ImmunityBio (IBRX) 10-Q 6 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Aug. 02, 2019
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Registrant Name	NANTKWEST, INC.
Entity Central Index Key	0001326110
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	true
Entity Small Business	true
Entity Ex Transition Period	true
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Trading Symbol	NK
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity File Number	1-37507
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	43-1979754
Entity Address, Address Line One	3530 John Hopkins Court
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	633-0300
Document Quarterly Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		98,307,859

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 17,279	$ 16,821
Restricted cash	250	0
Prepaid expenses and other current assets	2,746	13,900
Marketable debt securities, available-for-sale	66,773	57,328
Notes receivable, held-to-maturity	0	723
Total current assets	87,048	88,772
Marketable debt securities, noncurrent	1,483	5,701
Property, plant and equipment, net	65,089	76,885
Operating lease right-of-use assets, net	12,513	0
Investment in equity securities	9,253	8,500
Intangible assets, net	0	565
Other assets	310	1,527
Total assets	175,696	181,950
Current liabilities:
Accounts payable	1,927	2,793
Accrued expenses	6,466	21,104
Due to related parties	957	1,696
Other current liabilities	3,080	1,667
Total current liabilities	12,430	27,260
Operating lease liability, less current portion	11,997	0
Financing obligation, less current portion	0	5,945
Deferred rent	0	2,739
Total liabilities	24,427	35,944
Commitments and contingencies (Note 8)	0	0
Stockholders’ equity:
Common stock, $0.0001 par value per share; 500,000,000 shares authorized; 98,307,859 and 79,087,734 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively	10	8
Additional paid-in capital	782,312	741,246
Accumulated other comprehensive loss	(84)	(267)
Accumulated deficit	(630,969)	(594,981)
Total stockholders’ equity	151,269	146,006
Total liabilities and stockholders’ equity	$ 175,696	$ 181,950

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
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	98,307,859	79,087,734
Common stock, shares outstanding	98,307,859	79,087,734

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenue	$ 17	$ 4	$ 22	$ 9
Operating expenses:
Research and development (including amounts with related parties)	13,131	14,688	25,729	28,679
Selling, general and administrative (including amounts with related parties)	4,182	13,594	9,924	27,892
Total operating expenses	17,313	28,282	35,653	56,571
Loss from operations	(17,296)	(28,278)	(35,631)	(56,562)
Other income (expense):
Investment income, net	533	490	903	995
Interest expense (including amounts with related parties)	0	(106)	(3)	(139)
Other income, net (including amounts with related parties)	83	39	130	208
Total other income	616	423	1,030	1,064
Loss before income taxes	(16,680)	(27,855)	(34,601)	(55,498)
Income tax (expense) benefit	(2)	123	34	247
Net loss	$ (16,682)	$ (27,732)	$ (34,567)	$ (55,251)
Net loss per share:
Basic and diluted	$ (0.17)	$ (0.35)	$ (0.38)	$ (0.70)
Weighted-average number of shares during the period:
Basic and diluted	98,594,355	79,107,208	89,975,707	79,071,824

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (16,682)	$ (27,732)	$ (34,567)	$ (55,251)
Other comprehensive income (loss), net of income taxes:
Net unrealized gain (loss) on available-for-sale securities	122	107	183	(67)
Total other comprehensive income (loss)	122	107	183	(67)
Comprehensive loss	$ (16,560)	$ (27,625)	$ (34,384)	$ (55,318)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - 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
Stock-based compensation expense	18,007	$ 0	18,007	0	0
Exercise of warrants	35	$ 0	35	0	0
Exercise of warrants, Shares		21,675
Vesting of restricted stock units (RSUs)	0	$ 0	0	0	0
Vesting of restricted stock units (RSUs), Shares		154,123
Net share settlement for RSU vesting and exercise of stock options	$ (123)	$ 0	(123)	0	0
Net share settlement for RSU vesting and exercise of stock options, Shares		(31,857)
Repurchase of common stock, Shares	0
Cumulative effect of the adoption of the new standard | Accounting Standards Update 2014-09	$ 186	$ 0	0	0	186
Other comprehensive income (loss), net	(67)	0	0	(67)	0
Net loss	(55,251)	0	0	0	(55,251)
Ending Balance at Jun. 30, 2018	181,631	$ 8	735,849	(448)	(553,778)
Ending Balance, Shares at Jun. 30, 2018		79,165,819
Beginning Balance at Mar. 31, 2018	200,360	$ 8	726,953	(555)	(526,046)
Beginning Balance, Shares at Mar. 31, 2018		79,088,200
Stock-based compensation expense	8,934	$ 0	8,934	0	0
Exercise of warrants	12	$ 0	12	0	0
Exercise of warrants, Shares		7,405
Vesting of restricted stock units (RSUs)	0	$ 0	0	0	0
Vesting of restricted stock units (RSUs), Shares		83,923
Net share settlement for RSU vesting and exercise of stock options	$ (50)	$ 0	(50)	0	0
Net share settlement for RSU vesting and exercise of stock options, Shares		(13,709)
Repurchase of common stock, Shares	0
Other comprehensive income (loss), net	$ 107	$ 0	0	107	0
Net loss	(27,732)	0	0	0	(27,732)
Ending Balance at Jun. 30, 2018	181,631	$ 8	735,849	(448)	(553,778)
Ending Balance, Shares at Jun. 30, 2018		79,165,819
Beginning Balance at Dec. 31, 2018	$ 146,006	$ 8	741,246	(267)	(594,981)
Beginning Balance, Shares at Dec. 31, 2018	79,087,734	79,087,734
Stock-based compensation expense	$ 1,873	$ 0	1,873	0	0
Exercise of warrants	35,151	$ 2	35,149	0	0
Exercise of warrants, Shares		17,589,250
Exercise of stock options	4,070	$ 0	4,070	0	0
Exercise of stock options, Shares		1,986,300
Vesting of restricted stock units (RSUs)	0	$ 0	0	0	0
Vesting of restricted stock units (RSUs), Shares		157,291
Net share settlement for RSU vesting and exercise of stock options	(26)	$ 0	(26)	0	0
Net share settlement for RSU vesting and exercise of stock options, Shares		(39,130)
Repurchase of common stock	$ (501)	$ 0	0	0	(501)
Repurchase of common stock, Shares	(473,586)	(473,586)
Cumulative effect of the adoption of the new standard | Accounting Standards Update 2016-02	$ (920)	$ 0	0	0	(920)
Other comprehensive income (loss), net	183	0	0	183	0
Net loss	(34,567)	0	0	0	(34,567)
Ending Balance at Jun. 30, 2019	$ 151,269	$ 10	782,312	(84)	(630,969)
Ending Balance, Shares at Jun. 30, 2019	98,307,859	98,307,859
Beginning Balance at Mar. 31, 2019	$ 167,808	$ 10	781,790	(206)	(613,786)
Beginning Balance, Shares at Mar. 31, 2019		98,674,153
Stock-based compensation expense	522	$ 0	522	0	0
Vesting of restricted stock units (RSUs)	0	$ 0	0	0	0
Vesting of restricted stock units (RSUs), Shares		107,516
Net share settlement for RSU vesting and exercise of stock options	0	$ 0	0	0	0
Net share settlement for RSU vesting and exercise of stock options, Shares		(224)
Repurchase of common stock	$ (501)	$ 0	0	0	(501)
Repurchase of common stock, Shares	(473,586)	(473,586)
Other comprehensive income (loss), net	$ 122	$ 0	0	122	0
Net loss	(16,682)	0	0	0	(16,682)
Ending Balance at Jun. 30, 2019	$ 151,269	$ 10	$ 782,312	$ (84)	$ (630,969)
Ending Balance, Shares at Jun. 30, 2019	98,307,859	98,307,859

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities:
Net loss	$ (34,567)	$ (55,251)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	4,601	3,992
Stock-based compensation expense	1,873	18,007
Non-cash lease expense related to operating lease right-of-use assets	1,266	0
Loss on impairment and loss on disposal of assets	869	90
Non-cash interest items, net	63	91
Amortization of net premiums on marketable debt securities	1	343
Deferred income tax benefit	0	(248)
Changes in operating assets and liabilities:
Prepaid expenses, other current assets and other assets	10,857	(532)
Operating lease right-of-use assets	(247)	0
Accounts payable	(65)	1,875
Accrued expenses and other liabilities	(12,465)	603
Due to related parties	(682)	(508)
Operating lease liability, less current portion	(1,409)	0
Deferred rent	0	(239)
Net cash used in operating activities	(29,905)	(31,777)
Investing activities:
Purchases of property, plant and equipment	(3,089)	(7,394)
Purchase of debt securities, held-to-maturity	0	(361)
Purchase of Viracta common stock	(3)	0
Purchases of marketable debt securities, available-for-sale	(66,789)	(53,503)
Sales/maturities of marketable debt securities	61,800	85,571
Net cash (used in) provided by investing activities	(8,081)	24,313
Financing activities:
Principal payments of financing lease obligations	0	(198)
Proceeds from exercise of stock options and warrants	39,221	35
Repurchase of common stock	(501)	0
Net share settlement for RSU vesting, and option and warrant exercises	(26)	(123)
Net cash provided by (used in) financing activities	38,694	(286)
Net increase (decrease) in cash, cash equivalents, and restricted cash	708	(7,750)
Cash, cash equivalents and restricted cash, beginning of period	17,000	24,051
Cash, cash equivalents, and restricted cash, end of period	17,708	16,301
Reconciliation of cash, cash equivalents, and restricted cash at end of period:
Cash and cash equivalents	17,279
Restricted cash	429	179
Cash, cash equivalents, and restricted cash, end of period	17,708	16,301
Supplemental disclosure of cash flow information:
Interest	3	179
Income taxes	3	4
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment purchases included in accounts payable, accrued expenses, and other liabilities	1,308	6,704
Conversion of Viracta convertible notes and accrued interest into investment in equity securities of Viracta (Note 4)	751	0
Unrealized gains (losses) on marketable debt securities	240	(67)
Cashless exercise of stock options and warrants	$ 29	$ 1

Description of Business

Description of Business	6 Months Ended
	Jun. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business	1. Description of Business Organization NantKwest, Inc., or NantKwest, 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. We are 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. In these notes, the terms “we,” “our,” “our company” and “us” refer to NantKwest. We are focused on harnessing the power of the innate immune system by using the natural killer cell to treat cancer and viral infectious diseases. A critical aspect of our strategy is to invest significantly in innovating new therapeutic candidates, based upon our activated natural killer, or aNK, cell platform, as well as clinical testing and scale manufacturing of our leading product candidates. We hold the exclusive right to commercialize aNK cells, a commercially viable natural killer cell-line, and a variety of genetically modified derivatives capable of killing cancer and virally infected cells. We own corresponding United States, or U.S., and foreign composition and methods-of-use patents and applications covering the cells, improvements, methods of expansion and manufacture and use of aNK cells as a therapeutic to treat a spectrum of clinical conditions. We also license exclusive commercial rights to a CD16 receptor expressing improvement of our aNK cell line, covered in a portfolio of U.S. and foreign composition and methods-of-use patents and applications covering both 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. We have non-exclusively licensed or sub-licensed our CD16 bearing aNK cell lines and corresponding intellectual property to numerous pharmaceutical and biotechnology companies for such non-clinical uses. Liquidity As of June 30, 2019, the company had an accumulated deficit of approximately $631.0 million. We also had negative cash flow from operations of approximately $29.9 million during the six months ended June 30, 2019. The company expects that it will likely need additional capital to further fund development of, and seek regulatory approvals for, our product candidates, and to begin to commercialize any approved products. We are currently focused primarily on the development of immunotherapeutic treatments for cancers and debilitating viral infections using targeted cancer and viral killing cell lines, and we believe 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 our product candidates fail or produce unsuccessful results and those product candidates do not gain regulatory approval, or if any of our product candidates, if approved, fail to achieve market acceptance, we 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 us when needed and, if available, financing may not be obtained on terms favorable to the company or its stockholders. While we expect our existing cash and cash equivalents and marketable debt securities will enable us to fund operations and capital expenditure requirements for at least the next 12 months, we may not have sufficient funds to reach commercialization. Failure to obtain adequate financing when needed may require us to delay, reduce, limit, or terminate some or all of our development programs or future commercialization efforts or grant rights to develop and market product candidates that we might otherwise prefer to develop and market ourselves, which could adversely affect our ability to operate as a going concern. If we raise additional funds from the issuance of equity securities, substantial dilution to existing stockholders may result. If we raise 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 our ability to operate our business.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies There have been no material changes in our significant accounting policies other than the adoption of accounting pronouncements described below under Application of New or Revised Accounting Standards – Adopted Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP. The condensed consolidated financial statements reflect all adjustments which are, in the opinion of management, necessary to present fairly the results for the interim periods presented and have been prepared on the same basis as the audited consolidated financial statements for the fiscal year ended December 31, 2018. The condensed consolidated financial statements have been prepared assuming the company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from the outcome of this uncertainty. We believe our existing cash, cash equivalents, and investments in marketable debt securities, and our ability to borrow from affiliated entities, will be sufficient to fund operations through at least the next 12 months following the issuance date of the financial statements based upon our Chairman and CEO’s intent and ability to support the company’s operations with additional funds, including loans from affiliated entities, as required. We may also seek to sell additional equity, through one or more follow-on public offerings, or in separate financings, or obtain a credit facility. However, we may not be able to secure such financing in a timely manner or on favorable terms. Without additional funds, we may choose to delay or reduce our operating or investment expenditures. Further, because of the risk and uncertainties associated with the commercialization of the company’s drug product candidates in development, we may need additional funds to meet our needs sooner than planned. To date, the company’s primary sources of capital were its initial public offering and the concurrent private placement of common shares. In addition, during the six months ended June 30, 2019, our Chairman and Chief Executive Officer exercised warrants and options resulting in aggregate cash proceeds of $39.2 million. The unaudited condensed consolidated financial statements do not include all information and notes necessary for a complete presentation of results of income, comprehensive income, financial position, and cash flows in conformity with U.S. GAAP. Accordingly, these financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the fiscal year ended December 31, 2018 included in our 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 our audited financial statements, but does not include all disclosures required by U.S. GAAP. Principles of Consolidation and Equity Investments The condensed consolidated financial statements include the accounts of NantKwest and its wholly owned subsidiaries. All intercompany amounts have been eliminated. We apply the variable interest model under Accounting Standards Codification, or ASC, Topic 810, Consolidation For entities we hold as an equity investment that are not consolidated under the VIE Model, we consider whether our 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 we are able to exercise significant influence, but not control, are accounted for using the equity method. Our 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 we are not able to exercise significant influence will be subsequently measured at fair value with unrealized holding gains and losses included in other income, net on the condensed consolidated statements of operations. In the instance the equity investment does not have a readily determinable fair value and does not qualify for the practical expedient to estimate fair value in accordance with ASC 820, Fair Value Measurement Investments—Equity Securities We own non-marketable equity securities that are accounted for using the measurement alternative under ASC 321 because the preferred stock held by us 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’ earnings 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 we 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 our investment and the rights and preferences of those equity instruments compared to ours. Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP 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, we evaluate our estimates, including those related to valuation of equity-based awards, valuation of the allowance for deferred tax assets, preclinical and clinical trial accruals, impairment assessments, and the useful lives of long-lived assets. We base our estimates on historical experience and on various other market-specific and relevant assumptions that we believe to be reasonable under the circumstances. Actual results could differ from those estimates. Risks and Uncertainties Contingencies We record accruals for loss contingencies to the extent that we conclude it is probable that a liability has been incurred and the amount of the related loss can be reasonably estimated. We evaluate, 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, we record our rights to insurance recoveries, limited to the extent of incurred or probable losses, as a receivable when such recoveries have been agreed to with our third-party insurers and when receipt is deemed probable. This includes instances when our third-party insurers have agreed to pay, on our behalf, certain legal defense costs and settlement amounts directly to applicable law firms and a settlement fund. Concentration of Credit Risk and Other Risks and Uncertainties Financial instruments that potentially subject us to concentrations of risk consist principally of cash and cash equivalents and marketable debt securities. Our cash and cash equivalents are held by one major financial institution in the U.S. and one in Korea. Drug product candidates developed by us will require approvals or clearances from the U.S. Food and Drug Administration, or FDA, or international regulatory agencies prior to commercial sales. There can be no assurance that any of our drug product candidates will receive any of the required approvals or clearances. If we were to be denied approval or clearance or any such approval or clearance was to be delayed, it would have a material adverse impact on us. Impairment The company follows Financial Accounting Standard Board, or FASB, ASC 360 to evaluate its long-lived assets. The company’s long-lived assets, which include property and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. We assess the recoverability of our long-lived assets by comparing the projected undiscounted net cash flows associated with the related long-lived asset or group of long-lived assets over their remaining estimated useful lives against their respective carrying amounts. Impairment, if any, is based on the excess of the carrying amount over the fair value of those assets. Fair value is generally determined using the asset’s expected discounted cash flows or market value, if readily determinable. If long-lived assets are determined to be recoverable, but the newly determined remaining estimated useful lives are shorter than originally estimated, the net book values of the long-lived assets are depreciated over the newly determined remaining estimated useful lives. We consider the following to be some examples of important indicators that may trigger an impairment review: (i) a significant decrease in the market price of a long-lived asset, (ii) significant changes in the manner or use of assets or in the company’s overall strategy with respect to the manner or use of the acquired assets or changes in our overall business strategy; (iii) significant negative industry or economic trends; (iv) increased competitive pressures; (v) a significant decline in the company’s stock price for a sustained period of time; and (vi) regulatory changes. We evaluate assets for impairment at least annually and more frequently upon the occurrence of impairment indicators. Impairment charges, if any, are included in operating expenses. During the second quarter of 2019, we determined that certain bioreactor laboratory equipment could not be utilized in the production process. As a result, we recorded an impairment charge totaling approximately $0.9 million, which is included in research and development expense on the condensed consolidated statements of operations. Lease Obligations We adopted FASB ASC Topic 842, Leases Leases For all leases at the lease commencement date, a right-of-use asset and a lease liability are recognized. The right-of-use asset represents the right to use the leased asset for the lease term. At lease commencement, leases are classified as either finance leases or operating leases. A lease is classified as a finance lease if any one of the following criteria are met: (1) the lease transfers ownership of the underlying asset by the end of the lease term; (2) the lease contains an option to purchase the underlying asset that is reasonably certain to be exercised; (3) the lease term is for a major part of the remaining economic life of the underlying asset; (4) the present value of the sum of the lease payments and any guaranteed residual value that is not already included in the lease payments equals or exceeds substantially all of the fair value of the underlying asset; or (5) the underlying asset is of such a specialized nature that it is expected to have no alternative use to the lessor at the end of the lease term. A lease is classified as an operating lease if it does not meet any one of these criteria. We do not currently have any leases classified as finance leases. Our operating leases are included in operating lease right-of-use assets, net, other current liabilities, and operating lease liabilities on the condensed consolidated balance sheets. At the commencement date, operating lease right-of-use assets and operating lease liabilities are determined based on the present value of lease payments to be made over the lease term. Operating lease right-of-use assets also include any rent paid prior to the commencement date, less any lease incentives received, and initial direct costs incurred. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. We have elected to combine our lease components (e.g., fixed payments including rent, real estate taxes and insurance costs) with non-lease components (e.g., common-area maintenance costs and equipment maintenance costs) and as such, we account for lease and non-lease components as a single component. Lease expense also includes amounts relating to variable lease payments. Variable lease payments include amounts relating to common area maintenance and real estate taxes. We also elected not to recognize right-of-use assets and lease liabilities for qualifying short-term leases with an initial lease term of 12 months or less at lease inception. Such leases are expensed on a straight-line basis over the lease term. The depreciable life of operating right-of-use-assets and leasehold improvements is limited by the expected lease term. Basic and Diluted Net Loss per Share of Common Stock Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted loss per share is computed similarly to basic loss per share except that the denominator is increased to include the number of additional shares that would have been outstanding if the potential common shares had been issued and if the additional common shares were dilutive. For all periods presented, potentially dilutive securities are excluded from the computation of fully diluted loss per share as their effect is anti-dilutive. The following table details those securities that have been excluded from the computation of potentially dilutive securities: As of June 30, 2019 2018 Outstanding options 4,506,950 5,693,250 Outstanding RSUs 1,378,113 890,512 Outstanding warrants — 17,699,413 Total 5,885,063 24,283,175 Amounts in the table above reflect the common stock equivalents of the noted instruments. Recent Accounting Pronouncements Application of New or Revised Accounting Standards – Adopted We adopted ASC 842 on January 1, 2019, using the simplified transition approach which allows us to not recast the comparative periods presented when transitioning to the new lease standard, while including required disclosures under ASC 840 for all periods presented under ASC 840. In addition, we elected the package of practical expedients permitted under the transition guidance, which among other things, allowed us to not reassess (1) whether a contract is or contains a lease, and (2) the classification of existing leases. The adoption of ASC 842 had a substantial impact on our balance sheet. The most significant impacts were (i) the recognition of $13.5 million of operating lease right-of-use assets, net, and $16.4 million of operating lease liabilities, and (ii) the derecognition of assets and liabilities associated with the build-to-suit leases under ASC 840 (resulting in the derecognition of property, plant and equipment, net, of $6.6 million and net adjustments to related liabilities of $5.7 million). The build-to-suit leases were recorded as normal operating leases under ASC 842. The difference between the excess of build-to-suit related liabilities and assets of $0.9 million was recorded as an increase to our accumulated deficit. The cumulative-effect adjustment had no tax impact due to the valuation allowance against the gross deferred tax asset less reversing deferred tax liabilities. Adoption of this standard had no material impact on our results of operations and cash flows. In February 2018, the FASB issued Accounting Standards Update, or ASU, 2018‑02, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income Application of New or Revised Accounting Standards – Not Yet Adopted In June 2016, the FASB issued ASU 2016‑13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments Financial Instruments—Credit Losses (Topic 326): Targeted Transition Other recent authoritative guidance issued by the FASB (including technical corrections to the ASC), the American Institute of Certified Public Accountants, and the Securities and Exchange Commission during the three months ended June 30, 2019 did not, or are not expected to, have a material effect on our consolidated financial statements.

Financial Statement Details

Financial Statement Details	6 Months Ended
	Jun. 30, 2019
Financial Statement Details [Abstract]
Financial Statement Details	3. Financial Statement Details Prepaid expenses and other current assets As of June 30, 2019 and December 31, 2018, prepaid expenses and other current assets were made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Prepaid services $ 617 $ 230 Prepaid supplies 426 532 Interest receivable - marketable debt securities 405 473 Prepaid rent 370 536 Prepaid equipment maintenance 347 329 Insurance claim receivables 294 10,882 Prepaid insurance 129 343 Due from related parties 73 90 Prepaid license fees 34 104 Insurance premium financing asset — 339 Other 51 42 $ 2,746 $ 13,900 Property, plant and equipment, net As of June 30, 2019 and December 31, 2018, property, plant and equipment, net was made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Construction in progress $ — $ 2,480 Leasehold improvements 33,540 4,087 Buildings 23,463 59,356 Equipment 20,643 20,878 Software 1,236 1,264 Furniture & fixtures 369 381 79,251 88,446 Accumulated depreciation (14,162 ) (11,561 ) $ 65,089 $ 76,885 Depreciation expense related to property, plant and equipment was $2.2 million and $1.8 million for the three months ended June 30, 2019 and 2018, respectively, and $4.0 million and $2.9 million for the six months ended June 30, 2019 and 2018, respectively. As a result of adoption of ASC 842 (Note 2), we (i) reclassified $32.0 million of assets from buildings to leasehold improvements, and (ii) derecognized $6.6 million of assets associated with build-to-suit leases under ASC 840. The impact of adoption of ASC 842 on property, plant, and equipment at December 31, 2018 was as follows (in thousands): Balance December 31, 2018 Adoption of ASC 842 Increase (Decrease) Balance January 1, 2019 Leasehold improvements $ 4,087 $ 32,014 $ 36,101 Buildings $ 59,356 $ (39,893 ) $ 19,463 Property, plant and equipment, gross $ 88,446 $ (7,879 ) $ 80,567 Accumulated depreciation $ (11,561 ) $ 1,293 $ (10,268 ) Property, plant and equipment, net $ 76,885 $ (6,586 ) $ 70,299 Intangible assets, net As of June 30, 2019 and December 31, 2018, intangible assets were made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Technology license $ 9,042 $ 9,042 Less accumulated amortization (9,042 ) (8,477 ) $ — $ 565 The company’s intangible asset was fully amortized as of March 31, 2019. Amortization expense was $0 and $0.6 million for the three months ended June 30, 2019 and 2018, respectively, and $0.6 million and $1.1 million for the six months ended June 30, 2019 and 2018, respectively. Amortization of our technology license is included in research and development expense on the condensed consolidated statements of operations. Other assets As of June 30, 2019 and December 31, 2018, other assets were made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Restricted cash $ 179 $ 179 Security deposit 114 113 Prepaid rent — 1,205 Other 17 30 $ 310 $ 1,527 Restricted cash is comprised of a certificate of deposit that serves as collateral for a letter of credit required by our landlord as a security deposit related to our facility in San Diego, California. Accrued expenses As of June 30, 2019 and December 31, 2018, accrued expenses were made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Accrued bonus $ 1,511 $ 2,079 Accrued preclinical and clinical trial costs 1,188 704 Accrued professional and service fees 1,038 912 Accrued construction costs 949 3,341 Accrued compensation 781 943 Litigation settlement accruals 500 12,000 Accrued laboratory equipment and supplies 228 678 Accrued franchise, sales/use and property taxes 144 250 Other 127 197 $ 6,466 $ 21,104 Other current liabilities As of June 30, 2019 and December 31, 2018, other current liabilities were made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Operating lease liability - current portion $ 3,000 $ — Financing obligation - current portion — 965 Deferred rent - current portion — 598 Other 80 104 $ 3,080 $ 1,667 Investment income, net Net investment income is as follows for the three and six months ended June 30, 2019 and 2018 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Unaudited) (Unaudited) Interest income $ 491 $ 632 $ 901 $ 1,336 Investment accretion income (amortization expense), net 42 (142 ) 2 (343 ) Net realized gains on investments — — — 2 $ 533 $ 490 $ 903 $ 995 Interest income includes interest from marketable debt securities, notes receivable, and interest from our bank deposits. We did not recognize an impairment loss on any investments for the three and six months ended June 30, 2019 and 2018.

Viracta Investment and Converti

Viracta Investment and Convertible Notes	6 Months Ended
	Jun. 30, 2019
Investments All Other Investments [Abstract]
Viracta Investment and Convertible Notes	4. Viracta Investment and Convertible Notes In March 2017, we participated in a Series B convertible preferred stock financing and invested $8.5 million in Viracta Therapeutics, Inc., or Viracta, a clinical stage drug development company. In May 2017, we 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. In June 2018, Viracta executed a 2018 Note and Warrant Purchase Agreement with existing and new investors, including us. The initial closing under the Purchase Agreement occurred in June 2018, at which point we purchased a convertible note for $0.4 million, which under certain circumstances was convertible into preferred stock of Viracta, and a warrant to purchase Viracta’s common shares. The convertible note accrued interest at 8% and had a one-year maturity date. In September 2018, a milestone closing under the Purchase Agreement occurred, at which point we purchased an additional convertible note for $0.4 million, which under certain circumstances was convertible into preferred stock of Viracta, and a warrant to purchase Viracta’s common shares. We classified the convertible notes as held-to-maturity notes receivable on the condensed consolidated balance sheets. Effective January 31, 2019, the notes, together with accrued interest then outstanding, were converted to Series B preferred stock resulting in an increase to our investment in Viracta’s Series B convertible preferred stock of $0.8 million. In May 2019, we exercised warrants to acquire 253,120 shares of Viracta common stock. At June 30, 2019, our investment in Viracta totaled $9.3 million. Based on the level of equity investment at risk, Viracta is not a VIE and therefore is not consolidated under the VIE Model. In addition, we do not hold a controlling financial interest in Viracta and therefore we do not consolidate 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 and does not qualify for the practical expedient to estimate fair value in accordance with ASC 820, we have elected to apply the measurement alternative under ASC 321, pursuant to which we measure our investment in Viracta at cost, less impairment, adjusted for observable price changes in an orderly market for an identical or similar investment of the same issuer. As of June 30, 2019, our 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. We have not recorded any impairments as of June 30, 2019, or on a cumulative basis. Further, we have not identified any downward or upward adjustments due to observable price changes in the investment as of June 30, 2019, or on a cumulative basis. As of June 30, 2019, the $9.3 million carrying value of our investment is recorded in investment in equity securities on the condensed consolidated balance sheets.

Financial Instruments Investmen

Financial Instruments Investments in Debt Securities	6 Months Ended
	Jun. 30, 2019
Cash Equivalents And Marketable Securities [Abstract]
Financial Instruments Investments in Debt Securities	5. Financial Instruments – Investments in Debt Securities At June 30, 2019, our investments in debt securities are detailed below (in thousands): June 30, 2019 (Unaudited) Weighted- Average Remaining Contractual Life (in years) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Available-for-sale: Corporate debt securities 0.4 $ 59,000 $ 46 $ (31 ) $ 59,015 Foreign government bonds 0.3 3,244 3 — 3,247 Government sponsored securities 0.9 3,031 — (18 ) 3,013 Commercial paper 0.1 1,498 — — 1,498 Current portion 0.4 66,773 49 (49 ) 66,773 Noncurrent: Available-for-sale: Corporate debt securities 2.2 1,501 — (18 ) 1,483 Noncurrent portion 2.2 1,501 — (18 ) 1,483 Total 0.4 $ 68,274 $ 49 $ (67 ) $ 68,256 At December 31, 2018, our investments in debt securities are detailed below (in thousands): December 31, 2018 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Available-for-sale: Corporate debt securities $ 57,463 $ 1 $ (136 ) $ 57,328 Total available-for-sale 57,463 1 (136 ) 57,328 Held-to-maturity, notes receivable (Note 4): 723 — — 723 Current portion 58,186 1 (136 ) 58,051 Noncurrent: Available-for-sale: Corporate debt securities 3,067 — (76 ) 2,991 Government sponsored securities 2,756 — (46 ) 2,710 Noncurrent portion 5,823 — (122 ) 5,701 Total $ 64,009 $ 1 $ (258 ) $ 63,752 Accumulated unrealized losses on debt securities classified as available-for-sale that have been in a continuous loss position for less than 12 months and for more than 12 months at June 30, 2019 and December 31, 2018 were as follows (in thousands): June 30, 2019 (Unaudited) Less than 12 months More than 12 months Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Corporate debt securities $ 4,618 $ (1 ) $ 9,996 $ (48 ) Government sponsored securities — — 2,736 (18 ) Total $ 4,618 $ (1 ) $ 12,732 $ (66 ) December 31, 2018 Less than 12 months More than 12 months Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Corporate debt securities $ 32,010 $ (26 ) $ 26,663 $ (186 ) Government sponsored securities — — 2,710 (46 ) Total $ 32,010 $ (26 ) $ 29,373 $ (232 ) At June 30, 2019, 13 of the securities were in an unrealized loss position. We evaluated our securities for other-than-temporary impairment and concluded that the decline in value was primarily caused by current economic and market conditions. We do not intend to sell the investments and it is not more likely than not that we will be required to sell the investments before recovery of their amortized cost bases. Therefore, we did not recognize any other-than-temporary impairment loss during the six months ended June 30, 2019. Realized gains and losses on sales or maturities of available-for-sale debt securities during the three and six months ended June 30, 2019 and 2018 were immaterial.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. Fair Value Measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date, based on our principal or, in absence of a principal, most advantageous market for the specific asset or liability. We use a three-tier fair value hierarchy to classify and disclose all assets and liabilities measured at fair value on a recurring basis, as well as assets and liabilities measured at fair value on a non-recurring basis, in periods subsequent to their initial measurement. The hierarchy requires us to use observable inputs when available, and to minimize the use of unobservable inputs, when determining fair value. The three tiers are defined as follows: • Level 1— Observable inputs that reflect quoted market prices (unadjusted) for identical assets or liabilities in active markets at the measurement date. Since valuations are based on quoted prices that are readily and regularly available in an active market, valuation of these products does not entail a significant degree of judgment. Our Level 1 assets consist of bank deposits, money market funds, and U.S. treasury securities. • Level 2— Observable inputs other than quoted prices in active markets that are observable either directly or indirectly in the marketplace for identical or similar assets and liabilities. Our Level 2 assets consist of corporate debt securities including commercial paper, government sponsored securities and corporate bonds, as well as foreign municipal securities. • Level 3— Valuations based on inputs that are unobservable and significant to the overall fair value measurement. During the periods presented, no transfers were made into or out of the Level 1, 2 or 3 categories. We will continue to review the fair value inputs on quarterly basis. We utilize a third-party pricing service to assist in obtaining fair value pricing for our investments in marketable debt securities. Inputs are documented in accordance with the fair value disclosure hierarchy. Recurring Valuations The following tables present our assets that are measured at fair value on a recurring basis as of June 30, 2019 and December 31, 2018 (in thousands): Fair Value Measurements at June 30, 2019 (Unaudited) Total Level 1 Level 2 Level 3 Assets: Current: Cash and cash equivalents $ 17,279 $ 17,279 $ — $ — Corporate debt securities 59,015 — 59,015 — Foreign government bonds 3,247 — 3,247 — Government sponsored securities 3,013 — 3,013 — Commercial paper 1,498 — 1,498 — Noncurrent: Corporate debt securities 1,483 — 1,483 — Total assets measured at fair value $ 85,535 $ 17,279 $ 68,256 $ — Fair Value Measurements at December 31, 2018 Total Level 1 Level 2 Level 3 Assets: Current: Cash and cash equivalents $ 16,821 $ 16,821 $ — $ — Corporate debt securities 57,328 — 57,328 — Noncurrent: Corporate debt securities 2,991 — 2,991 — Government sponsored securities 2,710 — 2,710 — Total assets measured at fair value $ 79,850 $ 16,821 $ 63,029 $ — Non-recurring Valuations 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 June 30, 2019.

Collaboration and License Agree

Collaboration and License Agreements	6 Months Ended
	Jun. 30, 2019
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 June 30, 2019. Exclusive Co-Development Agreement In August 2016, we entered into an exclusive Co-Development Agreement, or the Co-Development Agreement, with Altor BioScience, LLC, or Altor. Altor is a related party, as it is a wholly owned subsidiary of ImmunityBio, Inc. (formerly known as NantCell, Inc.), or ImmunityBio (Note 9). Under the Co-Development Agreement, the parties agreed to exclusively collaborate on the development of therapeutic applications combining our proprietary natural killer cells with Altor's N‑801 and/or N‑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. We are 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 granted 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, or 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, we are 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 supplies 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. Each company owns 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. We have dosed patients with N‑803, an IL‑15 superagonist, in several phase Ib/II trials. No charges for supplies by Altor have been incurred in association with the above trials during the three and six months ended June 30, 2019 and 2018.

Commitment and Contingencies

Commitment and Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and contingencies	8. Commitments and Contingencies Contingencies We record accruals for loss contingencies to the extent that we conclude it is probable that a liability has been incurred and the amount of the related loss can be reasonably estimated. We evaluate, 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, we record our rights to insurance recoveries, limited to the extent of incurred or probable losses, as a receivable when such recoveries have been agreed to with our third-party insurers and when receipt is deemed probable. This includes instances where our third-party insurers have agreed to pay, on our behalf, certain legal defense costs and settlement amounts directly to applicable law firms and a settlement fund. Securities Litigation In March 2016, a putative securities class action complaint captioned Sudunagunta v. NantKwest, Inc., et al. Under the terms of the settlement, we paid $12.0 million to the plaintiffs as full and complete settlement of the litigation. We were responsible for $1.2 million of the settlement amount, which was recognized in selling, general and administrative expense during the third quarter of 2018, while the remaining $10.8 million was fully funded by our insurance carriers under our directors’ and officers’ insurance policy. We and the insurance carriers paid the settlement amount into a settlement fund in January 2019. Subsequent to receiving final approval of the settlement on May 13, 2019, the aforementioned settlement accrual, associated insurance claim receivable and restricted cash were released and are no longer reflected on our condensed consolidated balance sheets as of June 30, 2019. Stipulation of Settlement In early April 2019, following board approval, which occurred in late March 2019, we entered into a settlement agreement, or the Stipulation of Settlement, with three stockholders of the company, each of whom had submitted a stockholder demand for the board to take action to remedy purported harm to the company resulting from certain alleged wrongful conduct concerning, among other things, disclosures about Dr. Soon-Shiong’s compensation and a related-party lease agreement. The Stipulation of Settlement calls for us to adopt certain governance changes, and for the three stockholders to file a stockholder derivative action in the Superior Court of the State of California, County of San Diego, followed by an application for court approval of the Stipulation of Settlement. On May 31, 2019, the court entered an order preliminarily approving the Stipulation of Settlement and scheduling the final settlement hearing for August 9, 2019. Pursuant to the Stipulation of Settlement, we have provided stockholders with notice of the settlement and the final settlement hearing. Under the terms of the Stipulation of Settlement, which remains subject to final approval by the court, we have agreed to pay an attorney’s fee of $0.5 million to the plaintiffs as part of the settlement. Of that amount, we are responsible for half, which was recognized in selling, general and administrative expense on the condensed consolidated statements of operations during the first quarter of 2019, while the other half will be fully funded by our insurance carrier. We and the insurance carrier paid the settlement amount into a settlement fund in June 2019, and as of June 30, 2019, our share of the settlement is included in restricted cash on the condensed consolidated balance sheets. Insurance Recoveries We have reflected our right to insurance recoveries, limited to the extent of incurred or probable losses, as a receivable when such recoveries have been agreed to with our third-party insurers and receipt is deemed probable. This includes instances where our third-party insurers have agreed to pay, on our behalf, certain legal defense costs and settlement amounts directly to applicable law firms and a settlement fund. The amount of such receivable recorded at June 30, 2019 and December 31, 2018 was $0.3 million and $10.9 million, respectively, and is included in prepaid expenses and other current assets on the condensed consolidated balance sheets. Contractual Obligations - Leases We adopted ASC 842, as of January 1, 2019, using the simplified transition approach discussed in further detail in Note 2. As a result, prior periods were not recast. The following disclosures relate to our lease balances as of January 1, 2019 and June 30, 2019, under ASC 842 (in thousands): Balance January 1, 2019 Balance June 30, 2019 Operating lease right-of-use assets, net $ 13,532 $ 12,513 Other current liabilities $ 2,960 $ 3,000 Operating lease liability, less current portion $ 13,407 $ 11,997 Substantially all of our operating right-of-use assets and operating lease liabilities relate to facilities leases. We lease: (i) a research facility and office space in San Diego, California; (ii) a research and manufacturing space in Culver City, California, from a related party; (iii) a research and manufacturing facility in El Segundo, California, also from a related party; (iv) a research facility in Torrance, California, and (v) a research facility in Woburn, Massachusetts. See Note 9 – Related Party Agreements Operating lease expense of $1.3 million, including variable lease costs of $0.3 million, was recorded in research and development expense and selling, general and administrative expense on the condensed consolidated statements of operations for the three months ended June 30, 2019. Operating lease expense of $2.5 million, including variable lease costs of $0.5 million, was recorded in research and development expense and selling, general and administrative expense on the condensed consolidated statements of operations for the six months ended June 30, 2019. The weighted-average remaining lease term as of January 1, 2019 and June 30, 2019 was 5.4 years and 5.0 years, respectively. The weighted-average discount rate as of January 1, 2019 and June 30, 2019 was 9%. For the three and six months ended June 30, 2019, cash outflows from operating leases was $1.0 million and $2.3 million, respectively. Future minimum lease payments at June 30, 2019 are presented in the following table (in thousands). Common area maintenance costs and taxes are not included in these payments. Years ending December 31: Operating Leases (a) 2019 (excluding the six months ended June 30, 2019) $ 2,083 2020 4,080 2021 3,438 2022 3,538 2023 2,545 Thereafter 2,813 Total future minimum lease payments 18,497 Less: Interest 3,500 Present value of operating lease liabilities $ 14,997 (a) Operating lease payments include $3.3 million related to options to extend lease terms that are reasonably certain of being exercised. In August 2018, NantBio, Inc., or NantBio, a related party (Note 9), assigned an agreement to us for the use of a third-party research facility, which provides us with the exclusive right to use and access to a portion of the third party’s laboratory and vivarium premises. In conjunction with the assignment, we reimbursed NantBio for upfront payments which it had made to the third party of $0.9 million, and paid $0.5 million directly to the third party for an aggregate value of $1.4 million. The assigned agreement is for a term of ten years and expires in June 2027. The agreement may be terminated by us at any time, with or without cause. In case of termination of the agreement, the third party will reimburse us for a pro-rata amount based upon the passage of time. In September 2016, we 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 has been converted to a research and development laboratory and a cGMP manufacturing facility. The lease runs from July 2016 through July 2023. We have 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. In March 2016, we entered into a lease agreement for an approximately 7,893 square foot facility in Woburn, Massachusetts, for a research and development laboratory, related office and other related uses. The term of the lease is 48 months commencing on April 29, 2016. In June 2016, the lease was amended to add 260 square feet, for a total of 8,153 square feet. The base rent, including the amendment, is $19,000 per month with a $1 per square foot annual increase on each anniversary date. In November 2015, we entered into a facility license agreement with NantWorks LLC, or NantWorks, a related party (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. We have 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. In June 2015, we entered into a lease agreement for an approximately 44,700 square foot facility in San Diego, California, for a research and development laboratory, related office and other related uses. The term of the lease extends for seven years commencing on August 1, 2016. The base rent is $0.2 million per month with 3% annual increases on each anniversary date. We are currently subleasing approximately 2,000 square feet of the premises to a related party (Note 9). We leased a total of approximately 2,550 square feet of office space in Cardiff-by-the-Sea, California, for general office use, pursuant to an operating lease. The lease term was extended through August 31, 2018. Our total monthly lease payment was $13,200 per month. In August 2017, we subleased these premises for the remainder of the lease term for the same payment. The lease expired on August 31, 2018 and we vacated the premises. We recognized rent expense under operating leases on a straight-line basis. Rent expense under ASC 840 for the three and six months ended June 30, 2018, was $0.7 million, and $1.4 million, respectively. Commitments We did not enter into any significant contracts during the six months ended June 30, 2019, other than those disclosed in this document.

Related Party Agreements

Related Party Agreements	6 Months Ended
	Jun. 30, 2019
Related Party Transactions [Abstract]
Related Party Agreements	9. Related Party Agreements Our 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, we have entered into arrangements with NantWorks, and certain affiliates of NantWorks, to facilitate the development of new genetically modified NK cells for our product pipeline. NantHealth Labs, Inc. In March 2018, we entered into an agreement with NantHealth Labs, Inc., or NantHealth Labs, to obtain blood-based tumor profiling services. NantHealth Labs is a related party, as it is a wholly owned subsidiary of NantHealth, Inc., a majority owned subsidiary of NantWorks. We are obligated to pay NantHealth Labs fixed, per-patient fees. 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 June 30, 2019 and 2018, $0 and $0.1 million, respectively, has been recognized in research and development expense on the condensed consolidated statements of operations. During the six months ended June 30, 2019 and 2018, $10,000 and $0.1 million, respectively, has been recognized in research and development expense on the condensed consolidated statements of operations. At December 31, 2018, we owed NantHealth Labs $49,300, which is included in due to related parties on the condensed consolidated balance sheets. As of June 30, 2019, there was no balance due between the parties. Immuno-Oncology Clinic, Inc. In 2017 and 2018, we entered into multiple agreements with Immuno-Oncology Clinic, Inc., or the Clinic, to conduct various clinical trials. The Clinic was formerly known as John Lee, M.D. and Leonard Sender, M.D., Inc., a professional medical corporation, dba Chan Soon-Shiong Institutes for Medicine, El Segundo, California. The Clinic is a related party as it is owned by two officers of NantKwest and NantWorks manages the administrative operations of the Clinic. Prior to June 30, 2019, one of the company’s officers was an investigator or sub-investigator for all of the company’s trials conducted at the Clinic. During the three months ended June 30, 2019 and 2018, $0.2 million and $0.7 million, respectively, has been recognized in research and development expense on the condensed consolidated statements of operations. During the six months ended June 30, 2019 and 2018, $0.5 million and $1.4 million, respectively, has been recognized in research and development expense on the condensed consolidated statements of operations. As of June 30, 2019 and December 31, 2018, we owed the Clinic $0.3 million and $0.6 million, respectively, which is included in due to related parties on the condensed consolidated balance sheets. Tensorcom, LLC In April 2017, we entered into a sublease agreement with Tensorcom, LLC, or Tensorcom, for a portion of our San Diego, California, research and development laboratory and office space. The lease ran from May 1, 2017 through April 30, 2018. Tensorcom is a related party, as it is an affiliate of NantWorks. The sublease included a portion of the premises consisting of approximately 6,557 rentable square feet of space. The monthly base rent was $25,000 per month. For the three and six months ended June 30, 2018, we recognized $32,000 and $0.1 million, respectively, in other income on the condensed consolidated statements of operations under the sublease agreement. VivaBioCell S.p.A. In February 2017, we entered into a research grant agreement with VivaBioCell S.p.A., or VBC, a subsidiary of ImmunityBio. ImmunityBio is a related party, as it is an affiliate of NantWorks. VBC conducted research and development activities related to our NK cell lines using VBC’s proprietary technology. We recognized research and development expense of $0 and $0.1 million, respectively, on the condensed consolidated statements of operations for the three and six months ended June 30, 2018. No expense was incurred for the three and six months ended June 30, 2019. 605 Doug St. LLC In September 2016, we entered into a lease agreement with 605 Doug St, LLC, an entity owned by our Chairman and CEO, for approximately 24,250 square feet in El Segundo, California, which has been converted to a research and development laboratory and a cGMP manufacturing facility. The lease runs from July 2016 through July 2023. We have 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. Lease expense for this facility is recorded in research and development expense on the condensed consolidated statements of operations and was $0.2 million and $0.1 million, respectively, for the three months ended June 30, 2019 and 2018, and $0.4 million and $0.1 million, respectively, for the six months ended June 30, 2019 and 2018. At June 30, 2019 and December 31, 2018, there were no balances due between the parties. Altor In August 2016, we entered into an exclusive Co-Development Agreement with Altor as described in Note 7. Altor is a related party, as it is a wholly owned subsidiary of ImmunityBio. ImmunityBio is a related party, as it is an affiliate of NantWorks. No charges for supplies by Altor have been incurred in association with the trials during the three and six months ended June 30, 2019 and 2018. NantBio In January 2018, we entered into a laboratory services agreement with NantBio. NantBio is a related-party as it is an affiliate of NantWorks. The agreement, effective December 2017, includes a sublease of approximately 1,965 square feet of laboratory and office space at our 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 us and the landlord. The monthly sublease and service fee of $10,000 is subject to an annual 3% increase on the agreement anniversary date. Rent income from this sublease is recorded in other income on the condensed consolidated statements of operations and was $31,600 and $31,000, respectively, for the three months ended June 30, 2019 and 2018, and $0.1 million and $0.1 million, respectively, for the six months ended June 30, 2019 and 2018. At June 30, 2019 and December 31, 2018, NantBio owed us $23,900 and $49,000, respectively, which is included in prepaid expenses and other current assets on the condensed consolidated balance sheets. In March 2016, NantBio and the National Cancer Institute entered into a cooperative research and development agreement. The initial five year agreement covers NantBio and its affiliates, including us. Under the agreement, the parties are collaborating on the preclinical and clinical development of proprietary recombinant NK cells and monoclonal antibodies in monotherapy and in combination immunotherapies. We benefited from the preclinical and clinical research conducted during the first three years under this agreement and provided the first four years of funding under the agreement. In each of April 2016, April 2017, August 2018, and May 2019, we paid $0.6 million to the National Cancer Institute as a prepayment for services under the agreement. We recognized research and development expense relating to this agreement ratably over a 12 month period for each funding year and recorded $0.2 million and $0.3 million of expense for each of the three and six months ended June 30, 2019 and 2018, respectively. At June 30, 2019 and December 31, 2018, we had balances of $0.4 million and $0.1 million, respectively, included in prepaid expenses and other current assets related to this agreement, on the condensed consolidated balance sheets. NantWorks In May 2018, we entered into an assignment agreement with NantWorks and a third-party construction firm. In connection with the agreement, we assigned our deposit of $0.4 million with the third-party firm to NantWorks for which NantWorks reimbursed us. This assignment represented unutilized deposits that NantKwest had previously made with the construction company, for which NantWorks can now utilize in applying such funds to future planned construction projects. 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. We are 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 June 30, 2019 and 2018, we recorded selling, general and administrative expense of $0.5 million and $0.8 million, respectively. For the six months ended June 30, 2019 and 2018, we recorded selling, general and administrative expense of $1.2 million and $1.5 million, respectively. For the three months ended June 30, 2019 and 2018, we recorded research and development expense of $0.3 million and $0.9 million, respectively. For the six months ended June 30, 2019 and 2018, we recorded research and development expense of $0.6 million and $1.8 million, respectively. These amounts exclude certain general and administrative expenses provided by third party vendors directly for our benefit, which have been reimbursed to NantWorks based on those vendors’ invoiced amounts without markup by NantWorks. In June 2016, we amended the existing shared services agreement with NantWorks whereby we can provide such support services to NantWorks and/or any of its affiliates. For the three months ended June 30, 2019 and 2018, we recorded selling, general and administrative expense reimbursements of $0.2 million and $0.2 million, respectively. For the six months ended June 30, 2019 and 2018, we recorded selling, general and administrative expense reimbursements of $0.4 million and $0.3 million, respectively. For the three months ended June 30, 2019 and 2018, we recorded research and development expense reimbursements of $0.6 million and $0.7 million, respectively. For the six months ended June 30, 2019 and 2018, we recorded research and development expense reimbursements of $1.1 million and $1.3 million, respectively. We owed NantWorks a net amount of $0.6 million and $1.1 million for all agreements between the two affiliates at June 30, 2019 and December 31, 2018, respectively, which is included in due to related parties on the condensed consolidated balance sheets. In November 2015, we 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. Lease expense for this facility is recorded in research and development expense on the condensed consolidated statements of operations and was $0.2 million and $47,000, respectively, for the three months ended June 30, 2019 and 2018, and $0.3 million and $0.1 million, respectively, for the six months ended June 30, 2019 and 2018. NantOmics, LLC In June 2015, we entered into an agreement, as amended in May 2018, with NantOmics, LLC, or 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. We 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 owns the data and results, as well as any other intellectual property it creates in performing these services on our behalf. We are 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 June 30, 2019 and 2018, we recorded operating expense of $0.1 million and $0.1 million, respectively, to research and development under this arrangement on the condensed consolidated statements of operations. For the six months ended June 30, 2019 and 2018, we recorded operating expense of $0.1 million and $0.1 million, respectively, to research and development under this arrangement on the condensed consolidated statements of operations. We owed NantOmics $24,800 and $24,000, respectively, at June 30, 2019 and December 31, 2018, which is included in due to related parties on the condensed consolidated balance sheets. ImmunityBio In June 2015, we entered into a supply agreement with ImmunityBio, which is a related party, as it is an affiliate of NantWorks. Pursuant to this supply agreement we have the right to purchase ImmunityBio’s proprietary bioreactors, made according to specifications mutually agreed to with ImmunityBio. We also have the right to purchase reagents and consumables associated with such equipment from ImmunityBio. 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. As of June 30, 2019 and December 31, 2018, we had $1.2 million and $1.1 million in capitalized equipment, respectively, on the condensed consolidated balance sheets. During the three and six months ended June 30, 2019 and 2018, no expense was recorded in research and development expense on the condensed consolidated statement of operations. At June 30, 2019 and December 31, 2018 we had $0.4 million and $0.5 million, respectively, included in prepaid expenses and other current assets on the condensed consolidated balance sheets. As of June 30, 2019, ImmunityBio owed us $8,000, which is included in prepaid expenses and other current assets on the condensed consolidated balance sheets. As of December 31, 2018, there were no balances due between the parties.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Stockholders' Equity	10. Stockholders’ Equity Stock Repurchase – In November 2015, the board of directors approved a share repurchase program, or the 2015 Share Repurchase Program, allowing the CEO or CFO, on behalf of the company, to repurchase from time to time, in the open market or in privately negotiated transactions, up to $50.0 million of our outstanding shares of common stock, exclusive of any commissions, markups or expenses. The timing and amounts of any purchases were and will continue to 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. We have financed, and expect to continue to finance, the purchases with existing cash balances. During the three and six months ended June 30, 2019, we repurchased 473,586 shares of our common stock at prices ranging between $0.95 per share and $1.09 per share for a total cost of $0.5 million. In addition, we paid approximately $14,200 of broker commissions on these repurchases. During the three and six months ended June 30, 2018 we did not repurchase any shares of our common stock. To date, we have repurchased a total of 6,403,489 shares of our common stock under this program for a total cost of $31.7 million. In addition, we have paid approximately $0.1 million of broker commissions on these repurchases. The repurchased shares are formally retired through board approval upon repurchase. We account for the repurchases under the constructive retirement method and allocated the excess of the repurchase price over par value to accumulated deficit. At June 30, 2019, $18.3 million remained authorized for repurchase under the 2015 Share Repurchase Program. In July 2015, the company’s board of directors adopted and the company’s stockholders approved the 2015 Equity Incentive Plan, or the 2015 Plan. The 2015 Plan permits the grant of incentive stock options to the company’s employees, and for the grant of non-statutory stock options, restricted stock, restricted stock units, stock appreciation rights, performance units and performance shares to the company’s employees, directors and consultants. In April 2019, the company’s board of directors adopted, and in June 2019 the company’s stockholders approved, an amendment to the 2015 Plan to reserve a further 3,000,000 shares of common stock for issuance pursuant to the 2015 Plan. Following the approval of the amendment, a total of 7,249,857 shares of common stock were reserved for issuance pursuant to the 2015 Plan.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	11. Stock-Based Compensation The following table presents all stock-based compensation expense as included on the condensed consolidated statements of operations (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Unaudited) (Unaudited) Stock-based compensation expense: Warrants for common stock to an officer $ — $ 7,636 $ — $ 15,272 Employee stock options 104 970 1,101 1,948 Employee RSUs 313 294 563 686 Non-employee RSUs 105 34 209 101 $ 522 $ 8,934 $ 1,873 $ 18,007 Stock-based compensation expense in operating expenses: Research and development $ 150 $ 142 $ 261 $ 281 Selling, general and administrative 372 8,792 1,612 17,726 $ 522 $ 8,934 $ 1,873 $ 18,007 Stock Options The following table summarizes stock option activity for all equity incentive plans for the six months ended June 30, 2019: Number of Shares Weighted- Average Exercise Price Aggregate Intrinsic Value (in thousands) Weighted- Average Remaining Contractual Life (in years) Outstanding at December 31, 2018 6,493,250 $ 7.14 $ 563 4.8 Options exercised (1,986,300 ) $ 2.06 Outstanding at June 30, 2019 4,506,950 $ 9.37 $ 353 6.3 Vested and Exercisable at June 30, 2019 3,706,950 $ 10.73 $ 353 5.7 The total unrecognized compensation cost related to non-vested stock options as of June 30, 2019 is $1.3 million, which is expected to be recognized over a weighted-average period of 3.2 years. During the three and six months ended June 30, 2019, we recognized proceeds of $0 and $4.1 million, respectively, from exercises of stock options. The aggregate intrinsic value of stock options exercised during the three and six months ended June 30, 2019, was $0 and $0.2 million, respectively. There were no option exercises during the three and six months ended June 30, 2018. Restricted Stock Units The following table summarizes the RSUs activity under the 2015 Plan for the six months ended June 30, 2019: Number of Shares Weighted- Average Grant Date Fair Value Unvested balance at December 31, 2018 867,911 $ 6.69 Granted 716,293 $ 1.12 Vested (157,291 ) $ 4.22 Forfeited (48,800 ) $ 4.63 Unvested balance at June 30, 2019 1,378,113 $ 4.14 We may grant RSUs to both employees and directors of the company and to employees of related parties that provide shared services to the company under the company’s shared services agreement with NantWorks (Note 9). During the six months ended June 30, 2019, we granted 716,293 RSUs to employees and non-employee directors, with no grants to shared services employees. As of June 30, 2019, there was $2.3 million of unrecognized stock-based compensation expense related to RSUs that is expected to be recognized over a weighted-average remaining amortization period of 1.9 years. Of that amount, $2.0 million of unrecognized expense is related to employee and non-employee director grants with a remaining weighted-average amortization period of 2.0 years and $0.3 million of unrecognized expense is related to shared services employee grants with a remaining weighted-average amortization period of 1.0 years. Warrants The following table summarizes the warrant activity for the six months ended June 30, 2019: Number of Shares Outstanding at December 31, 2018 17,589,250 Warrants exercised (17,589,250 ) Outstanding at June 30, 2019 — During the three months ended June 30, 2019 and 2018, we recognized proceeds of $0 and $11,300, respectively, from exercises of warrants. During the six months ended June 30, 2019 and 2018, we recognized proceeds of $35.2 million and $34,400, respectively, from exercises of warrants.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes The difference between the federal statutory tax rate of 21% and our 0% tax rate is due to losses in jurisdictions from which we cannot benefit. Intraperiod tax allocation rules require us to allocate the provision for income taxes between continuing operations and other categories of earnings, such as other comprehensive income. In periods in which we have a year-to-date pre-tax loss from continuing operations and pre-tax income in other categories of earnings, such as other comprehensive income, we must allocate the tax provision to the other categories of earnings. We then record a related tax benefit in continuing operations. We recorded unrealized gains on marketable debt securities in other comprehensive income, net of taxes, during the three and six months ended June 30, 2019. We did not record any unrealized gains in other comprehensive income during the three and six months ended June 30, 2018. For the three months ended June 30, 2019 and 2018, we recorded a tax expense of $2,000 and $0, respectively, and a tax benefit of $34,000 and $0 for the six months ended June 30, 2019 and 2018, respectively, on the condensed consolidated statements of operations. We recorded an increase to other comprehensive income of $0.1 million and $0 for the six months ended June 30, 2019 and 2018, respectively, on the condensed consolidated balance sheets. No increase to other comprehensive income was recorded for the three months ended June 30, 2019 and 2018. The company is operating in Korea. During the three and six months ended June 30, 2018, the tax benefit related to Korea was $0.1 million and $0.3 million, respectively. During the three and six months ended June 30, 2019, there were no tax benefits related to Korea. We currently file federal and state income tax returns in the U.S. and in Korea. Income tax expense consists of U.S. federal, state, and Korean income taxes. To date, we have not been required to pay U.S. federal income taxes because of current and accumulated net operating losses.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events In July 2019, we entered into a new agreement with the Clinic, as defined and described in Note 9, that covers existing and prospective clinical trial and research related services, subject to the parties’ agreement on the financial terms of such services, among other things. The initial term of the agreement is for one year but allows for an automatic renewal and additional extensions beyond the initial term. The agreement supersedes the existing agreements with the Clinic and the cost under this agreement is estimated at $7.5 million, which will be paid in three (3) installment payments and represent prepayments towards services to be provided by the Clinic and as the Clinic provides the services, the prepayments will be consumed. The Clinic is a related party as it is owned by two officers of NantKwest and NantWorks manages the administrative operations of the Clinic. In addition, we executed a clinical trial work order under the new agreement with the Clinic in July 2019 for an open-label, phase I study of PD‑L1.t‑haNK for infusion in subjects with locally advanced or metastatic solid cancers. The costs under this study is estimated at $1.2 million and is covered under the aforementioned new agreement.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Liquidity	Liquidity As of June 30, 2019, the company had an accumulated deficit of approximately $631.0 million. We also had negative cash flow from operations of approximately $29.9 million during the six months ended June 30, 2019. The company expects that it will likely need additional capital to further fund development of, and seek regulatory approvals for, our product candidates, and to begin to commercialize any approved products. We are currently focused primarily on the development of immunotherapeutic treatments for cancers and debilitating viral infections using targeted cancer and viral killing cell lines, and we believe 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 our product candidates fail or produce unsuccessful results and those product candidates do not gain regulatory approval, or if any of our product candidates, if approved, fail to achieve market acceptance, we 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 us when needed and, if available, financing may not be obtained on terms favorable to the company or its stockholders. While we expect our existing cash and cash equivalents and marketable debt securities will enable us to fund operations and capital expenditure requirements for at least the next 12 months, we may not have sufficient funds to reach commercialization. Failure to obtain adequate financing when needed may require us to delay, reduce, limit, or terminate some or all of our development programs or future commercialization efforts or grant rights to develop and market product candidates that we might otherwise prefer to develop and market ourselves, which could adversely affect our ability to operate as a going concern. If we raise additional funds from the issuance of equity securities, substantial dilution to existing stockholders may result. If we raise 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 our ability to operate our business.
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP. The condensed consolidated financial statements reflect all adjustments which are, in the opinion of management, necessary to present fairly the results for the interim periods presented and have been prepared on the same basis as the audited consolidated financial statements for the fiscal year ended December 31, 2018. The condensed consolidated financial statements have been prepared assuming the company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from the outcome of this uncertainty. We believe our existing cash, cash equivalents, and investments in marketable debt securities, and our ability to borrow from affiliated entities, will be sufficient to fund operations through at least the next 12 months following the issuance date of the financial statements based upon our Chairman and CEO’s intent and ability to support the company’s operations with additional funds, including loans from affiliated entities, as required. We may also seek to sell additional equity, through one or more follow-on public offerings, or in separate financings, or obtain a credit facility. However, we may not be able to secure such financing in a timely manner or on favorable terms. Without additional funds, we may choose to delay or reduce our operating or investment expenditures. Further, because of the risk and uncertainties associated with the commercialization of the company’s drug product candidates in development, we may need additional funds to meet our needs sooner than planned. To date, the company’s primary sources of capital were its initial public offering and the concurrent private placement of common shares. In addition, during the six months ended June 30, 2019, our Chairman and Chief Executive Officer exercised warrants and options resulting in aggregate cash proceeds of $39.2 million. The unaudited condensed consolidated financial statements do not include all information and notes necessary for a complete presentation of results of income, comprehensive income, financial position, and cash flows in conformity with U.S. GAAP. Accordingly, these financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the fiscal year ended December 31, 2018 included in our 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 our audited financial statements, but does not include all disclosures required by U.S. GAAP.
Principles of Consolidation and Equity Investments	Principles of Consolidation and Equity Investments The condensed consolidated financial statements include the accounts of NantKwest and its wholly owned subsidiaries. All intercompany amounts have been eliminated. We apply the variable interest model under Accounting Standards Codification, or ASC, Topic 810, Consolidation For entities we hold as an equity investment that are not consolidated under the VIE Model, we consider whether our 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 we are able to exercise significant influence, but not control, are accounted for using the equity method. Our 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 we are not able to exercise significant influence will be subsequently measured at fair value with unrealized holding gains and losses included in other income, net on the condensed consolidated statements of operations. In the instance the equity investment does not have a readily determinable fair value and does not qualify for the practical expedient to estimate fair value in accordance with ASC 820, Fair Value Measurement Investments—Equity Securities We own non-marketable equity securities that are accounted for using the measurement alternative under ASC 321 because the preferred stock held by us 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’ earnings 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 we 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 our investment and the rights and preferences of those equity instruments compared to ours.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP 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, we evaluate our estimates, including those related to valuation of equity-based awards, valuation of the allowance for deferred tax assets, preclinical and clinical trial accruals, impairment assessments, and the useful lives of long-lived assets. We base our estimates on historical experience and on various other market-specific and relevant assumptions that we believe to be reasonable under the circumstances. Actual results could differ from those estimates.
Risks and Uncertainties	Risks and Uncertainties
Contingencies	Contingencies We record accruals for loss contingencies to the extent that we conclude it is probable that a liability has been incurred and the amount of the related loss can be reasonably estimated. We evaluate, 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, we record our rights to insurance recoveries, limited to the extent of incurred or probable losses, as a receivable when such recoveries have been agreed to with our third-party insurers and when receipt is deemed probable. This includes instances when our third-party insurers have agreed to pay, on our behalf, certain legal defense costs and settlement amounts directly to applicable law firms and a settlement fund.
Concentration of Credit Risk and Other Risks and Uncertainties	Concentration of Credit Risk and Other Risks and Uncertainties Financial instruments that potentially subject us to concentrations of risk consist principally of cash and cash equivalents and marketable debt securities. Our cash and cash equivalents are held by one major financial institution in the U.S. and one in Korea. Drug product candidates developed by us will require approvals or clearances from the U.S. Food and Drug Administration, or FDA, or international regulatory agencies prior to commercial sales. There can be no assurance that any of our drug product candidates will receive any of the required approvals or clearances. If we were to be denied approval or clearance or any such approval or clearance was to be delayed, it would have a material adverse impact on us.
Impairment	Impairment The company follows Financial Accounting Standard Board, or FASB, ASC 360 to evaluate its long-lived assets. The company’s long-lived assets, which include property and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. We assess the recoverability of our long-lived assets by comparing the projected undiscounted net cash flows associated with the related long-lived asset or group of long-lived assets over their remaining estimated useful lives against their respective carrying amounts. Impairment, if any, is based on the excess of the carrying amount over the fair value of those assets. Fair value is generally determined using the asset’s expected discounted cash flows or market value, if readily determinable. If long-lived assets are determined to be recoverable, but the newly determined remaining estimated useful lives are shorter than originally estimated, the net book values of the long-lived assets are depreciated over the newly determined remaining estimated useful lives. We consider the following to be some examples of important indicators that may trigger an impairment review: (i) a significant decrease in the market price of a long-lived asset, (ii) significant changes in the manner or use of assets or in the company’s overall strategy with respect to the manner or use of the acquired assets or changes in our overall business strategy; (iii) significant negative industry or economic trends; (iv) increased competitive pressures; (v) a significant decline in the company’s stock price for a sustained period of time; and (vi) regulatory changes. We evaluate assets for impairment at least annually and more frequently upon the occurrence of impairment indicators. Impairment charges, if any, are included in operating expenses. During the second quarter of 2019, we determined that certain bioreactor laboratory equipment could not be utilized in the production process. As a result, we recorded an impairment charge totaling approximately $0.9 million, which is included in research and development expense on the condensed consolidated statements of operations.
Lease Obligations	Lease Obligations We adopted FASB ASC Topic 842, Leases Leases For all leases at the lease commencement date, a right-of-use asset and a lease liability are recognized. The right-of-use asset represents the right to use the leased asset for the lease term. At lease commencement, leases are classified as either finance leases or operating leases. A lease is classified as a finance lease if any one of the following criteria are met: (1) the lease transfers ownership of the underlying asset by the end of the lease term; (2) the lease contains an option to purchase the underlying asset that is reasonably certain to be exercised; (3) the lease term is for a major part of the remaining economic life of the underlying asset; (4) the present value of the sum of the lease payments and any guaranteed residual value that is not already included in the lease payments equals or exceeds substantially all of the fair value of the underlying asset; or (5) the underlying asset is of such a specialized nature that it is expected to have no alternative use to the lessor at the end of the lease term. A lease is classified as an operating lease if it does not meet any one of these criteria. We do not currently have any leases classified as finance leases. Our operating leases are included in operating lease right-of-use assets, net, other current liabilities, and operating lease liabilities on the condensed consolidated balance sheets. At the commencement date, operating lease right-of-use assets and operating lease liabilities are determined based on the present value of lease payments to be made over the lease term. Operating lease right-of-use assets also include any rent paid prior to the commencement date, less any lease incentives received, and initial direct costs incurred. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. We have elected to combine our lease components (e.g., fixed payments including rent, real estate taxes and insurance costs) with non-lease components (e.g., common-area maintenance costs and equipment maintenance costs) and as such, we account for lease and non-lease components as a single component. Lease expense also includes amounts relating to variable lease payments. Variable lease payments include amounts relating to common area maintenance and real estate taxes. We also elected not to recognize right-of-use assets and lease liabilities for qualifying short-term leases with an initial lease term of 12 months or less at lease inception. Such leases are expensed on a straight-line basis over the lease term. The depreciable life of operating right-of-use-assets and leasehold improvements is limited by the expected lease term.
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 the net loss by the weighted-average number of common shares outstanding for the period. Diluted loss per share is computed similarly to basic loss per share except that the denominator is increased to include the number of additional shares that would have been outstanding if the potential common shares had been issued and if the additional common shares were dilutive. For all periods presented, potentially dilutive securities are excluded from the computation of fully diluted loss per share as their effect is anti-dilutive. The following table details those securities that have been excluded from the computation of potentially dilutive securities: As of June 30, 2019 2018 Outstanding options 4,506,950 5,693,250 Outstanding RSUs 1,378,113 890,512 Outstanding warrants — 17,699,413 Total 5,885,063 24,283,175 Amounts in the table above reflect the common stock equivalents of the noted instruments.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Application of New or Revised Accounting Standards – Adopted We adopted ASC 842 on January 1, 2019, using the simplified transition approach which allows us to not recast the comparative periods presented when transitioning to the new lease standard, while including required disclosures under ASC 840 for all periods presented under ASC 840. In addition, we elected the package of practical expedients permitted under the transition guidance, which among other things, allowed us to not reassess (1) whether a contract is or contains a lease, and (2) the classification of existing leases. The adoption of ASC 842 had a substantial impact on our balance sheet. The most significant impacts were (i) the recognition of $13.5 million of operating lease right-of-use assets, net, and $16.4 million of operating lease liabilities, and (ii) the derecognition of assets and liabilities associated with the build-to-suit leases under ASC 840 (resulting in the derecognition of property, plant and equipment, net, of $6.6 million and net adjustments to related liabilities of $5.7 million). The build-to-suit leases were recorded as normal operating leases under ASC 842. The difference between the excess of build-to-suit related liabilities and assets of $0.9 million was recorded as an increase to our accumulated deficit. The cumulative-effect adjustment had no tax impact due to the valuation allowance against the gross deferred tax asset less reversing deferred tax liabilities. Adoption of this standard had no material impact on our results of operations and cash flows. In February 2018, the FASB issued Accounting Standards Update, or ASU, 2018‑02, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income Application of New or Revised Accounting Standards – Not Yet Adopted In June 2016, the FASB issued ASU 2016‑13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments Financial Instruments—Credit Losses (Topic 326): Targeted Transition Other recent authoritative guidance issued by the FASB (including technical corrections to the ASC), the American Institute of Certified Public Accountants, and the Securities and Exchange Commission during the three months ended June 30, 2019 did not, or are not expected to, have a material effect on our consolidated financial statements.
Investment in Viracta Preferred Stock	Based on the level of equity investment at risk, Viracta is not a VIE and therefore is not consolidated under the VIE Model. In addition, we do not hold a controlling financial interest in Viracta and therefore we do not consolidate 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 and does not qualify for the practical expedient to estimate fair value in accordance with ASC 820, we have elected to apply the measurement alternative under ASC 321, pursuant to which we measure our investment in Viracta at cost, less impairment, adjusted for observable price changes in an orderly market for an identical or similar investment of the same issuer.
Fair Value Measurements	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date, based on our principal or, in absence of a principal, most advantageous market for the specific asset or liability. We use a three-tier fair value hierarchy to classify and disclose all assets and liabilities measured at fair value on a recurring basis, as well as assets and liabilities measured at fair value on a non-recurring basis, in periods subsequent to their initial measurement. The hierarchy requires us to use observable inputs when available, and to minimize the use of unobservable inputs, when determining fair value. The three tiers are defined as follows: • Level 1— Observable inputs that reflect quoted market prices (unadjusted) for identical assets or liabilities in active markets at the measurement date. Since valuations are based on quoted prices that are readily and regularly available in an active market, valuation of these products does not entail a significant degree of judgment. Our Level 1 assets consist of bank deposits, money market funds, and U.S. treasury securities. • Level 2— Observable inputs other than quoted prices in active markets that are observable either directly or indirectly in the marketplace for identical or similar assets and liabilities. Our Level 2 assets consist of corporate debt securities including commercial paper, government sponsored securities and corporate bonds, as well as foreign municipal securities. • Level 3— Valuations based on inputs that are unobservable and significant to the overall fair value measurement. During the periods presented, no transfers were made into or out of the Level 1, 2 or 3 categories. We will continue to review the fair value inputs on quarterly basis. We utilize a third-party pricing service to assist in obtaining fair value pricing for our investments in marketable debt securities. Inputs are documented in accordance with the fair value disclosure hierarchy.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2019
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 June 30, 2019 2018 Outstanding options 4,506,950 5,693,250 Outstanding RSUs 1,378,113 890,512 Outstanding warrants — 17,699,413 Total 5,885,063 24,283,175 Amounts in the table above reflect the common stock equivalents of the noted instruments.

Financial Statement Details (Ta

Financial Statement Details (Tables)	6 Months Ended
	Jun. 30, 2019
Financial Statement Details [Abstract]
Prepaid Expenses and Other Current Assets	As of June 30, 2019 and December 31, 2018, prepaid expenses and other current assets were made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Prepaid services $ 617 $ 230 Prepaid supplies 426 532 Interest receivable - marketable debt securities 405 473 Prepaid rent 370 536 Prepaid equipment maintenance 347 329 Insurance claim receivables 294 10,882 Prepaid insurance 129 343 Due from related parties 73 90 Prepaid license fees 34 104 Insurance premium financing asset — 339 Other 51 42 $ 2,746 $ 13,900
Property, Plant and Equipment, Net	As of June 30, 2019 and December 31, 2018, property, plant and equipment, net was made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Construction in progress $ — $ 2,480 Leasehold improvements 33,540 4,087 Buildings 23,463 59,356 Equipment 20,643 20,878 Software 1,236 1,264 Furniture & fixtures 369 381 79,251 88,446 Accumulated depreciation (14,162 ) (11,561 ) $ 65,089 $ 76,885
Impact of Adoption of ASC 842 on Property, Plant and Equipment	The impact of adoption of ASC 842 on property, plant, and equipment at December 31, 2018 was as follows (in thousands): Balance December 31, 2018 Adoption of ASC 842 Increase (Decrease) Balance January 1, 2019 Leasehold improvements $ 4,087 $ 32,014 $ 36,101 Buildings $ 59,356 $ (39,893 ) $ 19,463 Property, plant and equipment, gross $ 88,446 $ (7,879 ) $ 80,567 Accumulated depreciation $ (11,561 ) $ 1,293 $ (10,268 ) Property, plant and equipment, net $ 76,885 $ (6,586 ) $ 70,299
Intangible Assets, Net	As of June 30, 2019 and December 31, 2018, intangible assets were made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Technology license $ 9,042 $ 9,042 Less accumulated amortization (9,042 ) (8,477 ) $ — $ 565
Other Assets	As of June 30, 2019 and December 31, 2018, other assets were made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Restricted cash $ 179 $ 179 Security deposit 114 113 Prepaid rent — 1,205 Other 17 30 $ 310 $ 1,527 Restricted cash is comprised of a certificate of deposit that serves as collateral for a letter of credit required by our landlord as a security deposit related to our facility in San Diego, California.
Accrued Expenses	As of June 30, 2019 and December 31, 2018, accrued expenses were made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Accrued bonus $ 1,511 $ 2,079 Accrued preclinical and clinical trial costs 1,188 704 Accrued professional and service fees 1,038 912 Accrued construction costs 949 3,341 Accrued compensation 781 943 Litigation settlement accruals 500 12,000 Accrued laboratory equipment and supplies 228 678 Accrued franchise, sales/use and property taxes 144 250 Other 127 197 $ 6,466 $ 21,104
Other Current Liabilities	As of June 30, 2019 and December 31, 2018, other current liabilities were made up of (in thousands): June 30, 2019 December 31, 2018 (Unaudited) Operating lease liability - current portion $ 3,000 $ — Financing obligation - current portion — 965 Deferred rent - current portion — 598 Other 80 104 $ 3,080 $ 1,667
Investment Income, Net	Net investment income is as follows for the three and six months ended June 30, 2019 and 2018 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Unaudited) (Unaudited) Interest income $ 491 $ 632 $ 901 $ 1,336 Investment accretion income (amortization expense), net 42 (142 ) 2 (343 ) Net realized gains on investments — — — 2 $ 533 $ 490 $ 903 $ 995

Financial Instruments Investm_2

Financial Instruments Investments in Debt Securities (Tables)	6 Months Ended
	Jun. 30, 2019
Cash Equivalents And Marketable Securities [Abstract]
Schedule of Investments in Debt Securities	At June 30, 2019, our investments in debt securities are detailed below (in thousands): June 30, 2019 (Unaudited) Weighted- Average Remaining Contractual Life (in years) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Available-for-sale: Corporate debt securities 0.4 $ 59,000 $ 46 $ (31 ) $ 59,015 Foreign government bonds 0.3 3,244 3 — 3,247 Government sponsored securities 0.9 3,031 — (18 ) 3,013 Commercial paper 0.1 1,498 — — 1,498 Current portion 0.4 66,773 49 (49 ) 66,773 Noncurrent: Available-for-sale: Corporate debt securities 2.2 1,501 — (18 ) 1,483 Noncurrent portion 2.2 1,501 — (18 ) 1,483 Total 0.4 $ 68,274 $ 49 $ (67 ) $ 68,256 At December 31, 2018, our investments in debt securities are detailed below (in thousands): December 31, 2018 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Current: Available-for-sale: Corporate debt securities $ 57,463 $ 1 $ (136 ) $ 57,328 Total available-for-sale 57,463 1 (136 ) 57,328 Held-to-maturity, notes receivable (Note 4): 723 — — 723 Current portion 58,186 1 (136 ) 58,051 Noncurrent: Available-for-sale: Corporate debt securities 3,067 — (76 ) 2,991 Government sponsored securities 2,756 — (46 ) 2,710 Noncurrent portion 5,823 — (122 ) 5,701 Total $ 64,009 $ 1 $ (258 ) $ 63,752
Accumulated Unrealized Losses on Debt Securities Classified as Available-for-Sale in Continuous Loss Position	Accumulated unrealized losses on debt securities classified as available-for-sale that have been in a continuous loss position for less than 12 months and for more than 12 months at June 30, 2019 and December 31, 2018 were as follows (in thousands): June 30, 2019 (Unaudited) Less than 12 months More than 12 months Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Corporate debt securities $ 4,618 $ (1 ) $ 9,996 $ (48 ) Government sponsored securities — — 2,736 (18 ) Total $ 4,618 $ (1 ) $ 12,732 $ (66 ) December 31, 2018 Less than 12 months More than 12 months Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Corporate debt securities $ 32,010 $ (26 ) $ 26,663 $ (186 ) Government sponsored securities — — 2,710 (46 ) Total $ 32,010 $ (26 ) $ 29,373 $ (232 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Summary of Financial Assets Measured at Fair Value on Recurring Basis	The following tables present our assets that are measured at fair value on a recurring basis as of June 30, 2019 and December 31, 2018 (in thousands): Fair Value Measurements at June 30, 2019 (Unaudited) Total Level 1 Level 2 Level 3 Assets: Current: Cash and cash equivalents $ 17,279 $ 17,279 $ — $ — Corporate debt securities 59,015 — 59,015 — Foreign government bonds 3,247 — 3,247 — Government sponsored securities 3,013 — 3,013 — Commercial paper 1,498 — 1,498 — Noncurrent: Corporate debt securities 1,483 — 1,483 — Total assets measured at fair value $ 85,535 $ 17,279 $ 68,256 $ — Fair Value Measurements at December 31, 2018 Total Level 1 Level 2 Level 3 Assets: Current: Cash and cash equivalents $ 16,821 $ 16,821 $ — $ — Corporate debt securities 57,328 — 57,328 — Noncurrent: Corporate debt securities 2,991 — 2,991 — Government sponsored securities 2,710 — 2,710 — Total assets measured at fair value $ 79,850 $ 16,821 $ 63,029 $ —

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Schedule of Lease Balances	The following disclosures relate to our lease balances as of January 1, 2019 and June 30, 2019, under ASC 842 (in thousands): Balance January 1, 2019 Balance June 30, 2019 Operating lease right-of-use assets, net $ 13,532 $ 12,513 Other current liabilities $ 2,960 $ 3,000 Operating lease liability, less current portion $ 13,407 $ 11,997
Summary of Future Minimum Lease Payments	Future minimum lease payments at June 30, 2019 are presented in the following table (in thousands). Common area maintenance costs and taxes are not included in these payments. Years ending December 31: Operating Leases (a) 2019 (excluding the six months ended June 30, 2019) $ 2,083 2020 4,080 2021 3,438 2022 3,538 2023 2,545 Thereafter 2,813 Total future minimum lease payments 18,497 Less: Interest 3,500 Present value of operating lease liabilities $ 14,997 (a) Operating lease payments include $3.3 million related to options to extend lease terms that are reasonably certain of being exercised.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Based Compensation Expenses Included on Operations Statement	The following table presents all stock-based compensation expense as included on the condensed consolidated statements of operations (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Unaudited) (Unaudited) Stock-based compensation expense: Warrants for common stock to an officer $ — $ 7,636 $ — $ 15,272 Employee stock options 104 970 1,101 1,948 Employee RSUs 313 294 563 686 Non-employee RSUs 105 34 209 101 $ 522 $ 8,934 $ 1,873 $ 18,007 Stock-based compensation expense in operating expenses: Research and development $ 150 $ 142 $ 261 $ 281 Selling, general and administrative 372 8,792 1,612 17,726 $ 522 $ 8,934 $ 1,873 $ 18,007
Summarizes Stock Option Activity Under Equity Intensive Plan	The following table summarizes stock option activity for all equity incentive plans for the six months ended June 30, 2019: Number of Shares Weighted- Average Exercise Price Aggregate Intrinsic Value (in thousands) Weighted- Average Remaining Contractual Life (in years) Outstanding at December 31, 2018 6,493,250 $ 7.14 $ 563 4.8 Options exercised (1,986,300 ) $ 2.06 Outstanding at June 30, 2019 4,506,950 $ 9.37 $ 353 6.3 Vested and Exercisable at June 30, 2019 3,706,950 $ 10.73 $ 353 5.7
Summary of (RSUs) Activity	The following table summarizes the RSUs activity under the 2015 Plan for the six months ended June 30, 2019: Number of Shares Weighted- Average Grant Date Fair Value Unvested balance at December 31, 2018 867,911 $ 6.69 Granted 716,293 $ 1.12 Vested (157,291 ) $ 4.22 Forfeited (48,800 ) $ 4.63 Unvested balance at June 30, 2019 1,378,113 $ 4.14
Summary of Warrant Activity	The following table summarizes the warrant activity for the six months ended June 30, 2019: Number of Shares Outstanding at December 31, 2018 17,589,250 Warrants exercised (17,589,250 ) Outstanding at June 30, 2019 —

Description of Business - Addit

Description of Business - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit	$ (630,969)		$ (594,981)
Net cash used in operating activities	$ (29,905)	$ (31,777)

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Jan. 01, 2019	Dec. 31, 2018
Accounting Policies [Line Items]
Proceeds from exercise of stock options and warrants		$ 39,221	$ 35
Lease practical expedients package		true
Operating lease, description		elected not to recognize right-of-use assets and lease liabilities for qualifying short-term leases with an initial lease term of 12 months or less at lease inception
Operating lease right-of-use assets, net	$ 12,513	$ 12,513		$ 13,532	$ 0
Operating lease liabilities	14,997	14,997
Property, plant and equipment, net	65,089	65,089			76,885
Liabilities	24,427	$ 24,427			$ 35,944
Accounting Standards Update 2016-02
Accounting Policies [Line Items]
Operating lease right-of-use assets, net				13,500
Operating lease liabilities				16,400
Property, plant and equipment, net				70,299
Accounting Standards Update 2016-02 | Accumulated Deficit
Accounting Policies [Line Items]
Build-to-suit related liabilities and assets adjust as accumulated deficit				(900)
Accounting Standards Update 2016-02 | Difference between Lease Guidance in Effect before and after Topic 842
Accounting Policies [Line Items]
Property, plant and equipment, net				(6,600)
Liabilities				$ (5,700)
Research and Development
Accounting Policies [Line Items]
Impairment charge of long-lived assets	$ 900
VIE | Minimum
Accounting Policies [Line Items]
Percentage of ownership interest	20.00%	20.00%
VIE | Maximum
Accounting Policies [Line Items]
Percentage of ownership interest	50.00%	50.00%
Chairman and Chief Executive Officer
Accounting Policies [Line Items]
Proceeds from exercise of stock options and warrants		$ 39,200

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Securities Excluded from the Computation of Potentially Dilutive Securities (Detail) - shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	5,885,063	24,283,175
Employee Stock Option
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	4,506,950	5,693,250
Outstanding RSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	1,378,113	890,512
Outstanding Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	0	17,699,413

Financial Statement Details - P

Financial Statement Details - Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financial Statement Details [Abstract]
Prepaid services	$ 617	$ 230
Prepaid supplies	426	532
Interest receivable - marketable debt securities	405	473
Prepaid rent	370	536
Prepaid equipment maintenance	347	329
Insurance claim receivables	294	10,882
Prepaid insurance	129	343
Due from related parties	73	90
Prepaid license fees	34	104
Insurance premium financing asset	0	339
Other	51	42
Total prepaid expenses and other current assets	$ 2,746	$ 13,900

Financial Statement Details -_2

Financial Statement Details - Property, Plant and Equipment, Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 79,251	$ 88,446
Accumulated depreciation	(14,162)	(11,561)
Property, plant and equipment, net	65,089	76,885
Construction in Progress
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	0	2,480
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	33,540	4,087
Buildings
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	23,463	59,356
Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	20,643	20,878
Software
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	1,236	1,264
Furniture And Fixtures
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 369	$ 381

Financial Statement Details - A

Financial Statement Details - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financial Statement Details [Line Items]
Depreciation expense related to property, plant and equipment	$ 2,200,000	$ 1,800,000	$ 4,000,000	$ 2,900,000
Amortization expense	0	600,000	600,000	1,100,000
Impairment loss on recognized investments	0	$ 0	0	$ 0
Accounting Standards Update 2016-02
Financial Statement Details [Line Items]
Reclassification of assets from buildings to leasehold improvements	32,000,000		32,000,000
Derecognized build-to-suit lease assets	$ 6,600,000		$ 6,600,000

Financial Statement Details - I

Financial Statement Details - Impact of Adoption of ASC 842 on Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Financial Statement Details [Line Items]
Property, plant and equipment, gross	$ 79,251		$ 88,446
Accumulated depreciation	(14,162)		(11,561)
Property, plant and equipment, net	65,089		76,885
Leasehold Improvements
Financial Statement Details [Line Items]
Property, plant and equipment, gross	33,540		4,087
Buildings
Financial Statement Details [Line Items]
Property, plant and equipment, gross	$ 23,463		$ 59,356
Accounting Standards Update 2016-02
Financial Statement Details [Line Items]
Property, plant and equipment, gross		$ 80,567
Accumulated depreciation		(10,268)
Property, plant and equipment, net		70,299
Accounting Standards Update 2016-02 | Restatement Adjustment
Financial Statement Details [Line Items]
Property, plant and equipment, gross		(7,879)
Accumulated depreciation		1,293
Property, plant and equipment, net		(6,586)
Accounting Standards Update 2016-02 | Leasehold Improvements
Financial Statement Details [Line Items]
Property, plant and equipment, gross		36,101
Accounting Standards Update 2016-02 | Leasehold Improvements | Restatement Adjustment
Financial Statement Details [Line Items]
Property, plant and equipment, gross		32,014
Accounting Standards Update 2016-02 | Buildings
Financial Statement Details [Line Items]
Property, plant and equipment, gross		19,463
Accounting Standards Update 2016-02 | Buildings | Restatement Adjustment
Financial Statement Details [Line Items]
Property, plant and equipment, gross		$ (39,893)

Financial Statement Details -_3

Financial Statement Details - Intangible Assets, Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Finite Lived Intangible Assets [Line Items]
Intangible assets, net	$ 0	$ 565
Technology License
Finite Lived Intangible Assets [Line Items]
Total intangible assets	9,042	9,042
Less accumulated amortization	(9,042)	(8,477)
Intangible assets, net	$ 0	$ 565

Financial Statement Details - O

Financial Statement Details - Other Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financial Statement Details [Abstract]
Restricted cash	$ 179	$ 179
Security deposit	114	113
Prepaid rent	0	1,205
Other	17	30
Other Assets Noncurrent	$ 310	$ 1,527

Financial Statement Details -_4

Financial Statement Details - Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financial Statement Details [Abstract]
Accrued bonus	$ 1,511	$ 2,079
Accrued preclinical and clinical trial costs	1,188	704
Accrued professional and service fees	1,038	912
Accrued construction costs	949	3,341
Accrued compensation	781	943
Litigation settlement accruals	500	12,000
Accrued laboratory equipment and supplies	228	678
Accrued franchise, sales/use and property taxes	144	250
Other	127	197
Accrued Liabilities Current	$ 6,466	$ 21,104

Financial Statement Details -_5

Financial Statement Details - Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Financial Statement Details [Abstract]
Operating lease liability - current portion	$ 3,000	$ 2,960	$ 0
Financing obligation - current portion	0		965
Deferred rent - current portion	0		598
Other	80		104
Other current liabilities	$ 3,080		$ 1,667

Financial Statement Details -_6

Financial Statement Details - Investment Income, Net (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financial Statement Details [Abstract]
Interest income	$ 491	$ 632	$ 901	$ 1,336
Investment accretion income (amortization expense), net	42	(142)	2	(343)
Net realized gains on investments	0	0	0	2
Investment income, net	$ 533	$ 490	$ 903	$ 995

Viracta Investment and Conver_2

Viracta Investment and Convertible Notes - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		6 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Jun. 30, 2019	May 31, 2019	Jan. 31, 2019	Dec. 31, 2018	Mar. 31, 2017
Schedule Of Investments [Line Items]
Equity securities			$ 9,253			$ 8,500	$ 8,500
2018 Note and Warrant Purchase Agreement
Schedule Of Investments [Line Items]
Equity securities			$ 9,300
Purchase of convertible note	$ 400	$ 400
Convertible note accrued interest rate			8.00%
Debt instrument maturity date			1 year
2018 Note and Warrant Purchase Agreement | Common Stock
Schedule Of Investments [Line Items]
Warrants exercised to acquire shares				253,120
2018 Note and Warrant Purchase Agreement | Series B Preferred Stock
Schedule Of Investments [Line Items]
Preferred stock value					$ 800

Financial Instruments Investm_3

Financial Instruments Investments in Debt Securities - Schedule of Investments in Debt Securities (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	$ 68,274
Available-for-sale, Unrealized Gains	49
Available-for-sale, Unrealized Losses	(67)
Available-for-sale, Fair Value	$ 68,256
Available-for-sale, Weighted- Average Remaining Contractual Life	4 months 24 days
Notes Receivable
Schedule Of Available For Sale Securities [Line Items]
Held-to-maturity, Amortized Cost		$ 723
Held-to-maturity, Unrealized Gains		0
Held-to-maturity, Unrealized Losses		0
Held-to-maturity, Fair Value		723
Current Assets
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	$ 66,773	57,463
Available-for-sale, Unrealized Gains	49	1
Available-for-sale, Unrealized Losses	(49)	(136)
Available-for-sale, Fair Value	66,773	57,328
Available-for-sale and held-to-maturity, Amortized Cost		58,186
Available-for-sale and held-to-maturity, Unrealized Gains		1
Available-for-sale and held-to-maturity, Unrealized Losses		(136)
Available-for-sale and held-to-maturity, Fair Value		58,051
Current Assets | Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	59,000	57,463
Available-for-sale, Unrealized Gains	46	1
Available-for-sale, Unrealized Losses	(31)	(136)
Available-for-sale, Fair Value	$ 59,015	57,328
Available-for-sale, Weighted- Average Remaining Contractual Life	4 months 24 days
Current Assets | Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	$ 1,498
Available-for-sale, Unrealized Gains	0
Available-for-sale, Unrealized Losses	0
Available-for-sale, Fair Value	$ 1,498
Available-for-sale, Weighted- Average Remaining Contractual Life	1 month 6 days
Current Assets | Foreign Government Bonds
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	$ 3,244
Available-for-sale, Unrealized Gains	3
Available-for-sale, Unrealized Losses	0
Available-for-sale, Fair Value	$ 3,247
Available-for-sale, Weighted- Average Remaining Contractual Life	3 months 18 days
Current Assets | Government Sponsored Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	$ 3,031
Available-for-sale, Unrealized Gains	0
Available-for-sale, Unrealized Losses	(18)
Available-for-sale, Fair Value	$ 3,013
Available-for-sale, Weighted- Average Remaining Contractual Life	10 months 24 days
Noncurrent Assets
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	$ 1,501	5,823
Available-for-sale, Unrealized Gains	0	0
Available-for-sale, Unrealized Losses	(18)	(122)
Available-for-sale, Fair Value	$ 1,483	5,701
Available-for-sale, Weighted- Average Remaining Contractual Life	2 years 2 months 12 days
Available-for-sale and held-to-maturity, Amortized Cost		64,009
Available-for-sale and held-to-maturity, Unrealized Gains		1
Available-for-sale and held-to-maturity, Unrealized Losses		(258)
Available-for-sale and held-to-maturity, Fair Value		63,752
Noncurrent Assets | Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	$ 1,501	3,067
Available-for-sale, Unrealized Gains	0	0
Available-for-sale, Unrealized Losses	(18)	(76)
Available-for-sale, Fair Value	$ 1,483	2,991
Available-for-sale, Weighted- Average Remaining Contractual Life	2 years 2 months 12 days
Noncurrent Assets | Government Sponsored Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost		2,756
Available-for-sale, Unrealized Gains		0
Available-for-sale, Unrealized Losses		(46)
Available-for-sale, Fair Value		$ 2,710

Financial Instruments Investm_4

Financial Instruments Investments in Debt Securities - Additional Information (Detail) - Security	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Maximum
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, period of unrealized loss positions	12 months	12 months
Minimum
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, period of unrealized loss positions	12 months	12 months
Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Number of available-for-sale securities in unrealized loss positions	13

Financial Instruments Investm_5

Financial Instruments Investments in Debt Securities - Accumulated Unrealized Losses on Debt Securities Classified as Available-for-Sale in Continuous Loss Position (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	$ 4,618	$ 32,010
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	(1)	(26)
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	12,732	29,373
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	(66)	(232)
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	4,618	32,010
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	(1)	(26)
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	9,996	26,663
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	(48)	(186)
Government Sponsored Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Investments, Less than 12 months, Estimated Fair Value	0	0
Available-for-Sale Investments, Less than 12 months, Gross Unrealized Losses	0	0
Available-for-Sale Investments, More than 12 months, Estimated Fair Value	2,736	2,710
Available-for-Sale Investments, More than 12 months, Gross Unrealized Losses	$ (18)	$ (46)

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	$ 85,535	$ 79,850
Current Assets | Cash and cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	17,279	16,821
Current Assets | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	59,015	57,328
Current Assets | Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	3,247
Current Assets | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	1,498
Current Assets | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	3,013
Noncurrent Assets | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	1,483	2,991
Noncurrent Assets | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value		2,710
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	17,279	16,821
Level 1 | Current Assets | Cash and cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	17,279	16,821
Level 1 | Current Assets | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Level 1 | Current Assets | Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
Level 1 | Current Assets | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
Level 1 | Current Assets | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
Level 1 | Noncurrent Assets | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Level 1 | Noncurrent Assets | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value		0
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	68,256	63,029
Level 2 | Current Assets | Cash and cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Level 2 | Current Assets | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	59,015	57,328
Level 2 | Current Assets | Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	3,247
Level 2 | Current Assets | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	1,498
Level 2 | Current Assets | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	3,013
Level 2 | Noncurrent Assets | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	1,483	2,991
Level 2 | Noncurrent Assets | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value		2,710
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Level 3 | Current Assets | Cash and cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Level 3 | Current Assets | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0	0
Level 3 | Current Assets | Foreign Government Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
Level 3 | Current Assets | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
Level 3 | Current Assets | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	0
Level 3 | Noncurrent Assets | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	$ 0	0
Level 3 | Noncurrent Assets | Government Sponsored Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value		$ 0

Collaboration and License Agr_2

Collaboration and License Agreements - Additional Information (Detail) - Altor	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)Patient	Jun. 30, 2018USD ($)
Licensing Agreement [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	$ 0	$ 0

Commitment and Contingencies -

Commitment and Contingencies - Additional Information (Detail)

1 Months Ended

3 Months Ended

6 Months Ended

12 Months Ended

Apr. 30, 2019USD ($)

Aug. 31, 2018USD ($)

Dec. 31, 2017USD ($)ft²

Sep. 30, 2016USD ($)ft²

Jun. 30, 2016USD ($)ft²$ / ft²

Mar. 31, 2016

Nov. 30, 2015USD ($)ft²

Jun. 30, 2015USD ($)ft²

Jun. 30, 2019USD ($)ft²

Sep. 30, 2018USD ($)

Jun. 30, 2018USD ($)

Jun. 30, 2019USD ($)ft²

Jun. 30, 2018USD ($)

Dec. 31, 2018USD ($)ft²

Jan. 01, 2019

Commitments And Contingencies [Line Items]

Litigation settlement amount

$ 12,000,000

Attorney's fee to plaintiffs

$ 500,000

Weighted average remaining lease term

5 years

5 years

5 years 4 months 24 days

Weighted average discount rate

9.00%

9.00%

9.00%

Cash outflows from operating leases

$ 1,000,000

$ 2,300,000

Rent expense

$ 700,000

$ 1,400,000

Woburn, Massachusetts

Commitments And Contingencies [Line Items]

Number of square foot of facility leased | ft²

8,153

7,893

7,893

Term of lease arrangement

48 months

48 months

Lease commencement date

Apr. 29, 2016

Addition to number of square foot of facility leased | ft²

260

Base rent - yearly

$ 19,000

Annual increase of base rent | $ / ft²

1

Period of agreement

In June 2016, the lease was amended to add 260 square feet, for a total of 8,153 square feet. The base rent, including the amendment, is $19,000 per month with a $1 per square foot annual increase on each anniversary date

Commitment; San Diego

Commitments And Contingencies [Line Items]

Number of square foot of facility leased | ft²

44,700

Base rent - monthly

$ 200,000

Percentage of annual increase of base rent

3.00%

Base lease term

7 years

Sub Lease Agreements

Commitments And Contingencies [Line Items]

Number of square foot of facility leased | ft²

2,000

Cardiff-by-the-Sea, California

Commitments And Contingencies [Line Items]

Number of square foot of facility leased | ft²

2,550

Base rent - monthly

$ 13,200

Lease agreement extended lease period

Aug. 31, 2018

NantBioScience

Commitments And Contingencies [Line Items]

Reimbursed upfront payment to third-party

$ 900,000

Related party transaction, amount paid to third-party

500,000

Related party transaction, aggregate value

$ 1,400,000

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

10 years

5 years

Related party agreement expiration date

2027-06

Number of square foot of facility leased | ft²

1,965

Base rent - monthly

$ 10,000

Percentage of annual increase of base rent

3.00%

Doug St, LLC

Commitments And Contingencies [Line Items]

Period of agreement

The lease runs from July 2016 through July 2023. We have 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

Doug St, LLC | El Segundo California

Commitments And Contingencies [Line Items]

Number of square foot of facility leased | ft²

24,250

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. We have 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

Prepaid Expenses and Other Current Assets

Commitments And Contingencies [Line Items]

Insurance claim receivable

$ 300,000

$ 300,000

$ 10,900,000

Directors and Officers Insurance Policy

Commitments And Contingencies [Line Items]

Litigation settlement amount

10,800,000

Selling, General and Administrative

Commitments And Contingencies [Line Items]

Litigation settlement amount

$ 1,200,000

Research and Development Expense and Selling, General and Administrative Expense

Commitments And Contingencies [Line Items]

Operating lease expense

1,300,000

2,500,000

Variable lease costs

$ 300,000

$ 500,000

Commitment and Contingencies _2

Commitment and Contingencies - Schedule of Lease Balances (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets And Liabilities Lessee [Abstract]
Operating lease right-of-use assets, net	$ 12,513	$ 13,532	$ 0
Operating lease liability - current portion	3,000	2,960	0
Operating lease liability, less current portion	$ 11,997	$ 13,407	$ 0

Commitment and Contingencies _3

Commitment and Contingencies - Summary of Future Minimum Lease Payments (Detail) $ in Thousands	Jun. 30, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
2019 (excluding the six months ended June 30, 2019)	$ 2,083
2020	4,080
2021	3,438
2022	3,538
2023	2,545
Thereafter	2,813
Total future minimum lease payments	18,497
Less: Interest	3,500
Present value of operating lease liabilities	$ 14,997

Commitment and Contingencies _4

Commitment and Contingencies - Summary of Future Minimum Lease Payments (Parenthetical) (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
Operating lease payments related to options to extend lease terms	$ 3.3

Related Party Agreements - Addi

Related Party Agreements - Additional Information (Detail)	1 Months Ended										3 Months Ended			6 Months Ended		12 Months Ended
	May 31, 2019USD ($)	Aug. 31, 2018USD ($)	May 31, 2018USD ($)	Dec. 31, 2017USD ($)ft²	Apr. 30, 2017USD ($)ft²	Sep. 30, 2016USD ($)ft²	Apr. 30, 2016USD ($)	Mar. 31, 2016	Nov. 30, 2015USD ($)ft²	Jun. 30, 2015	Jun. 30, 2019USD ($)Officer	Mar. 31, 2019	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)Officer	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Related Party Transaction [Line Items]
Research and development											$ 13,131,000		$ 14,688,000	$ 25,729,000	$ 28,679,000
Due to related parties											957,000			957,000		$ 1,696,000
Selling, general and administrative expense											4,182,000		13,594,000	9,924,000	27,892,000
Prepaid expenses and other current assets											2,746,000			2,746,000		13,900,000
NantHealth Labs, 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		100,000	10,000	100,000
Due to related parties																49,300
Due between parties											0			0
Immuno-Oncology Clinic, Inc. | California
Related Party Transaction [Line Items]
Research and development											200,000		700,000	500,000	1,400,000
Due to related parties											$ 300,000			$ 300,000		600,000
Number of officers | Officer											2			2
Tensorcom, Inc | San Diego California
Related Party Transaction [Line Items]
Period of agreement														lease ran from May 1, 2017 through April 30, 2018
Number of square foot of facility leased | ft²					6,557
Base rent - monthly					$ 25,000
Tensorcom, Inc | San Diego California | Other Income
Related Party Transaction [Line Items]
Sublease revenue recognized													32,000		100,000
VivaBioCell S.p.A.
Related Party Transaction [Line Items]
Research and development											$ 0		0	$ 0	100,000
Doug St, LLC
Related Party Transaction [Line Items]
Due between parties											0			$ 0		0
Period of agreement														The lease runs from July 2016 through July 2023. We have the option to extend the lease for an additional three-year term through July 2026.
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
Doug St, LLC | Research and Development
Related Party Transaction [Line Items]
Lease expense											200,000		100,000	$ 400,000	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]
Supplies and milestone charges for conducting clinical trials											0		0	0	0
NantBioScience
Related Party Transaction [Line Items]
Initial term of agreement entered into with the related party by the entity		10 years						5 years
Research and development											200,000		300,000	$ 200,000	300,000
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
Research and development expense, ratable payment period														12 months
Prepayment for services amount	$ 600,000	$ 600,000			$ 600,000		$ 600,000
NantBioScience | Prepaid Expenses and Other Current Assets
Related Party Transaction [Line Items]
Research and development														$ 400,000		100,000
Due between parties											23,900			23,900		49,000
NantBioScience | Other Income
Related Party Transaction [Line Items]
Sublease revenue recognized											31,600		31,000	100,000	100,000
NantWorks
Related Party Transaction [Line Items]
Number of square foot of facility leased | ft²									9,500
Base rent - monthly									$ 47,000
Percentage of annual increase of base rent									3.00%
Annual percentage increases to base rent commencement date									Jan. 31, 2017
Transfer of deposit amount to third party			$ 400,000
NantWorks | Shared Services Agreement
Related Party Transaction [Line Items]
Research and development											300,000		900,000	600,000	1,800,000
Selling, general and administrative expense											500,000		800,000	1,200,000	1,500,000
NantWorks | Reimbursements | Shared Services Agreement
Related Party Transaction [Line Items]
Research and development											600,000		700,000	1,100,000	1,300,000
Due to related parties											600,000			600,000		1,100,000
Selling, general and administrative expense											200,000		200,000	400,000	300,000
NantWorks | Research and Development
Related Party Transaction [Line Items]
Lease expense											200,000		47,000	300,000	100,000
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											100,000		100,000	100,000	100,000
Due to related parties											24,800			24,800		24,000
ImmunityBio
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		$ 0	0	$ 0
Due between parties											8,000			8,000		0
Related parties, capitalized equipment amount														1,200,000		1,100,000
Prepaid expenses and other current assets											$ 400,000			$ 400,000		$ 500,000

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended		44 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Nov. 30, 2015
Class of Stock [Line Items]
Total amount authorized for repurchase							$ 50,000,000
Repurchase of common stock, shares		473,586	0	473,586	0	6,403,489
Repurchase of common stock excluding commissions, value		$ 500,000		$ 500,000		$ 31,700,000
Broker commissions on repurchases		14,200		14,200		100,000
Remaining authorized repurchase amount	$ 18,300,000	$ 18,300,000		$ 18,300,000		$ 18,300,000
Additional common shares reserved for future issuance	3,000,000
Common shares reserved for future issuance	7,249,857	7,249,857		7,249,857		7,249,857
Minimum
Class of Stock [Line Items]
Repurchase of common stock, price per share		$ 0.95		$ 0.95
Maximum
Class of Stock [Line Items]
Repurchase of common stock, price per share		$ 1.09		$ 1.09

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Based Compensation Expenses Related to Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 522	$ 8,934	$ 1,873	$ 18,007
Warrants For Common Stock | Officer
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	0	7,636	0	15,272
Employee Stock Option
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	104	970	1,101	1,948
Employee RSUs
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	313	294	563	686
Non-employee RSUs
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	105	34	209	101
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	150	142	261	281
Selling, General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 372	$ 8,792	$ 1,612	$ 17,726

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock Option Activity (Detail) - Employee Stock Option - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Number of Shares
Stock Options, Beginning Balance	6,493,250
Stock Options, Options exercised	(1,986,300)
Stock Options, Ending Balance	4,506,950	6,493,250
Stock Options, Vested and Exercisable	3,706,950
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding Beginning balance	$ 7.14
Weighted Average Exercise Price, Options exercised	2.06
Weighted Average Exercise Price, Outstanding Ending balance	9.37	$ 7.14
Weighted Average Exercise Price, Vested and Exercisable	$ 10.73
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding, Beginning balance	$ 353	$ 563
Aggregate Intrinsic Value, Vested and Exercisable	$ 353
Weighted Average Remaining Contractual Life
Weighted Average Remaining Contractual Life, Outstanding	6 years 3 months 18 days	4 years 9 months 18 days
Weighted Average Remaining Contractual Life, Vested and Exercisable	5 years 8 months 12 days

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise of stock options			$ 4,070,000
Proceeds from exercises of warrants	$ 0	$ 11,300	35,200,000	$ 34,400
Chief Executive Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Proceeds from stock options exercised	0		4,100,000
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested stock options	1,300,000		$ 1,300,000
Weighted-average period for recognition			3 years 2 months 12 days
Exercise of stock options, Shares			1,986,300
Exercise of stock options		$ 0		$ 0
Aggregate intrinsic value of stock option exercised	0		$ 200,000
Employees and Non-Employee Directors RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period for recognition			2 years
Grants of restricted stock			716,293
Unrecognized compensation cost related to non-vested stock options	2,000,000		$ 2,000,000
Shared Services Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period for recognition			1 year
Grants of restricted stock			0
Unrecognized compensation cost related to non-vested stock options	300,000		$ 300,000
Outstanding RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period for recognition			1 year 10 months 24 days
Grants of restricted stock			716,293
Unrecognized compensation cost related to non-vested stock options	$ 2,300,000		$ 2,300,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of (RSUs) Activity (Detail) - Outstanding RSUs	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested, Beginning balance | shares	867,911
Number of Shares, Granted | shares	716,293
Number of Shares, Vested | shares	(157,291)
Number of Shares, Forfeited | shares	(48,800)
Number of Shares, Unvested, Ending balance | shares	1,378,113
Weighted-Average Grant Date Fair Value, Unvested, beginning balance | $ / shares	$ 6.69
Weighted-Average Grant Date Fair Value, Granted | $ / shares	1.12
Weighted-Average Grant Date Fair Value, Vested | $ / shares	4.22
Weighted-Average Grant Date Fair Value, Forfeited | $ / shares	4.63
Weighted-Average Grant Date Fair Value, Unvested, ending balance | $ / shares	$ 4.14

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Warrant Activity (Detail) - Outstanding Warrants	6 Months Ended
	Jun. 30, 2019shares
Warrant [Line Items]
Number of shares Warrants, Beginning Balance	17,589,250
Number of shares Warrants exercised	(17,589,250)
Number of shares Warrants, Ending Balance	0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Tax [Line Items]
Federal statutory tax rate			21.00%
Company's effective tax rate			0.00%
Unrealized gains in other comprehensive income		$ 0		$ 0
Tax expense (benefit)	$ 2,000	0	$ (34,000)	0
Tax benefit in other comprehensive income	0	0	(100,000)	0
Korea
Income Tax [Line Items]
Tax benefit	$ 0	$ 100,000	$ 0	$ 300,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Subsequent Event $ in Millions	1 Months Ended
	Jul. 31, 2019USD ($)OfficerInstallment
Subsequent Event [Line Items]
Estimated cost for new agreement with clinic	$ 7.5
Initial term of agreement	1 year
Number of installments | Installment	3
Number of officers | Officer	2
Estimated costs for clinical trial and research	$ 1.2