the security or it is more likely than not it will be required to sell any investment before recovery of its amortized cost basis. Factors considered include quoted market prices, recent financial results and operating trends, implied values from any recent transactions or offers of investee securities, credit quality of debt instrument issuers, other publicly available information that may affect the value of our investments, duration and severity of the decline in value and the Company’s strategy and intentions for holding the investment. There were no other than temporary impairments recorded in 2016 or 2015. The Company had no investments in 2014.

The Company minimizes its credit risk associated with cash and cash equivalents by periodically evaluating the credit quality of its primary financial institutions. While the Company maintains cash deposits in FDIC insured financial institutions in excess of federally insured limits, management believes the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company has not experienced any losses on such accounts.

The Company has funded a certificate of deposit (CD) as a substitute letter of credit for one of the leased properties. This CD is reported as long-term restricted cash and is included in other assets on the consolidated balance sheet as the landlord is the beneficiary of the account and the Company is not able to access the funds during the term of the lease.

Property and Equipment

Property and equipment is stated at historical cost less accumulated depreciation. Historical cost includes expenditures that are directly attributable to the acquisition of the items. All repairs and maintenance are charged to net loss during the financial period in which they are incurred. Depreciation of property and equipment is calculated using the straight-line method over the estimated useful lives of the assets, as follows:

Buildings		39 years
Software		3 years
Laboratory equipment		5 years
Furniture & fixtures		5 years
IT equipment		3 years
Leasehold improvements		The lesser of the lease term or the life of the asset

On disposal or impairment of property and equipment, the cost and related accumulated depreciation is removed from the consolidated financial statements and the net amount, less any proceeds, is included in other income / (loss) in the consolidated statement of operations.

The Company is deemed to be the owner, for accounting purposes, during the construction phase of certain long-lived assets under build-to-suit lease arrangements because of its involvement with the construction, its exposure to any potential cost overruns and its other commitments under the arrangements. In these cases, the Company recognizes a build-to-suit lease asset under construction and a corresponding build-to-suit lease liability on the consolidated balance sheets. Upon completion of construction, the Company evaluates the de-recognition of the asset and liability under the provisions of ASC 840-40 Leases – Sales-Leaseback Transactions.

Intangible Assets

Intangible assets consist of the cost of reacquiring a technology license in the asset purchase of Inex Bio. The Company calculates amortization expense for acquired technology licenses using the straight-line method over the estimated useful lives, which is 4 years.

Patents

The Company expenses patent costs, including related legal costs, as incurred and records such costs within general and administrative expenses in the consolidated statements of operations.

Impairments

The Company’s long-lived assets include property, plant and equipment and intangible assets. The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparison of the carrying amount to the future net cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the projected undiscounted future cash flows arising from the asset using a discount rate determined by management to be commensurate with the risk inherent to the Company’s current business model. There were no impairment losses recognized during the years ended December 31, 2016, 2015 and 2014.

Transactions with Related Parties

As outlined in Note 8, the Company has various agreements with different related parties. Some are billed and settled in cash monthly. Others are billed quarterly and settled in cash the following month. Monthly accruals are made for all quarterly billing arrangements.

Fair Value of Financial Instruments

The accounting standard for fair value measurements provides a framework for measuring fair value and requires disclosures regarding fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date, based on the Company’s principal or, in absence of a principal, most advantageous market for the specific asset or liability.

The Company uses a three-tier fair value hierarchy to classify and disclose all assets and liabilities measured at fair value on a recurring basis, as well as assets and liabilities measured at fair value on a non-recurring basis, in periods subsequent to their initial measurement. The hierarchy requires the Company to use observable inputs when available, and to minimize the use of unobservable inputs, when determining fair value.

The three tiers are defined as follows:

•

Level 1—Observable inputs that reflect quoted market prices (unadjusted) for identical assets or liabilities in active markets at the measurement date. Since valuations are based on quoted prices that are readily and regularly available in an active market, valuation of these products does not entail a significant degree of judgment. The Company’s Level 1 assets consist of bank deposits and money market funds.

•

Level 2—Observable inputs other than quoted prices in active markets that are observable either directly or indirectly in the marketplace for identical or similar assets and liabilities. The Company’s Level 2 assets consist of corporate debt securities including commercial paper, government sponsored securities and corporate bonds, as well as foreign municipal securities.

•

Level 3— Valuations based on inputs that are unobservable and significant to the overall fair value measurement. The Company’s Level 3 liability includes a warrant derivative liability.

During the years ended December 31, 2016 and 2015, no transfers were made into or out of the Level 1, 2 or 3 categories. The Company will continue to review the fair value inputs on a quarterly basis.

The Company utilizes a third-party pricing service to assist in obtaining fair value pricing for investments. Inputs are documented in accordance with the fair value disclosure hierarchy.

Preclinical and Clinical Trial Accruals

As part of the process of preparing the financial statements, the Company is required to estimate expenses resulting from obligations under contracts with vendors, clinical research organizations and consultants. The financial terms of these contracts vary and may result in payment flows that do not match the periods over which materials or services are provided under such contracts.

The Company estimates clinical trial and research agreement related expenses based on the services performed, pursuant to contracts with research institutions and clinical research organizations and other vendors that conduct clinical trials and research on the Company’s behalf. In accruing clinical and research related fees, the Company estimates the time period over which services will be performed and activity expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Payments made to third parties under these arrangements in advance of the receipt of the related services are recorded as prepaid expenses until the services are rendered.

Lease Obligations

The Company categorizes leases at their inception as either operating or capital leases. On certain lease agreements, the Company may receive rent holidays and other incentives. The Company recognizes lease costs on a straight-line basis without regard to deferred payment terms, such as rent holidays that defer the commencement date of required payments. Additionally, incentives the Company receives for leases categorized as operating leases are treated as a reduction of cost over the term of the agreement.

The Company establishes assets and liabilities for the estimated construction costs incurred under build-to-suit lease arrangements to the extent the Company is involved in the construction of structural improvements or takes construction risk prior to commencement of a lease. Upon occupancy of facilities under build-to-suit leases, the Company assesses whether these arrangements qualify for sales recognition under the sale-leaseback accounting guidance. If the Company continues to be the deemed owner, the facilities are accounted for as financing leases.

Stock Repurchases

In November 2015, the board of directors approved a share repurchase program (2015 Share Repurchase Program) allowing the CEO or CFO, on behalf of the Company, to repurchase from time to time, in the open market or in privately negotiated transactions, up to $50.0 million of the Company’s outstanding shares of common stock, exclusive of any commissions, markups or expenses. The timing and amounts of any purchases will be based on market conditions and other factors, including price, regulatory requirements and other corporate considerations. The 2015 Share Repurchase Program does not require the purchase of any minimum number of shares and may be suspended, modified or discontinued at any time without prior notice. The Company expects to finance the purchases with existing cash balances. As it is the intent for the repurchased shares to be retired, the Company has elected to account for the shares repurchased under the constructive retirement method. For shares repurchased in excess of par, the Company will allocate the excess value to accumulated deficit.

Revenue Recognition and Deferred Revenue

The Company derives substantially all of its revenue from non-exclusive license agreements with numerous pharmaceutical and biotechnology companies granting them the right to use the Company’s cell lines and intellectual property for non-clinical use. These license agreements generally include nonrefundable upfront fees and annual research license fees for such use, as well as commercial fees for sales of the licensees’ products developed or manufactured using the Company’s intellectual property and cell lines. The Company’s license agreements also may include milestone payments, although to date, the Company has not generated any revenue from milestone payments. The Company recognizes revenue when (i) persuasive evidence of an arrangement exists; (ii) delivery of the products and/or services has occurred; (iii) the fees are fixed or determinable; and (iv) collectability is reasonably assured.

When entering into an arrangement, the Company first determines whether the arrangement includes multiple deliverables and is subject to accounting guidance in Accounting Standards Codification (ASC) Subtopic 605-25, Multiple-Element Arrangements. If the Company determines that an arrangement includes multiple elements, it determines whether the arrangement should be divided into separate units of accounting and how the arrangement consideration should be measured and allocated among the separate units of accounting.

An element qualifies as a separate unit of accounting when the delivered element has standalone value to the customer. The Company’s agreements do not include a general right of return relative to delivered elements. Any delivered elements that do not qualify as separate units of accounting are combined with other undelivered elements within the arrangement as a single unit of accounting. If the arrangement constitutes a single combined unit of accounting, the Company determines the revenue recognition method for the combined unit of accounting and recognizes the revenue over the period from inception through the date the last deliverable within the single unit of accounting is delivered.

License rights and non-contingent deliverables, such as knowledge transfer, do not have standalone value as they are not sold separately and they cannot be resold and, consequently are considered a single unit of accounting. Therefore, license revenue in the form of upfront payments is deferred and recognized over the applicable period of the Company’s substantive performance obligations or the period the rights granted are in effect.

The Company recognizes a milestone payment when earned if it is substantive and the Company has no ongoing performance obligations related to the milestone. A milestone payment is considered substantive if it 1) is commensurate with either the Company’s performance to achieve the milestone or the enhanced value of the delivered item as a result of a specific outcome resulting from the Company’s performance to achieve the milestone; 2) relates solely to past performance; and 3) is reasonable relative to all of the deliverables and payment terms, including other potential milestone consideration within the arrangement.

The Company records any amounts received prior to satisfying the revenue recognition criteria as deferred revenue in the accompanying consolidated balance sheets.

Research and Development Costs

Major components of research and development costs include cash compensation, stock-based compensation, depreciation and amortization expense on research and development property and equipment and intangible assets, costs of preclinical studies, clinical trials and related clinical manufacturing, costs of drug development, costs of materials and supplies, facilities cost, overhead costs, regulatory and compliance costs, and fees paid to consultants and other entities that conduct certain research and development activities on the Company’s behalf. Costs incurred in research and development are expensed as incurred.

Stock-Based Compensation

The Company accounts for stock-based compensation expense related to stock options granted to employees and members of its board of directors by estimating the fair value of each stock option on the date of grant using the Black-Scholes options-pricing model. For awards subject to service-based vesting conditions, stock-based compensation expense is recognized over the vesting period using the straight-line method. The fair value of restricted stock units is determined by the closing market price of the Company’s common stock on the date of grant and is also recognized over the vesting period using the straight-line method.

For performance-based awards to employees (i) the fair value of the award is determined on the grant date, (ii) the Company assesses the probability of the individual milestones under the award being achieved, and (iii) the fair value of the shares subject to the milestone is expensed over the service period commencing once management believes the performance criteria is probable of being met.

The Company also accounts for equity instruments issued to non-employees using a fair value approach under ASC Subtopic 505-50, Equity-Based Payments to Non-Employees. The Company adjusts the values of the restricted stock units and stock options granted based on the underlying Company stock price at the end of each quarter. Stock options adjustments are made via the Black-Scholes option-pricing model. The adjusted value of non-employee stock-based compensation is recognized as an expense over the period over which services are received.

In the second quarter of 2016, the Company implemented Financial Accounting Standards Board (FASB) Accounting Standard Update (ASU) 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. Therefore, the Company is accounting for share-based award forfeitures only as they occur rather than applying an estimated forfeiture rate.

Income Taxes

The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting and tax basis of assets and liabilities, as well as for operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using the tax rates that are expected to apply to taxable income for the years in which those tax assets and liabilities are expected to be realized or settled. The Company records valuation allowances to reduce deferred tax assets to the amount the Company believes is more likely than not to be realized.

The Company recognizes uncertain tax positions when the positions will be more likely than not upheld on examination by the taxing authorities based solely upon the technical merits of the positions. The Company recognizes interest and penalties, if any, related to unrecognized income tax uncertainties in income tax expense. The Company did not have any accrued interest or penalties associated with uncertain tax positions as of December 31, 2016 and 2015.

The Company is subject to U.S. federal income tax, as well as income tax in California and other states. The federal returns for tax years 2013 through 2016 remain open to examination; the California returns remain subject to examination for tax years 2012 through 2016. Carryforward attributes that were generated in years where the statute of limitations is closed may still be adjusted upon examination by the Internal Revenue Service or other respective tax authority. All other state jurisdictions remain open to examination. No income tax returns are currently under examination by taxing authorities.

Comprehensive Loss

Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. Comprehensive loss is composed of net loss and other comprehensive loss. The Company's other comprehensive loss consists of unrealized gains and losses on marketable securities classified as available-for-sale.

Basic and Diluted Net Loss per Share of Common Stock

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted loss per share is computed similarly to basic loss per share except that the denominator is increased to include the number of additional shares that would have been outstanding if the potential common shares had been issued and if the additional common shares were dilutive.

For all periods presented, potentially dilutive securities are excluded from the computation of fully diluted loss per share as their effect is anti-dilutive. The following table details those securities that have been excluded from the computation of potentially dilutive securities:

	As of December 31,
	2016		2015		2014
Outstanding options		6,307,384		8,777,893		5,138,410
Outstanding restricted stock units		814,456		1,129,638		—
Outstanding warrants		17,768,314		17,819,616		1,850,937
Total		24,890,154		27,727,147		6,989,347

Amounts in the table above reflect the common stock equivalents of the noted instruments.

Segment and Geographic Information

Operating segments are defined as components of an enterprise (business activity from which it earns revenue and incurs expenses) for which discrete financial information is available and regularly reviewed by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker (CODM) is its Chief Executive Officer (CEO). The Company views its operations and manages its business as a single operating and reporting segment. All assets of the Company were held in the United States as of December 31, 2016 and 2015.

Although all operations are based in the United States, the Company generated a portion of its revenue in prior years from customers outside of the United States. Information about the Company’s revenue from the different geographic regions for the years ended December 31, 2016, 2015 and 2014 is as follows (in thousands):

	Year Ended December 31,
	2016		2015		2014
United States	$	44	$	191	$	371
Europe		—		21		220
Other non-U.S.		—		24		50
Total	$	44	$	236	$	641

Recent Accounting Pronouncements

Application of New or Revised Accounting Standards – Not Yet Adopted

In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. This guidance requires restricted cash and restricted cash equivalents to be included with the cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the consolidated statement of cash flows. ASU 2016-18 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. Adoption of ASU 2016-18 is not expected to have a significant impact on the Company’s consolidated financial statements and disclosures.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This new guidance is intended to present credit losses on available for sale debt securities as an allowance rather than as a write-down. ASU 2016-13 is effective for annual reporting periods, including interim periods within those annual periods, beginning after December 15, 2019, with early adoption permitted for those fiscal years beginning after December 15, 2018. Adoption of ASU 2016-13 is not expected to have a significant impact on the Company’s consolidated financial statements and disclosures.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (ASU 2016-02), which requires lessees to recognize assets and liabilities for operating leases with lease terms greater than twelve months in the balance sheet. The update also requires improved disclosures to help users of financial statements better understand the amount, timing and uncertainty of cash flows arising from leases. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact of the adoption of ASU 2016-02 on its financial statements and disclosures.

In January 2016, the FASB issued ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. This new guidance changes the recognition of the periodic revaluation of financial assets for fair value purposes from unrealized gains and losses in the equity section of the consolidated balance sheet to realized gains and losses in the consolidated statement of operations from the time of purchase through the final conversion back to cash. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is not permitted. Adoption of ASU 2016-01 is not expected to have a significant impact on the Company’s consolidated financial statements and disclosures.

In May 2014, the FASB issued guidance codified in ASC Topic 606, ASU 2014-09, Revenue Recognition—Revenue from Contracts with Customers, which amends the guidance in former ASC Topic 605, Revenue Recognition, and was initially to be effective beginning January 1, 2017. This guidance requires that entities recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 defines a five-step process to achieve this core principle and, in doing so, it is possible more judgment and estimates may be required within the revenue recognition process than are required under existing GAAP, including identifying performance obligations in a contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. The new standard allows for two methods of adoption: (1) full retrospective adoption, meaning the standard is applied to all periods presented, or (2) modified retrospective adoption, meaning the cumulative effect of applying the new standard is recognized as an adjustment to the opening retained earnings balance. While adoption of ASU 2014-09 is not expected to have a significant impact, the Company is currently evaluating the impact of the adoption on the Company’s consolidated financial statements and disclosures. On August 12, 2015, the FASB issued guidance which defers the effective date of ASC Topic 606 by one year to January 1, 2018 for public companies.

Financial Statement Details

12 Months Ended

Dec. 31, 2016

Financial Statement Details [Abstract]

Financial Statement Details

3. Financial Statement Details

Prepaid expenses and other current assets

As of December 31, 2016 and 2015, prepaid expenses and other current assets were made up of (in thousands):

	As of December 31,
	2016		2015
Interest receivable - marketable securities	$	1,484	$	911
Prepaid services		1,191		631
Prepaid insurance		531		466
Equipment deposits		482		—
Prepaid license fees		462		101
Prepaid rent		360		—
Prepaid legal fees		350		350
Tax refund receivable		95		646
Other		180		—
	$	5,135	$	3,105

Property, plant and equipment, net

As of December 31, 2016 and 2015, property, plant and equipment was made up of (in thousands):

	As of December 31,
	2016			2015
Construction in progress	$	6,939		$	5,136
Equipment		5,458			241
Building under build-to-suit lease		4,348			—
Leasehold improvements		2,367			182
Software		769			6
Furniture & fixtures		203			125
		20,084			5,690
Accumulated depreciation		(1,178	)		(167	)
	$	18,906		$	5,523

Depreciation expense related to property, plant and equipment was $1.0 million, $0.1 million and $36,000 for the years ended December 31, 2016, 2015 and 2014, respectively.

Building value of $4.3 million under a build-to-suit lease represents the estimated fair market value of the building in Culver City, California, for which the Company is the “deemed owner” for accounting purposes only and related non-normal tenant improvements. See Note 7 section Financing Lease Obligation.

Construction in progress as of December 31, 2016 includes the estimated fair value of $ 5.1 million for the Company’s build-to-suit lease related to its facility in El Segundo, California, for which the Company is the “deemed owner” for accounting purposes only. See Note 7 section Build-to-suit Lease.

Intangible assets, net

As of December 31, 2016 and 2015, intangible assets were made up of (in thousands):

	As of December 31,
	2016			2015
Technology license	$	9,042		$	8,636
Less accumulated amortization		(3,956	)		(1,344	)
	$	5,086		$	7,292

Intangible valuation and related accumulated amortization were adjusted to correct a net immaterial amount related to the deferred tax liability recorded at acquisition. The deferred tax liability recorded is decreased proportionately as the underlying intangible asset is being amortized.

Amortization expense was $2.6 million, $1.3 million and $0 for the years ended December 31, 2016, 2015 and 2014, respectively. Amortization for the Company’s technology license is included in research and development expense on the consolidated statement of operations.

Future estimated amortization expense related to the Company’s technology license for the next five years and thereafter is as follows (in thousands):

Years ending December 31:
2017	$	2,260
2018		2,260
2019		566
2020		—
2021		—
Thereafter		—
	$	5,086

The remaining amortization period for the technology license is 2.25 years.

Other assets

As of December 31, 2016 and 2015, other assets were made up of (in thousands):

	As of December 31,
	2016		2015
Equipment not placed in service	$	362	$	624
Restricted cash		179		—
Security deposit		137		344
Software license and implementation costs		110		391
	$	788	$	1,359

Accrued expenses

As of December 31, 2016 and 2015, accrued expenses were made up of (in thousands):

	As of December 31,
	2016		2015
Accrued bonus	$	1,732	$	1,359
Accrued construction costs		1,243		132
Accrued professional and service fees		1,008		367
Accrued compensation		898		348
Accrued preclinical and clinical trial costs		662		—
Accrued software license fees		121		—
Accrued franchise and property taxes		62		225
Other		138		144
	$	5,864	$	2,575

Other current liabilities

As of December 31, 2016 and 2015, other current liabilities were made up of (in thousands):

	As of December 31,
	2016		2015
Build-to-suit lease liability - current portion	$	281	$	131
Financing obligation - current portion		253		—
Deferred rent - current portion		197		5
Other		160		—
	$	891	$	136

Investment income, net

Net investment income includes interest income from all bank accounts as well as marketable securities, dividend income, net realized gains or losses on sales of investments and the amortization of the premiums and discounts of the investments and is as follows for the years ended December 31, 2016, 2015 and 2014 (in thousands).

	Year Ended December 31,
	2016			2015			2014
Interest income	$	5,168		$	312		$	20
Investment amortization accretion expense, net		(2,182	)		(38	)		—
Dividend income		—			213			—
Net realized gains on investments		111			2,501			—
	$	3,097		$	2,988		$	20

The interest income includes interest from our bank deposits. No impairment losses were recognized on our investments during the years ended December 31, 2016, 2015 and 2014.

Cash Equivalents and Marketable Securities

12 Months Ended

Dec. 31, 2016

Cash Equivalents And Marketable Securities [Abstract]

Cash Equivalents and Marketable Securities

4. Cash Equivalents and Marketable Securities

As of December 31, 2016, all of the Company’s marketable securities are classified as available-for-sale and are scheduled to mature within 4.7 years. At December 31, 2016 and 2015, the Company’s cash equivalents and marketable securities are detailed below (in thousands). There were no investments at December 31, 2014.

	December 31, 2016
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Current:
Government sponsored securities	$	22,252	$	21	$	(1	)	$	22,272
Corporate debt securities		165,605		40		(76	)		165,569
Foreign government bonds		5,004		—		(2	)		5,002
Subtotal current		192,861		61		(79	)		192,843
Noncurrent:
Government sponsored securities		17,018		2		(38	)		16,982
Corporate debt securities		69,414		71		(290	)		69,195
Foreign government bonds		1,405		—		(11	)		1,394
Subtotal noncurrent		87,837		73		(339	)		87,571
Total	$	280,698	$	134	$	(418	)	$	280,414

Included in corporate debt securities is $2.0 million of cash equivalents at December 31, 2016.

	December 31, 2015
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Current:
Commercial paper	$	29,899	$	13	$	—		$	29,912
Corporate debt securities		99,600		2		(109	)		99,493
Foreign government bonds		6,951		—		(7	)		6,944
Subtotal current		136,450		15		(116	)		136,349
Noncurrent:
Corporate debt securities		51,215		1		(85	)		51,131
Foreign government bonds		4,011		—		(7	)		4,004
Subtotal noncurrent		55,226		1		(92	)		55,135
Total	$	191,676	$	16	$	(208	)	$	191,484

Included in commercial paper and corporate debt securities are $5.0 million and $13.0 million, respectively, of cash equivalents at December 31, 2015.

Available-for-sale investments that had been in an unrealized loss position for less than 12 months and for more than 12 months at December 31, 2016 and 2015 are as follows (in thousands):

	December 31, 2016
	Less than 12 months					More than 12 months
	Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses
Government sponsored securities	$	17,204	$	(39	)	$	—	$	—
Corporate debt securities		150,320		(366	)		—		—
Foreign government bonds		6,396		(13	)		—		—
Total	$	173,920	$	(418	)	$	—	$	—

	December 31, 2015
	Less than 12 months					More than 12 months
	Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses
Corporate debt securities	$	141,320	$	(194	)	$	—	$	—
Foreign government bonds		10,947		(14	)		—		—
Total	$	152,267	$	(208	)	$	—	$	—

At December 31, 2016, 80 of the securities and bonds are in an unrealized loss position. All securities have been in an unrealized loss position for less than 12 months. The Company evaluated its securities for other-than-temporary impairment and concluded that the decline in value was primarily caused by current economic and market conditions. The Company does not intend to sell the investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases. Therefore, the Company did not recognize any other-than-temporary impairment loss during the years ended December 31, 2016 and 2015.

The Company recorded realized gains and losses on sales or maturities of available-for-sale securities as follows (in thousands):

	Gross Realized Gains		Gross Realized Losses			Net Realized Gains
2016	$	190	$	(79	)	$	111
2015		2,501		—			2,501
2014		—		—			—

Fair Value Measurements

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Fair Value Measurements

5. Fair Value Measurements

Fair value is defined as an exit price that would be received from the sale of an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Authoritative guidance establishes a three-level hierarchy for disclosure that is based on the extent and level of judgment used to estimate the fair value of assets and liabilities.

Financial assets and liabilities measured at fair value on a recurring basis are summarized below at December 31, 2016 and 2015 (in thousands):

	December 31, 2016
	Total		Level 1		Level 2		Level 3
Assets:
Current:
Cash and cash equivalents*	$	2,005	$	—	$	2,005	$	—
Government sponsored securities		22,272		—		22,272		—
Corporate debt securities		163,564		—		163,564		—
Foreign government bonds		5,002		—		5,002		—
Noncurrent:
Government sponsored securities		16,982		—		16,982		—
Corporate debt securities		69,195		—		69,195		—
Foreign government bonds		1,394		—		1,394		—
Total assets measured at fair value	$	280,414	$	—	$	280,414	$	—

*This amount excludes $6.1 million in depository institutions that are classified as Level 1 assets.

	December 31, 2015
	Total		Level 1		Level 2		Level 3
Assets:
Current:
Cash and cash equivalents*	$	18,039	$	—	$	18,039	$	—
Commercial paper		24,917		—		24,917		—
Corporate debt securities		86,450		—		86,450		—
Foreign government bonds		6,943		—		6,943		—
Noncurrent:
Corporate debt securities		51,131		—		51,131		—
Foreign government bonds		4,004		—		4,004		—
Total assets measured at fair value	$	191,484	$	—	$	191,484	$	—

*This amount excludes $157.9 million in depository institutions that are classified as Level 1 assets.

Activity for the financial instrument using significant unobservable inputs (Level 3) measured at fair value is presented in the table below (in thousands):

	Warrant Derivative Liability
Balance December 31, 2013	$	19
Adjustment to estimated fair value		158
Balance at December 31, 2014		177
Adjustment to estimated fair value		1,366
Warrant exercised		(1,543	)
Balance at December 31, 2015	$	—

Collaboration and License Agreements	12 Months Ended
Collaboration and License Agreements	Dec. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration and License Agreements	6. Collaboration and License Agreements Collaborative Arrangement A collaborative arrangement is a contractual arrangement that involves a joint operating activity. These arrangements involve two or more parties who are (i) active participants in the activity, and (ii) exposed to significant risks and rewards dependent on the commercial success of the activity. Exclusive Co-Development Agreement—In August 2016, the Company entered into an exclusive Co-Development Agreement (the Co-Development Agreement) with Altor Bio Science Corporation (Altor), a related party (Note 8). Under the Co-Development Agreement, the Company and Altor agreed to exclusively collaborate on the development of therapeutic applications combining the Company’s proprietary natural killer cells with Altor's ALT-801 and/or ALT-803 products with respect to certain technologies and intellectual property rights as may be agreed between the parties for the purpose of jointly developing therapeutic applications of certain effector cell lines. The Company will be the lead developer for each product developed by the parties pursuant to the Co-Development Agreement unless otherwise agreed to under a given project plan. Under the terms of the Co-Development Agreement, both parties grant a co-exclusive, royalty free, fully paid-up, worldwide license, with the right to sublicense (only to a third-party contractor assisting with research and development activities under this Co-Development Agreement and subject to prior consent, not to be unreasonably withheld), under the intellectual property (IP), including the parties interest in the joint IP, solely to conduct any development activities agreed to by the steering committee as set forth in any development plan. Unless otherwise mutually agreed by the parties in the development plan for a project, the Company shall be responsible for all costs and expenses incurred by either party related to conducting clinical trials and other activities under each development program, including costs associated with patient enrollment, materials and supplies, third-party staffing and regulatory filings. Altor and the Company each will own an undivided interest in and to all rights, title and interest in and to the joint product rights. The Co-Development Agreement expires upon the fifth anniversary of the effective date. There was no joint research activity under the Co-Development Agreement during year ended December 31, 2016. Joint Development and License Agreement—In December 2014, the Company entered into a Joint Development and License Agreement (the Joint Development and License Agreement) with Sorrento Therapeutics, Inc. (Sorrento). Under the Joint Development and License Agreement, the Company and Sorrento agreed to exclusively collaborate on research, development and commercialization with respect to certain technologies and intellectual property rights as may be agreed between the parties for the purpose of jointly developing therapeutic applications of certain effector cell lines. To fund the Company’s joint research and development efforts, Sorrento agreed to make research credit payments to the Company of up to $2.0 million in 2015 and 2016, reduced by certain expenses for which the Company is responsible under the agreements. The research credit payments, due in December of each year, will be paid in the form of full-time employee expense credits by Sorrento to work on behalf of the Company and for the Company’s portion of any development costs and a laboratory credit towards maintaining a laboratory on Sorrento’s premises. For each cell line or product to be developed by the parties pursuant to the Joint Development and License Agreement, one party (the Primary Party), as mutually agreed upon by a designated steering committee comprised of three representatives from each party when a statement of work is agreed to by the parties, will have the right and authority to initiate and control the development, testing, regulatory approval or commercialization of such cell line or joint product, including the right to license and sublicense all applicable intellectual property rights (including joint product rights) with respect thereto. The Primary Party will also bear all costs associated with the development of the applicable cell line or product unless the other party shares in such costs. The ratio of such split between the parties is conditioned on the stage of development of the cell line or product and each party’s contribution towards development costs. Sorrento and the Company each will own an undivided interest in and to all rights, title and interest in and to the joint product rights. The Joint Development and License Agreement expires upon the later of three years or completion of the series of collaborative research and development efforts. In connection with the Joint Development and License Agreement, Sorrento entered into a subscription and investment agreement with the Company under which the Company sold to Sorrento 4,557,537 shares of the Company’s Class A common stock for gross proceeds of $8.0 million. Subsequently, Sorrento purchased 1,060,789 shares of the Company’s Class A common stock for an additional $2.0 million in gross proceeds. There was no joint research activity under the Joint Development and License Agreement during the years ended December 31, 2016, 2015 and 2014 and as a result, no payment was received during the years ended December 31, 2016 and 2015. As of the date hereof, the Company and Sorrento have not yet agreed upon any projects under the Joint Development and License Agreement; therefore, Sorrento has no rights to use the Company’s NK cells or other technologies or intellectual property rights or to begin related research, development or commercialization activities and the Company is free to pursue, and is actively pursuing, research, development and commercialization activities with antibodies that may bind to various targets, including PDL1, ROR-1, CD33 and CD123. Royalties and In-licensing Agreements Founder License Agreement—In 2003, the Company entered into a licensing agreement with a founding shareholder of the Company for the exclusive license to the NK-92 cell line and related know-how for payment of certain royalties related to the sales of licensed products (the Founder License Agreement). In 2009 and 2010, the Founder License Agreement was amended for the sale and assignment of the licensed patents to the Company. As consideration for the sale and assignment of the licensed patents and technical information to the Company, the founding shareholder was to receive a one-time cash payment of $0.1 million, which was converted to a non-interest bearing note (the Founder Note) (Note 13). In addition, the Company is obligated to (i) pay low single digit percentage royalties of net sales of licensed products for therapeutic and diagnostic use; (ii) issue additional shares of common stock of the Company in conjunction with the closing of a financing of at least $1.0 million after the 2013 Securities Purchase Agreement to ensure the founder retains no less than a 7% ownership interest of the total outstanding common shares of the Company on a fully diluted basis; (iii) pay the British Columbia Cancer Agency a low single digit percentage royalty on net sales on aNK cell-based products, a responsibility assumed by the Company for the founding shareholder; and (iv) issue a warrant (Founder Warrant) to purchase up to 123,433 additional shares of Class A common stock at a purchase price of $2.44 per share with a 10 year exercise term subject to the completion of five milestones pertaining to granting of a patent, completion of clinical trials and issuance of a commercial biologic license. In 2013, the first milestone, a claim granted for a certain patent application in the United States, was achieved and as a result 37,030 shares underlying the Founder Warrant became exercisable. In March 2014, the Founder License Agreement was amended to (i) provide for payment to the founder of low single digit percentage royalties on net sales of licensed products for therapeutic and diagnostic use and mid-single digit percentage royalties from sublicenses for net sales of licensed products; (ii) exchange warrants held by the founder to purchase up to 156,109 shares of Class A common stock for a fully-vested incentive stock option to purchase up to 740,600 shares of Class A common stock at fair market value on the date of issuance upon the Company closing a private placement of stock or other securities of at least $3.0 million (the Mandatory Exchange Financing); and (iii) remove the requirement for the founder to retain not less than a 7% ownership interest of the total outstanding common shares of the Company on a fully diluted basis. Through December 31, 2016, no royalties have been earned or paid. Fox Chase Cancer Center License Agreement—In 2004 and amended in 2008, the Company entered into an exclusive license agreement with Fox Chase Cancer Center (Fox Chase) for the exclusive, worldwide rights to certain patents and know-how pertaining to CD16 receptors bearing NK-92 cell lines. In consideration for this exclusive license, the Company agreed to pay Fox Chase (i) low single-digit percentage royalties on net sales of licensed products for therapeutic and diagnostic use; and (ii) mid-twenties percentage royalties on any compensation the Company receives from sublicensees. The Fox Chase license was assigned to Brink Biologics as a part of the Spin-out (Note 9). As a result, the Company recorded no royalty expense for the year ended December 31, 2016. The Company recorded royalty expense of $0.1 million and $0.2 million for the years ended December 31, 2015 and 2014, respectively, related to the Fox Chase Cancer Center License Agreement for the period of time before the Spin-out. Royalty expense is included in selling, general and administrative in the consolidated statements of operations. Rush University Medical Center License Agreement—In 2004, the Company entered into a 12-year licensing agreement with Rush University Medical Center for the exclusive rights to license and grant sublicenses of certain intellectual property related to clinical use of NK-92. The Company is required to pay low to mid-single digit percentage royalties on net sales depending upon the various fields of studies and other factors. The Company is required to pay a minimum annual royalty of $25,000. The Rush University Medical Center License Agreement also provides for payments in the aggregate amount of $2.5 million upon the Company achieving various milestones, including upon (i) the completion of Phase II clinical trial associated with the licensed intellectual property; (ii) the approval by the Food and Drug Administration (the FDA) of a new drug application for a licensed product; and (iii) the first year that sales of the licensed product equals or exceeds $0.3 million. The Rush University Medical Center License Agreement terminates on the 12th anniversary of the first payment of royalties, which occurred in 2006, at which point the license is deemed a perpetual, irrevocable, fully-paid royalty-free, exclusive license, and may be terminated earlier by either party for material breach. During the years ended December 31, 2016, 2015 and 2014, the Company recorded royalty expense of $25,000, $25,000 and $0.1 million, respectively, related to the Rush University Medical Center License Agreement. Royalty expense is included in selling, general and administrative in the consolidated statements of operations. No milestones were met during the years ended December 31, 2016, 2015 and 2014. Chemotherapeutisches Forschungsinstitut Georg-Speyer-Haus (GSH) and DRK-Blutspendedienst Baden-Wurttemberg-Hessen gGmbH (BSD) License Agreement—In August 2015, the Company entered into a license agreement with GSH and BSD under which the Company was granted an exclusive license to certain GSH-BSD patents, materials and know-how that specifically targets ErbB2 expressing cancers. In addition, GSH granted the Company an exclusive license to certain GSH only technology and materials. In consideration for the licenses, the Company agreed to pay initial and annual licensing fees, regulatory and commercial milestones and low single-digit percentage royalties on net sales of licensed products. The royalty term shall continue in a particular country until the later of (i) the expiration of the valid patent claims in such country, or (ii) a specified period of time after the first commercial sale of licensed product in such country. The license agreement shall continue until no further payments are due at which time the licenses and rights will continue on a non-exclusive, royalty-free basis. The license agreement can be terminated earlier: (i) for material breach by either party after 60 days cure period, (ii) if the Company declares bankruptcy or insolvency, (iii) by the Company in its sole discretion upon 60 days prior written notice. The Company paid and expensed $1.1 million for the initial license fees in 2015 under the license, which was included in research and development expenses in the consolidated statements of operations for the year ended December 31, 2015. Annual license fees under the agreement begin in 2018. Out-Licensing Agreement Intrexon License Agreement—In February 2010, the Company entered into a 17-year license agreement with Intrexon Corporation (Intrexon) pursuant to which the Company granted to Intrexon a non-exclusive, worldwide, sublicensable license to research and sell products under certain patents relating to modified NK-92 cells that express Intrexon’s proprietary gene sequences for use as a therapeutic and prophylactic agent in humans in specified therapeutic areas. In consideration for the license agreement, Intrexon paid the Company a one-time fee of $0.4 million, which was recorded in deferred revenue and is amortized over the term of the license agreement. Intrexon will pay the following milestone payments: $0.1 million upon the first IND filing; $0.1 million upon the commencement of the first Phase II clinical trial; $0.4 million upon the commencement of the first Phase III clinical trial; and $0.5 million upon the first commercial sale relating to the licensed products. Intrexon is obligated to pay the Company a low single digit percentage royalty based on net sales of the licensed products by Intrexon and a mid-teen percentage royalty based on revenues received by Intrexon in connection with sublicenses of the licensed products. No milestone payments were due or received in the years ended December 31, 2016, 2015 and 2014. For the years ended December 31, 2016, 2015 and 2014, the Company recorded revenue of $20,000 each year, related to the agreement in the consolidated statements of operations.

Commitment and Contingencies

12 Months Ended

Dec. 31, 2016

Commitments And Contingencies Disclosure [Abstract]

Commitments and contingencies

7. Commitments and Contingencies

Contingencies

Securities Litigation

In March 2016, a putative securities class action complaint captioned Sudunagunta v. NantKwest, Inc., et al., No. 16-cv-01947 was filed in federal district court for the Central District of California related to the Company’s restatement of certain interim financial statements for the periods ended June 30, 2015 and September 30, 2015 and asserting claims for violation of federal securities laws. Other putative class action complaints containing similar allegations were filed in federal court and in California Superior Court. The state court actions were removed to federal court and all of the actions have been consolidated. The consolidated complaint names as defendants the Company, certain of its current and former officers and directors, and various investment banks which served as underwriters for the Company’s IPO. The consolidated complaint alleges violations of Sections 11 and 15 of the Securities Act of 1933 and Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder. The complaint seeks unspecified damages, costs and attorneys’ fees, and equitable/injunctive or other relief on behalf of putative classes of persons who purchased or acquired the Company’s securities in the IPO and from July 28, 2015 through March 11, 2016. Defendants have filed a motion to dismiss the consolidated complaint. Management intends to vigorously defend these proceedings. At this time, the Company cannot predict how the Court will rule on the merits of the claims and/or the scope of the potential loss in the event of an adverse outcome. Therefore, based on the information available at present, the Company cannot reasonably estimate a range of loss for this action. Should the Company ultimately be found liable, the liability could have a material adverse effect on the Company’s results of operations for the period or periods in which it is incurred.

On September 6, 2016, a shareholder derivative complaint captioned Bushansky v. Soon-Shiong, et al., No. 37-2016-00030867-CU-SL-CTL was filed in California Superior Court, San Diego County also related to the Company’s restatement of certain interim financial statements. The complaint names as defendants the Company’s current and former directors and the Company’s outside auditor at the time of the IPO. The complaint alleges the directors breached their fiduciary duties to the Company’s shareholders and wasted corporate assets, and that the outside auditors committed malpractice. No causes of action are asserted against the Company, which is named solely as a nominal defendant. The complaint seeks, on behalf of the Company, unspecified damages, the return of directors’ salaries for unspecified periods, and injunctive relief. At this time, the Company cannot predict how the Court will rule on the merits of the claims and/or the scope of the potential loss in the event of an adverse outcome. Defendants have demurred to the complaint and the Company has filed a motion to dismiss the complaint based on a corporate charter provision specifying a Delaware forum. Should the Company ultimately be found liable, the liability could have a material adverse effect on the Company’s results of operations for the period or periods in which it is incurred.

Appeal of USPTO Decision

In March 2009, the Company received a final rejection in one of the Company’s original patent applications pertaining to certain limited methods of use claims for NK-92 from the U.S. Patent and Trademark Office (the USPTO) (but the USPTO allowed claims on all of the other proposed claims, including other methods of use). The Company appealed this decision with the USPTO Board of Appeals and, in the fall of 2013, the Board of Appeals reversed the Examiner’s rejection of the claim to certain limited methods of use with NK-92, but affirmed the Examiner’s rejection of the remaining patent claims. In December 2013, the Company brought an action in the U.S. District Court for the Eastern District of Virginia to review the decision of the USPTO as the Company disagreed with the decision as to the certain limited non-allowed claims. On September 2, 2015, the U.S. District Court granted the USPTO’s motion for summary judgment. On September 24, 2015, the Company filed a notice of appeal to the United States Court of Appeals for the Federal Circuit. On February 9, 2017, a three-judge panel of the Federal Circuit heard oral arguments on our appeal and took the matter under submission. Based on the information available at present, the Company cannot reasonably estimate a range of loss for this action. Accordingly, no liability associated with this action has been accrued. The Company is expensing legal costs associated with defending this litigation as the costs are incurred.

Contractual Obligations - Leases

The Company leases: (i) office space in Cardiff-by-the-Sea, California; (ii) a research and office facility in Woburn, Massachusetts; (iii) office space in Cary, North Carolina; (iv) a research and office facility in San Diego, California; (v) research and manufacturing space in Culver City, California from a related party (Note 8) and; (vi) a research and manufacturing facility in El Segundo, California, also from a related party (Note 8).

Build-to-suit Lease

In September 2016, the Company entered into a lease agreement with 605 Doug St, LLC, a related party (Note 8), for approximately 24,250 square feet in El Segundo, California, which is to be converted to a research and development laboratory and a Good Manufacturing Practices (GMP) laboratory. The lease runs from July 2016 through July 2023. The Company has the option to extend the lease for an additional three year term through July 2026. The monthly rent is $0.1 million with annual increases of 3% beginning in July 2017. For the year ended December 31, 2016, the Company recorded rent expense of $0.1 million, which is reflected in research and development expense on the consolidated statement of operations.

The Company is responsible for costs to build out the laboratory and has incurred costs of approximately $1.8 million as of December 31, 2016, which is reflected in construction in progress on the consolidated balance sheet. Additionally, in order for the facility to meet the Company's research and development and GMP laboratory specifications, the Company started to make certain structural changes to the facility as part of the conversion to laboratory space. As a result of these changes, the Company concluded that it is the “deemed owner” of the building (for accounting purposes only) during the construction period. Accordingly, the Company recorded a non-cash build-to-suit lease asset of $5.1 million, representing its estimate of the fair market value of the building, and a corresponding construction build-to-suit lease liability, recorded as a component of other current and non-current liabilities on the consolidated balance sheet as of December 31, 2016.

Upon completion of construction of this facility, the Company evaluates the de-recognition of the asset and liability under the provisions of ASC 840-40, Leases - Sale-Leaseback Transactions. However, if the Company does not comply with the provisions needed for sale-leaseback accounting, the lease will be accounted for as a financing obligation and lease payments will be attributed to (1) a reduction of the principal financing obligation; (2) imputed interest expense; and (3) land lease expense (which is considered an operating lease and a component of research and development expenses) representing an imputed cost to lease the underlying land of the facility. In addition, the underlying building asset will be depreciated over the building's estimated useful life, which is estimated at 39 years. At the conclusion of the lease term, the Company would de-recognize both the net book values of the asset and financing obligation.

Financing Lease Obligation

In November 2015, the Company entered into a facility license agreement with NantWorks (Note 8) for approximately 9,500 square feet of office space in Culver City, California, which has been converted to a research and development laboratory and a GMP laboratory. The license was effective in May 2015 and extends through December 2020. The Company has the option to extend the license through December 2023. The monthly license fee is $47,000 with annual increases of 3% beginning in January 2017. For the years ended December 31, 2016 and 2015, the Company recorded rent expense of $0.2 million and $0.2 million, respectively, which is reflected in research and development expense on the consolidated statement of operation.

Under the facility license agreement, the Company was responsible for costs to build out the laboratory and incurred costs of approximately $3.5 million. The Company concluded that it was the “deemed owner” of the building (for accounting purposes only) during the construction period. The Company recorded the build out costs as an asset with a corresponding build-to-suit liability, which was recorded as a component of other current and non-current liabilities on the consolidated balance sheet while the building was under construction.

Upon completion of construction of this building in August 2016, the Company evaluated the de-recognition of the asset and liability under the provisions of ASC 840-40, Leases – Sale-Leaseback Transactions. The Company determined that the lease does not meet the criteria for sale-leaseback accounting treatment, due to the continuing involvement in the project resulting from the significant collateral the Company provided to the landlord in the form of building improvements. As a result, the building is being accounted for as a financing obligation. The underlying assets of $4.3 million will be depreciated over the building’s estimated useful life, which is 39 years. At the conclusion of the lease term, the Company will de-recognize both the net book values of the assets and financing obligation.

Operating Leases

In March 2016, the Company entered into a lease agreement for an approximately 7,893 square foot facility in Woburn, Massachusetts for a research and development laboratory, related office and other related uses. The term of the lease is 48 months commencing on April 29, 2016. In June 2016, the lease was amended to add 260 square feet, for a total of 8,153 square feet. The base rent, including the amendment, is $19,000 per month with a $1 per square foot annual increase on each anniversary date.

In July 2015, the Company entered into an agreement for approximately 3,067 square feet of office space in Cary, North Carolina. The term of the lease is 26 months commencing on July 1, 2015. The base rent is $6,000 per month with 3% annual increases on each anniversary date.

In June 2015, the Company entered into a lease agreement for an approximately 44,681 square foot facility in San Diego, California for a research and development laboratory, related office and other related uses. The term of the lease extends for seven years commencing on August 1, 2016. The base rent is $0.2 million per month with 3% annual increases on each anniversary date. In July 2015 the Company entered into a sublease for the building with the then existing lessee for a term of one year commencing August 1, 2015. There is no fixed rent or operating expenses during the sublease term other than utilities.

The Company leases a total of approximately 2,550 square feet of office space at 2533 South Coast Highway 101, Cardiff-by-the-Sea, California 92007, for general office use, pursuant to an operating lease. The lease term was extended through August 31, 2018. Our total monthly lease payment is currently $12,800 per month, and will increase to $13,200 on September 1, 2017.

The Company recognizes rent expense under operating leases on a straight-line basis. Rent expense for the years ended December 31, 2016, 2015 and 2014 was $2.7 million, $1.5 million, $0.2 million, respectively.

The following table summarizes our future minimum lease payments at December 31, 2016 (in thousands). Common area maintenance costs and taxes are not included in these payments.

Years ending December 31:
2017	$	4,076
2018		4,094
2019		4,108
2020		4,056
2021		3,435
Thereafter		5,594
Total minimum lease payments	$	25,363

Related Party Agreements	12 Months Ended
Related Party Agreements	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Agreements	8. Related Party Agreements The Company had related party agreements with Inex Bio, Inc. (Inex Bio) until the Company acquired a majority of Inex Bio shares. See Note 14 – Investment in Inex Bio, Inc. for further details. In June 2015, the Company spun out Brink Biologics, Inc. (Brink Biologics) and Coneksis, Inc. (Coneksis) (Note 9). The Company’s Chairman and CEO has a controlling interest in Brink Biologics and Coneksis. The Company’s Chairman and CEO founded and has a controlling interest in NantWorks, Inc. (NantWorks), which is a collection of multiple companies in the healthcare and technology space. The Company has entered into arrangements with NantWorks and certain affiliates of NantWorks, as described below, to facilitate the development of new genetically modified NK cells for the Company’s product pipeline. In September 2016, the Company entered into a lease agreement with 605 Doug St, LLC, an entity owned by the Company’s Chairman and CEO, for approximately 24,250 square feet in El Segundo, California, which is to be converted to a research and development laboratory and a GMP laboratory. The lease runs from July 2016 through July 2023. The Company has the option to extend the lease for an additional three year term through July 2026. The monthly rent is $0.1 million with annual increases of 3% beginning in July 2017. See Note 7 section Build-to-Suit Lease for further details on this lease. For the year ended December 31, 2016, the Company recorded rent expense of $0.1 million, which is reflected in research and development expense on the consolidated statement of operations. At December 31, 2016, 605 Doug St, LLC, owed $0.8 million to the Company related to reimbursable tenant improvements, which is included in due from related parties on the consolidated balance sheet. In August 2016, the Company entered into a Co-Development Agreement with Altor as described in Note 6. The Company’s Chairman and CEO is also the Chairman of Altor and holds a greater than 20% ownership interest in Altor. Through December 31, 2016, the Company has not conducted any joint operating activities or incurred any costs under this Co-Development Agreement. In March 2016, NantBioScience, Inc. (NantBioScience), a NantWorks company, and the National Cancer Institute entered into a cooperative research and development agreement. The agreement covers NantBioScience and its affiliates, including the Company. Under the agreement, the parties will collaborate on the preclinical and clinical development of proprietary recombinant NK cells and monoclonal antibodies in monotherapy and in combination immunotherapies. The Company expects to benefit from the preclinical and clinical research conducted during the first year under this agreement and is providing the first year of funding under the five-year agreement. In April 2016, the Company paid $0.6 million to the National Cancer Institute as a prepayment for this first year of funding. The Company recognizes research and development expense ratably over a 12-month period and recorded $0.5 million of expense for the year ended December 31, 2016. Under the NantWorks shared services agreement executed in November 2015, but effective August 2015, NantWorks provides corporate, general and administrative, manufacturing strategy, research and development, regulatory and clinical trial strategy and other support services, and the Company is charged for the services at cost plus reasonable allocations for indirect costs that relate to the employees providing the services. For the years ended December 31, 2016 and 2015, the Company recorded $3.0 million and $1.0 million, respectively, to selling, general and administrative expense and $2.1 million and $0.3 million, respectively, in research and development expense under this arrangement on the consolidated statement of operations. In June 2016, the Company amended the existing shared services agreement with NantWorks whereby the Company can provide support services to NantWorks and/or any of its affiliates. For the year ended December 31, 2016, the Company recorded expense reimbursements of $0.1 million to selling, general and administrative expense and $0.2 million to research and development expense. The Company owed NantWorks a net amount of $1.7 million for all agreements between the two affiliates at December 31, 2016, which is included in due to related parties on the consolidated balance sheet. Under the November 2015 facility license agreement with NantWorks for office and laboratory space, which was effective May 22, 2015, the Company recorded rent expense of $0.2 million and $0.2 million for the years ended December 31, 2016 and 2015, respectively, which is included in research and development expense on the consolidated statement of operations. The Company was responsible for costs to build out the laboratory and incurred costs of approximately $3.5 million, which is reflected in property, plant and equipment, net, on the consolidated balance sheet. See Note 7 section Financing Lease Obligation for details relating to the accounting upon construction completion. In June 2015, the Company entered into an agreement with NantOmics, LLC (NantOmics) to obtain genomic sequencing and proteomic analysis services, as well as related data management and bioinformatics services, exclusively from NantOmics. The Company is obligated to pay NantOmics a fixed, per sample fee, determined based on the type of services being provided. The agreement has an initial term of five years and renews automatically for successive one year periods, unless terminated earlier. For the years ended December 31, 2016 and 2015, the Company recorded operating expense of $0.2 million and $0.1 million, respectively, to research and development under this arrangement in the consolidated statement of operations. The Company owed NantOmics $0 at December 31, 2016. In June 2015, the Company entered into an agreement with NanoCav, LLC (NanoCav), a related party, pursuant to which the Company obtained access to NanoCav’s virus-free cell transfection technologies on a non-exclusive basis. Under the agreement, NanoCav will conduct certain, mutually-agreed feasibility studies, on a fee for service basis, to evaluate the use of its cell transfection technologies with the Company’s aNK cells. The agreement has an initial term of five years and renews automatically for successive one year periods, unless terminated earlier. In September 2015, the Company made a $45,000 feasibility study retainer payment as required by the agreement, which is recorded in prepaid expenses on the consolidated balance sheet at December 31, 2015. For the years ended December 31, 2016 and 2015, the Company recorded operating expense of $0.1 million and $0, respectively, to research and development under this arrangement in the consolidated statement of operations. At December 31, 2016, the Company owed NanoCav $15,000, which is included in due to related parties on the consolidated balance sheet. In June 2015, the Company also entered into a supply agreement with NantCell, Inc. (NantCell) pursuant to which the Company has the right to purchase NantCell’s proprietary bioreactors, made according to specifications mutually agreed to with NantCell. The Company also has the right to purchase reagents and consumables associated with such equipment from NantCell. In September 2015, the Company made a $0.5 million nonrefundable, upfront payment to NantCell as required by the agreement, which upfront payment is creditable against the Company’s future development activities and equipment purchases under the agreement. The agreement has an initial term of five years and renews automatically for successive one year periods unless terminated earlier. The upfront payment is included in prepaid expenses on the consolidated balance sheets. The Company consumed $0.2 million of the $0.5 million prepayment through December 31, 2016. In December 2013, the Company entered into restricted stock purchase agreements with certain officers to sell 7,532,251 shares of the Company’s Class B common stock (Note 10). As consideration for the shares, the officers executed secured promissory notes totaling $1.5 million (the Secured Notes). The Secured Notes accrued interest at 1.64% per annum, and all principal and interest was due and payable on the earlier of (i) the sale of all or substantially all of the Company’s stock by the officer and (ii) December 2022. The Secured Notes were collateralized by the underlying Class B common stock. Since the Secured Notes were non-recourse, they were treated similar to stock options for accounting purposes with the fair value recognized through a charge to compensation expense. The shares of Class B common stock were not considered issued and outstanding in the consolidated financial statements until the Company received payment against the Secured Notes. In 2013 and 2014, the Company received principal payments under the Secured Notes of $0.2 million and $1.2 million, respectively. Additionally, in 2013 and 2014, an officer agreed to offset against his outstanding principal and interest $0.1 million and $23,000, respectively, of amounts the Company owed to him. Upon receipt of these payments, the Company issued to the officers 1,681,099 and 5,851,152 shares of Class B common stock in 2013 and 2014, respectively. As of December 31, 2014, the Secured Notes were settled in full.

Spin-out of Brink Biologics and Coneksis	12 Months Ended
Spin-out of Brink Biologics and Coneksis	Dec. 31, 2016
Spinout
Spin-out of Brink Biologics and Coneksis	9. Spin-out of Brink Biologics and Coneksis On June 9, 2015, the Company spun out its business related to testing and diagnostic products and services into the entity, Brink Biologics in exchange for all of the issued and outstanding shares of Brink Biologics, which were subsequently distributed by a dividend to our stockholders. Under the spin-out arrangement, the Company transferred to Brink Biologics all of the Company’s existing revenue-earning, non-exclusive license agreements that allow third parties to use the Company’s cell lines and intellectual property for non-clinical laboratory testing. In addition, the Company transferred or licensed to Brink Biologics the Company’s other assets associated with testing and diagnostics products and services. The Company granted to Brink Biologics worldwide, exclusive licenses to the use of certain cell lines limited to the field of in vitro and in vivo testing and diagnostic products and services, trademarks, intellectual property, and patents, including the Company’s rights under its license agreement with Fox Chase Cancer Center. As part of the agreement, the Company also has a non-exclusive license to any results and data arising from Brink Biologics’ use of the Company’s cell lines and intellectual property for the Company’s use for internal research purposes and outside of Brink Biologics’ field. In consideration for the license grants, Brink Biologics is obligated to pay the Company a low single-digit royalty on amounts received for the sale of licensed products and services, as well as a low single-digit percentage share of other revenue received by Brink Biologics from the grant of sublicenses under the Company’s rights. For the years ended December 31, 2016 and 2015, the Company recorded $21,000 and $11,000, respectively, in revenue for royalties on the consolidated statement of operations. Brink Biologics and the Company have the right to terminate the license agreement under certain conditions. Also, as part of the spin-out arrangement, the Company has agreed to provide certain services to Brink Biologics for a transitional period on a fee-for-service basis. Invoices for services are to be issued monthly and payments are due 30 days from the date invoiced. In the years ended December 31, 2016 and 2015, the Company invoiced $0.1 million and $22,000, respectively, for services to Brink Biologics, which are recorded in other income on the consolidated statement of operations. At December 31, 2016, Brink Biologics owes the Company $0.1 million which is included in due from related parties on the consolidated balance sheet. On June 9, 2015, the Company spun out its business related to veterinary oncology into the entity, Coneksis in exchange for all of the issued and outstanding shares of Coneksis, which were subsequently distributed by a dividend to our stockholders. In connection with the spin-out arrangement, the Company granted to Coneksis worldwide, exclusive licenses for use of certain cell lines in the field of veterinary medical research and therapeutics, trademarks, intellectual property, and patents, including the Company’s rights under its license agreement with Fox Chase Cancer Center. As part of the agreement, the Company also has a non-exclusive license to any results and data arising from Coneksis’ use of the Company’s cell lines and intellectual property for the Company’s use for internal research purposes and outside of Coneksis’ field. In consideration for the license grants, Coneksis is obligated to pay the Company a single-digit royalty on amounts received for the sale of licensed products and services, as well as a single-digit percentage share of other revenue received by Coneksis from the grant of sublicenses under the Company’s rights. Coneksis and the Company have the right to terminate the license agreement under certain conditions. Also, as part of the spin-out arrangement, the Company agreed to provide certain services to Coneksis for a transitional period on a fee-for-service basis. Invoices for services are to be issued monthly and payments are due 30 days from the date invoiced. For the years ended December 31, 2016 and 2015, the Company invoiced Coneksis for service fees in the amount of $19,000 and $6,000, which are recorded in other income on the consolidated statement of operations. At December 31, 2016, Coneksis owes the Company $25,000, which has been fully reserved. The Company determined it has a variable interest in both Brink Biologics and Coneksis through its royalty agreements. Based upon the level of equity investment at risk, Brink Biologics and Coneksis are considered variable interest entities (VIEs). The Company considered whether it is the primary beneficiary of the Brink Biologics and Coneksis VIEs and required to consolidate the entities. As the Company does not control the research and development or the sales of the potential licensed or commercialized products, the Company does not direct the activities of Brink Biologics and Coneksis that most significantly impact their economic performance. Therefore, the Company determined that it is not the primary beneficiary of the entities and does not consolidate the Brink Biologics VIE and the Coneksis VIE. ASU No. 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity, amended the definition of a discontinued operation, and requires additional disclosures about discontinued operations, as well as disposal transactions that do not meet the discontinued operations criteria. Under the new guidance, only disposals of a component representing a strategic shift in operations, that has or will have a major impact on the Company’s operations or financial results, should be classified as discontinued operations. The spin-out of Banks Biologics and Coneksis did not have a major impact on the Company’s operations or financial results, and accordingly, are not being reported as discontinued operations.

- Definition

The entire disclosure related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component.

+ References

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+ Details

Stockholders' Equity

12 Months Ended

Dec. 31, 2016

Equity [Abstract]

Stockholders' Equity

10. Stockholders’ Equity

Stock Repurchase—In November 2015, the board of directors approved a share repurchase program (the 2015 Share Repurchase Program) allowing the CEO or CFO, on behalf of the Company, to repurchase from time to time, in the open market or in privately negotiated transactions, up to $50.0 million of the Company’s outstanding shares of common stock, exclusive of any commissions, markups or expenses. The timing and amounts of any purchases will be based on market conditions and other factors, including price, regulatory requirements and other corporate considerations. The program does not require the purchase of any minimum number of shares and may be suspended, modified or discontinued at any time without prior notice. The Company expects to finance the purchases with existing cash balances. No shares were repurchased under the program for the year ended December 31, 2015.

During the year ended December 31, 2016, the Company repurchased 2,157,944 shares of its common stock, respectively, at prices ranging between $6.05 per share and $8.50 per share for a total of $15.8 million. The shares are formally retired through board approval upon repurchase. The Company incurred approximately $36,000 of broker commissions on the repurchases. The Company accounted for the repurchases under the constructive retirement method and allocated the excess of the repurchase price over par value to accumulated deficit. At December 31, 2016, $34.2 million remained authorized for repurchase under the Company’s 2015 Share Repurchase Program.

A summary of common stock repurchases for the year ended December 31, 2016 is as follows:

	Total number of shares purchased		Average price paid per share		Total number of shares purchased as part of publicly announced plans or programs		Maximum approximate dollar value of shares that may yet be purchased under the plans or programs
February		300,000	$	8.50		300,000	$47.5 million
May		346,200	$	6.77		646,200	$45.1 million
June		582,400	$	7.56		1,228,600	$40.7 million
August		335,440	$	7.01		1,564,040	$38.4 million
September		30,000	$	7.40		1,594,040	$38.1 million
November		439,618	$	7.14		2,033,658	$35.0 million
December		124,286	$	6.45		2,157,944	$34.2 million
Total		2,157,944	$	7.33

Conversion—In June 2015, the board of directors and the requisite shareholders approved the conversion of Class A common stock to common stock. Each share of Class A common stock (the 2015 Conversion) converted into 1.00 share of common stock. Additionally, the number of authorized shares of common stock was increased from 80,000,000 to 100,000,000.

In December 2014, the board of directors and the requisite shareholders of each class of stock approved the conversion of 8,295,402 shares of Class B common stock, 9,502,898 shares of Series B preferred stock and 5,754,984 shares of Series C preferred stock into Class A common stock (the 2014 Conversion). Each share of Series B common stock and Series C preferred stock converted into 1.00 share of Class A common stock and each share of Series B preferred stock converted into 5,132,548 shares of Class A common stock.

Forward Stock Split—On July 10, 2015, the Company amended its amended and restated certificate of incorporation effecting a 1.8515-for-1 forward stock split of its common stock. The forward stock split did not cause an adjustment to the par value or the authorized shares of the common stock or preferred stock. As a result of the forward stock split, the Company also adjusted the share and per-share amounts under its 2014 Equity Incentive Stock Plan and common stock warrant agreements with third parties. No fractional shares were issued in connection with the forward stock split. All disclosure of common shares and per common share data in the accompanying consolidated financial statements and related notes have been adjusted retroactively to reflect the forward stock split for all periods presented.

Amended and Restated Certificate of Incorporation—On July 31, 2015 the Company amended its Certificate of Incorporation to increase the number of authorized shares of common stock from 100,000,000 to 500,000,000.

Common Stock—In June 2015, the Company sold 3,698,695 shares of common stock in a private placement offering for net proceeds of $71.0 million after $28,000 of issuance costs. On July 8, 2015, the Company sold 364,638 shares of common stock in a private placement offering for gross proceeds of $7.0 million. On July 31, 2015, the Company closed its IPO and sold 9,531,200 shares of common stock for net proceeds of $221.5 million after underwriters’ discounts and commissions and offering expenses of $16.8 million. In addition, the Company completed a separate private placement concurrent with the completion of the IPO and sold 680,000 shares of common stock for proceeds of $17.0 million.

Redomestication—In March 2014, the Company entered into a definitive merger and share exchange agreement pursuant to which the Company redomesticated from the State of Illinois to the State of Delaware and the Illinois Company ceased to exist (the Redomestication). In connection with the Redomestication, the holders of Class A and Class B common stock received one share of Class A and Class B common stock of the Delaware Company, respectively, in exchange for fifteen shares of the Illinois Company. The holders of Series B preferred stock received one share of Series B preferred stock of the Delaware Company in exchange for one share of the Illinois Company. The holders of any options, warrants or other securities are subject to adjustment based on the ratio of 1 for 15. All share numbers and per share prices in the accompanying consolidated financial statements have been adjusted to reflect the 1 for 15 exchange.

Class A Common Stock—On June 18, 2015, the Company repurchased 249,952 shares of Class A common stock from an employee at $19.20 per share for $4.8 million. This was not part of the November 2015 share repurchase program described above.

In December 2014, the Company issued 4,557,537 shares of Class A common stock at $1.76 per share for gross proceeds of $8.0 million in a private placement transaction with Sorrento (Note 6). Subsequently in December 2014, the Company entered into a private placement offering and sold 26,252,262 shares of Class A common stock at $1.89 per share for gross proceeds of $49.5 million, of which Sorrento purchased 1,060,789 shares for $2.0 million. Related stock issuance costs totaled $0.2 million. In conjunction with the offering, the Company amended its Bylaws to increase the size of the board of directors to nine.

In 2014, the Company issued a restricted stock award for 129,605 shares of Class A common stock that vested upon achieving certain performance milestones. The holder met those milestones during 2014. In conjunction with the 2014 Securities Purchase Agreement (2014 Securities Purchase Agreement), the Company converted the 2009 Convertible Notes, the Other Creditor debt, and Side Agreement Notes into a total of 1,522,799 shares of Class A Common stock. Also in conjunction with the 2014 Securities Purchase Agreement, the placement agent agreed to exchange the CA Warrant and PA Warrant and $45,000 of its cash commission (Note 13) for a total of 3,087,324 shares of Class A Common stock. Refer to the table below for further details of the 2014 Securities Purchase Agreement.

In conjunction with the 2013 Securities Purchase Agreement (2013 Securities Purchase Agreement), 389,437 shares of Class A common stock were issued for conversion of certain debt and payables totaling $1.0 million, and 406,048 shares were issued in exchange for all outstanding shares of Series A preferred stock.

Class B Common Stock—In March 2014, the Company issued 763,151 shares of Class B common stock to a placement agent in exchange for an outstanding warrant. In December 2013, the Company sold 7,532,251 shares of Class B common stock to officers (Note 8).

In 2014 and 2013, the Company issued 5,851,152 and 1,681,099 shares of Class B common stock, respectively, to an officer of the Company as an offset against his outstanding principal and interest owed to the Company under a secured note (Note 8).

Series B Preferred Stock—In December 2014, all outstanding shares of Series B preferred stock were converted into 9,502,898 shares of Class A common stock during the 2014 Conversion.

Series C Preferred Stock—In December 2014, all outstanding shares of Series C preferred stock were converted into 5,754,984 shares of Class A common stock during the 2014 Conversion. In April 2014, the Company sold 4,983,526 Units in a private placement offering for gross proceeds of $6.5 million under the 2014 Securities Purchase Agreement. In addition, 771,458 Units were issued in conjunction with conversion of the 2013 Promissory Note (Note 13). Each Unit consists of one share of the Company’s Series C preferred stock and a warrant to purchase 0.25 share of Class A common stock at an initial exercise price of $1.62 per share (the Unit). The warrant expires three years following the date the Company becomes required to file reports under the Exchange Act.

The 2014 Securities Purchase Agreement qualified as a Mandatory Exchange Financing (Note 13).

The following summarizes changes in securities in conjunction with the 2014 Securities Purchase Agreement:

	Class A common stock		Class B common stock		Series C preferred stock		Warrants to purchase Class A common stock			Options to purchase Class A common stock
Share Balance in April 2014 prior to 2014 Securities Purchase Agreement		1,158,394		1,763,609		—		763,841			3,056,702
Exchange of Founder Warrant (Note 6)		—		—		—		(156,109	)		740,600
Conversion of 2013 Promissory Note (Note 13)		—		—		771,458		192,865			—
Conversion of 2009 Convertible Notes (Note 13)		985,229		—		—		—			—
Exchange the CA Warrant and the PA Warrant associated with 2009 Convertible notes (Note 13)		3,052,608		—		—		—			—
Exchange of Other Creditor debt (Note 13)		345,228		—		—		—			—
Exchange of Side Agreement Notes (Note 13)		192,341		—		—		—			—
Sale of Units in 2014 Securities Purchase Agreement (see above)		—		—		4,983,526		1,245,881			—
Cash commission to placement agent paid in Class A common stock (Note 13)		34,715		—		—		—			—
Exchange of placement agent warrant for stock (see above)		—		763,151		—		(193,413	)		—
Issuance of placement agent warrant associated with 2014 Securities Purchase Agreement (see below)		—		—		—		199,341			—
Share balance after closing of 2014 Securities Purchase Agreement		5,768,515		2,526,760		5,754,984		2,052,406			3,797,302

Common Stock Warrants—In March 2015, the board of directors approved the issuance of a stock option and a warrant to purchase Class A common stock to an officer of the Company (Note 11). In connection with its acquisition of Inex Bio in March 2015, the Company issued warrants to purchase 3,202,592 shares of Class A common stock with an exercise price of $2.00 per share (Note 14). In April 2015, the Company received $6.4 million for the full exercise of the warrants.

In April 2015, a warrant to purchase 114,822 shares of Class A common stock was exercised. The warrant, issued in 2010 in conjunction with a termination and release agreement, was initially exercisable at $2.44 per share, and was ultimately exercised at $1.76 per share. The warrant was exercisable through February 2020. The warrant included a provision that for a period through two years after a reverse merger, the exercise price of the warrant was protected against down-round financing unless 66.67% of shareholders consent to the new transaction. Pursuant to ASC Subtopic 815-15 and ASC Subtopic 815-40, the fair value of the warrant of $0.4 million was recorded as a derivative liability on the issuance date. The fair value of the warrant was estimated at the issuance date and was revalued at each reporting period and the exercise date using a Monte Carlo simulation. At April 30, 2015, the date of exercise, and December 31, 2014, the Company recorded a derivative liability of approximately $1.5 million and $0.2 million, respectively. The change in fair value of the derivative liability is included in other income (expense) on the consolidated statements of operations.

In March 2014, in conjunction with the amendment to the Founder License Agreement, the warrant held by the founder to purchase 156,109 shares of Class A common stock was exchanged for a fully-vested stock option to purchase up to 740,600 shares of Class A common stock (Note 6).

In June 2013, the Company engaged a placement agent in connection with the 2013 Securities Purchase Agreement (Note 13). The placement agent received a warrant to purchase 193,413 shares of Class A common stock (the Initial Warrant). On the date of a Mandatory Exchange Financing, the Initial Warrant would automatically be exchanged into shares of common stock equal to 2.5% of the fully-diluted number of shares of Class B common stock outstanding upon the closing of the Private Placement. In March 2014, the placement agent agreement was amended to exchange the Initial Warrant for 763,151 shares of Class B common stock and a new warrant for 199,341 shares of Class A common stock based on 4% of the number of shares of stock issued to investors introduced to the Company by the placement agent in the 2014 Securities Purchase Agreement (the New Warrant). The New Warrant has the same terms as the 2014 Warrant issued as part of the 2014 Securities Purchase Agreement.

Common Stock Reserved for Future Issuance

The Company is authorized to issue up to a total of 500,000,000 shares of common stock, par value $0.0001 per share at December 31, 2016 and 2015. As of December 31, 2016, there were 81,983,937 shares of common stock issued and outstanding.

The following table summarizes the common shares reserved for issuance on exercise or vesting of various awards at December 31, 2016:

Issued and outstanding stock options			6,307,384
Issued and outstanding restricted stock units			814,456
Outstanding financing warrants			179,064
Outstanding officer warrants			17,589,250
Total shares reserved for future issuance			24,890,154

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

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+ Details

Stock-Based Compensation

12 Months Ended

Dec. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

11. Stock-Based Compensation

2004 Equity Incentive Plan—In April 2004, the Company adopted the 2004 Stock Option Plan (the 2004 Plan) under which 81,695 shares of common stock were reserved for issuance. The 2004 Plan provides for the granting of stock options to employees, directors and consultants of the Company. Options granted under the 2004 Plan may be either incentive stock options (ISOs) or nonqualified stock options (NSOs). NSOs may be granted to the Company employees and consultants. No further shares are available for grant under the 2004 Plan.

2014 Equity Incentive Plan—In March 2014, the Company’s board of directors and stockholders approved the 2014 Equity Incentive Plan (2014 Plan) under which 11,109,000 shares of Class A common stock were reserved for the granting of ISOs, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock units and performance awards to employees, directors and consultants. Recipients of stock awards are eligible to purchase shares of the Company’s common stock at an exercise price equal to no less than the estimated fair market value of such stock on the date of grant. The maximum term of awards granted under the 2014 Plan is ten years. Stock awards are generally not exercisable prior to the applicable vesting date, unless otherwise accelerated under the terms of the applicable stock plan agreement. Unvested shares of the Company’s common stock issued in connection with an early exercise allowed by the Company may be repurchased by the Company upon termination of the optionee’s service with the Company.

2015 Equity Incentive Plan—In July 2015, the Company’s board of directors adopted the 2015 Equity Incentive Plan (2015 Plan). The 2015 Plan permits the grant of incentive stock options, within the meaning of Section 422 of the Code, to the Company’s employees and for the grant of non-statutory stock options, restricted stock, restricted stock units, stock appreciation rights, performance units and performance shares to the Company’s employees, directors and consultants. A total of 2,745,028 shares are reserved for future grants pursuant to the 2015 Plan as of December 31, 2016. In addition, the shares reserved for future grants under the 2015 Plan will include shares subject to stock options or similar awards granted under the 2014 Plan that expire or terminate without having been exercised in full and shares issued pursuant to awards granted under the 2014 Plan that are forfeited to or repurchased by the Company (provided that the maximum number of shares that may be added to the 2015 Plan pursuant to this provision is 6,914,754 shares as of December 31, 2016).

Modification of Stock-based Awards to an Officer—On March 24, 2015, the Company granted a non-qualified stock option (the Option) and a warrant (the Warrant) to purchase 1,851,500 shares and 17,589,250 shares of the Company’s common stock, respectively, to an officer of the Company. The Option had an exercise price of $2.00 per share, a ten-year term and vests monthly over 40 months from the grant date. The Warrant had an exercise price of $2.00 per share, a three-year term and included performance-based vesting conditions.

Subsequent to the original grant date, the Company modified the terms and conditions of the Option and the Warrant, and on May 8, 2015, the Company and the officer reached a mutual agreement on the revised terms of the Option and the Warrant. By mutual agreement, the Company increased the exercise price of the Option from $2.00 per share to $2.20 per share and reduced the term of the Option from ten to four years. The Warrant’s vesting conditions changed from performance based to a combination of performance based for 10,183,250 shares, including modified performance milestones from the original grant, and service based for 7,406,000 shares. In addition, the Company revised the term of the Warrant from three to four years.

The Company treated these changes to the Option and the Warrant as modifications of the terms and conditions of an equity award. The change in the term and exercise price of the Option did not result in incremental stock compensation expense as the higher exercise price and shorter term reduced the overall value of the modified Option.

The change in the terms for the Warrant resulted in incremental compensation expense of $91.5 million, of which $53.0 million is recognized upon achievement of performance milestones and $38.5 million is recognized over the service period, since the fair value of the modified Warrant is higher than the original fair value. Incremental compensation expense of $19.0 million and $53.8 million was recognized during the years ended December 31, 2016 and 2015, respectively, and the remaining $18.7 million is expected to be recognized over the remaining vesting period of 1.6 years.

Issuance of options and restricted stock units to Officers—In accordance with their employment agreements, the Company granted to its CEO and Chief Administrative Officer upon the IPO a total of 1,455,450 options to purchase common stock with an exercise price of $25.00 per share and 970,300 restricted stock units representing the right to receive one share of the Company’s common stock for each restricted stock unit that becomes vested. The options and restricted stock units vested 50% at grant and the remaining 50% vested upon the first anniversary of the IPO.

Stock-Based Compensation

The following table presents all stock-based compensation as included on the Company’s consolidated statements of operations (in thousands):

	For the Year Ended December 31,
	2016		2015		2014
Stock-based compensation expense:
Warrants for common stock to an officer	$	50,502	$	141,901	$	—
Warrants for common stock to an officer and a director related to Inex Bio, Inc. acquisition		—		22,747		—
Employee stock options		14,720		25,498		485
Non-employee stock options		—		3,300		76
Employee restricted stock units		8,166		17,505		228
Non-employee restricted stock units		464		270		—
	$	73,852	$	211,221	$	789
Stock-based compensation expense in operating expenses:
Research and development	$	852	$	1,221	$	222
Selling, general and administrative		73,000		210,000		567
	$	73,852	$	211,221	$	789

In the second quarter of 2016, the Company adopted ASU 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. ASU 2016-09 requires that certain other amendments relevant to the Company be applied using a modified-retrospective transition method by means of a cumulative-effect adjustment to accumulated deficit as of the beginning of the period in which the guidance is adopted. As a result of adopting ASU 2016-09 during the three months ended June 30, 2016, the Company adjusted accumulated deficit for amendments related to an entity-wide accounting policy election to recognize share-based award forfeitures only as they occur rather than an estimate by applying a forfeiture rate. The Company recorded a $31,000 charge to accumulated deficit as of January 1, 2016 and an associated charge to additional paid-in capital for previously unrecognized stock compensation expense as a result of applying this policy election. The Company also recorded $27,000 in additional stock compensation expense for the three months ended March 31, 2016 as a result of applying this policy election. That is, the Company’s consolidated statement of operations for the year ended December 31, 2016 reflects this additional expense.

ASU 2016-09 also requires the recognition of the income tax effects of awards in the consolidated statement of operations when the awards vest or are settled, thus eliminating addition paid-in capital pools. The Company elected to adopt the amendments related to the presentation of excess tax benefits on the consolidated statement of cash flows using a prospective transition method.

Stock Options

The following table summarizes stock option activity under all equity incentive plans for the years ended December 31, 2016, 2015 and 2014:

	Number of Shares			Weighted- Average Exercise Price		Aggregate Intrinsic Value (in 000)		Weighted- Average Remaining Contractual Life (in years)
Outstanding at December 31, 2013		1,727		$	0.41	$	—		1.3
Options granted		5,971,087		$	0.77
Options exercised		(833,173	)	$	0.22
Options forfeited/canceled		(1,231	)	$	0.41
Outstanding at December 31, 2014		5,138,410		$	0.85	$	5,298		9.7
Options granted		5,713,899		$	7.92
Options exercised		(1,127,105	)	$	0.86
Options forfeited/canceled		(947,311	)	$	1.87
Outstanding at December 31, 2015		8,777,893		$	5.36	$	116,273		7.2
Options exercised		(2,398,882	)	$	0.76
Options forfeited/canceled		(71,627	)	$	2.00
Outstanding at December 31, 2016		6,307,384		$	7.14	$	19,100		6.4
Vested and Exercisable at December 31, 2016		5,210,756		$	8.18	$	15,227		7.3

The vested and exercisable shares at December 31, 2015 and 2014 were 4,844,857 and 1,705,035, respectively.

The following table provides a summary of options outstanding and vested as of December 31, 2016:

Exercise Prices	Number Outstanding		Weighted- Average Life (in years)		Number Exercisable		Weighted- Average Life (in years)
$0.22		134,807		7.2		134,807		7.2
$0.42		589,660		7.9		589,660		7.9
$1.76		999,682		8.0		999,682		8.0
$2.00		1,276,285		8.1		1,221,126		8.1
$2.20		1,851,500		2.2		810,031		2.2
$25.00		1,455,450		8.6		1,455,450		8.6
		6,307,384		6.4		5,210,756		7.3

The aggregate intrinsic value of stock options exercised during the years ended December 31, 2016, 2015 and 2014 was $17.0 million, $2.4 million and $0.2 million, respectively. The cash received from exercised options was $1.4 million, $0.9 million and $0.2 million for the years ended December 31, 2016, 2015 and 2014, respectively. Total stock option expense was $14.7 million, $28.8 million and $0.6 million for the years ended December 31, 2016, 2015 and 2014, respectively.

The Company records equity instruments issued to non-employees as expense at the fair value over the related service period as determined in accordance with the authoritative guidance and periodically revalues the equity instruments as they vest. The Company granted to non-employees stock options for 231,437 shares during each of the years ended December 31, 2015 and 2014. No options were granted to non-employees in 2016. As of December 31, 2016, there were no non-employee options that were vested and outstanding. In the years ended December 31, 2016, 2015 and 2014, the Company recorded stock-based compensation expense related to non-employee consultants of $0, $3.3 million and $0.1 million, respectively, in selling, general and administrative expense.

The total unrecognized compensation cost related to non-vested stock options as of December 31, 2016 is $9.1 million, which is expected to be recognized over a weighted-average period of 2.1 years.

The Company uses a Black-Scholes option-pricing model to determine the fair value of stock-based compensation under ASC Topic 718, Stock Compensation. The assumptions used for employee and non-employee stock options are presented in the table below:

	Years Ended December 31,
	2015				2014
	Employee Grants		Non-Employee Grants		Employee Grants		Non-Employee Grants
Expected term (years)	4.0 - 5.5		8.4 - 9.9		5.0 - 5.6		9.3 - 9.9
Risk-free interest rate	1.5% - 1.8%		0% - 2.4%		1.6% - 1.9%			2.20%
Expected volatility		80%		80%	81% - 91%			81%
Dividend yield		0%		0%		0%		0%
Weighted-average measurement date fair value	$	12.08	$	15.25	$	0.53	$	0.18

The assumed dividend yield was based on the Company’s expectation of not paying dividends in the foreseeable future. The estimated volatility is based on a weighted-average calculation of a peer group of comparable companies whose share prices are publicly available. The risk-free interest rate assumption was based on the U.S. Treasury’s rates for U.S. Treasury zero-coupon bonds with maturities similar to those of the expected term of the award being valued. The weighted-average expected life of options was estimated using the average of the contractual term and the weighted-average vesting term of the options.

Restricted Stock Units

The following table summarizes the restricted stock units (RSUs) activity under the 2015 Plan:

	Number of Restricted Stock Units Outstanding			Weighted-Average Grant Date Fair Value
Unvested balance at December 31, 2014		—		$	—
Granted		1,614,788		$	21.86
Vested		(485,150	)	$	25.00
Unvested balance at December 31, 2015		1,129,638		$	20.51
Granted		407,800		$	7.76
Vested		(537,982	)	$	23.75
Forfeited/canceled		(185,000	)	$	11.75
Unvested balance at December 31, 2016		814,456		$	13.98

There was no RSU activity in 2014.

During the years ended December 31, 2016 and 2015, 67,500 and 353,188 of restricted stock units, respectively, were granted to employees of related companies (referred to as non-employees above) under the Company’s shared services agreement with NantWorks (Note 8).

As of December 31, 2016, there was $5.5 million of unrecognized stock-based compensation expense related to restricted stock units granted that is expected to be recognized over a weighted-average period of 3.0 years. Of that amount, $3.8 million of unrecognized expense is related to employee grants with a weighted-average period of 3.0 years and $1.7 million expense is related to non-employee grants with a weighted-average period of 2.9 years that is impacted by periodic mark-to-marked adjustments.

Restricted Stock Awards

In 2014, the Company issued a restricted stock award for 129,605 shares of Class A common stock that vested based on the holder achieving certain performance milestones. The holder met those performance milestones during the year ended December 31, 2014 and the Company recognized stock compensation expense of $0.2 million related to the award.

Warrants

The following table summarizes the Company’s warrant activity:

Outstanding at December 31, 2014	1,850,937
Warrants granted	20,791,842
Warrants exercised	(4,677,101	)
Warrants forfeited	(146,062	)
Outstanding at December 31, 2015	17,819,616
Warrants exercised	(51,302	)
Outstanding at December 31, 2016	17,768,314
Vested and exercisable at December 31, 2016	12,769,264

The total unrecognized compensation cost related to non-vested warrants as of December 31, 2016 is $49.4 million, which is expected to be recognized over a weighted-average period of 1.6 years.

Common Stock Reserved for Future Grants under the 2015 Equity Incentive Plan

At December 31, 2016, the Company has reserved authorized shares of common stock for future grants of equity awards as follows:

Shares approved for 2015 Equity Incentive Plan	3,500,000
Shares remaining from 2014 Equity Incentive Plan	749,857
Total shares authorized under the 2015 Plan	4,249,857
Grants	(3,070,238	)
Forfeitures added back to available pool	947,063
Shares reserved for future grants as of December 31, 2015	2,126,682
Grants	(407,800	)
Add backs approved under the Plan:
Forfeitures	185,000
Net share settlement	225,754
Shares repurchased	615,392
Shares reserved for future grants as of December 31, 2016	2,745,028

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Income Taxes

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Income Taxes

12. Income Taxes

The amount of loss before taxes is (in thousands):

	Year Ended December 31,
	2016			2015			2014
U.S. loss before taxes	$	(118,743	)	$	(235,750	)	$	(6,184	)
Foreign loss before taxes		(2,638	)		(1,427	)		—
Loss before income taxes	$	(121,381	)	$	(237,177	)	$	(6,184	)

Income tax (benefit) expense for the years ended December 31, 2016, 2015 and 2014 consists of the following (in thousands):

	Year Ended December 31,
	2016			2015			2014
Current:
Federal	$	—		$	—		$	—
State		3			1			1
Foreign		—			—			—
Total Current		3			1			1
Deferred:
Federal		—			—			—
State		—			—			—
Foreign		(575	)		(302	)		—
Total Deferred		(575	)		(302	)		—
Income tax (benefit) expense	$	(572	)	$	(301	)	$	1

The components that comprise the Company’s net deferred tax assets at December 31, 2016 and 2015 consist of the following (in thousands):

	Year Ended December 31,
	2016			2015
Deferred tax assets:
Stock compensation	$	87,239		$	67,559
Net operating loss carryforwards		37,507			—
Leases and other accrued liabilities		2,096			389
Accrued compensation		808			572
Depreciation and amortization		—			624
Total deferred tax assets		127,650			69,144
Deferred tax liabilities:
Foreign intangibles		(996	)		(1,165	)
Depreciation and amortization		(309	)		—
Total deferred tax liabilities		(1,305	)		(1,165	)
Net deferred tax assets		126,345			67,979
Valuation allowance		(127,341	)		(69,144	)
Net deferred tax liability	$	(996	)	$	(1,165	)

A reconciliation of the federal statutory income tax rate to the Company’s effective income tax rate is as follows:

	Year Ended December 31,
	2016				2015				2014
Tax computed at federal statutory rate		34.0		%		34.0		%		34.0		%
Section 382/383 NOL		8.6				(3.5	)			(40.0	)
State income taxes, net of federal tax benefit		3.6				2.6				4.8
Tax rate adjustment		1.5				—				0.5
Research and development credits		1.3				0.1				0.7
Stock-based compensation		(0.3	)			(0.4	)			(1.1	)
Other		(0.5	)			(3.8	)			(7.3	)
Valuation Allowance		(47.7	)			(28.9	)			8.4
Effective income tax rate		0.5		%		0.1		%		—		%

Pursuant of Internal Revenue Code (IRC) Sections 382 and 383, annual use of the Company's net operating loss and research and development credit carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period . The Company completed an IRC Section 382/383 analysis in 2016 regarding the limitation of net operating loss and research and development credit carryforwards. As a result of the analysis, the Company recognized deferred tax assets for net operating losses of $11.1 million and federal and state research and development credits of $0.4 million. The Company has derecognized the deferred tax assets for net operating losses and federal and state research and development credits of $1.2 million from its deferred tax asset schedule as of December 31, 2016. The Company had previously derecognized $12.7 million deferred tax assets for net operating losses and federal and state research and development credits as of December 31, 2015. The Company also recorded a corresponding increase to its valuation allowance as a result of recognizing the additional deferred tax assets upon completion of the Section 382/383 analysis. The Company does not expect that the unrecognized tax benefits will change within 12 months of this reporting date. Due to the existence of the valuation allowance, future changes in the Company's unrecognized tax benefits will not impact the Company's effective tax rate.

The Company has removed the deferred tax assets for foreign net operating losses in the amount of $28,000.

In assessing the realization of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment. Based on the level of historical operating results and the uncertainty of the economic conditions, the Company has recorded a full valuation allowance of $127.3 million at December 31, 2016. The change in the valuation allowance for the year end December 31, 2016 was an increase of $58.2 million.

The Company has not incurred any material interest or penalties as of the current reporting date with respect to income tax matters. The Company does not expect that there will be unrecognized tax benefits of a significant nature that will increase or decrease within 12 months of the reporting date. The Company is subject to U.S. federal income tax, as well as income tax in California and other states. The federal returns for tax years 2013 through 2016 remain open to examination; the California returns remain subject to examination for tax years 2012 through 2016. Carryforward attributes that were generated in years where the statute of limitations is closed may still be adjusted upon examination by the Internal Revenue Service or other respective tax authority. All other state jurisdictions remain open to examination.

At December 31, 2016, the Company has federal net operating losses (NOLs) of approximately $100.0 million, state NOLs of $60.0 million, and foreign NOLs of $0.2 million. The federal NOL carryforwards begin to expire in 2024, the state NOL carryforwards begin to expire in 2030 and the foreign NOL carryforwards begin to expire in 2023. At December 31, 2016, the Company also had federal research tax credit carryforwards of approximately $1.7 million and California research tax credits of $0.7 million. The federal research tax credit carryforwards begin to expire in 2026 and the state research tax credit carryforwards begin to expire in 2029.

The following table summarizes the changes to the amount of unrecognized tax benefits (in thousands):

Unrecognized tax benefits at December 31, 2014	$	—
Increase for prior year tax positions		120
Increase for current year tax positions		1,083
Unrecognized tax benefits at December 31, 2015		1,203
Decrease for prior year tax positions		(1,203	)
Increase for prior year tax positions		2,578
Increase for current year tax positions		2,056
Unrecognized tax benefits at December 31, 2016	$	4,634

Included in the balance of unrecognized tax benefits at December 31, 2016, is $4.3 million that, if recognized, would not impact the Company’s income tax benefit or effective tax rate as long as the deferred tax asset remains subject to a full valuation allowance. The Company does not expect any significant increases or decreases to our unrecognized tax benefits within the next 12 months.

Notes Payable	12 Months Ended
Notes Payable	Dec. 31, 2016
Debt Disclosure [Abstract]
Notes Payable	13. Notes Payable 2013 Promissory Note—In June 2013, the Company entered into a securities purchase agreement (the 2013 Securities Purchase Agreement) whereby the Company issued to an institutional investor a $1.0 million note payable (the 2013 Promissory Note) plus 1,851 shares of Series B preferred stock at a per share price of $0.05 for aggregate proceeds of $1.0 million. The 2013 Promissory Note accrued interest at 5% per annum and was scheduled to mature on June 20, 2014. The 2013 Promissory Note was secured by all of the assets of the Company. The Company allocated the proceeds under the 2013 Securities Purchase Agreement to the 2013 Promissory Note and Series B preferred stock based on their relative fair values, which resulted in $0.4 million and $0.6 million being allocated to the 2013 Promissory Note and Series B preferred stock, respectively. The Company recorded a debt discount of $0.6 million, which was being amortized to interest expense over the term of the 2013 Promissory Note using the effective interest method. In April 2014, the Company entered into the 2014 Securities Purchase Agreement (Note 10) at which time the holder of the 2013 Promissory Note agreed to convert the $1.0 million principal into 771,458 shares of Series C preferred stock plus a warrant to purchase 192,865 shares of Class A common stock having the same terms as the warrants issued in the 2014 Securities Purchase Agreement (the 2014 Warrant, Note 10). The Company paid accrued interest of $39,000 in cash upon conversion of the 2013 Promissory Note. The 2014 Warrant was outstanding at December 31, 2014 and was exercised in 2015. 2009 Convertible Notes—In 2009, the Company entered into a bridge loan agreement (the 2009 Bridge Loan Agreement) whereby the Company agreed to sell and issue $0.4 million of convertible promissory notes (the 2009 Convertible Notes). The 2009 Convertible Notes accrued interest at 15% per annum until maturity on September 30, 2010 (the Maturity Date). After the Maturity Date, the 2009 Convertible Notes accrued interest at 24% per annum. The 2009 Convertible Notes were convertible at the option of the holders into securities issued in the Company’s next financing. The 2009 Convertible Notes were secured by all assets of the Company. As discussed below, the 2009 Convertible Notes were exchanged for shares of Class A common stock, and there was no balance outstanding on the 2009 Convertible Notes at December 31, 2014. Each holder of the 2009 Convertible Notes also received a warrant to purchase shares of Class A common stock (the 2009 Warrants). The 2009 Warrants were exercisable only if and to the extent that the holder subscribed to the next financing for a number of shares equal to 300% of the number of shares issued to the holder in the next financing. The exercise price of the 2009 Warrants initially was the purchase price for the shares in the next financing. However, for up to two years after the date that the Company becomes a public company, the exercise price is adjusted to a price equal to the price of the new equity securities should the Company enter into any new equity transaction whereby the price of the equity in the new transaction is lower than the exercise price of the 2009 Warrants. In conjunction with the 2013 Securities Purchase Agreement in June 2013, each holder of the 2009 Convertible Notes entered into a consent, amendment and exchange agreement (the Exchange Agreement). The Exchange Agreement (i) modified the Maturity Date to June 20, 2014; (ii) caused each holder to execute a subordination and shareholder lock-up agreement, and; (iii) upon a Mandatory Exchange Financing (Company closing a private placement of stock or other securities of at least $3.0 million, Note 10), automatically exchanged the outstanding principal and accrued interest under the 2009 Convertible Notes and the 2009 Warrants for shares of Class A common stock at an exchange rate of three times the principal amount of the 2009 Convertible Notes divided by the per share price of the Mandatory Exchange Financing. In April 2014, the 2014 Securities Purchase Agreement qualified as a Mandatory Exchange Financing and the $0.4 million outstanding principal balance plus $0.4 million accrued interest on the 2009 Convertible Notes and the 2009 Warrants were exchanged for 985,229 shares of the Company’s Class A common stock. The 2009 Convertible Notes and the 2009 Warrants were no longer outstanding at December 31, 2014. In connection with the sale of the 2009 Convertible Notes, the Company used a placement agent. The placement agent received a corporate advisory warrant (the CA Warrant) for common stock equal to 20% of the issued and outstanding common stock of the Company on a fully diluted basis immediately following the final closing of the Bridge Loan Agreement financing. The CA Warrant had an exercise price of $2.44 per share and was to expire on September 30, 2019. The placement agent also received a warrant for common stock for the number of shares equal to 9% of the number of warrant shares issued to the holders who subscribe to the next financing (the PA Warrant). The initial exercise price of the PA Warrant is equal to the price of the next financing. In conjunction with the 2013 Securities Purchase Agreement in June 2013, the placement agent agreed to exchange the CA Warrant and PA Warrant into shares of Class A common stock equal to 10% of the shares of fully-diluted stock outstanding immediately following the closing of a Mandatory Exchange Financing less certain exempted issuances. At the 2014 Securities Purchase Agreement closing in April 2014, the CA Warrant and PA Warrant were exchanged for 3,052,608 shares of the Company’s Class A common stock. The Company also issued to the placement agent 34,715 shares of Class A common stock in exchange for a cash commission in conjunction with the 2014 Securities Purchase Agreement. Settlement Agreement Note—In 2007, the Company entered into a settlement agreement with a former officer of the Company (the Settlement Agreement Note). The Settlement Agreement Note included a cash payment to the former officer of $0.3 million payable upon the Company’s receipt of any debt or equity financing. As part of the 2009 Convertible Notes financing, the Settlement Agreement Note was amended so that the Note will convert into Class A common stock at a conversion price of $2.44 per share on the second anniversary of Company being a publicly traded company. The $0.3 million outstanding Settlement Agreement Note balance is reflected in other current liabilities on the consolidated balance sheets as of December 31, 2014. In March 2015, the Company entered into a Supplemental Agreement and General Release (the Supplemental Agreement) with the former officer related to the Settlement Agreement. As a result, (i) the Company agreed to pay $0.13 million in exchange for retiring the note and (ii) the former officer agreed to exercise a warrant from 2008 to purchase 32,675 shares of Class A common stock at an exercise price of $2.44 per share. The Settlement Agreement Note is no longer outstanding as of December 31, 2015 and the $0.13 million difference between the carrying value of the Settlement Agreement Note and the amount paid to retire the Settlement Agreement Note is reflected in other income on the consolidated statement of operations for the year ended December 31, 2015. Founder Note— As consideration for the sale and assignment of the license and technical information to the NK-92 cell line to the Company in 2009 and 2010 in connection with the amendment to the Founder License Agreement (Note 6), the Company issued a non-interest bearing note (the Founder Note) to a founder for $23,000. In April 2014, the outstanding balance was paid in full. Other Notes and Creditors—As part of the 2009 Convertible Notes financing, certain other note holders and creditors with obligations totaling $0.2 million (Other Creditors) executed agreements either to defer payment for three years or convert the obligations into Class A common stock upon the Company closing a financing of at least $1.2 million at a conversion price of $2.44 per share. In conjunction with the 2013 Securities Purchase Agreement, Other Creditors holding $20,000 of principal plus $29,000 of accrued interest elected to convert their obligations into 20,205 shares of Class A common stock. Other Creditors holding $0.1 million of principal entered into exchange agreements whereby, upon the Company completing a Mandatory Exchange Financing, the balance plus any accrued interest is automatically exchanged for shares of Class A common stock at an exchange rate of three times the amount owed divided by the per share price of the Mandatory Exchange Financing. At the close of the 2014 Securities Purchase Agreement in April 2014, the $50,000 principal plus accrued interest of $0.1 million were exchanged for 230,859 shares of Class A common stock. In April 2014, an Other Creditor with $0.1 million of outstanding principal and interest agreed to sell its note to a third party who agreed to exchange the note for 114,369 shares of Class A common stock. Other Creditors with $29,000 of outstanding principal plus $13,000 of accrued interest were repaid in cash in April 2014. Side Agreement Notes—Payables and debt totaling $0.2 million were sold by certain creditors to existing investors (the Side Agreements). In conjunction with the Side Agreements, the Company issued to the investors convertible notes (the Side Agreement Notes) pursuant to an exchange agreement whereby upon the Company completing a Mandatory Exchange Financing, the outstanding balance under the (the Side Agreement Notes) are automatically exchanged for shares of Class A common stock at an exchange rate of the amount divided by the per share price of the Mandatory Exchange Financing. At the close of the 2014 Securities Purchase Agreement in April 2014, the $0.2 million balance of the (the Side Agreement Notes) was exchanged for 192,341 shares of Class A common stock.

Investment In Inex Bio, Inc

12 Months Ended

Dec. 31, 2016

Schedule Of Investments [Abstract]

Investment in Inex Bio, Inc

14. Investment in Inex Bio, Inc.

In April 2012, the Company made a strategic decision to enter into a License Agreement with Inex Bio, Inc. (Inex Bio), a Republic of Korea corporation (the Inex License Agreement). Under the Inex License Agreement, the Company provided Inex Bio with an exclusive license to the Company’s technology to be used in products only in certain Asian countries. In exchange for the Inex License Agreement, the Company received a $0.3 million up-front license fee. In addition, the Company was eligible to receive milestone payments of up to $0.8 million based upon completion of clinical trials and a 5% royalty on net sales of applicable products using the aNK cells. No milestone payments were due or received for the years ended December 31, 2015, 2014 or 2013.

In May 2012, the Company acquired 57,000 shares of Inex Bio for $0.2 million, which represented 22.2% of the outstanding shares and 17.4% of the fully-diluted shares of Inex Bio. The Company accounted for its investment under the equity method. The Company reviewed its investment for impairment in accordance with ASC Topic 320, Investments—Debt and Equity Securities.

In February and March 2015, InexBio Holdings (Holdings), an entity owned fifty percent (50%) by Cambridge Equities, L.P., an entity in which Dr. Soon-Shiong, the Company’s CEO and one of the Company’s directors, is the sole member of its general partner, and fifty percent (50%) by Eragon Ventures, LLC, an entity of which Dr. Ji, one of our former directors, is managing member, acquired 220,000 shares or 67.3% of Inex Bio from third party owners for $1.1 million.

On March 30, 2015, the Company entered into a Stock Purchase Agreement with Holdings and the third party owners, pursuant to which the Company acquired all the remaining outstanding shares of Inex Bio not previously held by the Company.

The Company paid to the other owners of Inex Bio cash of $1.5 million and issued warrants to acquire 593,072 shares of the Company’s Class A common stock at an exercise price of $2.00 per share. The Company valued the warrants using the Black-Sholes option-pricing model with a stock price of $10.72 per share as of March 30, 2015, an expected term of 0.04 years, and a volatility of 80%. This resulted in a total fair value of the warrants of $5.2 million. In April 2015, the Company received $1.2 million for the full exercise of the warrants.

The Company recorded the transaction as an asset purchase because Inex Bio was a shell corporation without any employees or other significant assets and did not meet the definition of a business under ASC Topic 805, Business Combinations.

The purchase price paid to acquire Inex Bio from the other owners is as follows (in thousands):

Consideration	Total
Cash paid by InexBio Holdings, LLC	$	1,100
Cash paid by Company		1,482
Fair value of warrants		5,170
Aggregate purchase price	$	7,752

The following table summarizes the assets acquired and liabilities assumed (in thousands):

Cash	$	763
Intangible assets—reacquired rights of Company technology		8,636
Other assets		42
Investment in Inex Bio		(221	)
Deferred tax liability		(1,467	)
Accounts payable		(1	)
Total assets acquired and liabilities assumed	$	7,752

The license solely covers pending patent applications at this time. The Company will amortize the intangible assets related to the reacquired rights of the Company technology over 4 years, which represents the period until the next action date of the pending patent application in the territory of the license issued to Inex Bio.

The Company paid Holdings cash of $6.5 million and issued warrants to acquire 2,609,520 shares of the Company’s Class A common stock at an exercise price of $2.00 per share for its assistance in negotiating the acquisition of Inex Bio from the other owners. The Company valued the warrants using the Black-Sholes option-pricing model with a stock price of $10.72 per share as of March 30, 2015, an expected term of 0.04 years, and a volatility of 80%. This resulted in a fair value of total warrants of $22.7 million. In April 2015, the Company received $5.2 million for the full exercise of the warrants.

The following summarizes the net consideration paid to Holdings (in thousands):

Consideration	Total
Cash	$	6,518
Fair value of warrants		22,747
Less cash paid to acquire shares in Inex Bio		(1,100	)
Net consideration	$	28,165

The Company recorded compensation expense for the portion of the cash and warrants issued to Holdings that exceeded the fair value of the shares acquired consistent with ASC Topic 718. The Company recorded $22.7 million of stock-based compensation and $5.4 million of cash compensation to the Company’s CEO and the former director as a result of acquiring their interest in Inex Bio.

Summarized Quarterly Data (Unaudited)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Summarized Quarterly Data (Unaudited)

15. Summarized Quarterly Data (Unaudited)

The following financial information reflects all normal recurring adjustments that are, in the opinion of management, necessary for a fair statement of the results of the interim periods.

The table below presents unaudited quarterly data for fiscal 2016 and 2015 (in thousands, except for share and per share amounts):

	1st Quarter			2nd Quarter			3rd Quarter			4th Quarter
2016
Revenue	$	6		$	12		$	12		$	14
Operating expenses		31,622			34,977			32,787			25,157
Operating loss		(31,616	)		(34,965	)		(32,775	)		(25,143	)
Net loss		(30,677	)		(33,997	)		(31,897	)		(24,238	)
Net loss per share - basic and diluted	$	(0.38	)	$	(0.41	)	$	(0.39	)	$	(0.29	)
Shares used in calculating net loss per share - basic and diluted		81,574,709			81,959,248			82,154,219			82,235,571

	1st Quarter			2nd Quarter			3rd Quarter			4th Quarter
2015
Revenue	$	120		$	91		$	10		$	15
Operating expenses		32,221			130,486			46,467			29,938
Operating loss		(32,101	)		(130,395	)		(46,457	)		(29,923	)
Net loss		(32,849	)		(130,893	)		(46,312	)		(26,822	)
Net loss per share - basic and diluted	$	(0.54	)	$	(1.99	)	$	(0.60	)	$	(0.33	)
Shares used in calculating net loss per share - basic and diluted		61,137,625			65,789,041			77,837,586			81,247,430

Employee Benefits	12 Months Ended
Employee Benefits	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Employee Benefits	16. Employee Benefits Benefit Plan - In December 2015, the Company adopted a 401(k) retirement and savings plan (the 401(k) Plan) covering all employees. The 401(k) Plan allows employees to make pre- and post-tax contributions up to the maximum allowable amount set by the IRS. The Company, at its discretion, may make certain contributions to the 401(k) Plan. The Company made contributions of $0.2 million and $4,000 during the years ended December 31, 2016 and 2015, respectively. Compensated Absences – Under the Company’s vacation policy, certain salaried employees are provided unlimited vacation leave. Therefore, the Company does not record an accrual for paid leave related to these employees since the Company is unable to reasonably estimate the compensated absences that these employees will take.

Subsequent Event	12 Months Ended
Subsequent Event	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Event	17. Subsequent Event Related Party Agreement In February 2017, the Company entered into a research grant agreement with VivaBioCell, S.p.A. (VBC), an affiliated company of NantWorks, under which VBC will conduct research and development activities related to the Company’s NK cell lines using VBC’s proprietary technology. Within 60 days after the one year anniversary of the agreement, VBC will provide the Company a final report summarizing the progress and results of the research and development activities including a description of any inventions and intellectual property rights derived from the work performed. The Company has the first right of refusal in the event any third party offers to purchase such derived inventions and intellectual properties from VBC. The Company paid $0.6 million to VBC and expects to benefit from the research and development activities over a one year timeframe.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Principles of Consolidation

The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, Inex Bio, Inc., and have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). All intercompany amounts have been eliminated.

The Company applies the variable interest model under Accounting Standards Codification (ASC) Topic 810, Consolidation, to any entity in which the Company holds an equity investment or to which the Company has the power to direct the entity's most significant economic activities and the ability to participate in the entity's economics. If the entity is within the scope of the model, and meets the definition of a variable interest entity (VIE), the Company considers whether it must consolidate the VIE or provide additional disclosures regarding the Company's involvement with the VIE. If the Company determines that it is the primary beneficiary of the VIE, the Company will consolidate the VIE. This analysis is performed at the initial investment in the entity or upon any reconsideration event.

Liquidity

As of December 31, 2016, the Company had an accumulated deficit of approximately $387.1 million. The Company also had negative cash flow from operations of approximately $38.6 million during the year ended December 31, 2016. The Company expects that it will likely need additional capital to further fund development of, and seek regulatory approvals for, its product candidates, and begin to commercialize any approved products.

The Company is currently focused primarily on the development of immunotherapeutic treatments for cancers and debilitating viral infections using targeted cancer killing cell lines, and believes such activities will result in the Company’s continued incurrence of significant research and development and other expenses related to those programs. If the clinical trials for any of the Company’s product candidates fail or produce unsuccessful results and those product candidates do not gain regulatory approval, or if any of the Company’s product candidates, if approved, fails to achieve market acceptance, the Company may never become profitable. Even if the Company achieves profitability in the future, it may not be able to sustain profitability in subsequent periods. The Company intends to cover its future operating expenses through cash and cash equivalents, marketable securities, and through a combination of equity offerings, debt financings, government or other third-party funding, marketing and distribution arrangements and other collaborations, strategic alliances and licensing arrangements. Additional financing may not be available to the Company when needed and, if available, financing may not be obtained on terms favorable to the Company or its stockholders.

While the Company expects its existing cash and cash equivalents and marketable securities will enable it to fund operations and capital expenditure requirements for at least the next twelve months, it may not have sufficient funds to reach commercialization. Failure to obtain adequate financing when needed may require the Company to delay, reduce, limit or terminate some or all of its development programs or future commercialization efforts or grant rights to develop and market product candidates that the Company might otherwise prefer to develop and market itself, which could adversely affect the Company’s ability to operate as a going concern. If the Company raises additional funds from the issuance of equity securities, substantial dilution to existing stockholders may result. If the Company raises additional funds by incurring debt financing, the terms of the debt may involve significant cash payment obligations, as well as covenants and specific financial ratios that may restrict the Company’s ability to operate its business.

Use of Estimates

Risks and Uncertainties

Contingencies

Cash, Cash Equivalents and Marketable Securities

Property and Equipment

Buildings		39 years
Software		3 years
Laboratory equipment		5 years
Furniture & fixtures		5 years
IT equipment		3 years
Leasehold improvements		The lesser of the lease term or the life of the asset

Intangible Assets

Patents

The Company expenses patent costs, including related legal costs, as incurred and records such costs within general and administrative expenses in the consolidated statements of operations.

Impairments

Transactions with Related Parties

Fair Value of Financial Instruments

The three tiers are defined as follows:

•

Level 3— Valuations based on inputs that are unobservable and significant to the overall fair value measurement. The Company’s Level 3 liability includes a warrant derivative liability.

The Company utilizes a third-party pricing service to assist in obtaining fair value pricing for investments. Inputs are documented in accordance with the fair value disclosure hierarchy.

Preclinical and Clinical Trial Accruals

Lease Obligations

Stock Repurchases

Revenue Recognition and Deferred Revenue

The Company records any amounts received prior to satisfying the revenue recognition criteria as deferred revenue in the accompanying consolidated balance sheets.

Research and Development Costs

Stock-Based Compensation

Income Taxes

Comprehensive Loss

Basic and Diluted Net Loss Per Share of Common Stock

Basic and Diluted Net Loss per Share of Common Stock

	As of December 31,
	2016		2015		2014
Outstanding options		6,307,384		8,777,893		5,138,410
Outstanding restricted stock units		814,456		1,129,638		—
Outstanding warrants		17,768,314		17,819,616		1,850,937
Total		24,890,154		27,727,147		6,989,347

Amounts in the table above reflect the common stock equivalents of the noted instruments.

Segment and Geographic Information

	Year Ended December 31,
	2016		2015		2014
United States	$	44	$	191	$	371
Europe		—		21		220
Other non-U.S.		—		24		50
Total	$	44	$	236	$	641

Recent Accounting Pronouncements

Application of New or Revised Accounting Standards – Not Yet Adopted

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Schedule of Estimated Useful Lives of Property and Equipment

Depreciation of property and equipment is calculated using the straight-line method over the estimated useful lives of the assets, as follows:

Buildings		39 years
Software		3 years
Laboratory equipment		5 years
Furniture & fixtures		5 years
IT equipment		3 years
Leasehold improvements		The lesser of the lease term or the life of the asset

Securities Excluded from the Computation of Potentially Dilutive Securities

The following table details those securities that have been excluded from the computation of potentially dilutive securities:

	As of December 31,
	2016		2015		2014
Outstanding options		6,307,384		8,777,893		5,138,410
Outstanding restricted stock units		814,456		1,129,638		—
Outstanding warrants		17,768,314		17,819,616		1,850,937
Total		24,890,154		27,727,147		6,989,347

Amounts in the table above reflect the common stock equivalents of the noted instruments.

Schedule of Revenue from Different Geographic Regions

Information about the Company’s revenue from the different geographic regions for the years ended December 31, 2016, 2015 and 2014 is as follows (in thousands):

	Year Ended December 31,
	2016		2015		2014
United States	$	44	$	191	$	371
Europe		—		21		220
Other non-U.S.		—		24		50
Total	$	44	$	236	$	641

Financial Statement Details (Tables)

12 Months Ended

Dec. 31, 2016

Financial Statement Details [Abstract]

Prepaid Expenses and Other Current Assets

As of December 31, 2016 and 2015, prepaid expenses and other current assets were made up of (in thousands):

	As of December 31,
	2016		2015
Interest receivable - marketable securities	$	1,484	$	911
Prepaid services		1,191		631
Prepaid insurance		531		466
Equipment deposits		482		—
Prepaid license fees		462		101
Prepaid rent		360		—
Prepaid legal fees		350		350
Tax refund receivable		95		646
Other		180		—
	$	5,135	$	3,105

Property, Plant and Equipment, Net

As of December 31, 2016 and 2015, property, plant and equipment was made up of (in thousands):

	As of December 31,
	2016			2015
Construction in progress	$	6,939		$	5,136
Equipment		5,458			241
Building under build-to-suit lease		4,348			—
Leasehold improvements		2,367			182
Software		769			6
Furniture & fixtures		203			125
		20,084			5,690
Accumulated depreciation		(1,178	)		(167	)
	$	18,906		$	5,523

Intangible Assets, Net

As of December 31, 2016 and 2015, intangible assets were made up of (in thousands):

	As of December 31,
	2016			2015
Technology license	$	9,042		$	8,636
Less accumulated amortization		(3,956	)		(1,344	)
	$	5,086		$	7,292

Future Estimated Amortization Expense

Future estimated amortization expense related to the Company’s technology license for the next five years and thereafter is as follows (in thousands):

Years ending December 31:
2017	$	2,260
2018		2,260
2019		566
2020		—
2021		—
Thereafter		—
	$	5,086

Other Assets

As of December 31, 2016 and 2015, other assets were made up of (in thousands):

	As of December 31,
	2016		2015
Equipment not placed in service	$	362	$	624
Restricted cash		179		—
Security deposit		137		344
Software license and implementation costs		110		391
	$	788	$	1,359

Accrued Expenses

As of December 31, 2016 and 2015, accrued expenses were made up of (in thousands):

	As of December 31,
	2016		2015
Accrued bonus	$	1,732	$	1,359
Accrued construction costs		1,243		132
Accrued professional and service fees		1,008		367
Accrued compensation		898		348
Accrued preclinical and clinical trial costs		662		—
Accrued software license fees		121		—
Accrued franchise and property taxes		62		225
Other		138		144
	$	5,864	$	2,575

Other Current Liabilities

As of December 31, 2016 and 2015, other current liabilities were made up of (in thousands):

	As of December 31,
	2016		2015
Build-to-suit lease liability - current portion	$	281	$	131
Financing obligation - current portion		253		—
Deferred rent - current portion		197		5
Other		160		—
	$	891	$	136

Investment Income, Net

	Year Ended December 31,
	2016			2015			2014
Interest income	$	5,168		$	312		$	20
Investment amortization accretion expense, net		(2,182	)		(38	)		—
Dividend income		—			213			—
Net realized gains on investments		111			2,501			—
	$	3,097		$	2,988		$	20

Cash Equivalents and Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2016

Cash Equivalents And Marketable Securities [Abstract]

Schedule of Cash Equivalents and Marketable Securities Available-for-Sale

At December 31, 2016 and 2015, the Company’s cash equivalents and marketable securities are detailed below (in thousands). There were no investments at December 31, 2014.

	December 31, 2016
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Current:
Government sponsored securities	$	22,252	$	21	$	(1	)	$	22,272
Corporate debt securities		165,605		40		(76	)		165,569
Foreign government bonds		5,004		—		(2	)		5,002
Subtotal current		192,861		61		(79	)		192,843
Noncurrent:
Government sponsored securities		17,018		2		(38	)		16,982
Corporate debt securities		69,414		71		(290	)		69,195
Foreign government bonds		1,405		—		(11	)		1,394
Subtotal noncurrent		87,837		73		(339	)		87,571
Total	$	280,698	$	134	$	(418	)	$	280,414

	December 31, 2015
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Current:
Commercial paper	$	29,899	$	13	$	—		$	29,912
Corporate debt securities		99,600		2		(109	)		99,493
Foreign government bonds		6,951		—		(7	)		6,944
Subtotal current		136,450		15		(116	)		136,349
Noncurrent:
Corporate debt securities		51,215		1		(85	)		51,131
Foreign government bonds		4,011		—		(7	)		4,004
Subtotal noncurrent		55,226		1		(92	)		55,135
Total	$	191,676	$	16	$	(208	)	$	191,484

Available-for-Sale Investments in Unrealized Loss Position

Available-for-sale investments that had been in an unrealized loss position for less than 12 months and for more than 12 months at December 31, 2016 and 2015 are as follows (in thousands):

	December 31, 2016
	Less than 12 months					More than 12 months
	Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses
Government sponsored securities	$	17,204	$	(39	)	$	—	$	—
Corporate debt securities		150,320		(366	)		—		—
Foreign government bonds		6,396		(13	)		—		—
Total	$	173,920	$	(418	)	$	—	$	—

	December 31, 2015
	Less than 12 months					More than 12 months
	Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses
Corporate debt securities	$	141,320	$	(194	)	$	—	$	—
Foreign government bonds		10,947		(14	)		—		—
Total	$	152,267	$	(208	)	$	—	$	—

Schedule of Realized Gains and Losses on Sales or Maturities of Available-for-Sale Securities

The Company recorded realized gains and losses on sales or maturities of available-for-sale securities as follows (in thousands):

	Gross Realized Gains		Gross Realized Losses			Net Realized Gains
2016	$	190	$	(79	)	$	111
2015		2,501		—			2,501
2014		—		—			—

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis

Financial assets and liabilities measured at fair value on a recurring basis are summarized below at December 31, 2016 and 2015 (in thousands):

	December 31, 2016
	Total		Level 1		Level 2		Level 3
Assets:
Current:
Cash and cash equivalents*	$	2,005	$	—	$	2,005	$	—
Government sponsored securities		22,272		—		22,272		—
Corporate debt securities		163,564		—		163,564		—
Foreign government bonds		5,002		—		5,002		—
Noncurrent:
Government sponsored securities		16,982		—		16,982		—
Corporate debt securities		69,195		—		69,195		—
Foreign government bonds		1,394		—		1,394		—
Total assets measured at fair value	$	280,414	$	—	$	280,414	$	—

*This amount excludes $6.1 million in depository institutions that are classified as Level 1 assets.

	December 31, 2015
	Total		Level 1		Level 2		Level 3
Assets:
Current:
Cash and cash equivalents*	$	18,039	$	—	$	18,039	$	—
Commercial paper		24,917		—		24,917		—
Corporate debt securities		86,450		—		86,450		—
Foreign government bonds		6,943		—		6,943		—
Noncurrent:
Corporate debt securities		51,131		—		51,131		—
Foreign government bonds		4,004		—		4,004		—
Total assets measured at fair value	$	191,484	$	—	$	191,484	$	—

*This amount excludes $157.9 million in depository institutions that are classified as Level 1 assets.

Schedule of Financial Instrument Using Significant Unobservable Inputs (Level 3) Measured at Fair Value

Activity for the financial instrument using significant unobservable inputs (Level 3) measured at fair value is presented in the table below (in thousands):

	Warrant Derivative Liability
Balance December 31, 2013	$	19
Adjustment to estimated fair value		158
Balance at December 31, 2014		177
Adjustment to estimated fair value		1,366
Warrant exercised		(1,543	)
Balance at December 31, 2015	$	—

Commitment and Contingencies (Tables)

12 Months Ended

Dec. 31, 2016

Commitments And Contingencies Disclosure [Abstract]

Summary of Future Minimum Lease Payments

The following table summarizes our future minimum lease payments at December 31, 2016 (in thousands). Common area maintenance costs and taxes are not included in these payments.

Years ending December 31:
2017	$	4,076
2018		4,094
2019		4,108
2020		4,056
2021		3,435
Thereafter		5,594
Total minimum lease payments	$	25,363

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2016

Equity [Abstract]

Summary of Common Stock Repurchases

A summary of common stock repurchases for the year ended December 31, 2016 is as follows:

	Total number of shares purchased		Average price paid per share		Total number of shares purchased as part of publicly announced plans or programs		Maximum approximate dollar value of shares that may yet be purchased under the plans or programs
February		300,000	$	8.50		300,000	$47.5 million
May		346,200	$	6.77		646,200	$45.1 million
June		582,400	$	7.56		1,228,600	$40.7 million
August		335,440	$	7.01		1,564,040	$38.4 million
September		30,000	$	7.40		1,594,040	$38.1 million
November		439,618	$	7.14		2,033,658	$35.0 million
December		124,286	$	6.45		2,157,944	$34.2 million
Total		2,157,944	$	7.33

Summary Of Changes In Securities

The following summarizes changes in securities in conjunction with the 2014 Securities Purchase Agreement:

	Class A common stock		Class B common stock		Series C preferred stock		Warrants to purchase Class A common stock			Options to purchase Class A common stock
Share Balance in April 2014 prior to 2014 Securities Purchase Agreement		1,158,394		1,763,609		—		763,841			3,056,702
Exchange of Founder Warrant (Note 6)		—		—		—		(156,109	)		740,600
Conversion of 2013 Promissory Note (Note 13)		—		—		771,458		192,865			—
Conversion of 2009 Convertible Notes (Note 13)		985,229		—		—		—			—
Exchange the CA Warrant and the PA Warrant associated with 2009 Convertible notes (Note 13)		3,052,608		—		—		—			—
Exchange of Other Creditor debt (Note 13)		345,228		—		—		—			—
Exchange of Side Agreement Notes (Note 13)		192,341		—		—		—			—
Sale of Units in 2014 Securities Purchase Agreement (see above)		—		—		4,983,526		1,245,881			—
Cash commission to placement agent paid in Class A common stock (Note 13)		34,715		—		—		—			—
Exchange of placement agent warrant for stock (see above)		—		763,151		—		(193,413	)		—
Issuance of placement agent warrant associated with 2014 Securities Purchase Agreement (see below)		—		—		—		199,341			—
Share balance after closing of 2014 Securities Purchase Agreement		5,768,515		2,526,760		5,754,984		2,052,406			3,797,302

Summary Of Common Stock Reserved For Issuance

The following table summarizes the common shares reserved for issuance on exercise or vesting of various awards at December 31, 2016:

Issued and outstanding stock options			6,307,384
Issued and outstanding restricted stock units			814,456
Outstanding financing warrants			179,064
Outstanding officer warrants			17,589,250
Total shares reserved for future issuance			24,890,154

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Stock Based Compensation Expenses Included on Operations Statement

The following table presents all stock-based compensation as included on the Company’s consolidated statements of operations (in thousands):

	For the Year Ended December 31,
	2016		2015		2014
Stock-based compensation expense:
Warrants for common stock to an officer	$	50,502	$	141,901	$	—
Warrants for common stock to an officer and a director related to Inex Bio, Inc. acquisition		—		22,747		—
Employee stock options		14,720		25,498		485
Non-employee stock options		—		3,300		76
Employee restricted stock units		8,166		17,505		228
Non-employee restricted stock units		464		270		—
	$	73,852	$	211,221	$	789
Stock-based compensation expense in operating expenses:
Research and development	$	852	$	1,221	$	222
Selling, general and administrative		73,000		210,000		567
	$	73,852	$	211,221	$	789

Summarizes Stock Option Activity Under Equity Intensive Plan

The following table summarizes stock option activity under all equity incentive plans for the years ended December 31, 2016, 2015 and 2014:

	Number of Shares			Weighted- Average Exercise Price		Aggregate Intrinsic Value (in 000)		Weighted- Average Remaining Contractual Life (in years)
Outstanding at December 31, 2013		1,727		$	0.41	$	—		1.3
Options granted		5,971,087		$	0.77
Options exercised		(833,173	)	$	0.22
Options forfeited/canceled		(1,231	)	$	0.41
Outstanding at December 31, 2014		5,138,410		$	0.85	$	5,298		9.7
Options granted		5,713,899		$	7.92
Options exercised		(1,127,105	)	$	0.86
Options forfeited/canceled		(947,311	)	$	1.87
Outstanding at December 31, 2015		8,777,893		$	5.36	$	116,273		7.2
Options exercised		(2,398,882	)	$	0.76
Options forfeited/canceled		(71,627	)	$	2.00
Outstanding at December 31, 2016		6,307,384		$	7.14	$	19,100		6.4
Vested and Exercisable at December 31, 2016		5,210,756		$	8.18	$	15,227		7.3

Summary of Options Outstanding and Vested

The following table provides a summary of options outstanding and vested as of December 31, 2016:

Exercise Prices	Number Outstanding		Weighted- Average Life (in years)		Number Exercisable		Weighted- Average Life (in years)
$0.22		134,807		7.2		134,807		7.2
$0.42		589,660		7.9		589,660		7.9
$1.76		999,682		8.0		999,682		8.0
$2.00		1,276,285		8.1		1,221,126		8.1
$2.20		1,851,500		2.2		810,031		2.2
$25.00		1,455,450		8.6		1,455,450		8.6
		6,307,384		6.4		5,210,756		7.3

Weighted Average of Fair Value of Options Under Black-Scholes Option-Pricing Model

	Years Ended December 31,
	2015				2014
	Employee Grants		Non-Employee Grants		Employee Grants		Non-Employee Grants
Expected term (years)	4.0 - 5.5		8.4 - 9.9		5.0 - 5.6		9.3 - 9.9
Risk-free interest rate	1.5% - 1.8%		0% - 2.4%		1.6% - 1.9%			2.20%
Expected volatility		80%		80%	81% - 91%			81%
Dividend yield		0%		0%		0%		0%
Weighted-average measurement date fair value	$	12.08	$	15.25	$	0.53	$	0.18

Restricted Stock Units (RSUs) Activity

The following table summarizes the restricted stock units (RSUs) activity under the 2015 Plan:

	Number of Restricted Stock Units Outstanding			Weighted-Average Grant Date Fair Value
Unvested balance at December 31, 2014		—		$	—
Granted		1,614,788		$	21.86
Vested		(485,150	)	$	25.00
Unvested balance at December 31, 2015		1,129,638		$	20.51
Granted		407,800		$	7.76
Vested		(537,982	)	$	23.75
Forfeited/canceled		(185,000	)	$	11.75
Unvested balance at December 31, 2016		814,456		$	13.98

Summary of Warrant Activity

The following table summarizes the Company’s warrant activity:

Outstanding at December 31, 2014	1,850,937
Warrants granted	20,791,842
Warrants exercised	(4,677,101	)
Warrants forfeited	(146,062	)
Outstanding at December 31, 2015	17,819,616
Warrants exercised	(51,302	)
Outstanding at December 31, 2016	17,768,314
Vested and exercisable at December 31, 2016	12,769,264

2015 Equity Incentive Plan

Reserved Authorized Shares Of Common Stock For Future Grants Of Equity Awards

At December 31, 2016, the Company has reserved authorized shares of common stock for future grants of equity awards as follows:

Shares approved for 2015 Equity Incentive Plan	3,500,000
Shares remaining from 2014 Equity Incentive Plan	749,857
Total shares authorized under the 2015 Plan	4,249,857
Grants	(3,070,238	)
Forfeitures added back to available pool	947,063
Shares reserved for future grants as of December 31, 2015	2,126,682
Grants	(407,800	)
Add backs approved under the Plan:
Forfeitures	185,000
Net share settlement	225,754
Shares repurchased	615,392
Shares reserved for future grants as of December 31, 2016	2,745,028

- Definition

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.

+ References + Details

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Summary of Loss Before Taxes

The amount of loss before taxes is (in thousands):

	Year Ended December 31,
	2016			2015			2014
U.S. loss before taxes	$	(118,743	)	$	(235,750	)	$	(6,184	)
Foreign loss before taxes		(2,638	)		(1,427	)		—
Loss before income taxes	$	(121,381	)	$	(237,177	)	$	(6,184	)

Summary of Income Tax (Benefit) Expense

Income tax (benefit) expense for the years ended December 31, 2016, 2015 and 2014 consists of the following (in thousands):

	Year Ended December 31,
	2016			2015			2014
Current:
Federal	$	—		$	—		$	—
State		3			1			1
Foreign		—			—			—
Total Current		3			1			1
Deferred:
Federal		—			—			—
State		—			—			—
Foreign		(575	)		(302	)		—
Total Deferred		(575	)		(302	)		—
Income tax (benefit) expense	$	(572	)	$	(301	)	$	1

Components of Net Deferred Tax Assets and Liabilities

The components that comprise the Company’s net deferred tax assets at December 31, 2016 and 2015 consist of the following (in thousands):

	Year Ended December 31,
	2016			2015
Deferred tax assets:
Stock compensation	$	87,239		$	67,559
Net operating loss carryforwards		37,507			—
Leases and other accrued liabilities		2,096			389
Accrued compensation		808			572
Depreciation and amortization		—			624
Total deferred tax assets		127,650			69,144
Deferred tax liabilities:
Foreign intangibles		(996	)		(1,165	)
Depreciation and amortization		(309	)		—
Total deferred tax liabilities		(1,305	)		(1,165	)
Net deferred tax assets		126,345			67,979
Valuation allowance		(127,341	)		(69,144	)
Net deferred tax liability	$	(996	)	$	(1,165	)

Reconciliation of Federal Statutory Income Tax Rate

A reconciliation of the federal statutory income tax rate to the Company’s effective income tax rate is as follows:

	Year Ended December 31,
	2016				2015				2014
Tax computed at federal statutory rate		34.0		%		34.0		%		34.0		%
Section 382/383 NOL		8.6				(3.5	)			(40.0	)
State income taxes, net of federal tax benefit		3.6				2.6				4.8
Tax rate adjustment		1.5				—				0.5
Research and development credits		1.3				0.1				0.7
Stock-based compensation		(0.3	)			(0.4	)			(1.1	)
Other		(0.5	)			(3.8	)			(7.3	)
Valuation Allowance		(47.7	)			(28.9	)			8.4
Effective income tax rate		0.5		%		0.1		%		—		%

Summarizes of Changes in Unrecognized Tax Benefits

The following table summarizes the changes to the amount of unrecognized tax benefits (in thousands):

Unrecognized tax benefits at December 31, 2014	$	—
Increase for prior year tax positions		120
Increase for current year tax positions		1,083
Unrecognized tax benefits at December 31, 2015		1,203
Decrease for prior year tax positions		(1,203	)
Increase for prior year tax positions		2,578
Increase for current year tax positions		2,056
Unrecognized tax benefits at December 31, 2016	$	4,634

Investment In Inex Bio, Inc (Tables)

12 Months Ended

Dec. 31, 2016

Summary of Purchase Price Paid to Inex Bio

The following summarizes the net consideration paid to Holdings (in thousands):

Consideration	Total
Cash	$	6,518
Fair value of warrants		22,747
Less cash paid to acquire shares in Inex Bio		(1,100	)
Net consideration	$	28,165

Summary of Assets and Liabilities Assumed

The following table summarizes the assets acquired and liabilities assumed (in thousands):

Cash	$	763
Intangible assets—reacquired rights of Company technology		8,636
Other assets		42
Investment in Inex Bio		(221	)
Deferred tax liability		(1,467	)
Accounts payable		(1	)
Total assets acquired and liabilities assumed	$	7,752

Inex Bio Inc

Summary of Purchase Price Paid to Inex Bio

The purchase price paid to acquire Inex Bio from the other owners is as follows (in thousands):

Consideration	Total
Cash paid by InexBio Holdings, LLC	$	1,100
Cash paid by Company		1,482
Fair value of warrants		5,170
Aggregate purchase price	$	7,752

Summarized Quarterly Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Table Text Block Supplement [Abstract]

Summary of Quarterly Data (Unaudited)

The table below presents unaudited quarterly data for fiscal 2016 and 2015 (in thousands, except for share and per share amounts):

	1st Quarter			2nd Quarter			3rd Quarter			4th Quarter
2016
Revenue	$	6		$	12		$	12		$	14
Operating expenses		31,622			34,977			32,787			25,157
Operating loss		(31,616	)		(34,965	)		(32,775	)		(25,143	)
Net loss		(30,677	)		(33,997	)		(31,897	)		(24,238	)
Net loss per share - basic and diluted	$	(0.38	)	$	(0.41	)	$	(0.39	)	$	(0.29	)
Shares used in calculating net loss per share - basic and diluted		81,574,709			81,959,248			82,154,219			82,235,571

	1st Quarter			2nd Quarter			3rd Quarter			4th Quarter
2015
Revenue	$	120		$	91		$	10		$	15
Operating expenses		32,221			130,486			46,467			29,938
Operating loss		(32,101	)		(130,395	)		(46,457	)		(29,923	)
Net loss		(32,849	)		(130,893	)		(46,312	)		(26,822	)
Net loss per share - basic and diluted	$	(0.54	)	$	(1.99	)	$	(0.60	)	$	(0.33	)
Shares used in calculating net loss per share - basic and diluted		61,137,625			65,789,041			77,837,586			81,247,430

Description of Business and Basis of Presentation - Additional Information (Detail) $ / shares in Units, $ in Thousands		1 Months Ended	12 Months Ended
	Jul. 10, 2015	Jul. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Jan. 01, 2016 USD ($)
Description Of Business And Basis Of Presentation [Line Items]
Forward stock split of its outstanding common stock	1.8515
Proceeds from sale of common stock		$ 221,500
Underwriting discounts, commissions and offering expenses		$ 16,800
Accumulated deficit			$ (387,063)	$ (250,376)		$ 31,000
Net cash used in operating activities			$ (38,593)	$ (25,305)	$ (5,418)
Common Stock
Description Of Business And Basis Of Presentation [Line Items]
Forward stock split of its outstanding common stock	1.8515
Common stock sold \| shares					0
Initial Public Offering
Description Of Business And Basis Of Presentation [Line Items]
Common stock price per share \| $ / shares		$ 25
Proceeds from sale of common stock		$ 221,500
Underwriting discounts, commissions and offering expenses		$ 16,800
Initial Public Offering \| Common Stock
Description Of Business And Basis Of Presentation [Line Items]
Common stock sold \| shares		9,531,200		9,531,200
Series B Preferred Stock
Description Of Business And Basis Of Presentation [Line Items]
Common stock, conversion basis			In March 2014, the Company entered into a definitive merger and share exchange agreement pursuant to which the Company redomesticated from the State of Illinois to the State of Delaware and the Illinois Company ceased to exist (the Redomestication). In connection with the Redomestication, the holders of Class A and Class B common stock received one share of Class A and Class B common stock of the Delaware Company, respectively, in exchange for fifteen shares of the Illinois Company. The holders of Series B preferred stock received one share of Series B preferred stock of the Delaware Company in exchange for one share of the Illinois Company. The holders of any options, warrants or other securities are subject to adjustment based on the ratio of 1 for 15. All share numbers and per share prices in the accompanying consolidated financial statements have been adjusted to reflect the 1 for 15 exchange.
Forward stock split of its outstanding common stock			0.067

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Nov. 30, 2015
Accounting Policies [Line Items]
Cash and cash equivalents original maturities	3 months
Maximum original maturity period of short-term marketable securities	12 months
Minimum original maturity period of long-term marketable securities	12 months
Other than temporary impairments for marketable securities	$ 0	$ 0
Marketable securities, investments			$ 0
Estimated useful lives of intangible assets	4 years
Impairment losses of long-lived assets	$ 0	0	$ 0
Fair value inputs, transfers into or out of Level 1, 2 or 3 categories	0	0
Total amount authorized for repurchase				$ 50,000,000
Accrued interest or penalties associated with uncertain tax positions	$ 0	$ 0
Minimum
Accounting Policies [Line Items]
Marketable securities original maturities	3 months
Minimum \| California
Accounting Policies [Line Items]
Tax year open for examination	2012
Minimum \| Federal
Accounting Policies [Line Items]
Tax year open for examination	2013
Maximum \| California
Accounting Policies [Line Items]
Tax year open for examination	2016
Maximum \| Federal
Accounting Policies [Line Items]
Tax year open for examination	2016

Summary of Significant Accounting Policies - Schedule of Estimated Useful Lives of Property and Equipment (Detail)	12 Months Ended
	Dec. 31, 2016
Buildings
Property Plant And Equipment [Line Items]
Property and equipment estimated useful lives	39 years
Software
Property Plant And Equipment [Line Items]
Property and equipment estimated useful lives	3 years
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment estimated useful lives	5 years
Furniture And Fixtures
Property Plant And Equipment [Line Items]
Property and equipment estimated useful lives	5 years
IT Equipment
Property Plant And Equipment [Line Items]
Property and equipment estimated useful lives	3 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment estimated useful lives, term	The lesser of the lease term or the life of the asset

Summary of Significant Accounting Policies - Securities Excluded from the Computation of Potentially Dilutive Securities (Detail) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	24,890,154	27,727,147	6,989,347
Employee Stock Option
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	6,307,384	8,777,893	5,138,410
Outstanding Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	814,456	1,129,638	0
Outstanding Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	17,768,314	17,819,616	1,850,937

Summary of Significant Accounting Policies - Schedule of Revenue from Different Geographic Regions (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenue	$ 14	$ 12	$ 12	$ 6	$ 15	$ 10	$ 91	$ 120	$ 44	$ 236	$ 641
United States
Segment Reporting Information [Line Items]
Revenue									44	191	371
Europe
Segment Reporting Information [Line Items]
Revenue									0	21	220
Other non-U.S.
Segment Reporting Information [Line Items]
Revenue									$ 0	$ 24	$ 50

Financial Statement Details - Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financial Statement Details [Abstract]
Interest receivable - marketable securities	$ 1,484	$ 911
Prepaid services	1,191	631
Prepaid insurance	531	466
Equipment deposits	482	0
Prepaid license fees	462	101
Prepaid rent	360	0
Prepaid legal fees	350	350
Tax refund receivable	95	646
Other	180	0
Total prepaid expenses and other current assets	$ 5,135	$ 3,105

Financial Statement Details - Property, plant and equipment, net (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 20,084	$ 5,690
Accumulated depreciation	(1,178)	(167)
Property, plant and equipment, net	18,906	5,523
Construction in Progress
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	6,939	5,136
Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	5,458	241
Building Under Build-to-Suit Lease
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	4,348	0
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	2,367	182
Software
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	769	6
Furniture And Fixtures
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 203	$ 125

Financial Statement Details - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financial Statement Details [Line Items]
Depreciation expense related to property, plant and equipment	$ 1,000,000	$ 100,000	$ 36,000
Property, plant and equipment, gross	20,084,000	5,690,000
Amortization expense	2,600,000	1,300,000	0
Impairment losses on recognized investments	$ 0	0	$ 0
Technology License
Financial Statement Details [Line Items]
Remaining amortization period	2 years 3 months
El Segundo California
Financial Statement Details [Line Items]
Non cash build to suit lease asset	$ 5,100,000
Building Under Build-to-Suit Lease
Financial Statement Details [Line Items]
Property, plant and equipment, gross	4,348,000	$ 0
Building Under Build-to-Suit Lease \| Culver City California
Financial Statement Details [Line Items]
Property, plant and equipment, gross	$ 4,300,000

Financial Statement Details - Intangible Assets, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Finite Lived Intangible Assets [Line Items]
Intangible assets, net	$ 5,086	$ 7,292
Technology License
Finite Lived Intangible Assets [Line Items]
Total intangible assets	9,042	8,636
Less accumulated amortization	(3,956)	(1,344)
Intangible assets, net	$ 5,086	$ 7,292

Financial Statement Details - Future Estimated Amortization Expense (Detail) - Technology License $ in Thousands	Dec. 31, 2016 USD ($)
Finite Lived Intangible Assets [Line Items]
2017	$ 2,260
2018	2,260
2019	566
2020	0
2021	0
Thereafter	0
Intangible assets, net	$ 5,086

Financial Statement Details - Other Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financial Statement Details [Abstract]
Equipment not placed in service	$ 362	$ 624
Restricted cash	179	0
Security deposit	137	344
Software license and implementation costs	110	391
Other Assets Noncurrent	$ 788	$ 1,359

Financial Statement Details - Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financial Statement Details [Abstract]
Accrued bonus	$ 1,732	$ 1,359
Accrued construction costs	1,243	132
Accrued professional and service fees	1,008	367
Accrued compensation	898	348
Accrued preclinical and clinical trial costs	662	0
Accrued software license fees	121	0
Accrued franchise and property taxes	62	225
Other	138	144
Accrued Liabilities Current	$ 5,864	$ 2,575

Financial Statement Details - Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financial Statement Details [Abstract]
Build-to-suit lease liability - current portion	$ 281	$ 131
Financing obligation - current portion	253	0
Deferred rent - current portion	197	5
Other	160	0
Other current liabilities	$ 891	$ 136

Financial Statement Details - Investment Income, Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financial Statement Details [Abstract]
Interest income	$ 5,168	$ 312	$ 20
Investment amortization accretion expense, net	(2,182)	(38)	0
Dividend income	0	213	0
Net realized gains on investments	111	2,501	0
Investment income, net	$ 3,097	$ 2,988	$ 20

Cash Equivalents and Marketable Securities - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016 USD ($) Security	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities maturity period	4 years 8 months 12 days
Investments in securities	$ 280,414,000	$ 191,484,000	$ 0
Maximum
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, period of unrealized loss positions	12 months	12 months
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Cash equivalent portions included in current fair values		$ 5,000,000
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Cash equivalent portions included in current fair values	$ 2,000,000	$ 13,000,000
Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Number of available-for-sale securities in unrealized loss positions \| Security	80

Cash Equivalents and Marketable Securities - Schedule of Cash Equivalents and Marketable Securities Available-for-Sale (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 280,698,000	$ 191,676,000
Unrealized Gains	134,000	16,000
Unrealized Losses	(418,000)	(208,000)
Fair Value	280,414,000	191,484,000	$ 0
Current Assets
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	192,861,000	136,450,000
Unrealized Gains	61,000	15,000
Unrealized Losses	(79,000)	(116,000)
Fair Value	192,843,000	136,349,000
Current Assets \| Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		29,899,000
Unrealized Gains		13,000
Unrealized Losses		0
Fair Value		29,912,000
Current Assets \| Government Sponsored Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	22,252,000
Unrealized Gains	21,000
Unrealized Losses	(1,000)
Fair Value	22,272,000
Current Assets \| Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	165,605,000	99,600,000
Unrealized Gains	40,000	2,000
Unrealized Losses	(76,000)	(109,000)
Fair Value	165,569,000	99,493,000
Current Assets \| Foreign Government Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	5,004,000	6,951,000
Unrealized Gains	0	0
Unrealized Losses	(2,000)	(7,000)
Fair Value	5,002,000	6,944,000
Noncurrent Assets
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	87,837,000	55,226,000
Unrealized Gains	73,000	1,000
Unrealized Losses	(339,000)	(92,000)
Fair Value	87,571,000	55,135,000
Noncurrent Assets \| Government Sponsored Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	17,018,000
Unrealized Gains	2,000
Unrealized Losses	(38,000)
Fair Value	16,982,000
Noncurrent Assets \| Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	69,414,000	51,215,000
Unrealized Gains	71,000	1,000
Unrealized Losses	(290,000)	(85,000)
Fair Value	69,195,000	51,131,000
Noncurrent Assets \| Foreign Government Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	1,405,000	4,011,000
Unrealized Gains	0	0
Unrealized Losses	(11,000)	(7,000)
Fair Value	$ 1,394,000	$ 4,004,000

Cash Equivalents and Marketable Securities - Available-for-Sale Investments in Unrealized Loss Position (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	$ 173,920	$ 152,267
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	(418)	(208)
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	0	0
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	0	0
Government Sponsored Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	17,204
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	(39)
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	0
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	0
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	150,320	141,320
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	(366)	(194)
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	0	0
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	0	0
Foreign Government Bonds
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	6,396	10,947
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	(13)	(14)
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	0	0
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	$ 0	$ 0

Cash Equivalents and Marketable Securities -Schedule of Realized Gains and Losses on Sales or Maturities of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Equivalents And Marketable Securities [Abstract]
Available-for-sale Securities, Gross Realized Gains	$ 190	$ 2,501	$ 0
Available-for-sale Securities, Gross Realized Losses	(79)	0	0
Available-for-sale Securities, Net Realized Gains	$ 111	$ 2,501	$ 0

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash in depository institutions	$ 6.1	$ 157.9

Fair Value Measurements - Schedule of Financial Instrument Using Significant Unobservable Inputs (Level 3) Measured at Fair Value (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Derivative Liabilities, Beginning Balance	$ 0	$ 177	$ 19
Change in value of warrant liability	$ 0	1,366	158
Warrant exercised		(1,543)
Derivative Liabilities, Ending Balance		$ 0	$ 177

Collaboration and License Agreements - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended								12 Months Ended
	Mar. 31, 2014	Feb. 28, 2010	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2009	Dec. 31, 2003	Jun. 30, 2013
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue			$ 14,000	$ 12,000	$ 12,000	$ 6,000	$ 15,000	$ 10,000	$ 91,000	$ 120,000	$ 44,000	$ 236,000	$ 641,000
Intrexon Corporation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement term (years)		17 years
Agreement one time fee		$ 400,000
Milestone payment amount											0	0	0
Revenue											20,000	20,000	20,000
Intrexon Corporation \| First IND Filing
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment amount		100,000
Intrexon Corporation \| First Phase II Clinical Trial
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment amount		100,000
Intrexon Corporation \| First Phase III Clinical Trial
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment amount		400,000
Intrexon Corporation \| Commercial Sale Related to Licensed Products
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment amount		$ 500,000
Fox Chase Cancer Center License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalty expense earned or paid											0	100,000	200,000
Rush University Medical Center License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalty expense earned or paid											25,000	25,000	$ 100,000
Period of license agreement													12 years
Minimum annual royalty payment													$ 25,000
Payments in license agreement													2,500,000
Milestone payments											0	0	$ 0
Founder License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Proceeds from issuance of common stock gross of issuance costs	$ 3,000,000
Exchange of warrants for options, Exercise term																10 years
Exchange of warrants for options, Exercisable														37,030
Warrants tendered in exchange for stock options	156,109
Stock option granted in exchange for warrants	740,600
Percentage of equity owned by partners	7.00%
Royalty expense earned or paid											$ 0
GSH-BSD
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement termination notice period											60 days
Payments for initial license fees												1,100,000
2013 Securities Purchase Agreement \| Founder License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Consideration for the sale of the licensed patents															$ 100,000
Minimum financing amount required to issue more stock														$ 1,000,000
Ownership interest of the total outstanding common shares											7.00%
Common Class A
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock, Shares													30,809,800
Exchanged warrants, in share			123,433								123,433
Stock price of warrants																	$ 2.44
Common Class A \| Private Placement Two
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock, Shares													26,252,262
Proceeds from issuance of common stock gross of issuance costs													$ 49,500,000
Minimum \| Rush University Medical Center License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Minimum sales milestone of license for first year													$ 300,000
Sorrento
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment received from collaboration agreement											$ 0	0
Sorrento \| Common Class A \| Private Placement One
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock, Shares													4,557,537
Proceeds from issuance of common stock gross of issuance costs													$ 8,000,000
Sorrento \| Common Class A \| Private Placement Two
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock, Shares													1,060,789
Proceeds from issuance of common stock gross of issuance costs													$ 2,000,000
Sorrento \| Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Reimbursements for Research and development Projects											$ 2,000,000	$ 2,000,000

Commitment and Contingencies - Additional Information (Detail)		1 Months Ended				12 Months Ended
	Sep. 01, 2017 USD ($)	Jun. 30, 2016 USD ($) ft² $ / ft²	Mar. 31, 2016 ft²	Jul. 31, 2015 USD ($) ft²	Jun. 30, 2015 USD ($) ft²	Dec. 31, 2016 USD ($) ft²	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2016 ft²	Nov. 30, 2015 ft²
Commitments And Contingencies [Line Items]
Liability accrued						$ 0
Accumulated depreciation on building						1,178,000	$ 167,000
Rent expense						$ 2,700,000	1,500,000	$ 200,000
Woburn, Massachusetts
Commitments And Contingencies [Line Items]
Number of square foot of facility leased \| ft²		8,153	7,893
Period of agreement						In June 2016, the lease was amended to add 260 square feet, for a total of 8,153 square feet. The base rent, including the amendment, is $19,000 per month with a $1 per square foot annual increase on each anniversary date.
Term of lease arrangement			48 months
Lease commencement date			Apr. 29, 2016
Addition to number of square foot of facility leased \| ft²		260
Base rent - yearly		$ 19,000
Annual increase of base rent \| $ / ft²		1
Commitment; San Diego
Commitments And Contingencies [Line Items]
Number of square foot of facility leased \| ft²					44,681
Base rent - monthly					$ 200,000
Percentage of annual increase of base rent					3.00%
Base lease term					7 years
Sub Lease Agreements
Commitments And Contingencies [Line Items]
Base lease term				1 year
Rent expense				$ 0
Sublease inception date				Aug. 01, 2015
Cardiff-by-the-Sea, California
Commitments And Contingencies [Line Items]
Number of square foot of facility leased \| ft²						2,550
Base rent - monthly						$ 12,800
Lease agreement extended lease period						Aug. 31, 2018
Cardiff-by-the-Sea, California \| Scenario Forecast [Member]
Commitments And Contingencies [Line Items]
Base rent - monthly	$ 13,200
El Segundo California
Commitments And Contingencies [Line Items]
Non cash build to suit lease asset						$ 5,100,000
Cary, North Carolina
Commitments And Contingencies [Line Items]
Number of square foot of facility leased \| ft²				3,067
Period of agreement						The term of the lease is 26 months commencing on July 1, 2015. The base rent is $6,000 per month with 3% annual increases on each anniversary date.
Base rent - monthly				$ 6,000
Percentage of annual increase of base rent				3.00%
Term of lease arrangement				26 months
Lease commencement date				Jul. 01, 2015
Doug St, LLC
Commitments And Contingencies [Line Items]
Period of agreement						The lease runs from July 2016 through July 2023. The Company has the option to extend the lease for an additional three year term through July 2026. The monthly rent is $0.1 million with annual increases of 3% beginning in July 2017.
Optional extended lease term						3 years
Base rent - monthly						$ 100,000
Percentage of annual increase of base rent						3.00%
Annual percentage increases to base rent commencement date						Jul. 31, 2017
Costs incurred						$ 1,800,000
Non cash build to suit lease asset						$ 5,100,000
Property and equipment estimated useful lives						39 years
Doug St, LLC \| El Segundo California
Commitments And Contingencies [Line Items]
Number of square foot of facility leased \| ft²									24,250
Doug St, LLC \| Research and Development
Commitments And Contingencies [Line Items]
Rent expense						$ 100,000
NantWorks
Commitments And Contingencies [Line Items]
Number of square foot of facility leased \| ft²										9,500
Period of agreement						The license was effective in May 2015 and extends through December 2020. The Company has the option to extend the license through December 2023. The monthly license fee is $47,000 with annual increases of 3% beginning in January 2017.
Base rent - monthly						$ 47,000
Percentage of annual increase of base rent						3.00%
Annual percentage increases to base rent commencement date						Jan. 31, 2017
Costs incurred						$ 3,500,000
Property and equipment estimated useful lives						39 years
Accumulated depreciation on building						$ 4,300,000
NantWorks \| Research and Development
Commitments And Contingencies [Line Items]
Rent expense						$ 200,000	$ 200,000

Commitment and Contingencies - Summary of Future Minimum Lease Payments (Detail) $ in Thousands	Dec. 31, 2016 USD ($)
Commitments And Contingencies Disclosure [Abstract]
2017	$ 4,076
2018	4,094
2019	4,108
2020	4,056
2021	3,435
Thereafter	5,594
Total minimum lease payments	$ 25,363

Related Party Agreements - Additional Information (Detail)	1 Months Ended			12 Months Ended
	Apr. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2013 USD ($) shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($) shares	Sep. 30, 2016 ft²	Aug. 31, 2016	Nov. 30, 2015 ft²	Jul. 31, 2015 shares
Related Party Transaction [Line Items]
Due from related parties				$ 1,089,000	$ 217,000
Research and development				29,153,000	11,434,000	$ 1,595,000
Selling, general and administrative				95,391,000	227,678,000	4,621,000
Due to related parties				1,753,000	1,352,000
Outstanding debt principal and interest offset converted into shares				$ 0	$ 0	1,000,000
Stock issued to offset the loan \| shares				81,983,937	81,311,686						9,531,200
Officers
Related Party Transaction [Line Items]
Proceed from secured note						1,200,000	$ 200,000
Outstanding debt principal and interest offset converted into shares						$ 23,000	$ 100,000
Common Class B
Related Party Transaction [Line Items]
Stock issued to offset the loan \| shares			1,681,099			5,851,152	1,681,099
Common Class B \| Officers
Related Party Transaction [Line Items]
Restricted stock purchase agreements \| shares			7,532,251
Secured promissory notes			$ 1,500,000				$ 1,500,000
Percentage of accrued interest			1.64%				1.64%
Percentage of accrued interest			2022-12
Doug St, LLC
Related Party Transaction [Line Items]
Period of agreement				The lease runs from July 2016 through July 2023. The Company has the option to extend the lease for an additional three year term through July 2026. The monthly rent is $0.1 million with annual increases of 3% beginning in July 2017.
Base rent - monthly				$ 100,000
Percentage of annual increase of base rent				3.00%
Annual percentage increases to base rent commencement date				Jul. 31, 2017
Due from related parties				$ 800,000
Costs incurred				1,800,000
Doug St, LLC \| El Segundo California
Related Party Transaction [Line Items]
Number of square foot of facility leased \| ft²								24,250
Doug St, LLC \| Research and Development
Related Party Transaction [Line Items]
Rent expense				100,000
Altor \| Minimum
Related Party Transaction [Line Items]
Percentage of ownership interest owned by CEO									20.00%
NantBioScience
Related Party Transaction [Line Items]
Research and development	$ 600,000			$ 500,000
Research and development expense, ratable payment period				12 months
NantWorks
Related Party Transaction [Line Items]
Number of square foot of facility leased \| ft²										9,500
Base rent - monthly				$ 47,000
Percentage of annual increase of base rent				3.00%
Annual percentage increases to base rent commencement date				Jan. 31, 2017
Due to related parties				$ 1,700,000
Costs incurred				3,500,000
NantWorks \| Shared Services Agreement
Related Party Transaction [Line Items]
Research and development				2,100,000	$ 300,000
Selling, general and administrative				3,000,000	1,000,000
NantWorks \| Reimbursements \| Shared Services Agreement
Related Party Transaction [Line Items]
Research and development				200,000
Selling, general and administrative				100,000
NantWorks \| Research and Development
Related Party Transaction [Line Items]
Rent expense				200,000	200,000
NantOmics
Related Party Transaction [Line Items]
Research and development				200,000	100,000
Due to related parties				$ 0
Initial term of agreement entered into with the related party by the entity				5 years
Related party, agreement renewal term				1 year
NanoCav
Related Party Transaction [Line Items]
Research and development				$ 100,000	$ 0
Due to related parties				$ 15,000
Initial term of agreement entered into with the related party by the entity				5 years
Related party, agreement renewal term				1 year
Prepaid expenses for research and development		$ 45,000
NantCell
Related Party Transaction [Line Items]
Research and development				$ 200,000
Initial term of agreement entered into with the related party by the entity				5 years
Related party, agreement renewal term				1 year
Non refundable upfront payment		$ 500,000

Spin-out of Brink Biologics and Coneksis - Additional Information (Detail) - Spinout - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Brink Biologics Inc
Related Party Transaction [Line Items]
Royalty revenue	$ 21,000	$ 11,000
Number of days due for payment	30 days
Invoiced for services	$ 100,000	22,000
Amount owed to the company	$ 100,000
Coneksis
Related Party Transaction [Line Items]
Number of days due for payment	30 days
Invoiced for services	$ 19,000	$ 6,000
Amount owed to the company	$ 25,000

Stockholders' Equity - Additional Information (Detail)				1 Months Ended															12 Months Ended
Stockholders' Equity - Additional Information (Detail)	Jul. 10, 2015	Jul. 08, 2015 USD ($) shares	Jun. 18, 2015 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Nov. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) $ / shares shares	Aug. 31, 2016 USD ($) $ / shares shares	Jun. 30, 2016 USD ($) $ / shares shares	May 31, 2016 USD ($) $ / shares shares	Feb. 29, 2016 USD ($) $ / shares shares	Jul. 31, 2015 USD ($) shares	Jun. 30, 2015 USD ($) shares	Apr. 30, 2015 USD ($) $ / shares shares	Mar. 31, 2015 $ / shares shares	Apr. 30, 2014 USD ($) $ / shares shares	Mar. 31, 2014 shares	Dec. 31, 2013 USD ($) shares	Jun. 30, 2013 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) Director $ / shares shares	Nov. 30, 2015 USD ($)	Dec. 31, 2010 USD ($) $ / shares
Class Of Stock [Line Items]
Total amount authorized for repurchase \| $																						$ 50,000,000
Repurchase of common stock, shares				124,286	439,618	30,000	335,440	582,400	346,200	300,000									2,157,944	0
Repurchase of common stock, par value \| $ / shares				$ 6.45	$ 7.14	$ 7.40	$ 7.01	$ 7.56	$ 6.77	$ 8.50									$ 7.33
Repurchase of common stock, value \| $																			$ 15,847,000	$ 4,798,000
Broker commissions on the repurchases \| $																			36,000
Remained authorized shares for repurchase \| $				$ 34,200,000	$ 35,000,000	$ 38,100,000	$ 38,400,000	$ 40,700,000	$ 45,100,000	$ 47,500,000									$ 34,200,000
Forward stock split of its outstanding common stock	1.8515
Common stock, shares authorized				500,000,000								100,000,000							500,000,000	500,000,000
Proceeds from issuance of common stock net of issuance costs \| $		$ 7,000,000										$ 71,000,000
Common stock, shares issued				81,983,937							9,531,200								81,983,937	81,311,686
Proceeds from sale of common stock \| $											$ 221,500,000
Underwriting discounts, commissions and offering expenses \| $											$ 16,800,000
Stock issued to offset the loan				81,983,937							9,531,200								81,983,937	81,311,686
Proceeds from exercise of warrants \| $																			$ 52,000	$ 7,348,000	$ 0
Derivative liability \| $																	$ 19,000			$ 0	$ 177,000
Common stock, par value \| $ / shares				$ 0.0001															$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares outstanding				81,983,937															81,983,937	81,311,686
Common Stock Warrant
Class Of Stock [Line Items]
Derivative liability \| $													$ 1,500,000								$ 200,000		$ 400,000
Inex Bio Inc
Class Of Stock [Line Items]
Stock price of warrants \| $ / shares														$ 2.00
Warrants issued to purchase common shares														3,202,592
Proceeds from exercise of warrants \| $													$ 6,400,000
Officers
Class Of Stock [Line Items]
Forward stock split of its outstanding common stock																			1
2013 Promissory Note
Class Of Stock [Line Items]
Convertible notes payable current \| $																		$ 1,000,000
Private Placement
Class Of Stock [Line Items]
Issuance of common stock, Shares												3,698,695
Proceeds from issuance of common stock net of issuance costs \| $											$ 17,000,000
Issuance costs \| $												$ 28,000
Common stock, shares issued		364,638									680,000
Stock issued to offset the loan		364,638									680,000
Common Class A
Class Of Stock [Line Items]
Repurchase of common stock, shares			249,952																0	249,952
Repurchase of common stock, par value \| $ / shares			$ 19.20
Repurchase of common stock, value \| $			$ 4,800,000																$ 0	$ 0
Forward stock split of its outstanding common stock												1.00
Issuance of common stock, Shares																					30,809,800
Issuance of restricted stock, Shares																					129,605
Conversion of debt and payables to Class A common stock, Shares																					1,522,799
Conversion of Class A common stock to common stock, Shares																				(65,900,303)
Issuance of stock for placement agent in shares																					3,087,324
Stock price of warrants \| $ / shares																		$ 2.44
Conversion of stock for placement agent in shares and exchange of warrant																		193,413
Debt instrument, percentage of common stock																		4.00%
Issuance of placement agent warrant associated with 2014 Securities Purchase Agreement																		199,341
Common Class A \| Common Stock Warrant
Class Of Stock [Line Items]
Stock price of warrants \| $ / shares													$ 1.76
Warrant exercised and shares issued													114,822
Warrant exercisable price per share \| $ / shares																							$ 2.44
Warrant expiration date																			Feb. 29, 2020
Period of warrant holder protected against down-round financing after reverse merger																			2 years
Percentage of shareholders consent																			66.67%
Common Class A \| Private Placement
Class Of Stock [Line Items]
Issuance of common stock, Shares																				0
Common Class A \| Private Placement One \| Sorrento
Class Of Stock [Line Items]
Issuance of common stock, Shares																					4,557,537
Common stock issued, par value \| $ / shares																					$ 1.76
Proceeds from issuance of common stock gross of issuance costs \| $																					$ 8,000,000
Common Class A \| Private Placement Two
Class Of Stock [Line Items]
Issuance of common stock, Shares																					26,252,262
Common stock issued, par value \| $ / shares																					$ 1.89
Proceeds from issuance of common stock gross of issuance costs \| $																					$ 49,500,000
Number of board of directors \| Director																					9
Common Class A \| Private Placement Two \| Sorrento
Class Of Stock [Line Items]
Issuance of common stock, Shares																					1,060,789
Issuance costs \| $																					$ 200,000
Proceeds from issuance of common stock gross of issuance costs \| $																					2,000,000
Common Class A \| 2014 Securities Purchase Agreement
Class Of Stock [Line Items]
Broker commissions on the repurchases \| $																					$ 45,000
Stock issued for placement agent commission																					3,087,324
Common Class A \| 2014 Securities Purchase Agreement \| Outstanding Warrants
Class Of Stock [Line Items]
Issuance of common stock, Shares															1,245,881
Conversion of stock for placement agent in shares and exchange of warrant															193,413
Issuance of placement agent warrant associated with 2014 Securities Purchase Agreement															199,341
Common Class A \| 2014 Securities Purchase Agreement \| Outstanding Warrants \| Founders License Agreement March 2014 Amendment
Class Of Stock [Line Items]
Conversion of warrant to purchase common stock																156,109
Common Class A \| 2014 Securities Purchase Agreement \| Employee Stock Option \| Founders License Agreement March 2014 Amendment
Class Of Stock [Line Items]
Conversion of options to purchase common stock																740,600
Common Class A \| 2014 Securities Purchase Agreement \| 2013 Promissory Note \| Outstanding Warrants
Class Of Stock [Line Items]
Common stock issued for conversion of debt															192,865
Common Class A \| 2013 Securities Purchase Agreement
Class Of Stock [Line Items]
Conversion of Class A common stock to common stock, Shares																			406,048
Common Class A \| 2013 Securities Purchase Agreement \| 2013 Converted Creditors
Class Of Stock [Line Items]
Common stock issued for conversion of debt																			389,437
Common Stock Class Undefined
Class Of Stock [Line Items]
Common stock, shares authorized																					80,000,000
Common Class B
Class Of Stock [Line Items]
Repurchase of common stock, shares																			0	0
Repurchase of common stock, value \| $																			$ 0	$ 0
Stock approved for conversion to Class A common stock.																					8,295,402
Issuance of common stock, Shares																					0
Common stock, shares issued																	1,681,099				5,851,152
Issuance of restricted stock, Shares																					0
Conversion of debt and payables to Class A common stock, Shares																					0
Conversion of Class A common stock to common stock, Shares																				0
Issuance of stock for placement agent in shares															763,151	763,151					763,151
Stock issued to offset the loan																	1,681,099				5,851,152
Debt instrument, percentage of common stock																		2.50%
Common Class B \| Officers
Class Of Stock [Line Items]
Restricted stock purchase agreements, shares																	7,532,251
Common Class B \| Private Placement
Class Of Stock [Line Items]
Issuance of common stock, Shares																				0
Series B Preferred Stock
Class Of Stock [Line Items]
Forward stock split of its outstanding common stock																			0.067
Stock approved for conversion to Class A common stock.																					9,502,898
Common stock, conversion basis																			In March 2014, the Company entered into a definitive merger and share exchange agreement pursuant to which the Company redomesticated from the State of Illinois to the State of Delaware and the Illinois Company ceased to exist (the Redomestication). In connection with the Redomestication, the holders of Class A and Class B common stock received one share of Class A and Class B common stock of the Delaware Company, respectively, in exchange for fifteen shares of the Illinois Company. The holders of Series B preferred stock received one share of Series B preferred stock of the Delaware Company in exchange for one share of the Illinois Company. The holders of any options, warrants or other securities are subject to adjustment based on the ratio of 1 for 15. All share numbers and per share prices in the accompanying consolidated financial statements have been adjusted to reflect the 1 for 15 exchange.
Series C Preferred Stock
Class Of Stock [Line Items]
Stock approved for conversion to Class A common stock.																					5,754,984
Series C Preferred Stock \| 2014 Securities Purchase Agreement
Class Of Stock [Line Items]
Issuance of common stock, Shares															4,983,526
Proceeds from issuance of common stock net of issuance costs \| $															$ 6,500,000
Conversion of Promissory Note															0.25
Warrant term															3 years
Series C Preferred Stock \| 2014 Securities Purchase Agreement \| 2013 Promissory Note
Class Of Stock [Line Items]
Common stock issued for conversion of debt															771,458
Stock price of warrants \| $ / shares															$ 1.62
Series B Common Stock and Series C Preferred Stock
Class Of Stock [Line Items]
Forward stock split of its outstanding common stock																					1.00
Series B Preferred Stock
Class Of Stock [Line Items]
Stock approved for conversion to Class A common stock.																					5,132,548
Minimum
Class Of Stock [Line Items]
Repurchase of common stock, par value \| $ / shares																			$ 6.05
Common stock, shares authorized											100,000,000
Maximum
Class Of Stock [Line Items]
Repurchase of common stock, par value \| $ / shares																			$ 8.50
Common stock, shares authorized											500,000,000

Stockholders' Equity - Summary of Common Stock Repurchases (Detail) - USD ($)	1 Months Ended							12 Months Ended
	Dec. 31, 2016	Nov. 30, 2016	Sep. 30, 2016	Aug. 31, 2016	Jun. 30, 2016	May 31, 2016	Feb. 29, 2016	Dec. 31, 2016	Dec. 31, 2015
Equity [Abstract]
Total number of shares purchased	124,286	439,618	30,000	335,440	582,400	346,200	300,000	2,157,944	0
Average price paid per share	$ 6.45	$ 7.14	$ 7.40	$ 7.01	$ 7.56	$ 6.77	$ 8.50	$ 7.33
Total number of shares purchased as part of publicly announced plans or programs	2,157,944	2,033,658	1,594,040	1,564,040	1,228,600	646,200	300,000
Maximum approximate dollar value of shares that may yet be purchased under the plans or programs	$ 34,200,000	$ 35,000,000	$ 38,100,000	$ 38,400,000	$ 40,700,000	$ 45,100,000	$ 47,500,000	$ 34,200,000

Stockholders' Equity - Summary Of Changes In Securities (Detail) - shares	1 Months Ended			12 Months Ended
	Apr. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Dec. 31, 2014
Common Class A
Class Of Stock [Line Items]
Issuance of common stock less issuance costs, Shares				30,809,800
Issuance of stock to placement agent, Shares				3,087,324
Conversion of stock for placement agent in shares and exchange of warrant			(193,413)
Issuance of placement agent warrant associated with 2014 Securities Purchase Agreement			199,341
Common Class A \| 2014 Other Creditor One
Class Of Stock [Line Items]
Promissory note agreed to convert	230,859
Common Class A \| Prior to 2014 Securities Purchase Agreement
Class Of Stock [Line Items]
Share balance	1,158,394
Common Class A \| 2014 Securities Purchase Agreement
Class Of Stock [Line Items]
Common stock issued for placement agent commission	34,715
Common Class A \| 2014 Securities Purchase Agreement \| 2014 Other Creditor One
Class Of Stock [Line Items]
Stock approved for conversion to Class A common stock.	345,228
Common Class A \| 2014 Securities Purchase Agreement \| 2009 Convertible Notes
Class Of Stock [Line Items]
Promissory note agreed to convert	985,229
Common Class A \| 2014 Securities Purchase Agreement \| CA Warrant and PA Warrant
Class Of Stock [Line Items]
Warrant exchanged	3,052,608
Common Class A \| 2014 Securities Purchase Agreement \| Side Agreement Notes
Class Of Stock [Line Items]
Promissory note agreed to convert	192,341
Common Class A \| After Closing Of Two Thousand Fourteen Securities Purchase Agreement
Class Of Stock [Line Items]
Share balance	5,768,515
Common Class A \| Outstanding Warrants \| Prior to 2014 Securities Purchase Agreement
Class Of Stock [Line Items]
Share balance	763,841
Common Class A \| Outstanding Warrants \| 2014 Securities Purchase Agreement
Class Of Stock [Line Items]
Exchange of Founder Warrant	(156,109)
Issuance of common stock less issuance costs, Shares	1,245,881
Conversion of stock for placement agent in shares and exchange of warrant	(193,413)
Issuance of placement agent warrant associated with 2014 Securities Purchase Agreement	199,341
Common Class A \| Outstanding Warrants \| 2014 Securities Purchase Agreement \| 2013 Promissory Note
Class Of Stock [Line Items]
Promissory note agreed to convert	192,865
Common Class A \| Outstanding Warrants \| After Closing Of Two Thousand Fourteen Securities Purchase Agreement
Class Of Stock [Line Items]
Share balance	2,052,406
Common Class A \| Options to Purchase
Class Of Stock [Line Items]
Conversion Of Warrant To Option To Purchase Of Common Stock	740,600
Common Class A \| Options to Purchase \| Prior to 2014 Securities Purchase Agreement
Class Of Stock [Line Items]
Share balance	3,056,702
Common Class A \| Options to Purchase \| After Closing Of Two Thousand Fourteen Securities Purchase Agreement
Class Of Stock [Line Items]
Share balance	3,797,302
Common Class B
Class Of Stock [Line Items]
Stock approved for conversion to Class A common stock.				8,295,402
Issuance of common stock less issuance costs, Shares				0
Issuance of stock to placement agent, Shares	763,151	763,151		763,151
Common Class B \| Prior to 2014 Securities Purchase Agreement
Class Of Stock [Line Items]
Share balance	1,763,609
Common Class B \| After Closing Of Two Thousand Fourteen Securities Purchase Agreement
Class Of Stock [Line Items]
Share balance	2,526,760
Series C Preferred Stock
Class Of Stock [Line Items]
Stock approved for conversion to Class A common stock.				5,754,984
Series C Preferred Stock \| 2014 Securities Purchase Agreement
Class Of Stock [Line Items]
Issuance of common stock less issuance costs, Shares	4,983,526
Series C Preferred Stock \| 2014 Securities Purchase Agreement \| 2013 Promissory Note
Class Of Stock [Line Items]
Promissory note agreed to convert	771,458
Series C Preferred Stock \| After Closing Of Two Thousand Fourteen Securities Purchase Agreement
Class Of Stock [Line Items]
Share balance	5,754,984

Stockholders' Equity - Summary of Common Shares Reserved for Issuance (Detail)	Dec. 31, 2016 shares
Class Of Stock [Line Items]
Total shares reserved for future issuance	24,890,154
Issued and Outstanding Stock Options
Class Of Stock [Line Items]
Total shares reserved for future issuance	6,307,384
Issued and Outstanding Restricted Stock Units
Class Of Stock [Line Items]
Total shares reserved for future issuance	814,456
Outstanding Financing Warrants
Class Of Stock [Line Items]
Total shares reserved for future issuance	179,064
Outstanding Officer Warrants
Class Of Stock [Line Items]
Total shares reserved for future issuance	17,589,250

Stock-Based Compensation - Additional Information (Detail) $ / shares in Units, $ in Thousands				1 Months Ended			3 Months Ended		12 Months Ended
	Jul. 10, 2015	May 08, 2015 $ / shares shares	Mar. 24, 2015 $ / shares shares	Jul. 31, 2015 shares	Jun. 30, 2015	Mar. 31, 2014 shares	Mar. 31, 2016 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Jan. 01, 2016 USD ($)	Dec. 31, 2013 $ / shares shares	Jun. 30, 2013 $ / shares	Apr. 30, 2004 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance \| shares										4,249,857
Remaining incremental compensation expense \| $							$ 27,000
Forward stock split of its outstanding common stock	1.8515
Accumulated deficit \| $									$ (387,063)	$ (250,376)		$ 31,000
Cash received from exercised options \| $									1,373	878	$ 180
Stock-based compensation expense \| $									73,852	211,221	789
Outstanding Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested stock options \| $									$ 49,400
Weighted-average period for recognition									1 year 7 months 6 days
Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option vesting period									1 year 7 months 6 days
Incremental compensation cost \| $										91,500
Incremental compensation expense \| $									$ 19,000	$ 53,800
Remaining incremental compensation expense \| $									$ 18,700
Forward stock split of its outstanding common stock									1
Officer \| Vest over a 40-month service period beginning on April 1, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement, Award Vesting Rights, Percentage				50.00%
Officer \| Vest based on the achievement of various milestones
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement, Award Vesting Rights, Percentage									50.00%
Officer \| Non Qualified Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation, expiration period		4 years	10 years
Number of shares granted \| shares			1,851,500
Shares granted at an exercise price \| $ / shares		$ 2.20	$ 2.00
Option vesting period			40 months
Officer \| Outstanding Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation, expiration period		4 years
Common Class A
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock price of warrants \| $ / shares														$ 2.44
Forward stock split of its outstanding common stock					1.00
Stock-based compensation expense \| $											$ 200
Issuance of restricted stock, Shares \| shares											129,605
2015 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance \| shares									2,745,028	3,500,000
Additional Shares that may be added to shares reserved for issuance \| shares									6,914,754
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares granted \| shares										5,713,899	5,971,087
Shares granted at an exercise price \| $ / shares										$ 7.92	$ 0.77
Stock option outstanding \| shares									6,307,384	8,777,893	5,138,410		1,727
Shares outstanding at an exercise price \| $ / shares									$ 7.14	$ 5.36	$ 0.85		$ 0.41
Stock options, vested and exercisable \| shares									5,210,756	4,844,857	1,705,035
Aggregate intrinsic value of stock options exercised \| $									$ 17,000	$ 2,400	$ 200
Cash received from exercised options \| $									1,400	900	200
Total stock option expense \| $									14,700	$ 28,800	$ 600
Unrecognized compensation cost related to non-vested stock options \| $									$ 9,100
Weighted-average period for recognition									2 years 1 month 6 days
Employee Stock Option \| Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option outstanding \| shares									1,455,450
Shares outstanding at an exercise price \| $ / shares									$ 25.00
Employee Stock Option \| 2004 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance \| shares															81,695
Employee Stock Option \| 2014 Equity Incentive Plan \| Common Class A
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance \| shares						11,109,000
Employee Stock Option \| 2014 Equity Incentive Plan \| Common Class A \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation, expiration period						10 years
Performance Shares \| Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock price of warrants \| $ / shares			$ 2.00
Incremental compensation cost \| $									$ 53,000
Performance Shares \| Officer \| Outstanding Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation, expiration period			3 years
Number of shares granted \| shares		10,183,250	17,589,250
Service \| Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental compensation cost \| $								$ 38,500
Service \| Officer \| Outstanding Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares granted \| shares		7,406,000
Outstanding Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares granted \| shares									407,800	1,614,788
Weighted-average period for recognition									3 years
Unrecognized compensation cost related to non-vested stock options \| $									$ 5,500
Outstanding Restricted Stock Units \| Employees Of Related Company
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares granted \| shares									67,500	353,188
Outstanding Restricted Stock Units \| Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares granted \| shares				970,300
Non Employee Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option outstanding \| shares									0
Shares granted to employee \| shares									0	231,437	231,437
Option vested \| shares									0
Stock-based compensation expense \| $									$ 0	$ 3,300	$ 100
Employee Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period for recognition									3 years
Unrecognized compensation cost related to non-vested stock options \| $									$ 3,800
Non Employee Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period for recognition									2 years 10 months 24 days
Unrecognized compensation cost related to non-vested stock options \| $									$ 1,700

Stock-Based Compensation - Stock Based Compensation Expenses Related to Statement of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 73,852	$ 211,221	$ 789
Warrants For Common Stock \| Officer
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	50,502	141,901	0
Warrants For Common Stock \| Director Related to Inex Bio, Inc
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	0	22,747	0
Employee Stock Option
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	14,720	25,498	485
Non Employee Stock Options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	0	3,300	76
Employee Restricted Stock Units
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	8,166	17,505	228
Non Employee Restricted Stock Units
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	464	270	0
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	852	1,221	222
Selling, General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 73,000	$ 210,000	$ 567

Stock-Based Compensation - Stock Option Activity (Detail) - Employee Stock Option - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Number of Shares
Stock Options, Beginning Balance	8,777,893	5,138,410	1,727
Stock Options, Options granted		5,713,899	5,971,087
Stock Options, Options exercised	(2,398,882)	(1,127,105)	(833,173)
Stock Options, Options forfeited/canceled	(71,627)	(947,311)	(1,231)
Stock Options, Ending Balance	6,307,384	8,777,893	5,138,410	1,727
Stock Options, Vested and Exercisable	5,210,756	4,844,857	1,705,035
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding Beginning balance	$ 5.36	$ 0.85	$ 0.41
Weighted Average Exercise Price, Options granted		7.92	0.77
Weighted Average Exercise Price, Options exercised	0.76	0.86	0.22
Weighted Average Exercise Price, Options forfeited/canceled	2.00	1.87	0.41
Weighted Average Exercise Price, Outstanding Ending balance	7.14	$ 5.36	$ 0.85	$ 0.41
Weighted Average Exercise Price, Vested and Exercisable	$ 8.18
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding, Beginning balance	$ 19,100	$ 116,273	$ 5,298	$ 0
Aggregate Intrinsic Value, Outstanding, Beginning balance	19,100	$ 116,273	$ 5,298	$ 0
Aggregate Intrinsic Value, Vested and Exercisable	$ 15,227
Weighted Average Remaining Contractual Life
Weighted Average Remaining Contractual Life, Outstanding	6 years 4 months 24 days	7 years 2 months 12 days	9 years 8 months 12 days	1 year 3 months 18 days
Weighted Average Remaining Contractual Life, Vested and Exercisable	7 years 3 months 18 days

Stock-Based Compensation - Summary of Options Outstanding and Vested Pricing of Exercise Prices (Detail) - Employee Stock Option	12 Months Ended
	Dec. 31, 2016 $ / shares shares
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	6,307,384
Options Outstanding, Weighted-Average Life (in Years)	6 years 4 months 24 days
Options Outstanding, Number Exercisable	5,210,756
Options Outstanding, Weighted- Average Life (in years)	7 years 3 months 18 days
$0.22
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices \| $ / shares	$ 0.22
Options Outstanding, Number Outstanding	134,807
Options Outstanding, Weighted-Average Life (in Years)	7 years 2 months 12 days
Options Outstanding, Number Exercisable	134,807
Options Outstanding, Weighted- Average Life (in years)	7 years 2 months 12 days
$0.42
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices \| $ / shares	$ 0.42
Options Outstanding, Number Outstanding	589,660
Options Outstanding, Weighted-Average Life (in Years)	7 years 10 months 24 days
Options Outstanding, Number Exercisable	589,660
Options Outstanding, Weighted- Average Life (in years)	7 years 10 months 24 days
$1.76
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices \| $ / shares	$ 1.76
Options Outstanding, Number Outstanding	999,682
Options Outstanding, Weighted-Average Life (in Years)	8 years
Options Outstanding, Number Exercisable	999,682
Options Outstanding, Weighted- Average Life (in years)	8 years
$2.00
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices \| $ / shares	$ 2.00
Options Outstanding, Number Outstanding	1,276,285
Options Outstanding, Weighted-Average Life (in Years)	8 years 1 month 6 days
Options Outstanding, Number Exercisable	1,221,126
Options Outstanding, Weighted- Average Life (in years)	8 years 1 month 6 days
$2.20
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices \| $ / shares	$ 2.20
Options Outstanding, Number Outstanding	1,851,500
Options Outstanding, Weighted-Average Life (in Years)	2 years 2 months 12 days
Options Outstanding, Number Exercisable	810,031
Options Outstanding, Weighted- Average Life (in years)	2 years 2 months 12 days
$ 25.00
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Prices \| $ / shares	$ 25.00
Options Outstanding, Number Outstanding	1,455,450
Options Outstanding, Weighted-Average Life (in Years)	8 years 7 months 6 days
Options Outstanding, Number Exercisable	1,455,450
Options Outstanding, Weighted- Average Life (in years)	8 years 7 months 6 days

Stock-Based Compensation - Black-Scholes Option-Pricing Model to Determine Fair Value of Assumptions Used for Employee Grants and Non-Employee Grants Stock Options (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Employee Grants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	1.50%	1.60%
Risk-free interest rate, maximum	1.80%	1.90%
Expected volatility	80.00%
Expected volatility, minimum		81.00%
Expected volatility, maximum		91.00%
Dividend yield	0.00%	0.00%
Weighted-average measurement date fair value	$ 12.08	$ 0.53
Employee Grants \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	4 years	5 years
Employee Grants \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	5 years 6 months	5 years 7 months 6 days
Non-Employee Grants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate		2.20%
Risk-free interest rate, minimum	0.00%
Risk-free interest rate, maximum	2.40%
Expected volatility	80.00%	81.00%
Dividend yield	0.00%	0.00%
Weighted-average measurement date fair value	$ 15.25	$ 0.18
Non-Employee Grants \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	8 years 4 months 24 days	9 years 3 months 18 days
Non-Employee Grants \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	9 years 10 months 24 days	9 years 10 months 24 days

Stock-Based Compensation - Restricted Stock Units (RSUs) Activity (Detail) - Outstanding Restricted Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested, Beginning balance	1,129,638	0
Number of Shares, Granted	407,800	1,614,788
Number of Shares, Vested	(537,982)	(485,150)
Number of Shares, Forfeited/Canceled	(185,000)
Number of Shares, Unvested, Ending balance	814,456	1,129,638
Weighted-Average Grant Date Fair Value, Unvested, beginning balance	$ 20.51	$ 0
Weighted-Average Grant Date Fair Value, Granted	7.76	21.86
Weighted-Average Grant Date Fair Value, Vested	23.75	25.00
Weighted-Average Grant Date Fair Value, Forfeited/Canceled	11.75
Weighted-Average Grant Date Fair Value, Unvested, ending balance	$ 13.98	$ 20.51

Stock-Based Compensation - Summary of Warrant Activity (Detail) - Outstanding Warrants - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Warrant [Line Items]
Warrants, Beginning Balance	17,819,616	1,850,937
Warrants granted		20,791,842
Warrants exercised	(51,302)	(4,677,101)
Warrants forfeited		(146,062)
Warrants, Ending Balance	17,768,314	17,819,616
Warrants, Vested and exercisable Ending Balance	12,769,264

Stock-Based Compensation - Reserved Authorized Shares of Common Stock for Future Grants of Equity Awards (Detail) - shares	1 Months Ended							12 Months Ended
	Dec. 31, 2016	Nov. 30, 2016	Sep. 30, 2016	Aug. 31, 2016	Jun. 30, 2016	May 31, 2016	Feb. 29, 2016	Dec. 31, 2016	Dec. 31, 2015	Jul. 31, 2015
Common Stock Reserved For Future Issuance [Line Items]
Total shares authorized									4,249,857
Shares repurchased	124,286	439,618	30,000	335,440	582,400	346,200	300,000	2,157,944	0
Shares reserved for future grants as of December 31, 2016	24,890,154							24,890,154
2015 Equity Incentive Plan
Common Stock Reserved For Future Issuance [Line Items]
Total shares authorized	2,745,028							2,745,028	3,500,000
Shares reserved for future grants as of December 31, 2015								2,126,682
Grants								(407,800)	(3,070,238)
Forfeitures added back to available pool									947,063
Forfeitures	185,000							185,000
Net share settlement								225,754
Shares repurchased								615,392
Shares reserved for future grants as of December 31, 2016	2,745,028							2,745,028	2,126,682
2014 Equity Incentive Plan
Common Stock Reserved For Future Issuance [Line Items]
Shares remaining from 2014 Equity Incentive Plan										749,857

Income Taxes - Summary of Loss Before Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
U.S. loss before taxes	$ (118,743)	$ (235,750)	$ (6,184)
Foreign loss before taxes	(2,638)	(1,427)	0
Loss before income taxes	$ (121,381)	$ (237,177)	$ (6,184)

Income Taxes - Summary of Income Tax (Benefit) Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ 0	$ 0	$ 0
State	3	1	1
Foreign	0	0	0
Total Current	3	1	1
Deferred:
Federal	0	0	0
State	0	0	0
Foreign	(575)	(302)	0
Total Deferred	(575)	(302)	0
Income tax (benefit) expense	$ (572)	$ (301)	$ 1

Income Taxes - Components of Net Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Stock compensation	$ 87,239	$ 67,559
Net operating loss carryforwards	37,507	0
Leases and other accrued liabilities	2,096	389
Accrued compensation	808	572
Depreciation and amortization	0	624
Total deferred tax assets	127,650	69,144
Deferred tax liabilities:
Foreign intangibles	(996)	(1,165)
Depreciation and amortization	(309)	0
Total deferred tax liabilities	(1,305)	(1,165)
Net deferred tax assets	126,345	67,979
Valuation allowance	(127,341)	(69,144)
Net deferred tax liability	$ (996)	$ (1,165)

Income Taxes - Reconciliation of Federal Statutory Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Tax computed at federal statutory rate	34.00%	34.00%	34.00%
Section 382/383 NOL	8.60%	(3.50%)	(40.00%)
State income taxes, net of federal tax benefit	3.60%	2.60%	4.80%
Tax rate adjustment	1.50%	0.00%	0.50%
Research and development credits	1.30%	0.10%	0.70%
Stock-based compensation	(0.30%)	(0.40%)	(1.10%)
Other	(0.50%)	(3.80%)	(7.30%)
Valuation Allowance	(47.70%)	(28.90%)	8.40%
Effective income tax rate	0.50%	0.10%	0.00%

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Tax [Line Items]
Cumulative change in ownership	50.00%
Period of cumulative ownership change	3 years
Recognized deferred tax assets for net operating losses	$ 11,100,000
Federal research and development credits	1,200,000	$ 12,700,000
State research and development credits	1,200,000	12,700,000
Deferred tax assets for foreign net operating loss	28,000
Deferred tax assets valuation allowance	127,341,000	$ 69,144,000
Deferred tax assets change in valuation allowance	58,200,000
Unrecognized tax benefits that would not impact effective tax rate	4,300,000
California \| Research Tax Credits
Income Tax [Line Items]
Tax credit carryforwards	$ 700,000
California \| Minimum
Income Tax [Line Items]
Tax year open for examination	2012
California \| Maximum
Income Tax [Line Items]
Tax year open for examination	2016
Federal
Income Tax [Line Items]
Research and development credits	$ 400,000
Net operating loss carryforwards	$ 100,000,000
Net operating loss carryforwards expiration date	2024
Federal \| Research Tax Credits
Income Tax [Line Items]
Tax credit carryforwards	$ 1,700,000
Tax credit carryforward expiration period	2026
Federal \| Minimum
Income Tax [Line Items]
Tax year open for examination	2013
Federal \| Maximum
Income Tax [Line Items]
Tax year open for examination	2016
State
Income Tax [Line Items]
Research and development credits	$ 400,000
Net operating loss carryforwards	$ 60,000,000
Net operating loss carryforwards expiration date	2030
State \| Research Tax Credits
Income Tax [Line Items]
Tax credit carryforward expiration period	2029
Foreign
Income Tax [Line Items]
Net operating loss carryforwards	$ 200,000
Net operating loss carryforwards expiration date	2023

Income Taxes - Summarizes of Changes in Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized tax benefits at beginning balance	$ 1,203	$ 0
Decrease for prior year tax positions	(1,203)
Increase for prior year tax positions	2,578	120
Increase for current year tax positions	2,056	1,083
Unrecognized tax benefits at ending balance	$ 4,634	$ 1,203

Notes Payable - Additional Information (Detail) - USD ($)	1 Months Ended			12 Months Ended
	Mar. 31, 2015	Apr. 30, 2014	Jun. 30, 2013	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013	Dec. 31, 2010
Debt Instrument [Line Items]
Payments on notes payable	$ 130,000			$ 0	$ 132,000	$ 53,000
2014 Other Creditor One
Debt Instrument [Line Items]
Debt instrument, face amount		$ 50,000
Debt instrument, increase, accrued interest		$ 100,000
2014 Other Creditor Two
Debt Instrument [Line Items]
Promissory note agreed to convert		114,369
Other creditors outstanding principal		$ 100,000
2014 Other Creditors Three
Debt Instrument [Line Items]
Other creditors outstanding principal		29,000
Accrued interest were repaid by cash		13,000
Founder License Agreement
Debt Instrument [Line Items]
Payments on notes payable		23,000
Outstanding Warrants
Debt Instrument [Line Items]
Outstanding warrants				17,768,314	17,819,616	1,850,937
2013 Promissory Note
Debt Instrument [Line Items]
Convertible notes payable current			$ 1,000,000
Percentage of accrued interest							5.00%
Proceeds from security purchase agreement			400,000
Debt discount			600,000
Accrued interest paid		39,000
2009 Convertible Notes
Debt Instrument [Line Items]
Convertible notes payable current		$ 400,000
Percentage of accrued interest						24.00%		24.00%	15.00%
Outstanding convertible note payable						$ 0
Warrant exercisable as a percentage of shares issued				300.00%
2009 Convertible Notes \| 2014 Other Creditors Total
Debt Instrument [Line Items]
Debt and capital lease obligations						$ 200,000
Payment deferral period						3 years
2009 Convertible Notes \| 2014 Other Creditors Four
Debt Instrument [Line Items]
Debt instrument, face amount						$ 20,000
Debt instrument, increase, accrued interest						$ 29,000
2009 Convertible Notes \| CA Warrant
Debt Instrument [Line Items]
Warrant percentage						20.00%
Stock price of warrants						$ 2.44
Warrant expiration date				Sep. 30, 2019
2009 Convertible Notes \| PA Warrant
Debt Instrument [Line Items]
Warrant percentage						9.00%
2009 Warrants
Debt Instrument [Line Items]
Outstanding warrants		0
2007 Settlement Agreement Note
Debt Instrument [Line Items]
Notes payable						$ 300,000
2007 Settlement Agreement Note \| 2015 Supplemental Agreement
Debt Instrument [Line Items]
Notes payable				$ 0
Difference amount of notes payable and amount paid to retire	$ 130,000
Series B Preferred Stock
Debt Instrument [Line Items]
Proceeds from issuance of preferred stock			$ 600,000
Common Class A
Debt Instrument [Line Items]
Stock price of warrants			$ 2.44
Common Class A \| 2014 Other Creditor One
Debt Instrument [Line Items]
Promissory note agreed to convert		230,859
Common Class A \| 2007 Settlement Agreement Note with 2015 Supplemental Agreement
Debt Instrument [Line Items]
Common stock exercise of warrants purchase of share	32,675
Common stock exercise of warrants purchase price per share	$ 2.44
Common Class A \| Twenty Fourteen Securities Purchase Agreement C A And P A Warrants
Debt Instrument [Line Items]
Diluted stock outstanding, percentage			10.00%
Warrant exchanged		3,052,608
Common Class A \| 2009 Convertible Notes
Debt Instrument [Line Items]
Minimum financing needed to convert other Creditors total shares			$ 1,200,000
Common Class A \| 2009 Convertible Notes \| 2014 Other Creditors Four
Debt Instrument [Line Items]
Promissory note agreed to convert				20,205
Conversion price of common stock				$ 2.44
Common Class A \| Side Agreement Notes
Debt Instrument [Line Items]
Convertible notes payable current		$ 200,000
2013 Securities Purchase Agreement
Debt Instrument [Line Items]
Proceeds from issuance of preferred stock			1,000,000
2013 Securities Purchase Agreement \| 2009 Convertible Notes
Debt Instrument [Line Items]
Outstanding principal and accrued interest			$ 3,000,000
2013 Securities Purchase Agreement \| Series B Preferred Stock
Debt Instrument [Line Items]
Preferred stock shares issued			1,851
Preferred stock per share price			$ 0.05
2014 Securities Purchase Agreement \| Series C Preferred Stock \| 2013 Promissory Note
Debt Instrument [Line Items]
Promissory note agreed to convert		771,458
Stock price of warrants		$ 1.62
2014 Securities Purchase Agreement \| Common Class A
Debt Instrument [Line Items]
Common stock issued for placement agent commission		34,715
2014 Securities Purchase Agreement \| Common Class A \| 2013 Promissory Note \| Outstanding Warrants
Debt Instrument [Line Items]
Promissory note agreed to convert		192,865
2014 Securities Purchase Agreement \| Common Class A \| 2009 Convertible Notes
Debt Instrument [Line Items]
Promissory note agreed to convert		985,229
2014 Securities Purchase Agreement \| Common Class A \| Side Agreement Notes
Debt Instrument [Line Items]
Promissory note agreed to convert		192,341

Investment in Inex Bio, Inc - Additional Information (Detail) - USD ($)		1 Months Ended			2 Months Ended	12 Months Ended
	Mar. 30, 2015	Apr. 30, 2015	May 31, 2012	Apr. 30, 2012	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2013
Asset Purchase [Line Items]
Number of shares acquired during period			57,000
Stock issued during period, value, acquisitions			$ 200,000
Outstanding shares acquired, percentage			22.20%
Percentage of fully diluted shares acquired			17.40%
Proceeds from exercise of warrants						$ 52,000	$ 7,348,000	$ 0
Stock-based compensation expense						73,852,000	211,221,000	789,000
Common Class A
Asset Purchase [Line Items]
Stock price of warrants										$ 2.44
Stock-based compensation expense								200,000
Inex Bio Holdings, LLC
Asset Purchase [Line Items]
Payments to acquire business						6,500,000
Stock price of warrants	$ 10.72
Term of warrants after closing date of the purchase agreement	15 days
Expected volatility rate	80.00%
Issuance of warrants in Inex Bio acquisition						22,747,000
Stock-based compensation expense						22,700,000
Cash based compensation						$ 5,400,000
Inex Bio Holdings, LLC \| Common Class A
Asset Purchase [Line Items]
Warrants issued to acquire shares						2,609,520
Common stock exercise price						$ 2.00
Proceeds from exercise of warrants		$ 5,200,000
Other Owner Of Inex Bio Inc
Asset Purchase [Line Items]
Payments to acquire business	$ 1,500,000
Stock price of warrants	$ 10.72
Term of warrants after closing date of the purchase agreement	15 days
Expected volatility rate	80.00%
Issuance of warrants in Inex Bio acquisition						$ 5,170,000
Other Owner Of Inex Bio Inc \| Common Class A
Asset Purchase [Line Items]
Warrants issued to acquire shares	593,072
Common stock exercise price	$ 2.00
Proceeds from exercise of warrants		$ 1,200,000
Inex Bio
Asset Purchase [Line Items]
Intangible assets amortizes period						4 years
Cambridge Equities, L.P \| Inex Bio Holdings, LLC
Asset Purchase [Line Items]
Ownership percentage of third party business					50.00%
Eragon Ventures, LLC
Asset Purchase [Line Items]
Number of shares acquired during period					220,000
Ownership percentage of third party business					50.00%
Percentage shares acquired					67.30%
Payments to acquire business					$ 1,100,000
Inex license agreement
Asset Purchase [Line Items]
Milestone payment amount							$ 0	$ 0	$ 0
Percentage of royalty on net sales				5.00%
Up front fee \| Inex license agreement
Asset Purchase [Line Items]
License fees received				$ 300,000
Maximum \| Inex license agreement
Asset Purchase [Line Items]
Milestone payment amount				$ 800,000

Investment in Inex Bio, Inc - Summary of Purchase Price Paid to Inex Bio (Detail) - Other Owner Of Inex Bio Inc $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Asset Purchase [Line Items]
Cash paid by InexBio Holdings, LLC	$ 1,100
Cash paid by Company	1,482
Fair value of warrants	5,170
Aggregate purchase price	$ 7,752

Investment in Inex Bio, Inc - Summary of Assets and Liabilities Assumed (Detail) - Other Owner Of Inex Bio Inc $ in Thousands	Dec. 31, 2016 USD ($)
Asset Purchase [Line Items]
Cash	$ 763
Intangible assets—reacquired rights of Company technology	8,636
Other assets	42
Investment in Inex Bio	(221)
Deferred tax liability	(1,467)
Accounts payable	(1)
Total assets acquired and liabilities assumed	$ 7,752

Investment in Inex Bio, Inc - Summary of Net Consideration Paid to Holdings (Detail) - Inex Bio Holdings, LLC $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Asset Purchase [Line Items]
Cash	$ 6,518
Fair value of warrants	22,747
Less cash paid to acquire shares in Inex Bio	(1,100)
Aggregate purchase price	$ 28,165

Summary of Quarterly Data (Unaudited) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Data [Abstract]
Revenue	$ 14	$ 12	$ 12	$ 6	$ 15	$ 10	$ 91	$ 120	$ 44	$ 236	$ 641
Operating expenses	25,157	32,787	34,977	31,622	29,938	46,467	130,486	32,221	124,544	239,112	6,216
Operating loss	(25,143)	(32,775)	(34,965)	(31,616)	(29,923)	(46,457)	(130,395)	(32,101)	(124,500)	(238,876)	(5,575)
Net loss	$ (24,238)	$ (31,897)	$ (33,997)	$ (30,677)	$ (26,822)	$ (46,312)	$ (130,893)	$ (32,849)	$ (120,809)	$ (236,876)	$ (6,185)
Net loss per share - basic and diluted	$ (0.29)	$ (0.39)	$ (0.41)	$ (0.38)	$ (0.33)	$ (0.60)	$ (1.99)	$ (0.54)	$ (1.47)	$ (3.31)	$ (0.75)
Shares used in calculating net loss per share - basic and diluted	82,235,571	82,154,219	81,959,248	81,574,709	81,247,430	77,837,586	65,789,041	61,137,625	81,979,005	71,519,609	8,246,028

Employee Benefits - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Employee benefit plan, company contributions	$ 200,000	$ 4,000

Subsequent Event - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Subsequent Event [Line Items]
Research and development		$ 29,153	$ 11,434	$ 1,595
VivaBioCell S.p.A.
Subsequent Event [Line Items]
Research and development final report description		Within 60 days after the one year anniversary of the agreement, VBC will provide the Company a final report summarizing the progress and results of the research and development activities including a description of any inventions and intellectual property rights derived from the work performed.
VivaBioCell S.p.A. \| Subsequent Event
Subsequent Event [Line Items]
Research and development	$ 600

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	$ 280,414	$ 191,484
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	280,414	191,484
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Current Assets \| Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	5,002	6,943
Current Assets \| Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	22,272
Current Assets \| Cash and cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	2,005	18,039
Current Assets \| Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value		24,917
Current Assets \| Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	163,564	86,450
Current Assets \| Level 1 \| Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Current Assets \| Level 1 \| Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
Current Assets \| Level 1 \| Cash and cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Current Assets \| Level 1 \| Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value		0
Current Assets \| Level 1 \| Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Current Assets \| Level 2 \| Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	5,002	6,943
Current Assets \| Level 2 \| Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	22,272
Current Assets \| Level 2 \| Cash and cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	2,005	18,039
Current Assets \| Level 2 \| Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value		24,917
Current Assets \| Level 2 \| Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	163,564	86,450
Current Assets \| Level 3 \| Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Current Assets \| Level 3 \| Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
Current Assets \| Level 3 \| Cash and cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Current Assets \| Level 3 \| Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value		0
Current Assets \| Level 3 \| Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Noncurrent Assets \| Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	1,394	4,004
Noncurrent Assets \| Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	16,982
Noncurrent Assets \| Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	69,195	51,131
Noncurrent Assets \| Level 1 \| Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Noncurrent Assets \| Level 1 \| Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
Noncurrent Assets \| Level 1 \| Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Noncurrent Assets \| Level 2 \| Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	1,394	4,004
Noncurrent Assets \| Level 2 \| Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	16,982
Noncurrent Assets \| Level 2 \| Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	69,195	51,131
Noncurrent Assets \| Level 3 \| Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Noncurrent Assets \| Level 3 \| Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
Noncurrent Assets \| Level 3 \| Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	$ 0	$ 0