ImmunityBio (IBRX) 10-Q 7 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 03, 2018
Document Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Trading Symbol	NK
Entity Registrant Name	NANTKWEST, INC.
Entity Central Index Key	1,326,110
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		78,088,476

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 11,196	$ 23,872
Due from related parties	55	154
Prepaid expenses and other current assets	4,958	4,152
Marketable debt securities	110,593	104,280
Total current assets	126,802	132,458
Marketable debt securities, noncurrent	15,091	29,600
Property, plant and equipment, net	76,826	76,726
Equity investment	8,500	8,500
Intangible assets, net	2,260	2,826
Other assets	366	330
Total assets	229,845	250,440
Current liabilities:
Accounts payable	3,566	5,865
Accrued expenses	12,077	11,267
Due to related parties	2,456	2,363
Other current liabilities	1,299	1,373
Total current liabilities	19,398	20,868
Build-to-suit liability, less current portion	4,797	4,909
Financing obligation, less current portion	1,663	1,741
Deferred rent	3,188	3,325
Deferred tax liability	374	498
Other liabilities	65	255
Total liabilities	29,485	31,596
Commitments and contingencies (Note 8)	0	0
Stockholders’ equity
Common stock, $0.0001 par value; 500,000,000 shares authorized; 79,088,200 and 79,021,878 issued and outstanding as of March 31, 2018 and December 31, 2017	8	8
Additional paid-in capital	726,953	717,930
Accumulated other comprehensive loss	(555)	(381)
Accumulated deficit	(526,046)	(498,713)
Total stockholders’ equity	200,360	218,844
Total liabilities and stockholders’ equity	$ 229,845	$ 250,440

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	79,088,200	79,021,878
Common stock, shares outstanding	79,088,200	79,021,878

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenue	$ 5	$ 11
Operating expenses:
Research and development (including amounts to related parties)	13,991	9,248
Selling, general and administrative (including amounts to related parties)	14,298	16,227
Total operating expenses	28,289	25,475
Loss from operations	(28,284)	(25,464)
Other income:
Investment income, net	505	779
Interest expense (including amounts to related parties)	(33)	(37)
Other income, net (including amounts to related parties)	169	109
Total other income	641	851
Loss before income taxes	(27,643)	(24,613)
Income tax benefit	(124)	(98)
Net loss	$ (27,519)	$ (24,515)
Net loss per share:
Basic and diluted	$ (0.35)	$ (0.30)
Weighted average number of shares during the period:
Basic and diluted	79,036,614	82,138,438

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (27,519)	$ (24,515)
Other comprehensive income, net of income taxes:
Net unrealized gain (loss) on available-for-sale securities	(174)	44
Total other comprehensive income (loss)	(174)	44
Comprehensive loss	$ (27,693)	$ (24,471)

Condensed Consolidated Stateme6

Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - 3 months ended Mar. 31, 2018 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance at Dec. 31, 2017	$ 218,844	$ 8	$ 717,930	$ (381)	$ (498,713)
Beginning Balance, Shares at Dec. 31, 2017	79,021,878	79,021,878
Stock-based compensation expense	$ 9,073	$ 0	9,073	0	0
Vesting of restricted stock units	0	$ 0	0	0	0
Vesting of restricted stock units, Shares		70,200
Exercise of warrants	23	$ 0	23	0	0
Exercise of warrants, Shares		14,270
Employee payroll taxes withheld related to vesting of restricted stock units	(73)	$ 0	(73)	0	0
Employee payroll taxes withheld related to vesting of restricted stock units, Shares		(18,148)
Cumulative effect of the adoption of the new revenue standard	186	$ 0	0	0	186
Other comprehensive income, net	(174)	0	0	(174)	0
Net loss	(27,519)	0	0	0	(27,519)
Ending Balance at Mar. 31, 2018	$ 200,360	$ 8	$ 726,953	$ (555)	$ (526,046)
Ending Balance, Shares at Mar. 31, 2018	79,088,200	79,088,200

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities:
Net loss	$ (27,519)	$ (24,515)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,623	1,162
Stock-based compensation expense	9,073	10,018
Deferred income tax benefit	(124)	(93)
Non-cash interest items, net	149	253
Loss on disposal of assets	36	0
Amortization of net premiums on marketable debt securities	201	572
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(847)	(13)
Other assets	0	126
Accounts payable	117	725
Accrued expenses and other liabilities	1,878	434
Due to related parties	20	1,314
Deferred rent and revenue	(118)	(40)
Net cash used in operating activities	(15,511)	(10,057)
Investing activities:
Purchases of property, plant and equipment	(4,902)	(4,509)
Purchase of equity investment	0	(8,500)
Purchases of marketable debt securities	(32,038)	(25,207)
Sales/maturities of marketable debt securities	39,860	54,254
Net cash provided by investing activities	2,920	16,038
Financing activities:
Principal payments of financing obligations	(65)	(22)
Proceeds from exercise of stock options and warrants	23	1,154
Repurchase of common stock with commissions	0	(1,050)
Net share settlement for RSU vesting and option exercises	(43)	(550)
Net cash used in financing activities	(85)	(468)
Net increase (decrease) in cash, cash equivalents and restricted cash	(12,676)	5,513
Cash, cash equivalents and restricted cash, beginning of period	24,051	8,262
Cash, cash equivalents and restricted cash, end of period	11,375	13,775
Reconciliation of cash, cash equivalents and restricted cash at end of period:
Cash and cash equivalents	11,196	13,596
Restricted cash included in other assets	179	179
Cash, cash equivalents and restricted cash, end of period	11,375	13,775
Supplemental disclosure of cash flow information:
Interest	34	37
Income taxes	0	0
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment purchases included in accounts payable and accrued expenses	5,930	2,492
Unrealized gain (loss) on marketable debt securities	$ (174)	$ 70

Description of Business and Bas

Description of Business and Basis of Presentation	3 Months Ended
	Mar. 31, 2018
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 the Company’s strategy is to invest significantly in expanding the aNK platform and the development of the Company’s 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 CD16 bearing aNK cell lines and intellectual property to numerous pharmaceutical and biotechnology companies for such non-clinical uses. The Company also licensed exclusive commercial rights to a unique HER2-specific receptor bearing aNK cell line along with the corresponding U.S. and foreign composition and methods-of-use patents and applications covering clinical use as a therapeutic to treat cancers. 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. Unaudited Interim The accompanying condensed consolidated balance sheet at March 31, 2018, the condensed consolidated statements of operations and comprehensive loss for the three months ended March 31, 2018 and 2017, the condensed consolidated statements of cash flows for the three months ended March 31, 2018 and 2017, and the condensed consolidated statement of stockholders’ equity for the three months ended March 31, 2018 have been prepared by management of the Company and have not been audited. These financial statements have been prepared on the same basis as the audited consolidated financial statements for the fiscal year ended December 31, 2017 and, in the opinion of management, include all normal recurring adjustments necessary for a fair statement of the Company’s results for the periods presented. These financial statements should be read in conjunction with the financial statements and notes thereto for the fiscal year ended December 31, 2017 included in the Company’s Annual Report on Form 10-K. Interim operating results are not necessarily indicative of operating results for the full year. The year-end consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America (GAAP). Liquidity As of March 31, 2018, the Company had an accumulated deficit of approximately $526.0 million. The Company also had negative cash flow from operations of approximately $15.5 million during the three months ended March 31, 2018. 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, fail 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 and marketable debt securities on hand 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 debt 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies There have been no material changes in the Company’s significant accounting policies other than the adoption of accounting pronouncements below, as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017. Principles of Consolidation and Equity Investments The Company’s condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, Inex Bio, Inc. and 557 Doug St, LLC, and have been prepared in accordance with GAAP. All intercompany amounts have been eliminated. The Company applies the variable interest model under Accounting Standards Codification (ASC) Topic 810, Consolidation For entities the Company holds as an equity investment and are not consolidated under the VIE Model, the Company considers whether its investment constitutes ownership of a majority of the voting interests in the entity and therefore should be considered for consolidation under the voting interest model. Unconsolidated equity investments in the common stock or in-substance common stock of an entity under which the Company is able to exercise significant influence, but not control, are accounted for using the equity method. The Company’s ability to exercise significant influence is generally indicated by ownership of 20 to 50 percent interest in the voting securities of the entity. All other unconsolidated equity investments on which the Company is not able to exercise significant influence will be subsequently measured at fair value with unrealized Use of Estimates The preparation of condensed 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 condensed 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 stock-based compensation, the valuation allowance for deferred tax assets, preclinical and clinical trial accruals, impairment assessments, 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. Basic and Diluted Net Loss per Share of Common Stock Basic net loss per share is calculated by dividing 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 March 31, 2018 2017 Outstanding options 5,693,250 5,693,250 Outstanding restricted stock units 874,164 1,060,381 Outstanding warrants 17,706,818 17,768,314 Total 24,274,232 24,521,945 Amounts in the table above reflect the common stock equivalents of the noted instruments. Recently Adopted Accounting Policies Financial Assets and Liabilities and Equity Investment Effective January 1, 2018, the Company adopted Accounting Standard Update (ASU) 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities The Company owns non-marketable equity securities that are accounted for as an equity investment at cost minus impairment and plus or minus changes resulting from observable price changes because the preferred stock held by the Company is not considered in-substance common stock and such preferred stock does not have a readily determinable fair value. All investments are reviewed on a regular basis for possible impairment. If an investment's fair value is determined to be less than its net carrying value, the investment is written down to its fair value. Such an evaluation is judgmental and dependent on specific facts and circumstances. Factors considered in determining whether an impairment indicator is present include: the investees’ earning performance and clinical trial performance, change in the investees’ industry and geographic area in which it operates, offers to purchase or sell the security for a price less than the cost of the investment, issues that raise concerns about the investee's ability to continue as a going concern and any other information that the Company may be aware of related to the investment. Factors considered in determining whether an observable price change has occurred include: the price at which the investee issues equity instruments similar to those of the Company’s investment and the rights and preferences of those equity instruments compared to the Company’s. Revenue Recognition Beginning January 1, 2018, the Company follows the provisions of ASC Topic 606, Revenue from Contracts with Customers The Company derives substantially all of its revenue from non-exclusive license agreements with a limited number of pharmaceutical and biotechnology companies granting them the right to use the Company’s cell lines and intellectual property for non-clinical use. These agreements generally include upfront fees and annual research license fees for such use, as well as commercial license fees for sales of the Company’s licensee’s products developed or manufactured using the Company’s intellectual property and cell lines. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account in ASC Topic 606. A contract’s transaction price is allocated to each distinct performance obligation based on relative standalone selling price and recognized as revenue when, or as, the performance obligation is satisfied. Under the Company’s license agreements with customers, the Company typically promises to provide a license to use certain cell lines and related patents, the related know-how, and future research and development data that affects the license. The Company concluded that these promises represent one performance obligation due to the highly interrelated nature of the promises. The Company provides the cell lines and know-how immediately upon entering into the contracts. The research and development data is provided throughout the term of the contract when and if available. The Company’s license agreement with Intrexon included a nonrefundable upfront payment of $0.4 million, received when the Company entered into the contract in 2010. In this instance, the Company determined that under ASC 606 it would be appropriate to recognize the initial milestone payment at a point in time, when it transferred the license. In this case, the intellectual property provided under the contract is functional intellectual property under ASC 606 and was determined to be a distinct performance obligation in the context of the arrangement. Prior to adoption, the upfront payment had been initially recorded as deferred revenue and was being recognized into revenue on a straight-line basis. As a result, upon adoption of ASC 606, the Company adjusted its opening retained deficit for the effects of recognizing revenue upfront for the initial milestone. The adjustment to opening retained deficit upon adoption was not material. The license agreements may include nonrefundable upfront payments, event-based milestone payments, sales-based royalty payments, or some combination of these. The event-based milestone payments represent variable consideration and the Company uses the most likely amount method to estimate this variable consideration. Given the high degree of uncertainly around achievement of these milestones, the Company does not recognize revenue from these milestone payments until the uncertainty associated with these payments is resolved. The Company currently estimates variable consideration related to milestone payments to be zero and, as such, no revenue has been recognized for milestone payments. The Company will recognize revenue from sales-based royalty payments when or as the sales occur. On a quarterly basis, the Company will re-evaluate its estimate of milestone variable consideration to determine whether any amount should be included in the transaction price and recorded in revenue prospectively. Upon adoption, the Company changed its accounting policy from accounting for milestones payments under the milestone method to accounting for variable consideration as discussed above. The change in accounting policy did not change any amounts in the financial statements because of the significant uncertainty surrounding the estimate of variable consideration for milestone payments. The Company’s revenue from non-clinical license agreements is nominal. In the future, the Company may generate revenue from license agreements entered into for therapeutic uses. To date, the Company has not generated any revenue from product sales. If the Company fails to complete the development of its product candidates in a timely manner or fails to obtain regulatory approval for them, the Company may never be able to generate substantial future revenue. Statement of Cash Flows Effective January 1, 2018, the Company adopted ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments . ASU 2016-15 adds or clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows. Also, effective January 1, 2018, the Company adopted Statement of Cash Flows: Restricted Cash, a consensus of the FASB’s Emerging Issues Task Force . ASU 2016-18 requires that the statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Entities will also be required to reconcile such total to amounts on the balance sheet and disclose the nature of the restrictions. Both Updates will be effective for annual reporting periods beginning after December 15, 2017, including interim periods within those annual periods. Prior periods were retrospectively adjusted to conform to the current period’s presentation. There was no material impact on the Company’s statement of cash flows on adoption of either Update. Recent Accounting Pronouncements – Not Yet Adopted In February 2018, the FASB issued ASU 2018-02, Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. Adoption of ASU 2018-02 is not expected to have a significant impact in 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. Adoption of ASU 2016-13 is not expected to have a significant impact in the Company’s consolidated financial statements and disclosures. In February 2016, the FASB issued ASU 2016-02, Leases

Financial Statement Details

Financial Statement Details	3 Months Ended
	Mar. 31, 2018
Financial Statement Details [Abstract]
Financial Statement Details	3. Financial Statement Details Prepaid Expenses and Other Current Assets As of March 31, 2018 and December 31, 2017, prepaid expenses and other current assets consisted of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Insurance claim receivable $ 1,576 $ 340 Prepaid license fees 843 597 Interest receivable - marketable debt securities 615 764 Equipment deposits 442 482 Prepaid insurance 381 572 Prepaid rent 373 373 Prepaid supplies 243 210 Prepaid services 157 416 Other 328 398 $ 4,958 $ 4,152 Property, Plant and Equipment, Net As of March 31, 2018 and December 31, 2017, property, plant and equipment, net consisted of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Construction in progress $ 43,339 $ 42,281 Buildings 23,811 23,811 Equipment 9,702 9,625 Leasehold improvements 3,967 3,918 Software 1,095 1,092 Furniture & fixtures 279 302 82,193 81,029 Accumulated depreciation (5,367 ) (4,303 ) $ 76,826 $ 76,726 Depreciation expense related to property, plant and equipment was $1.1 million and $0.6 million for the three months ended March 31, 2018 and 2017, respectively. Buildings of $23.8 million are comprised of $19.5 million related to the purchased warehouse and distribution facility in El Segundo, California, originally accounted for as a capital lease and $4.3 million under a financing lease representing 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 8 section Financing Lease Obligation Construction in progress as of March 31, 2018 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 8 – Build-to-suit Lease Intangible Assets, Net As of March 31, 2018 and December 31, 2017, intangible assets consisted of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Technology license $ 9,042 $ 9,042 Less accumulated amortization (6,782 ) (6,216 ) $ 2,260 $ 2,826 Amortization expense was $0.6 million for both the three months ended March 31, 2018 and 2017. Amortization for the Company’s technology license is included in research and development expense on the condensed consolidated statement of operations. Other Assets As of March 31, 2018 and December 31, 2017, other assets consisted of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Restricted cash $ 179 $ 179 Security deposits 127 127 Other 60 24 $ 366 $ 330 Restricted cash is a certificate of deposit that is collateral for the letter of credit required as a security deposit for the Company’s San Diego, California, facility by the Company’s landlord. Accrued Expenses As of March 31, 2018 and December 31, 2017, accrued expenses consisted of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Accrued construction costs $ 5,019 $ 6,212 Accrued bonus 2,476 1,930 Accrued professional and service fees 1,471 1,048 Accrued compensation 1,396 944 Accrued preclinical and clinical trial costs 938 521 Accrued laboratory equipment and supplies 467 — Other 310 612 $ 12,077 $ 11,267 Other Current Liabilities As of March 31, 2018 and December 31, 2017, other current liabilities were made up of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Deferred rent - current portion $ 539 $ 520 Financing obligation - current portion 292 284 Build-to-suit lease liability - current portion 271 334 Other 197 235 $ 1,299 $ 1,373 Investment Income, Net Net investment income includes interest income from all bank accounts as well as marketable debt securities, 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 three months ended March 31, 2018 and 2017 (in thousands): Three Months Ended March 31, (Unaudited) 2018 2017 Interest income $ 704 $ 1,354 Investment amortization accretion expense, net (201 ) (572 ) Net realized gains (losses) on investments 2 (3 ) $ 505 $ 779 Interest income includes interest from the Company’s bank deposits. The Company did not recognize an impairment loss on any investments for the three months ended March 31, 2018 and 2017.

Equity Investment

Equity Investment	3 Months Ended
	Mar. 31, 2018
Investments All Other Investments [Abstract]
Equity Investment	4. Equity Investment In March 2017, the Company participated in a Series B convertible preferred stock financing and invested $8.5 million in Viracta Therapeutics, Inc. (Viracta), a clinical stage drug development company. The Company did not exercise the option to purchase up to an additional $8.5 million worth of shares of the Series B convertible preferred stock by the expiration date of September 30, 2017. In May 2017, the Company executed an exclusive worldwide license with Viracta to develop and commercialize Viracta’s proprietary histone deacetylase inhibitor drug candidate for use in combination with NK cell therapy and possibly additional therapies. Based on the level of equity investment at risk, Viracta is not a Variable Interest Entity (VIE) and therefore is not consolidated under the VIE Model. Also, the Company does not hold a controlling financial interest in Viracta and therefore is not consolidating Viracta under the voting interest model. As the preferred stock is not considered in-substance common stock, the investment is not within the scope of accounting for the investment under the equity method. As the preferred stock does not have a readily determinable fair value, the Company has elected to apply the practicability exception noted under ASC 825 and estimates the fair value at its $8.5 million cost minus impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. As of March 31, 2018, the Company’s qualitative impairment assessment did not indicate there were events or changes in circumstances that may have had a significant adverse effect on the fair value of the investment. The Company has not recorded any impairments as of March 31, 2018 or on a cumulative basis. Further, the Company has not identified any downward or upward adjustments due to observable price changes in the investment as of the March 31, 2018 or on a cumulative basis. The $8.5 million cost of the investment is recorded in equity investment on the condensed consolidated balance sheet as of March 31, 2018.

Cash Equivalents and Marketable

Cash Equivalents and Marketable Debt Securities	3 Months Ended
	Mar. 31, 2018
Cash Equivalents And Marketable Securities [Abstract]
Cash Equivalents and Marketable Debt Securities	5. Cash Equivalents and Marketable Debt Securities As of March 31, 2018, all of the Company’s marketable debt securities are classified as available-for-sale and are scheduled to mature within 3.5 years. At March 31, 2018, the detail of the Company’s cash equivalents and marketable debt securities is as follows (in thousands): March 31, 2018 (unaudited) Amortized Cost Unrealized Unrealized Losses Fair Value Current: Corporate debt securities $ 86,952 $ 1 $ (222 ) $ 86,731 Government sponsored securities 12,508 — (15 ) 12,493 Foreign government bonds 5,936 — (5 ) 5,931 Commercial paper 5,441 — (3 ) 5,438 Current portion 110,837 1 (245 ) 110,593 Noncurrent: Corporate debt securities 12,642 — (248 ) 12,394 Government sponsored securities 2,759 — (62 ) 2,697 Noncurrent portion 15,401 - (310 ) 15,091 Total $ 126,238 $ 1 $ (555 ) $ 125,684 At December 31, 2017, the detail of the Company’s cash equivalents and marketable debt securities is as follows (in thousands): December 31, 2017 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt securities $ 82,188 $ 5 $ (84 ) $ 82,109 Government sponsored securities 19,261 — (28 ) 19,233 Foreign government bonds 6,441 — (5 ) 6,436 Current portion 107,890 5 (117 ) 107,778 Noncurrent: Corporate debt securities 27,109 — (226 ) 26,883 Government sponsored securities 2,760 — (43 ) 2,717 Noncurrent portion 29,869 — (269 ) 29,600 Total $ 137,759 $ 5 $ (386 ) $ 137,378 Included in foreign government bonds is $3.5 million of cash equivalents at December 31, 2017. Available-for-sale investments that had been in an unrealized loss position for more and less than 12 months at March 31, 2018 and December 31, 2017 are as follows (in thousands): March 31, 2018 (unaudited) Less than 12 months More than 12 months Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Corporate debt securities $ 73,914 $ (208 ) $ 23,211 $ (262 ) Government sponsored securities 1,999 (7 ) 13,191 (70 ) Foreign government bonds 4,533 (2 ) 1,397 (3 ) Commercial paper 5,438 (3 ) — — Total $ 85,884 $ (220 ) $ 37,799 $ (335 ) December 31, 2017 Less than 12 months More than 12 months Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Corporate debt securities $ 67,522 $ (104 ) $ 35,918 $ (206 ) Government sponsored securities 9,744 (20 ) 12,205 (51 ) Foreign government bonds 1,542 — 1,396 (5 ) Total $ 78,808 $ (124 ) $ 49,519 $ (262 ) 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 have any other-than-temporary impairment loss during the three months ended March 31, 2018. At March 31, 2018, 63 of the securities and bonds are in an unrealized loss position. The Company recorded realized gains and losses on sales or maturities of available-for-sale securities as follows (in thousands): Three Months Ended March 31, (unaudited) 2018 2017 Gross realized gains $ 2 $ 2 Gross realized losses — (5 ) Net realized gains $ 2 $ (3 )

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. 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. Recurring Valuations In accordance with the authoritative guidance for financial assets and liabilities measured at fair value on a recurring basis (ASC Topic 820), the Company prioritizes the inputs used to measure fair value from market-based assumptions to entity specific assumptions as follows: • Level 1—Inputs based on quoted market prices for identical assets or liabilities in active markets at the measurement date. • Level 2—Observable inputs other than quoted prices in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data. • Level 3—Inputs which reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. The inputs are unobservable in the market and significant to the instruments valuation. The following tables present the Company’s hierarchy for its assets measured at fair value on a recurring basis as of March 31, 2018 and December 31, 2017 (in thousands): Fair Value Measurements at March 31, 2018 (unaudited) Total Level 1 Level 2 Level 3 Assets: Current: Cash and cash equivalents $ 11,196 $ 11,196 $ — $ — Corporate debt securities 86,731 — 86,731 — Government sponsored securities 12,493 — 12,493 — Foreign government bonds 5,931 — 5,931 — Commercial paper 5,438 — 5,438 — Noncurrent: Corporate debt securities 12,394 — 12,394 — Government sponsored securities 2,697 — 2,697 — Total assets measured at fair value $ 136,880 $ 11,196 $ 125,684 $ — Fair Value Measurements at December 31, 2017 Total Level 1 Level 2 Level 3 Assets: Current: Cash and cash equivalents $ 23,872 $ 20,374 $ 3,498 $ — Corporate debt securities 82,109 — 82,109 — Government sponsored securities 19,233 — 19,233 — Foreign government bonds 2,938 — 2,938 — Noncurrent: Corporate debt securities 26,883 — 26,883 — Government sponsored securities 2,717 — 2,717 Total assets measured at fair value $ 157,752 $ 20,374 $ 137,378 $ — Non-recurring Valuation Non-financial assets and liabilities are recognized at fair value subsequent to initial recognition when they are deemed to be other-than-temporarily impaired. There were no material non-financial assets and liabilities deemed to be other-than-temporarily impaired and measured at fair value on a non-recurring basis for the three months ended March 31, 2018.

Collaboration and License Agree

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration and License Agreements	7. 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. There were no new collaborative agreements during the three months ended March 31, 2018 and 2017. License Agreement Chemotherapeutisches Forschungsinstitut Georg-Speyer-Haus (GSH) and DRK-Blutspendedienst Baden-Wurttenberg-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 or (iii) by the Company in its sole discretion upon 60 days prior written notice. In January 2018, the Company began expensing the first annual license fee of $0.5 million. The license fee is currently in prepaid expenses and other current assets on the condensed consolidated balance sheet. The Company is amortizing the license over the twelve month period and recording the expense in research and development on the condensed consolidated statement of operations.

Commitment and Contingencies

Commitment and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and contingencies	8. Commitments and Contingencies 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. Additionally, the Company records receivables from third-party insurers when recovery has been determined to be probable. This includes instances when the Company’s third-party insurers have agreed to reimburse certain legal defense costs incurred with the applicable law firms by the Company. 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. In September 2015, the USPTO filed a Motion for Expenses seeking $0.1 million for attorney’s fees and the USPTO’s expert witness fees. In February 2016, the U.S. District Court denied the USPTO’s Motion for Expenses for attorney’s fees and granted Director’s Motion for Expenses for the USPTO’s expert witness fees. The USPTO filed a notice of appeal on April 5, 2016. In May 2017, the Federal Circuit affirmed the U.S. District Court’s summary judgment ruling. The formal mandate was issued on June 26, 2017. In June 2017, the Federal Circuit reversed the U.S. District Court and remanded the case for the U.S. District Court to enter an award of $0.1 million in favor of the USPTO. On August 31, 2017, a majority of active Federal Circuit judges voted to vacate the June 2017 decision and hear the case en banc sua sponte. The USPTO filed its opening brief on November 15, 2017. The Company filed its opening brief on January 16, 2018. The USPTO filed its reply brief on January 31, 2018. Oral argument was heard on March 8, 2018. Based on the information available at present, the Company cannot reasonably estimate a range of loss for this action beyond the attorney and expert witness fees. Accordingly, the awarded fees have been accrued, but no liability associated with this action beyond the fees has been accrued. The Company is expensing legal costs associated with defending this litigation as the costs are incurred. Securities Litigation In March 2016, a putative securities class action complaint captioned Sudunagunta v. NantKwest, Inc., et al. The actions originally filed in state court were removed to federal court, and the various related actions have been consolidated. Plaintiffs assert causes of action for alleged Plaintiffs during various time periods from In September 2017, the court denied defendants' motion to dismiss the third amended consolidated complaint. On September 6, 2016, a putative Bushansky v. Soon-Shiong, et al. The Company is named solely as a nominal defendant. In October 2017, the first of two putative stockholder derivative complaints was filed in the Delaware Court of Chancery. The Delaware actions have been consolidated as In re NantKwest, Inc. Derivative Litigation, Cons. C.A. No. 2017-0774- Sudunagunta Bushansky On February 5, 2018, the defendants filed a motion to dismiss the consolidated complaint. 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. Insurance Recoveries The Company has reflected its right to insurance recoveries, limited to the extent of incurred or probable losses, as a receivable when such recoveries have been agreed to with its third-party insurers and receipt is deemed probable. This includes instances where the Company’s third-party insurers have agreed to reimburse certain legal defense costs incurred with applicable law firms by the Company. The amount of such receivable recorded at March 31, 2018 was $1.6 million included in prepaid expenses and current assets on the Company’s condensed consolidated balance sheet. Contractual Obligations - Leases The Company leases: (i) office space in Cardiff-by-the-Sea, California; (ii) a research facility in Woburn, Massachusetts; (iii) a research facility and office space in San Diego, California; (iv) research and manufacturing space in Culver City, California, from a related party (Note 9); and (v) a research and manufacturing facility in El Segundo, California, also from a related party (Note 9). The Company recognizes rent expense under its operating leases on a straight-line basis. Rent expense for the three months ended March 31, 2018 and 2017 was $0.7 million for both periods. Build-to-suit Lease In September 2016, the Company entered into a lease agreement with 605 Doug St, LLC, a related party (Note 9), for approximately 24,250 square feet in El Segundo, California, which is to be converted to a research and development laboratory and a current Good Manufacturing Practices (cGMP) manufacturing facility. 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. During the construction period, the Company records the rent payments as (1) a reduction of the build-to-suit lease liability; (2) deferred rent; and (3) rent expense on the imputed cost to lease the underlying land of the facility, which is considered an operating lease. For the three months ended March 31, 2018 and 2017, the Company recorded $0.1 million for both periods in rent expense, which is recorded in research and development expense on the condensed consolidated statement of operations. The Company is responsible for costs to build out the facility and has incurred costs of approximately $30.1 million as of March 31, 2018, which is reflected in construction in progress as part of property, plant and equipment, net on the condensed consolidated balance sheet. Additionally, in order for the facility to meet the Company's research and development laboratory and cGMP specifications, the Company started to make certain structural changes to the facility as part of the conversion. 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 condensed consolidated balance sheet as of March 31, 2018. 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 Financing Lease Obligation In November 2015, the Company entered into a facility license agreement with NantWorks LLC (NantWorks) (Note 9) 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 cGMP manufacturing facility. 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. The Company records the rent payments as (1) a reduction of the financing obligation; (2) imputed interest expense; and (3) rent expense on the imputed cost to lease the underlying land of the facility, which is considered an operating lease. For the three months ended March 31, 2018 and 2017, the Company recorded $47,000 for both periods in rent expense, which is reflected in research and development expense in the condensed consolidated statement of operations. Under the facility license agreement, the Company was responsible for costs to build out the laboratory and manufacturing facility space 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 in the condensed 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. Commitments The Company did not enter into any significant contracts during the three months ended March 31, 2018 other than those disclosed in this document .

Related Party Agreements

Related Party Agreements	3 Months Ended
	Mar. 31, 2018
Related Party Transactions [Abstract]
Related Party Agreements	9. Related Party Agreements The Company’s Chairman and CEO founded and has a controlling interest in NantWorks, which is a collection of multiple companies in the healthcare and technology space. As described below, the Company has entered into arrangements with NantWorks and certain affiliates of NantWorks to facilitate the development of new genetically modified NK cells for the Company’s product pipeline. Liquid Genomics, Inc. In March 2018, the Company entered into an agreement with Liquid Genomics, Inc. (Liquid Genomics) to obtain blood-based tumor profiling services. Liquid Genomics is a related party of the Company as it is a wholly owned subsidiary of NantHealth, Inc., a majority owned subsidiary of NantWorks. The Company is obligated to pay Liquid Genomics fixed, per patient fees. The agreement has an initial term of five years and renews automatically for successive one year periods, unless terminated earlier. All payments are due 30 days from the invoice date. During the three months ended March 31, 2018, $37,000 has been recognized in research and development expense on the condensed consolidated statement of operations. As of March 31, 2018, the Company owes Liquid Genomics $37,000, which is included in due to related parties on the condensed consolidated balance sheet. John Lee, M.D. and Leonard Sender, M.D., Inc., a professional medical corporation, dba In 2017 and 2018, the Company entered into multiple agreements with John Lee, M.D. and Leonard Sender, M.D., Inc., a professional medical corporation, dba Chan Soon-Shiong Institutes for Medicine (CSSIM), in El Segundo, California, to conduct various clinical trials. CSSIM is a related party as it is owned by two officers of the Company and NantWorks provides administrative services to CSSIM. One of the Company’s officers is the principal investigator for the trials on behalf of CSSIM. During the three months ended March 31, 2018, $0.7 million has been recognized in research and development expense on the condensed consolidated statement of operations and accrued expense on the condensed consolidated balance sheet. As of March 31, 2018, the Company owes CSSIM $0.7 million, which is included in due to related parties on the condensed consolidated balance sheet. Tensorcom, Inc. In April 2017, the Company entered into a sublease agreement with Tensorcom, Inc. (Tensorcom) related to its San Diego, California, research and development laboratory and office space, with a lease from May 1, 2017 through April 30, 2018. The Company’s Chairman and CEO indirectly owns all of the outstanding equity of Tensorcom. The sublease includes a portion of the premises consisting of approximately 6,557 rentable square feet of space. The monthly base rent is $25,000 per month, with an annual 3% increase. For the three months ended March 31, 2018, the Company recognized $0.1 million in other income on the condensed consolidated statement of operations under the sublease agreement. At March 31, 2018, there was no balance due between the parties. VivaBioCell S.p.A. 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 conducted research and development activities related to the Company’s NK cell lines using VBC’s proprietary technology. The Company paid $0.6 million to VBC, which is recorded in prepaid expenses and other current assets on the condensed consolidated balance sheet and expects to benefit from the research and development activities over a one year timeframe. For the three months ended March 31, 2018 and 2017, $0.1 million for both periods has been recognized in research and development expense on the condensed consolidated statement of operations and prepaid expenses and other current assets on the condensed consolidated balance sheet has been reduced by that amount. 605 Doug St. LLC 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 cGMP manufacturing facility. 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 8 – Build-to-suit Lease Altor BioScience, LLC In August 2016, the Company entered into an exclusive Co-Development Agreement (the Co-Development Agreement) with Altor BioScience, LLC, formerly known as Altor BioScience Corporation (Altor). Altor is a related party of the Company as it is a wholly owned subsidiary of NantCell, Inc. (NantCell), which is a majority owned subsidiary of NantWorks. 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 will supply free of charge sufficient amounts of Altor products for all pre-clinical requirements and all clinical requirements for up to 400 patients in phase I and/or phase II clinical trials, as required under the development plan for a project per the Co-Development agreement. 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. T he Company has dosed several patients with ALT-803 in its phase II Merkel cell carcinoma and phase Ib/II pancreatic trials. No charges for supplies or milestones by Altor have been incurred in association with the above trial during the three months ended March 31, 2018 and 2017. NantBio, Inc. In January 2018, the Company entered into a laboratory services agreement with NantBio, Inc. (NantBio) a NantWorks company. The agreement, effective December 1, 2017, includes a sublease of approximately 1,965 square feet of laboratory and office space at the Company’s San Diego, California, research facility. The term of the sublease is 24 months, but can be terminated by either party with 30 days prior written notice. The sublease agreement converts to a month-to-month lease after the initial term, not to exceed the expiration of the lease agreement between the Company and the landlord. The monthly sublease and service fee of $10,000 is subject to an annual 3% increase on the agreement anniversary date. The Company recognized $31,000 in other income on the consolidated statement of operations for the three months ended March 31, 2018. At March 31, 2018, NantBio owes the Company $10,000, which is included in prepaid expenses and other current assets on the condensed consolidated balance sheet. In March 2016, NantBio and the National Cancer Institute entered into a cooperative research and development agreement. The agreement covers NantBio 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 and second year under this agreement and is providing the first and second year funding under the five-year agreement. In both April 2016 and April 2017, the Company paid $0.6 million to the National Cancer Institute as a prepayment for the first and second year of funding. The Company recognizes research and development expense ratably over a 12 month period for each funding year and recorded $0.1 million of expense for both periods for the three months ended March 31, 2018 and 2017. NantWorks 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. 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 three months ended March 31, 2018 and 2017, the Company recorded selling, general and administrative expense of $0.8 million and $1.2 million, respectively. For the three months ended March 31, 2018 and 2017, the Company recorded research and development expense of $0.9 million and $0.8 million, respectively, under this arrangement on the condensed consolidated statement of operations. These amounts exclude certain general and administrative expenses provided by third party vendors directly for the Company’s benefit, which have been reimbursed to NantWorks based on those vendors’ invoiced amounts without markup by NantWorks. In November 2015, the Company entered into a facility license agreement with NantWorks, which became effective May 2015, for approximately 9,500 square feet in Culver City, California, which has been converted to a research and development laboratory and a cGMP manufacturing facility. See Note 8 - Financing Lease Obligation NantOmics, LLC In June 2015, the Company entered into an agreement with NantOmics, LLC (NantOmics), an affiliate of NantWorks, to obtain genomic sequencing and proteomic analysis services, as well as related data management and bioinformatics services, exclusively from NantOmics. The Company will have rights to use the data and results generated from NantOmics’ services in connection with the performance of the particular oncology trial with respect to which the services were performed, but NantOmics will own the data and results, as well as any other intellectual property it creates in performing these services on the Company’s behalf. 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 three months ended March 31, 2018 and 2017, the Company recorded operating expense of $42,000 and $0, respectively, under the agreement to research and development expense on the condensed consolidated statement of operations. At March 31, 2018, the Company owes NantOmics $0.1 million. NantCell In June 2015, the Company also entered into a supply agreement with NantCell, a majority owned subsidiary of NantWorks, 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. When an upfront payment is made, it is included in prepaid expenses on the condensed consolidated balance sheets until the product is received. The agreement has an initial term of five years and renews automatically for successive one year periods unless terminated earlier. During the three months ended March 31, 2018 and 2017, the Company recorded research and development expense of $0 and $0.3 million, respectively, on the condensed consolidated statement of operations. At March 31, 2018, the Company owed NantCell $0 and has a prepaid balance of $0.2 million included in prepaid expenses and other current assets on the condensed consolidated balance sheet.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Stockholders' Equity	10. Stockholders’ Equity Stock Repurchase— 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. At March 31, 2018, $19.1 million remained authorized for repurchase under the Company’s 2015 Share Repurchase Program and no shares were repurchased during the three months ended March 31, 2018.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	11. Stock-Based Compensation The following table presents stock-based compensation expense included on the Company’s condensed consolidated statement of operations (in thousands): Three Months Ended March 31, (unaudited) 2018 2017 Stock-based compensation expense: Warrants for common stock to an officer $ 7,636 $ 8,486 Employee stock options 978 1,351 Employee restricted stock units 392 318 Non-employee restricted stock units 67 (137 ) $ 9,073 $ 10,018 Stock-based compensation expense in operating expenses: Research and development $ 139 $ 92 Selling, general and administrative 8,934 9,926 $ 9,073 $ 10,018 Stock Options The following table summarizes stock option activity for the three months ended March 31, 2018 (in thousands, except for share and year amounts): Number of Shares Weighted- Average Exercise Price Aggregate Intrinsic Value Weighted- Average Remaining Contractual Life (in years) Outstanding at December 31, 2017 5,693,250 $ 7.71 $ 11,920 5.3 Options granted/exercised/forfeited — $ - Outstanding at March 31, 2018 5,693,250 $ 7.71 $ 8,987 5.0 Vested and Exercisable at March 31, 2018 5,230,375 $ 8.20 $ 8,192 5.4 The total unrecognized stock-based compensation expense related to non-vested stock options as of March 31, 2018 is $3.8 million, which is expected to be recognized over a weighted-average period of 1.0 years. Restricted Stock Units The following table summarizes the activity for restricted stock units: Number of Restricted Stock Units Outstanding Weighted-Average Grant Date Fair Value Unvested balance at December 31, 2017 888,189 $ 8.14 Granted 139,300 $ 3.74 Vested (70,200 ) $ 6.31 Forfeited (83,125 ) $ 8.13 Unvested balance at March 31, 2018 874,164 $ 7.58 During the three months ended March 31, 2018, the Company granted 139,300 shares of restricted stock units to employees. As of March 31, 2018, there was $3.7 million of unrecognized stock-based compensation expense related to restricted stock units that is expected to be recognized over a weighted-average period of 2.6 years. Of that amount, $3.1 million of unrecognized expense is related to employee grants with a weighted-average period of 2.9 years and $0.6 million of unrecognized expense is related to non-employee grants with a weighted-average period of 1.4 years that is impacted by periodic mark-to-market adjustments. Warrants The following table summarizes the warrant activity for the three months ended March 31, 2018: Outstanding at December 31, 2017 17,721,088 Warrants exercised (14,270 ) Outstanding at March 31, 2018 17,706,818 Vested and exercisable at March 31, 2018 16,966,218 The total unrecognized stock-based compensation expense related to non-vested warrants as of March 31, 2018 is $10.2 million, which is expected to be recognized over a weighted-average period of 0.3 years.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes The difference between the federal statutory tax rate of 21% and the Company’s 0% tax rate is due to losses in jurisdictions from which the Company cannot benefit. Intraperiod tax allocation rules require the Company to allocate the provision for income taxes between continuing operations and other categories of earnings, such as other comprehensive income. In periods in which the Company has a year-to-date pre-tax loss from continuing operations and pre-tax income in other categories of earnings, such as other comprehensive income, the Company must allocate the tax provision to the other categories of earnings. The Company then records a related tax benefit in continuing operations. The Company did not record any unrealized gains in other comprehensive income during the three months ended March 31, 2018. The Company did record unrealized gains in other comprehensive income during the three months ended March 31, 2017. As a result, the Company recorded a tax benefit of $0 and $6,000 for the three months ended March 31, 2018 and 2017, respectively, on the condensed consolidated statement of operations and $0 and $ 26,000, respectively, in other comprehensive income on the condensed consolidated balance sheet. The Company is operating in Korea. During the three months ended March 31, 2018 and 2017, the tax benefit related to Korea is $0.1 million for each period. The Company currently files federal and state income tax returns in the United States and in Korea. Income tax expense consists of U.S. federal, state, and Korean income taxes. To date, the Company has not been required to pay U.S. federal income taxes because of current and accumulated net operating losses. The Tax Cuts and Jobs Act In March 2018, the FASB issued ASU 2018-05, Income Taxes – Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118.

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Liquidity	Liquidity As of March 31, 2018, the Company had an accumulated deficit of approximately $526.0 million. The Company also had negative cash flow from operations of approximately $15.5 million during the three months ended March 31, 2018. 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, fail 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 and marketable debt securities on hand 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 debt 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.
Principles of Consolidation and Equity Investments	Principles of Consolidation and Equity Investments The Company’s condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, Inex Bio, Inc. and 557 Doug St, LLC, and have been prepared in accordance with GAAP. All intercompany amounts have been eliminated. The Company applies the variable interest model under Accounting Standards Codification (ASC) Topic 810, Consolidation For entities the Company holds as an equity investment and are not consolidated under the VIE Model, the Company considers whether its investment constitutes ownership of a majority of the voting interests in the entity and therefore should be considered for consolidation under the voting interest model. Unconsolidated equity investments in the common stock or in-substance common stock of an entity under which the Company is able to exercise significant influence, but not control, are accounted for using the equity method. The Company’s ability to exercise significant influence is generally indicated by ownership of 20 to 50 percent interest in the voting securities of the entity. All other unconsolidated equity investments on which the Company is not able to exercise significant influence will be subsequently measured at fair value with unrealized
Use of Estimates	Use of Estimates The preparation of condensed 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 condensed 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 stock-based compensation, the valuation allowance for deferred tax assets, preclinical and clinical trial accruals, impairment assessments, 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.
Basic and Diluted Net Loss Per Share of Common Stock	Basic and Diluted Net Loss per Share of Common Stock Basic net loss per share is calculated by dividing 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 March 31, 2018 2017 Outstanding options 5,693,250 5,693,250 Outstanding restricted stock units 874,164 1,060,381 Outstanding warrants 17,706,818 17,768,314 Total 24,274,232 24,521,945 Amounts in the table above reflect the common stock equivalents of the noted instruments.
Recently Adopted Accounting Policies	Recently Adopted Accounting Policies Financial Assets and Liabilities and Equity Investment Effective January 1, 2018, the Company adopted Accounting Standard Update (ASU) 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities The Company owns non-marketable equity securities that are accounted for as an equity investment at cost minus impairment and plus or minus changes resulting from observable price changes because the preferred stock held by the Company is not considered in-substance common stock and such preferred stock does not have a readily determinable fair value. All investments are reviewed on a regular basis for possible impairment. If an investment's fair value is determined to be less than its net carrying value, the investment is written down to its fair value. Such an evaluation is judgmental and dependent on specific facts and circumstances. Factors considered in determining whether an impairment indicator is present include: the investees’ earning performance and clinical trial performance, change in the investees’ industry and geographic area in which it operates, offers to purchase or sell the security for a price less than the cost of the investment, issues that raise concerns about the investee's ability to continue as a going concern and any other information that the Company may be aware of related to the investment. Factors considered in determining whether an observable price change has occurred include: the price at which the investee issues equity instruments similar to those of the Company’s investment and the rights and preferences of those equity instruments compared to the Company’s. Revenue Recognition Beginning January 1, 2018, the Company follows the provisions of ASC Topic 606, Revenue from Contracts with Customers The Company derives substantially all of its revenue from non-exclusive license agreements with a limited number of pharmaceutical and biotechnology companies granting them the right to use the Company’s cell lines and intellectual property for non-clinical use. These agreements generally include upfront fees and annual research license fees for such use, as well as commercial license fees for sales of the Company’s licensee’s products developed or manufactured using the Company’s intellectual property and cell lines. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account in ASC Topic 606. A contract’s transaction price is allocated to each distinct performance obligation based on relative standalone selling price and recognized as revenue when, or as, the performance obligation is satisfied. Under the Company’s license agreements with customers, the Company typically promises to provide a license to use certain cell lines and related patents, the related know-how, and future research and development data that affects the license. The Company concluded that these promises represent one performance obligation due to the highly interrelated nature of the promises. The Company provides the cell lines and know-how immediately upon entering into the contracts. The research and development data is provided throughout the term of the contract when and if available. The Company’s license agreement with Intrexon included a nonrefundable upfront payment of $0.4 million, received when the Company entered into the contract in 2010. In this instance, the Company determined that under ASC 606 it would be appropriate to recognize the initial milestone payment at a point in time, when it transferred the license. In this case, the intellectual property provided under the contract is functional intellectual property under ASC 606 and was determined to be a distinct performance obligation in the context of the arrangement. Prior to adoption, the upfront payment had been initially recorded as deferred revenue and was being recognized into revenue on a straight-line basis. As a result, upon adoption of ASC 606, the Company adjusted its opening retained deficit for the effects of recognizing revenue upfront for the initial milestone. The adjustment to opening retained deficit upon adoption was not material. The license agreements may include nonrefundable upfront payments, event-based milestone payments, sales-based royalty payments, or some combination of these. The event-based milestone payments represent variable consideration and the Company uses the most likely amount method to estimate this variable consideration. Given the high degree of uncertainly around achievement of these milestones, the Company does not recognize revenue from these milestone payments until the uncertainty associated with these payments is resolved. The Company currently estimates variable consideration related to milestone payments to be zero and, as such, no revenue has been recognized for milestone payments. The Company will recognize revenue from sales-based royalty payments when or as the sales occur. On a quarterly basis, the Company will re-evaluate its estimate of milestone variable consideration to determine whether any amount should be included in the transaction price and recorded in revenue prospectively. Upon adoption, the Company changed its accounting policy from accounting for milestones payments under the milestone method to accounting for variable consideration as discussed above. The change in accounting policy did not change any amounts in the financial statements because of the significant uncertainty surrounding the estimate of variable consideration for milestone payments. The Company’s revenue from non-clinical license agreements is nominal. In the future, the Company may generate revenue from license agreements entered into for therapeutic uses. To date, the Company has not generated any revenue from product sales. If the Company fails to complete the development of its product candidates in a timely manner or fails to obtain regulatory approval for them, the Company may never be able to generate substantial future revenue. Statement of Cash Flows Effective January 1, 2018, the Company adopted ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments . ASU 2016-15 adds or clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows. Also, effective January 1, 2018, the Company adopted Statement of Cash Flows: Restricted Cash, a consensus of the FASB’s Emerging Issues Task Force . ASU 2016-18 requires that the statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Entities will also be required to reconcile such total to amounts on the balance sheet and disclose the nature of the restrictions. Both Updates will be effective for annual reporting periods beginning after December 15, 2017, including interim periods within those annual periods. Prior periods were retrospectively adjusted to conform to the current period’s presentation. There was no material impact on the Company’s statement of cash flows on adoption of either Update.
Recent Accounting Pronouncements – Not Yet Adopted	Recent Accounting Pronouncements – Not Yet Adopted In February 2018, the FASB issued ASU 2018-02, Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. Adoption of ASU 2018-02 is not expected to have a significant impact in 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. Adoption of ASU 2016-13 is not expected to have a significant impact in the Company’s consolidated financial statements and disclosures. In February 2016, the FASB issued ASU 2016-02, Leases

Summary of Significant Accoun21

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
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 March 31, 2018 2017 Outstanding options 5,693,250 5,693,250 Outstanding restricted stock units 874,164 1,060,381 Outstanding warrants 17,706,818 17,768,314 Total 24,274,232 24,521,945 Amounts in the table above reflect the common stock equivalents of the noted instruments.

Financial Statement Details (Ta

Financial Statement Details (Tables)	3 Months Ended
	Mar. 31, 2018
Financial Statement Details [Abstract]
Prepaid Expenses and Other Current Assets	As of March 31, 2018 and December 31, 2017, prepaid expenses and other current assets consisted of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Insurance claim receivable $ 1,576 $ 340 Prepaid license fees 843 597 Interest receivable - marketable debt securities 615 764 Equipment deposits 442 482 Prepaid insurance 381 572 Prepaid rent 373 373 Prepaid supplies 243 210 Prepaid services 157 416 Other 328 398 $ 4,958 $ 4,152
Property, Plant and Equipment, Net	As of March 31, 2018 and December 31, 2017, property, plant and equipment, net consisted of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Construction in progress $ 43,339 $ 42,281 Buildings 23,811 23,811 Equipment 9,702 9,625 Leasehold improvements 3,967 3,918 Software 1,095 1,092 Furniture & fixtures 279 302 82,193 81,029 Accumulated depreciation (5,367 ) (4,303 ) $ 76,826 $ 76,726
Intangible Assets, Net	As of March 31, 2018 and December 31, 2017, intangible assets consisted of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Technology license $ 9,042 $ 9,042 Less accumulated amortization (6,782 ) (6,216 ) $ 2,260 $ 2,826
Other Assets	As of March 31, 2018 and December 31, 2017, other assets consisted of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Restricted cash $ 179 $ 179 Security deposits 127 127 Other 60 24 $ 366 $ 330 Restricted cash is a certificate of deposit that is collateral for the letter of credit required as a security deposit for the Company’s San Diego, California, facility by the Company’s landlord.
Accrued Expenses	As of March 31, 2018 and December 31, 2017, accrued expenses consisted of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Accrued construction costs $ 5,019 $ 6,212 Accrued bonus 2,476 1,930 Accrued professional and service fees 1,471 1,048 Accrued compensation 1,396 944 Accrued preclinical and clinical trial costs 938 521 Accrued laboratory equipment and supplies 467 — Other 310 612 $ 12,077 $ 11,267
Other Current Liabilities	As of March 31, 2018 and December 31, 2017, other current liabilities were made up of (in thousands): March 31, 2018 December 31, 2017 (Unaudited) Deferred rent - current portion $ 539 $ 520 Financing obligation - current portion 292 284 Build-to-suit lease liability - current portion 271 334 Other 197 235 $ 1,299 $ 1,373
Investment Income, Net	Net investment income includes interest income from all bank accounts as well as marketable debt securities, 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 three months ended March 31, 2018 and 2017 (in thousands): Three Months Ended March 31, (Unaudited) 2018 2017 Interest income $ 704 $ 1,354 Investment amortization accretion expense, net (201 ) (572 ) Net realized gains (losses) on investments 2 (3 ) $ 505 $ 779

Cash Equivalents and Marketab23

Cash Equivalents and Marketable Debt Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Cash Equivalents And Marketable Securities [Abstract]
Schedule of Cash Equivalents and Marketable Debt Securities Available-for-Sale	As of March 31, 2018, all of the Company’s marketable debt securities are classified as available-for-sale and are scheduled to mature within 3.5 years. At March 31, 2018, the detail of the Company’s cash equivalents and marketable debt securities is as follows (in thousands): March 31, 2018 (unaudited) Amortized Cost Unrealized Unrealized Losses Fair Value Current: Corporate debt securities $ 86,952 $ 1 $ (222 ) $ 86,731 Government sponsored securities 12,508 — (15 ) 12,493 Foreign government bonds 5,936 — (5 ) 5,931 Commercial paper 5,441 — (3 ) 5,438 Current portion 110,837 1 (245 ) 110,593 Noncurrent: Corporate debt securities 12,642 — (248 ) 12,394 Government sponsored securities 2,759 — (62 ) 2,697 Noncurrent portion 15,401 - (310 ) 15,091 Total $ 126,238 $ 1 $ (555 ) $ 125,684 At December 31, 2017, the detail of the Company’s cash equivalents and marketable debt securities is as follows (in thousands): December 31, 2017 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Corporate debt securities $ 82,188 $ 5 $ (84 ) $ 82,109 Government sponsored securities 19,261 — (28 ) 19,233 Foreign government bonds 6,441 — (5 ) 6,436 Current portion 107,890 5 (117 ) 107,778 Noncurrent: Corporate debt securities 27,109 — (226 ) 26,883 Government sponsored securities 2,760 — (43 ) 2,717 Noncurrent portion 29,869 — (269 ) 29,600 Total $ 137,759 $ 5 $ (386 ) $ 137,378
Available-for-Sale Investments in Unrealized Loss Position	Available-for-sale investments that had been in an unrealized loss position for more and less than 12 months at March 31, 2018 and December 31, 2017 are as follows (in thousands): March 31, 2018 (unaudited) Less than 12 months More than 12 months Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Corporate debt securities $ 73,914 $ (208 ) $ 23,211 $ (262 ) Government sponsored securities 1,999 (7 ) 13,191 (70 ) Foreign government bonds 4,533 (2 ) 1,397 (3 ) Commercial paper 5,438 (3 ) — — Total $ 85,884 $ (220 ) $ 37,799 $ (335 ) December 31, 2017 Less than 12 months More than 12 months Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Corporate debt securities $ 67,522 $ (104 ) $ 35,918 $ (206 ) Government sponsored securities 9,744 (20 ) 12,205 (51 ) Foreign government bonds 1,542 — 1,396 (5 ) Total $ 78,808 $ (124 ) $ 49,519 $ (262 )
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): Three Months Ended March 31, (unaudited) 2018 2017 Gross realized gains $ 2 $ 2 Gross realized losses — (5 ) Net realized gains $ 2 $ (3 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Summary of Financial Assets Measured at Fair Value on Recurring Basis	The following tables present the Company’s hierarchy for its assets measured at fair value on a recurring basis as of March 31, 2018 and December 31, 2017 (in thousands): Fair Value Measurements at March 31, 2018 (unaudited) Total Level 1 Level 2 Level 3 Assets: Current: Cash and cash equivalents $ 11,196 $ 11,196 $ — $ — Corporate debt securities 86,731 — 86,731 — Government sponsored securities 12,493 — 12,493 — Foreign government bonds 5,931 — 5,931 — Commercial paper 5,438 — 5,438 — Noncurrent: Corporate debt securities 12,394 — 12,394 — Government sponsored securities 2,697 — 2,697 — Total assets measured at fair value $ 136,880 $ 11,196 $ 125,684 $ — Fair Value Measurements at December 31, 2017 Total Level 1 Level 2 Level 3 Assets: Current: Cash and cash equivalents $ 23,872 $ 20,374 $ 3,498 $ — Corporate debt securities 82,109 — 82,109 — Government sponsored securities 19,233 — 19,233 — Foreign government bonds 2,938 — 2,938 — Noncurrent: Corporate debt securities 26,883 — 26,883 — Government sponsored securities 2,717 — 2,717 Total assets measured at fair value $ 157,752 $ 20,374 $ 137,378 $ —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Based Compensation Expense Included in Operations Statement	The following table presents stock-based compensation expense included on the Company’s condensed consolidated statement of operations (in thousands): Three Months Ended March 31, (unaudited) 2018 2017 Stock-based compensation expense: Warrants for common stock to an officer $ 7,636 $ 8,486 Employee stock options 978 1,351 Employee restricted stock units 392 318 Non-employee restricted stock units 67 (137 ) $ 9,073 $ 10,018 Stock-based compensation expense in operating expenses: Research and development $ 139 $ 92 Selling, general and administrative 8,934 9,926 $ 9,073 $ 10,018
Summary of Stock Option Activity	The following table summarizes stock option activity for the three months ended March 31, 2018 (in thousands, except for share and year amounts): Number of Shares Weighted- Average Exercise Price Aggregate Intrinsic Value Weighted- Average Remaining Contractual Life (in years) Outstanding at December 31, 2017 5,693,250 $ 7.71 $ 11,920 5.3 Options granted/exercised/forfeited — $ - Outstanding at March 31, 2018 5,693,250 $ 7.71 $ 8,987 5.0 Vested and Exercisable at March 31, 2018 5,230,375 $ 8.20 $ 8,192 5.4
Restricted Stock Units Activity	The following table summarizes the activity for restricted stock units: Number of Restricted Stock Units Outstanding Weighted-Average Grant Date Fair Value Unvested balance at December 31, 2017 888,189 $ 8.14 Granted 139,300 $ 3.74 Vested (70,200 ) $ 6.31 Forfeited (83,125 ) $ 8.13 Unvested balance at March 31, 2018 874,164 $ 7.58
Summary of Warrant Activity	The following table summarizes the warrant activity for the three months ended March 31, 2018: Outstanding at December 31, 2017 17,721,088 Warrants exercised (14,270 ) Outstanding at March 31, 2018 17,706,818 Vested and exercisable at March 31, 2018 16,966,218

Description of Business and B26

Description of Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit	$ (526,046)		$ (498,713)
Net cash used in operating activities	$ (15,511)	$ (10,057)

Summary of Significant Accoun27

Summary of Significant Accounting Policies - Securities Excluded from the Computation of Potentially Dilutive Securities (Detail) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	24,274,232	24,521,945
Employee Stock Option
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	5,693,250	5,693,250
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	874,164	1,060,381
Outstanding Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	17,706,818	17,768,314

Summary of Significant Accoun28

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Feb. 28, 2010	Mar. 31, 2018
Accounting Policies [Line Items]
Variable consideration related to milestone payment		$ 0
Revenue recognized for milestone payment		$ 0
Intrexon Corporation
Accounting Policies [Line Items]
Nonrefundable upfront payment	$ 400

Financial Statement Details - P

Financial Statement Details - Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financial Statement Details [Abstract]
Insurance claim receivable	$ 1,576	$ 340
Prepaid license fees	843	597
Interest receivable - marketable debt securities	615	764
Equipment deposits	442	482
Prepaid insurance	381	572
Prepaid rent	373	373
Prepaid supplies	243	210
Prepaid services	157	416
Other	328	398
Total prepaid expenses and other current assets	$ 4,958	$ 4,152

Financial Statement Details -30

Financial Statement Details - Property, Plant and Equipment, Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 82,193	$ 81,029
Accumulated depreciation	(5,367)	(4,303)
Property, plant and equipment, net	76,826	76,726
Construction in Progress
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	43,339	42,281
Buildings
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	23,811	23,811
Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	9,702	9,625
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	3,967	3,918
Software
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	1,095	1,092
Furniture And Fixtures
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 279	$ 302

Financial Statement Details - A

Financial Statement Details - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Financial Statement Details [Line Items]
Depreciation expense related to property, plant and equipment	$ 1,100,000	$ 600,000
Property, plant and equipment, gross	82,193,000		$ 81,029,000
Non cash build to suit lease asset	5,100,000
Amortization expense	600,000	600,000
Impairment loss on recognized investments	0	$ 0
Buildings
Financial Statement Details [Line Items]
Property, plant and equipment, gross	23,811,000		23,811,000
Capital Lease
Financial Statement Details [Line Items]
Property, plant and equipment, gross	19,500,000		19,500,000
Culver City California | Financing Lease
Financial Statement Details [Line Items]
Property, plant and equipment, gross	$ 4,300,000		$ 4,300,000

Financial Statement Details - I

Financial Statement Details - Intangible Assets, Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Intangible assets, net	$ 2,260	$ 2,826
Technology License
Finite Lived Intangible Assets [Line Items]
Total intangible assets	9,042	9,042
Less accumulated amortization	(6,782)	(6,216)
Intangible assets, net	$ 2,260	$ 2,826

Financial Statement Details - O

Financial Statement Details - Other Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financial Statement Details [Abstract]
Restricted cash	$ 179	$ 179
Security deposits	127	127
Other	60	24
Other Assets Noncurrent	$ 366	$ 330

Financial Statement Details -34

Financial Statement Details - Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financial Statement Details [Abstract]
Accrued construction costs	$ 5,019	$ 6,212
Accrued bonus	2,476	1,930
Accrued professional and service fees	1,471	1,048
Accrued compensation	1,396	944
Accrued preclinical and clinical trial costs	938	521
Accrued laboratory equipment and supplies	467	0
Other	310	612
Accrued Liabilities Current	$ 12,077	$ 11,267

Financial Statement Details -35

Financial Statement Details - Other Current Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financial Statement Details [Abstract]
Deferred rent - current portion	$ 539	$ 520
Financing obligation - current portion	292	284
Build-to-suit lease liability - current portion	271	334
Other	197	235
Other current liabilities	$ 1,299	$ 1,373

Financial Statement Details -36

Financial Statement Details - Investment Income, Net (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Financial Statement Details [Abstract]
Interest income	$ 704	$ 1,354
Investment amortization accretion expense, net	(201)	(572)
Net realized gains (losses) on investments	2	(3)
Investment income, net	$ 505	$ 779

Equity Investment - Additional

Equity Investment - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Mar. 31, 2017
Schedule Of Cost Method Investments [Line Items]
Equity investment	$ 8,500,000	$ 8,500,000		$ 8,500,000
Equity investment, description	As the preferred stock is not considered in-substance common stock, the investment is not within the scope of accounting for the investment under the equity method. As the preferred stock does not have a readily determinable fair value, the Company has elected to apply the practicability exception noted under ASC 825 and estimates the fair value at its $8.5 million cost minus impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer.
Maximum
Schedule Of Cost Method Investments [Line Items]
Option to purchase additional shares under equity investment			$ 8,500,000

Cash Equivalents and Marketab38

Cash Equivalents and Marketable Debt Securities - Additional Information (Detail) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018Security	Dec. 31, 2017USD ($)
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities maturity period	3 years 6 months
Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Number of available-for-sale securities in unrealized loss positions | Security	63
Maximum
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, period of unrealized loss positions	12 months	12 months
Foreign Government Bonds
Schedule Of Available For Sale Securities [Line Items]
Cash equivalent portions included in current fair values | $		$ 3.5

Cash Equivalents and Marketab39

Cash Equivalents and Marketable Debt Securities - Schedule of Cash Equivalents and Marketable Debt Securities Available-for-Sale (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 126,238	$ 137,759
Unrealized Gains	1	5
Unrealized Losses	(555)	(386)
Fair Value	125,684	137,378
Current Assets
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	110,837	107,890
Unrealized Gains	1	5
Unrealized Losses	(245)	(117)
Fair Value	110,593	107,778
Current Assets | Government Sponsored Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	12,508	19,261
Unrealized Gains	0	0
Unrealized Losses	(15)	(28)
Fair Value	12,493	19,233
Current Assets | Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	86,952	82,188
Unrealized Gains	1	5
Unrealized Losses	(222)	(84)
Fair Value	86,731	82,109
Current Assets | Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	5,441
Unrealized Gains	0
Unrealized Losses	(3)
Fair Value	5,438
Current Assets | Foreign Government Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	5,936	6,441
Unrealized Gains	0	0
Unrealized Losses	(5)	(5)
Fair Value	5,931	6,436
Noncurrent Assets
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	15,401	29,869
Unrealized Gains	0	0
Unrealized Losses	(310)	(269)
Fair Value	15,091	29,600
Noncurrent Assets | Government Sponsored Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	2,759	2,760
Unrealized Gains	0	0
Unrealized Losses	(62)	(43)
Fair Value	2,697	2,717
Noncurrent Assets | Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	12,642	27,109
Unrealized Gains	0	0
Unrealized Losses	(248)	(226)
Fair Value	$ 12,394	$ 26,883

Cash Equivalents and Marketab40

Cash Equivalents and Marketable Debt Securities - Available-for-Sale Investments in Unrealized Loss Position (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	$ 85,884	$ 78,808
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	(220)	(124)
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	37,799	49,519
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	(335)	(262)
Government Sponsored Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	1,999	9,744
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	(7)	(20)
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	13,191	12,205
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	(70)	(51)
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	73,914	67,522
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	(208)	(104)
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	23,211	35,918
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	(262)	(206)
Foreign Government Bonds
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	4,533	1,542
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	(2)	0
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	1,397	1,396
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	(3)	$ (5)
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	5,438
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	(3)
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	0
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	$ 0

Cash Equivalents and Marketab41

Cash Equivalents and Marketable Debt Securities -Schedule of Realized Gains and Losses on Sales or Maturities of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash Equivalents And Marketable Securities [Abstract]
Available-for-sale Securities, Gross Realized Gains	$ 2	$ 2
Available-for-sale Securities, Gross Realized Losses	0	(5)
Available-for-sale Securities, Net Realized Gains	$ 2	$ (3)

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	$ 136,880	$ 157,752
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	11,196	20,374
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	125,684	137,378
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Current Assets | Cash and cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	11,196	23,872
Current Assets | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	86,731	82,109
Current Assets | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	12,493	19,233
Current Assets | Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	5,931	2,938
Current Assets | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	5,438
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	11,196	20,374
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 1 | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
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 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
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	0	3,498
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	86,731	82,109
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	12,493	19,233
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	5,931	2,938
Current Assets | Level 2 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	5,438
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 | 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 3 | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
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 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
Noncurrent Assets | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	12,394	26,883
Noncurrent Assets | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	2,697	2,717
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 1 | Government Sponsored 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 | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	12,394	26,883
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	2,697	2,717
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
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	$ 0

Collaboration and License Agr43

Collaboration and License Agreements - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2018	Mar. 31, 2018
Licensing Agreement [Abstract]
Annual license fee	$ 0.5
License fee amortization period		12 months

Commitment and Contingencies -

Commitment and Contingencies - Additional Information (Detail)	1 Months Ended				3 Months Ended
	Jun. 30, 2017USD ($)	Sep. 30, 2016USD ($)ft²	Nov. 30, 2015USD ($)ft²	Sep. 30, 2015USD ($)	Mar. 31, 2018USD ($)	Mar. 31, 2017USD ($)	Aug. 31, 2016USD ($)
Commitments And Contingencies [Line Items]
Rent expense					$ 700,000	$ 700,000
Non cash build to suit lease asset					$ 5,100,000
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					$ 30,100,000
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	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					47,000	$ 47,000
Prepaid Expenses and Current Assets
Commitments And Contingencies [Line Items]
Insurance claim receivable					$ 1,600,000
USPTO
Commitments And Contingencies [Line Items]
Attorney's fees and expert witness fees				$ 100,000
Award amount in favour to other party	$ 100,000

Related Party Agreements - Addi

Related Party Agreements - Additional Information (Detail)

Dec. 01, 2017USD ($)ft²

Mar. 31, 2018USD ($)Officer

Apr. 30, 2017USD ($)ft²

Sep. 30, 2016USD ($)ft²

Apr. 30, 2016USD ($)

Mar. 31, 2016

Nov. 30, 2015USD ($)ft²

Jun. 30, 2015

Mar. 31, 2018USD ($)OfficerPatient

Mar. 31, 2017USD ($)

Dec. 31, 2017USD ($)

Feb. 28, 2017USD ($)

Related Party Transaction [Line Items]

Research and development

$ 13,991,000

$ 9,248,000

Due to related parties

$ 2,456,000

2,456,000

$ 2,363,000

Prepaid expenses and other current assets

$ 4,958,000

4,958,000

$ 4,152,000

Selling, general and administrative expense

14,298,000

16,227,000

Liquid Genomics, Inc.

Related Party Transaction [Line Items]

Initial term of agreement entered into with the related party by the entity

5 years

Related party, agreement renewal term

1 year

Related party agreement payments due period from invoice date

30 days

Research and development

37,000

Due to related parties

$ 37,000

37,000

Chan Soon-Shiong Institutes for Medicine (CSSIM) | California

Related Party Transaction [Line Items]

Research and development

700,000

Due to related parties

$ 700,000

$ 700,000

Number of officers | Officer

2

2

Tensorcom, Inc | San Diego California

Related Party Transaction [Line Items]

Period of agreement

Lease from May 1, 2017 through April 30, 2018

Number of square foot of facility leased | ft²

6,557

Base rent - monthly

$ 25,000

Percentage of annual increase of base rent

3.00%

Due between parties

$ 0

$ 0

Tensorcom, Inc | San Diego California | Other Income

Related Party Transaction [Line Items]

Sublease revenue recognized

100,000

VivaBioCell S.p.A.

Related Party Transaction [Line Items]

Research and development

$ 100,000

100,000

Prepaid expenses and other current assets

$ 600,000

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%

Due between parties

0

$ 0

Annual percentage increases to base rent commencement date

Jul. 31, 2017

Doug St, LLC | Research and Development

Related Party Transaction [Line Items]

Rent expense

$ 100,000

100,000

Doug St, LLC | El Segundo California

Related Party Transaction [Line Items]

Number of square foot of facility leased | ft²

24,250

Altor

Related Party Transaction [Line Items]

Maximum number of patients in phase 1 and 2 for clinical trials | Patient

400

Supplies and milestone charges for conducting clinical trials

$ 0

0

NantBioScience

Related Party Transaction [Line Items]

Initial term of agreement entered into with the related party by the entity

5 years

Research and development

$ 100,000

$ 100,000

Number of square foot of facility leased | ft²

1,965

Base rent - monthly

$ 10,000

Percentage of annual increase of base rent

3.00%

Sublease term

24 months

Sublease termination notice period

30 days

Prepayment of funding amount

$ 600,000

$ 600,000

Research and development expense, ratable payment period

12 months

12 months

NantBioScience | Prepaid Expenses and Current Assets

Related Party Transaction [Line Items]

Due between parties

$ 10,000

NantBioScience | Other Income

Related Party Transaction [Line Items]

Sublease revenue recognized

31,000

NantWorks

Related Party Transaction [Line Items]

Due to related parties

1,600,000

$ 1,600,000

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

NantWorks | Shared Services Agreement

Related Party Transaction [Line Items]

Research and development

900,000

800,000

Selling, general and administrative expense

800,000

1,200,000

NantWorks | Reimbursements | Shared Services Agreement

Related Party Transaction [Line Items]

Research and development

600,000

100,000

Selling, general and administrative expense

100,000

100,000

NantWorks | Research and Development

Related Party Transaction [Line Items]

Rent expense

47,000

47,000

NantOmics

Related Party Transaction [Line Items]

Initial term of agreement entered into with the related party by the entity

5 years

Related party, agreement renewal term

1 year

Research and development

42,000

0

Due to related parties

100,000

100,000

NantCell Inc

Related Party Transaction [Line Items]

Initial term of agreement entered into with the related party by the entity

5 years

Related party, agreement renewal term

1 year

Research and development

0

$ 300,000

Due to related parties

0

0

Prepaid expenses and other current assets

$ 200,000

$ 200,000

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Nov. 30, 2015
Equity [Abstract]
Total amount authorized for repurchase		$ 50,000,000
Repurchase of common stock, shares	0
Remaining authorized repurchase amount	$ 19,100,000

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Based Compensation Expenses Related to Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 9,073	$ 10,018
Warrants For Common Stock | Officer
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	7,636	8,486
Employee Stock Option
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	978	1,351
Employee Restricted Stock Units
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	392	318
Non Employee Restricted Stock Units
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	67	(137)
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	139	92
Selling, General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 8,934	$ 9,926

Stock-Based Compensation - St48

Stock-Based Compensation - Stock Option Activity (Detail) - Employee Stock Option - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Number of Shares
Stock Options, Beginning Balance	5,693,250
Stock Options, Options granted/exercised/forfeited	0
Stock Options, Ending Balance	5,693,250	5,693,250
Stock Options, Vested and Exercisable	5,230,375
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding Beginning balance	$ 7.71
Weighted Average Exercise Price, Options granted/exercised/forfeited	0
Weighted Average Exercise Price, Outstanding Ending balance	7.71	$ 7.71
Weighted Average Exercise Price, Vested and Exercisable	$ 8.20
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding, Beginning balance	$ 8,987	$ 11,920
Aggregate Intrinsic Value, Vested and Exercisable	$ 8,192
Weighted Average Remaining Contractual Life
Weighted Average Remaining Contractual Life, Outstanding	5 years	5 years 3 months 18 days
Weighted Average Remaining Contractual Life, Vested and Exercisable	5 years 4 months 24 days

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)shares
Outstanding Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense related to non-vested stock options	$ 10.2
Weighted-average period for recognition	3 months 18 days
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense related to non-vested stock options	$ 3.8
Weighted-average period for recognition	1 year
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
Number of shares granted | shares	139,300
Unrecognized compensation cost related to non-vested stock options	$ 3.1
Outstanding Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period for recognition	2 years 7 months 6 days
Number of shares granted | shares	139,300
Unrecognized compensation cost related to non-vested stock options	$ 3.7
Non Employee Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period for recognition	1 year 4 months 24 days
Unrecognized compensation cost related to non-vested stock options	$ 0.6

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Units Activity (Detail) - Outstanding Restricted Stock Units	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested, Beginning balance | shares	888,189
Number of Shares, Granted | shares	139,300
Number of Shares, Vested | shares	(70,200)
Number of Shares, Forfeited | shares	(83,125)
Number of Shares, Unvested, Ending balance | shares	874,164
Weighted-Average Grant Date Fair Value, Unvested, beginning balance | $ / shares	$ 8.14
Weighted-Average Grant Date Fair Value, Granted | $ / shares	3.74
Weighted-Average Grant Date Fair Value, Vested | $ / shares	6.31
Weighted-Average Grant Date Fair Value, Forfeited | $ / shares	8.13
Weighted-Average Grant Date Fair Value, Unvested, ending balance | $ / shares	$ 7.58

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Warrant Activity (Detail) - Outstanding Warrants	3 Months Ended
	Mar. 31, 2018shares
Warrant [Line Items]
Warrants, Beginning Balance	17,721,088
Warrants exercised	(14,270)
Warrants, Ending Balance	17,706,818
Warrants, Vested and exercisable Ending Balance	16,966,218

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax [Line Items]
Federal statutory tax rate	21.00%		35.00%
Company's effective tax rate	0.00%
Unrealized gains in other comprehensive income	$ 0
Tax benefit	0	$ 6,000
Tax benefit in other comprehensive income	0	26,000
Korea
Income Tax [Line Items]
Tax benefit	$ 100,000	$ 100,000