Nektar Therapeutics (NKTR) 10-Q 7 Nov 23 2023 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2023	Oct. 31, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	0-24006
Entity Registrant Name	NEKTAR THERAPEUTICS
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3134940
Entity Address, Address Line One	455 Mission Bay Boulevard South
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94158
City Area Code	415
Local Phone Number	482-5300
Title of 12(b) Security	Common Stock, $0.0001 par value
Trading Symbol	NKTR
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		190,770,566
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000906709
Current Fiscal Year End Date	--12-31

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 64,921	$ 88,227
Short-term investments	307,737	416,750
Accounts receivable	2,204	5,981
Inventory, net	15,130	19,202
Other current assets	9,033	15,808
Total current assets	399,025	545,968
Property, plant and equipment, net	19,949	32,451
Operating lease right-of-use assets	18,747	53,435
Goodwill	0	76,501
Other assets	4,523	2,245
Total assets	442,244	710,600
Current liabilities:
Accounts payable	3,288	12,980
Accrued expenses	29,729	36,557
Operating lease liabilities, current portion	19,095	18,667
Total current liabilities	52,112	68,204
Operating lease liabilities, less current portion	102,193	112,829
Liabilities related to the sales of future royalties, net	123,610	155,378
Other long-term liabilities	4,961	7,551
Total liabilities	282,876	343,962
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.0001 par value; 10,000 shares authorized; no shares designated or outstanding at September 30, 2023 or December 31, 2022, respectively	0	0
Common stock, $0.0001 par value; 300,000 shares authorized; 190,771 shares and 188,560 shares issued and outstanding at September 30, 2023 and December 31, 2022, respectively	19	19
Capital in excess of par value	3,600,871	3,574,719
Accumulated other comprehensive loss	(6,352)	(6,907)
Accumulated deficit	(3,435,170)	(3,201,193)
Total stockholders’ equity	159,368	366,638
Total liabilities and stockholders’ equity	$ 442,244	$ 710,600

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares designated (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock shares, issued (in shares)	190,771,000	188,560,000
Common stock, shares outstanding (in shares)	190,771,000	188,560,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue:
Total revenue	$ 24,144	$ 23,625	$ 66,237	$ 70,032
Operating costs and expenses:
Cost of goods sold	12,431	4,972	26,485	15,402
Research and development	24,070	33,590	84,220	183,583
General and administrative	21,147	22,534	60,097	70,394
Restructuring, impairment and costs of terminated program	11,360	16,830	49,107	124,350
Impairment of goodwill	0	0	76,501	0
Total operating costs and expenses	69,008	77,926	296,410	393,729
Loss from operations	(44,864)	(54,301)	(230,173)	(323,697)
Non-operating income (expense):
Change in fair value of development derivative liability	0	0	0	33,427
Non-cash interest expense on liabilities related to the sales of future royalties	(5,910)	(6,953)	(18,467)	(21,710)
Interest income and other income (expense), net	4,876	2,050	14,492	3,541
Total non-operating income (expense), net	(1,034)	(4,903)	(3,975)	15,258
Loss before provision for income taxes	(45,898)	(59,204)	(234,148)	(308,439)
Provision (benefit) for income taxes	(61)	(155)	(171)	71
Net loss	$ (45,837)	$ (59,049)	$ (233,977)	$ (308,510)
Basic net loss per share (in dollars per share)	$ (0.24)	$ (0.31)	$ (1.23)	$ (1.65)
Diluted net loss per share (in dollars per share)	$ (0.24)	$ (0.31)	$ (1.23)	$ (1.65)
Weighted average shares outstanding used in computing basic net loss per share (in shares)	190,406	187,641	189,651	186,767
Weighted average shares outstanding used in computing diluted net loss per share (in shares)	190,406	187,641	189,651	186,767
Product sales
Revenue:
Total revenue	$ 5,822	$ 4,969	$ 15,198	$ 15,969
Non-cash royalty revenue related to the sales of future royalties
Revenue:
Total revenue	18,167	18,342	50,860	52,167
License, collaboration and other revenue
Revenue:
Total revenue	$ 155	$ 314	$ 179	$ 1,896

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net loss	$ (45,837)	$ (59,049)	$ (233,977)	$ (308,510)
Other comprehensive income (loss):
Net unrealized gain (loss) on available-for-sale securities	196	490	1,527	(2,589)
Net foreign currency translation loss	(98)	(468)	(972)	(1,423)
Other comprehensive income (loss)	98	22	555	(4,012)
Comprehensive loss	$ (45,739)	$ (59,027)	$ (233,422)	$ (312,522)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Shares	Capital in Excess of Par Value	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2021		185,468
Beginning balance at Dec. 31, 2021	$ 679,508	$ 19	$ 3,516,641	$ (4,157)	$ (2,832,995)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under equity compensation plans (in shares)		806
Shares issued under equity compensation plans	188		188
Stock-based compensation	20,961		20,961
Comprehensive income (loss)	(92,768)			(2,375)	(90,393)
Ending balance (in shares) at Mar. 31, 2022		186,274
Ending balance at Mar. 31, 2022	607,889	$ 19	3,537,790	(6,532)	(2,923,388)
Beginning balance (in shares) at Dec. 31, 2021		185,468
Beginning balance at Dec. 31, 2021	679,508	$ 19	3,516,641	(4,157)	(2,832,995)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(312,522)
Ending balance (in shares) at Sep. 30, 2022		187,954
Ending balance at Sep. 30, 2022	412,223	$ 19	3,561,878	(8,169)	(3,141,505)
Beginning balance (in shares) at Mar. 31, 2022		186,274
Beginning balance at Mar. 31, 2022	607,889	$ 19	3,537,790	(6,532)	(2,923,388)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under equity compensation plans (in shares)		1,131
Shares issued under equity compensation plans	467		467
Stock-based compensation	11,103		11,103
Comprehensive income (loss)	(160,727)			(1,659)	(159,068)
Ending balance (in shares) at Jun. 30, 2022		187,405
Ending balance at Jun. 30, 2022	458,732	$ 19	3,549,360	(8,191)	(3,082,456)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under equity compensation plans (in shares)		549
Stock-based compensation	12,518		12,518
Comprehensive income (loss)	(59,027)			22	(59,049)
Ending balance (in shares) at Sep. 30, 2022		187,954
Ending balance at Sep. 30, 2022	$ 412,223	$ 19	3,561,878	(8,169)	(3,141,505)
Beginning balance (in shares) at Dec. 31, 2022	188,560	188,560
Beginning balance at Dec. 31, 2022	$ 366,638	$ 19	3,574,719	(6,907)	(3,201,193)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under equity compensation plans (in shares)		675
Stock-based compensation	10,019		10,019
Comprehensive income (loss)	(135,792)			1,226	(137,018)
Ending balance (in shares) at Mar. 31, 2023		189,235
Ending balance at Mar. 31, 2023	$ 240,865	$ 19	3,584,738	(5,681)	(3,338,211)
Beginning balance (in shares) at Dec. 31, 2022	188,560	188,560
Beginning balance at Dec. 31, 2022	$ 366,638	$ 19	3,574,719	(6,907)	(3,201,193)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	$ (233,422)
Ending balance (in shares) at Sep. 30, 2023	190,771	190,771
Ending balance at Sep. 30, 2023	$ 159,368	$ 19	3,600,871	(6,352)	(3,435,170)
Beginning balance (in shares) at Mar. 31, 2023		189,235
Beginning balance at Mar. 31, 2023	240,865	$ 19	3,584,738	(5,681)	(3,338,211)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under equity compensation plans (in shares)		884
Shares issued under equity compensation plans	18		18
Stock-based compensation	7,966		7,966
Comprehensive income (loss)	(51,891)			(769)	(51,122)
Ending balance (in shares) at Jun. 30, 2023		190,119
Ending balance at Jun. 30, 2023	196,958	$ 19	3,592,722	(6,450)	(3,389,333)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under equity compensation plans (in shares)		652
Stock-based compensation	8,149		8,149
Comprehensive income (loss)	$ (45,739)			98	(45,837)
Ending balance (in shares) at Sep. 30, 2023	190,771	190,771
Ending balance at Sep. 30, 2023	$ 159,368	$ 19	$ 3,600,871	$ (6,352)	$ (3,435,170)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss	$ (233,977)	$ (308,510)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash royalty revenue related to the sales of future royalties	(50,860)	(52,167)
Non-cash interest expense on liabilities related to the sales of future royalties	18,467	21,710
Change in fair value of development derivative liability	0	(33,427)
Non-cash research and development expense	0	4,951
Stock-based compensation	26,134	44,582
Depreciation and amortization	6,163	9,848
Deferred income tax expense	(1,854)	0
Impairment of right-of-use assets and property, plant and equipment	36,628	58,521
Impairment of goodwill	76,501	0
Provision for inventory obsolescence	4,444
Amortization of premiums (discounts), net and other non-cash transactions	(12,137)	(372)
Changes in operating assets and liabilities:
Accounts receivable	3,777	10,960
Inventory	(372)	(3,256)
Operating leases, net	(6,078)	(1,423)
Other assets	4,450	4,861
Accounts payable	(9,328)	(4,184)
Accrued expenses	(7,517)	1,602
Net cash used in operating activities	(145,559)	(246,304)
Cash flows from investing activities:
Purchases of investments	(372,821)	(295,439)
Maturities of investments	494,385	626,424
Purchases of property, plant and equipment	(628)	(5,164)
Sale of property, plant and equipment	1,245	0
Net cash provided by investing activities	122,181	325,821
Cash flows from financing activities:
Proceeds from shares issued under equity compensation plans	18	655
Cash receipts from development derivative liability	0	750
Net cash provided by financing activities	18	1,405
Effect of foreign exchange rates on cash and cash equivalents	54	(382)
Net increase (decrease) in cash and cash equivalents	(23,306)	80,540
Cash and cash equivalents at beginning of period	88,227	25,218
Cash and cash equivalents at end of period	64,921	105,758
Supplemental disclosures of cash flow information:
Cash paid for income taxes	$ 2,656	$ 0

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Summary of Significant Accounting Policies	Note 1 — Organization and Summary of Significant Accounting Policies Organization We are a research-based biopharmaceutical company headquartered in San Francisco, California and incorporated in Delaware. We (individually or with a partner) are developing a pipeline of drug candidates that utilize our advanced polymer conjugate technology platforms, which are designed to enable the development of new molecular entities that target known mechanisms of action. Our research and development pipeline of new investigational drugs includes investigational treatments in the field of immunotherapy. Our research and development activities have required significant ongoing investment to date and are expected to continue to require significant investment. As a result, we expect to continue to incur substantial losses and negative cash flows from operations in the future. We have financed our operations primarily through cash generated from licensing, collaboration and manufacturing agreements and financing transactions. As of September 30, 2023, we had approximately $ 372.7 million in cash and investments in marketable securities. Results of Clinical Trial Programs and the Restructuring Plans In March and April 2022, we announced that our registrational trials of bempegaldesleukin in combination with Opdivo ® in metastatic melanoma, renal cell carcinoma and locally advanced or metastatic urothelial cancer under our Strategic Collaboration Agreement (BMS Collaboration Agreement) with Bristol-Myers Squibb Company (BMS) did not meet their primary endpoints. Based on these results, in April 2022, we announced our decisions to discontinue all development of bempegaldesleukin in combination with checkpoint inhibitors, including these trials, our registrational trial in adjuvant melanoma under our BMS Collaboration Agreement, and our Phase 2/3 study of bempegaldesleukin in combination with Keytruda ® in squamous cell cancer of the head and neck under our Co-Development Agreement with SFJ Pharmaceuticals. See Note 5 for additional information regarding our BMS Collaboration Agreement and Co-Development Agreement with SFJ Pharmaceuticals. On September 6, 2023, BMS and we terminated the BMS Collaboration Agreement, however, we continue our efforts to wind down the bempegaldesleukin program following the same cost sharing provisions provided for in the BMS Collaboration Agreement. In April 2022, we also announced new strategic reorganization and cost restructuring plans (together, the 2022 Restructuring Plan), pursuant to which we completed an approximate 70 % reduction of our workforce during 2022 and sold our research facility in India in December 2022. We also decided to sublease certain of our leased premises in San Francisco, CA, including all of our office leased space on Third St. and portions of our office and laboratory space on Mission Bay Blvd. South. On February 23, 2023, we announced the topline data from the Phase 2 study of rezpegaldesleukin in adult patients with systemic lupus erythematosus (SLE) (Phase 2 Lupus Study) under our collaboration agreement with Eli Lilly and Company (Lilly). Lilly subsequently notified us that it did not intend to advance rezpegaldesleukin into Phase 3 development for SLE. On April 27, 2023, we announced that we would be regaining the full rights to rezpegaldesleukin from Lilly, and the collaboration agreement has subsequently terminated. We have initiated a Phase 2b study of rezpegaldesleukin in patients with moderate-to-severe atopic dermatitis, and we are planning to initiate in late 2023 or in early 2024 a new Phase 2b study of rezpegaldesleukin in patients with alopecia areata. We will also explore other auto-immune indications for the development of rezpegaldesleukin. On August 7, 2023, we announced that the interim efficacy data previously generated by Lilly for rezpegaldesleukin that were presented at the European Academy of Dermatology and Venereolgy (EADV) conference in September 2022 were incorrectly calculated by Lilly. The erroneous interim data were reported in connection with the Phase 1b study of rezpegaldesleukin in adult patients with atopic dermatitis (Phase 1b AD Study) and the Phase 1b study of rezpegaldesleukin in adult patients with psoriasis. We reported the new and corrected data from the Phase 1b AD Study of rezpegaldesleukin. On October 13, 2023, we announced final efficacy data from the Phase 1b AD Study at the 2023 EADV conference. The final data from the study demonstrated rezpegaldesleukin resulted in dose-dependent improvements in EASI, validated investigated global assessment (vIGA), body surface area (BSA), and itch numeric rating scale (NRS) over twelve weeks of treatment compared to placebo, which were sustained post-treatment over an additional thirty-six weeks. Pursuant to plans approved by our Board of Directors (the Board) on March 29, 2023, we announced on April 17, 2023, a new strategic reprioritization and cost restructuring plan (the 2023 Restructuring Plan). Under the 2023 Restructuring Plan, we reduced our San Francisco-based workforce by approximately 60 %, which was substantially completed by June 2023. In addition, under the 2023 Restructuring Plan, we decided to sublease our remaining office and laboratory space on Mission Bay Blvd. South which we had not planned to sublease pursuant to the 2022 Restructuring Plan. We have incurred significant costs resulting from the 2022 and 2023 Restructuring Plans. See Note 6 for additional information on the effect on our Condensed Consolidated Financial Statements. Basis of Presentation and Principles of Consolidation Our Condensed Consolidated Financial Statements include the financial position, results of operations and cash flows of Nektar Therapeutics and our wholly-owned subsidiaries. We have eliminated all intercompany accounts and transactions in consolidation. We prepared our Condensed Consolidated Financial Statements following the requirements of the Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, we may condense or omit certain footnotes or other financial information that are normally required by U.S. generally accepted accounting principles (GAAP) for annual periods. In the opinion of management, these financial statements include all normal and recurring adjustments that we consider necessary for the fair presentation of our financial position and operating results. Our Condensed Consolidated Financial Statements are denominated in U.S. dollars. Accordingly, changes in exchange rates between the applicable foreign currency and the U.S. dollar will affect the translation of each foreign subsidiary’s financial results into U.S. dollars for purposes of reporting our consolidated financial results. We include translation gains and losses in accumulated other comprehensive loss in the stockholders’ equity section of our Condensed Consolidated Balance Sheets. Our comprehensive loss consists of our net loss plus our foreign currency translation gains and losses and unrealized gains and losses on available-for-sale securities. There were no significant reclassifications out of accumulated other comprehensive loss to the statements of operations during the three and nine months ended September 30, 2023 and 2022 except as otherwise disclosed below in Note 3. The accompanying Condensed Consolidated Financial Statements are unaudited. The Condensed Consolidated Balance Sheet data as of December 31, 2022 was derived from the audited consolidated financial statements which are included in our Annual Report on Form 10-K for the year ended December 31, 2022 filed with the SEC on February 28, 2023. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and the accompanying notes to those financial statements. Revenue, expenses, assets, and liabilities can vary during each quarter of the year. The results and trends in these interim Condensed Consolidated Financial Statements are not necessarily indicative of the results to be expected for the full year or any other period. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Accounting estimates and assumptions are inherently uncertain. Actual results could differ materially from those estimates and assumptions. As appropriate, we assess estimates each period, update them to reflect current information, and generally reflect any changes in estimates in the period first identified. Significant Concentrations Our customers are primarily pharmaceutical companies that are located in the U.S. and Europe and with whom we have multi-year arrangements. Our accounts receivable balance contains billed and unbilled trade receivables from product sales, milestones (to the extent that they have been achieved and are due from the counterparty), and other contingent payments, as well as reimbursable costs from collaborative research and development agreements. We generally do not require collateral from our customers. We perform a regular review of our customers’ credit risk and payment histories, including payments made after period end. Historically, we have no t experienced credit losses from our accounts receivable. We have not recorded reserves for credit losses for the three and nine months ended September 30, 2023 and 2022, nor have recorded such an allowance as of September 30, 2023 or December 31, 2022. We are dependent on our suppliers and contract manufacturers to provide raw materials and drugs of appropriate quality and reliability and to meet applicable contract and regulatory requirements. In certain cases, we rely on single sources of supply of one or more critical materials. Consequently, in the event that supplies are delayed or interrupted for any reason, our ability to develop and produce our drug candidates or our ability to meet our supply obligations could be significantly impaired, which could have a material adverse effect on our business, financial condition and results of operations. For our available-for-sale securities, we have significant concentrations of issuers in the banking and financial services industries. While our investment policy requires that we only invest in highly-rated securities and limit our exposure to any single issuer, various factors may materially affect the financial condition of issuers. Additionally, pursuant to our investment policy, we may sell securities before maturity if the issuer’s credit rating has been downgraded below our minimum credit rating requirements, which may result in a loss on the sale. Accordingly, if various factors result in downgrades below our minimum credit rating requirements and if we decide to sell these securities, we may experience losses on such sales. Restructuring We recognize restructuring charges related to reorganization plans that have been committed to by management when liabilities have been incurred. In connection with these activities, we record restructuring charges at fair value for: • contractual or other employee termination benefits provided that the obligations result from services already rendered based on rights that vest or accumulated when the payment of benefits becomes probable and the amount can be reasonably estimated, • one-time employee termination benefits on the communication date from management to the employees provided that management has committed to a plan of termination, the plan identifies the employees and their expected termination dates, the details of termination benefits are complete, and it is unlikely that changes to the plan will be made or the plan will be withdrawn, • contract termination costs when we cancel the contract in accordance with its terms, and • costs to be incurred over the remaining contract term without economic benefit to us at the cease-use date. For one-time employee terminations benefits, we recognize the liability in full on the communication date when future services are not required or amortize the liability ratably over the service period, if required. The fair value of termination benefits reflects our estimates of expected utilization of certain Company-funded post-employment benefits. See Note 6 for additional information on the severance expense that we recognized for employees terminated in connection with our reductions-in-force. Impairment of Goodwill Goodwill is assessed for impairment on an annual basis and whenever events and circumstances indicate that it may be impaired. Factors that may indicate potential impairment and trigger an impairment test include, but are not limited to, current economic, market and geopolitical conditions, including a significant, sustained decline in our stock price and market capitalization compared to the net book value; an adverse change in legal factors, business climate or operational performance of the business; or significant changes in the ability of the reporting unit to generate positive cash flows for our strategic business objectives. If the carrying value of the reporting unit, including goodwill, exceeds the reporting unit’s fair value, we will recognize a goodwill impairment loss, and we will write down goodwill such that the carrying value of the reporting unit equals its fair value, provided that we cannot reduce goodwill below zero. See Note 6 for additional information regarding the impairment charges we recorded in connection with our goodwill. Long-Lived Asset Impairment We assess the impairment of long-lived assets whenever events or changes in business circumstances indicate that the carrying amounts of the assets may not be fully recoverable. In the case of property, plant and equipment and right-of-use assets for our leases, we determine whether there has been an impairment by comparing the carrying value of the asset to the anticipated undiscounted net cash flows associated with the asset. If such cash flows are less than the carrying value, we write down the asset to its fair value, which may be measured as anticipated net cash flows associated with the asset, discounted at a rate that we believe a market participant would utilize to reflect the risks associated with the cash flows, such as credit risk. See Note 6 for additional information regarding the impairment charges we recorded in connection with our leased facilities and certain property and equipment. Net Loss per Share For all periods presented in the Condensed Consolidated Statements of Operations, the net loss available to common stockholders is equal to the reported net loss. We calculate basic net loss per share based on the weighted-average number of common shares outstanding during the periods presented. For the three and nine months ended September 30, 2023 and 2022 , basic and diluted net loss per share are the same due to our net losses and the requirement to exclude potentially dilutive securities which would have an antidilutive effect on net loss per share. We excluded shares underlying the weighted average outstanding stock options, restricted stock units (RSUs) and performance stock units (PSUs), as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Potentially dilutive securities 17,476 19,575 20,513 20,809

Cash and Investments in Marketa

Cash and Investments in Marketable Securities	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Cash and Investments in Marketable Securities	Note 2 — Cash and Investments in Marketable Securities Cash and investments in marketable securities, including cash equivalents, are as follows (in thousands): Estimated Fair Value at September 30, 2023 December 31, 2022 Cash and cash equivalents $ 64,921 $ 88,227 Short-term investments 307,737 416,750 Total cash and investments in marketable securities $ 372,658 $ 504,977 Our portfolio of cash and investments in marketable securities includes (in thousands): September 30, 2023 December 31, 2022 Fair Value Hierarchy Level Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fair Value Corporate notes and bonds 2 $ 11,251 $ — $ ( 20 ) $ 11,231 $ 83,522 Corporate commercial paper 2 294,184 — ( 229 ) 293,955 344,204 Available-for-sale investments $ 305,435 $ — $ ( 249 ) $ 305,186 $ 427,726 Money market funds 1 46,858 47,054 Certificates of deposit 2 15,186 21,399 Cash N/A 5,428 8,798 Total cash and investments in marketable securities $ 372,658 $ 504,977 For the three and nine months ended September 30, 2023 and 2022, there were no transfers between Level 1 and Level 2 of the fair value hierarchy. At December 31, 2022 , our gross unrealized losses totaled $ 1.8 million, and our gross unrealized gains were insignificant.

Condensed Consolidated Financia

Condensed Consolidated Financial Statement Details	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Condensed Consolidated Financial Statement Details	Note 3 — Condensed Consolidated Financial Statement Details Inventory Inventory consists of the following (in thousands): September 30, 2023 December 31, 2022 Raw materials $ 1,918 $ 2,575 Work-in-process 12,291 10,749 Finished goods 921 5,878 Total inventory, net $ 15,130 $ 19,202 We manufacture finished goods inventory upon receipt of firm purchase orders, and we may manufacture certain intermediate work-in-process materials and purchase raw materials based on purchase forecasts from our partners. We include direct materials, direct labor, and manufacturing overhead in inventory and determine cost on a first-in, first-out basis for raw materials and on a specific identification basis for work-in-process and finished goods. We value inventory at the lower of cost or net realizable value, and we write down defective or excess inventory to net realizable value based on historical experience or projected usage. We expense inventory related to our research and development activities as manufactured by us or when purchased. During the three months ended September 30, 2023 , we recorded a provision for inventory obsolescence of $ 3.7 million for certain production batches manufactured in our Huntsville, Alabama facility. As a result of our identification of a quality concern of a solvent obtained from a third party that was used in the manufacturing of these batches, the batches are currently being held from further processing pending an investigation and assessment. If the results of the investigation and assessment determine that the held batches can be used for further processing, we may release these batches to our partner. Other Current Assets Other current assets consist of the following (in thousands): September 30, 2023 December 31, 2022 Prepaid research and development expenses $ 2,014 $ 7,398 Non-trade receivables and other 1,226 2,423 Other prepaid expenses 5,793 5,987 Total other current assets $ 9,033 $ 15,808 Property, Plant and Equipment Property, plant and equipment consists of the following (in thousands): September 30, 2023 December 31, 2022 Building and leasehold improvements $ 42,641 $ 74,889 Computer equipment and computer software 24,586 26,205 Manufacturing equipment 25,352 25,052 Laboratory equipment 14,592 24,243 Furniture, fixtures and other 533 4,263 Depreciable property, plant and equipment at cost 107,704 154,652 Less: accumulated depreciation ( 88,243 ) ( 124,731 ) Depreciable property, plant and equipment, net 19,461 29,921 Construction in process 488 2,530 Property, plant and equipment, net $ 19,949 $ 32,451 As a result of the sustained decrease in the fair value of our single reporting unit during the three months ended March 31, 2023, plans to sublease all of our laboratory and office space, and the weakening sublease markets, we have recorded non-cash impairment charges of $ 6.1 million for property, plant and equipment for the nine months ended September 30, 2023, which we report in restructuring, impairment and costs of terminated program in our Condensed Consolidated Statement of Operations. See Note 6 for additional information. Goodwill The following is a reconciliation of the changes in our goodwill for the nine months ended September 30, 2023 (in thousands): Nine months ended September 30, 2023 Goodwill – beginning balance $ 76,501 Impairment of goodwill ( 76,501 ) Goodwill – ending balance $ — As a result of the decrease in the fair value of our single reporting unit during the three months ended March 31, 2023, we recorded a non-cash goodwill impairment charge of $ 76.5 million, which we report as impairment of goodwill in our Condensed Consolidated Statement of Operations. We had previously recognized goodwill primarily from our acquisitions of Shearwater Corp. and Aerogen, Inc. in 2001 and 2005, respectively. See Note 6 for additional information. Accrued Expenses Accrued expenses consist of the following (in thousands): September 30, 2023 December 31, 2022 Accrued compensation $ 11,477 $ 9,582 Accrued clinical trial expenses 4,236 12,262 Liability to collaboration partners 4,444 3,808 Accrued contract termination costs 2,624 3,902 Other accrued expenses 6,948 7,003 Total accrued expenses $ 29,729 $ 36,557 Liabilities Related to the Sales of Future Royalties In 2012 and 2020, we sold to RPI Finance Trust (RPI) and entities managed by Healthcare Royalty Management, LLC (collectively, HCR), respectively, our rights to receive royalties under our license and manufacturing agreements with certain pharmaceutical partners under the 2012 Purchase and Sale Agreement and the 2020 Purchase and Sale Agreement, respectively. We account for these transactions as debt and recognize non-cash royalty revenue and non-cash interest expense to amortize the proceeds over the lives of the respective arrangements. We periodically update our prospective non-cash interest rate based on our estimates of future royalties. As of September 30, 2023 , our imputed interest rates for the arrangements with RPI and HCR were 10 % and 20 %, respectively. The following is a reconciliation of the changes in our liabilities related to the sales of future royalties for the nine months ended September 30, 2023 (in thousands): Nine Months Ended September 30, 2023 2012 Purchase and Sale Agreement 2020 Purchase and Sale Agreement Total Liabilities related to the sales of future royalties, net – beginning balance $ 55,167 $ 100,211 $ 155,378 Non-cash royalty revenue ( 28,035 ) ( 22,825 ) ( 50,860 ) Non-cash interest expense 3,551 14,916 18,467 Amortization of transaction costs — 625 625 Liabilities related to the sales of future royalties, net – ending balance $ 30,683 $ 92,927 $ 123,610 Accumulated Other Comprehensive Income (Loss) The following table summarizes the changes in accumulated other comprehensive income (loss) by component (in thousands): Foreign currency translation Available-for-sale securities Accumulated Other Comprehensive Income Balance at December 31, 2022 $ ( 5,131 ) $ ( 1,776 ) $ ( 6,907 ) Foreign currency translation adjustments 139 — 139 Unrealized gain on available-for-sale securities — 1,087 1,087 Balance at March 31, 2023 $ ( 4,992 ) $ ( 689 ) $ ( 5,681 ) Foreign currency translation adjustments 13 — 13 Unrealized gain on available-for-sale securities — 244 244 Reclassification adjustments to income ( 1,026 ) — ( 1,026 ) Balance at June 30, 2023 $ ( 6,005 ) $ ( 445 ) $ ( 6,450 ) Foreign currency translation adjustments ( 98 ) — ( 98 ) Unrealized gain on available-for-sale securities — 196 196 Balance at September 30, 2023 $ ( 6,103 ) $ ( 249 ) $ ( 6,352 ) The reclassification from accumulated other comprehensive loss relates to the closure of one of our foreign subsidiaries and has been included within interest income and other income (expense), net in our Condensed Consolidated Statement of Operations for the nine months ended September 30, 2023.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 4 — Commitments and Contingencies Legal Matters From time to time, we are involved in lawsuits, arbitrations, claims, investigations and proceedings, consisting of intellectual property, commercial, employment and other matters, which arise in the ordinary course of business. We make provisions for liabilities when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Such provisions are reviewed at least quarterly and adjusted to reflect the impact of settlement negotiations, judicial and administrative rulings, advice of legal counsel, and other information and events pertaining to a particular case. Litigation is inherently unpredictable. If any unfavorable ruling were to occur in any specific period, there exists the possibility of a material adverse impact on the results of our operations for that period and on our cash flows and liquidity. On August 7, 2023, we filed a complaint in the United States District Court for the Northern District of California against Lilly alleging, among other claims, breach of contract and breach of implied covenant of good faith and fair dealing, in connection with our collaboration with Lilly. We have recorded no liability for any litigation matters in our Condensed Consolidated Balance Sheets at either September 30, 2023 or December 31, 2022. Indemnifications in Connection with Commercial Agreements As part of our collaboration agreements with our partners related to the license, development, manufacture and supply of drugs and PEGylation materials based on our proprietary technologies and drug candidates, we generally agree to defend, indemnify and hold harmless our partners from and against third party liabilities arising out of the agreement, including product liability (with respect to our activities) and infringement of intellectual property to the extent the intellectual property is developed by us and licensed to our partners. The term of these indemnification obligations is generally perpetual commencing after execution of the agreement. There is generally no limitation on the potential amount of future payments we could be required to make under these indemnification obligations. From time to time, we enter into other strategic agreements such as divestitures and financing transactions pursuant to which we are required to make representations and warranties and undertake to perform or comply with certain covenants. For example, we made certain intellectual property representations in connection with our RPI and HCR transactions, however, the time limitation we have to indemnify RPI with respect to any breach of these intellectual property-based representations and warranties has passed. In the event it is determined that we breached certain of the representations and warranties or covenants made by us in any such agreements or certain express indemnification provisions are applicable, we could incur substantial indemnification liabilities depending on the timing, nature, and amount of any such claims. To date, we have not incurred any costs to defend lawsuits or settle claims related to these indemnification obligations, nor any breaches of representations or warranties or covenants. Because the aggregate amount of any potential indemnification obligation is not a stated amount, we cannot reasonably estimate the overall maximum amount of any such obligations.

License and Collaboration Agree

License and Collaboration Agreements	9 Months Ended
	Sep. 30, 2023
License And Collaboration Agreements [Abstract]
License and Collaboration Agreements	Note 5 — License and Collaboration Agreements We have entered into various collaboration agreements including license agreements and collaborative research, development and commercialization agreements with various pharmaceutical and biotechnology companies. Under these collaboration arrangements, we are entitled to receive license fees, upfront payments, milestone and other contingent payments, royalties, sales milestone payments, and payments for the manufacture and supply of our proprietary PEGylation materials and/or reimbursement for research and development activities. We generally include our costs of performing these services in research and development expense, except for costs for product sales to our collaboration partners which we include in cost of goods sold. We analyze our agreements to determine whether we should account for the agreements within the scope of ASC 808 Collaborative Arrangements , and, if so, we analyze whether we should account for any elements under ASC 606 Revenue from Contracts with Customers . Eli Lilly and Company (Lilly) : Rezpegaldesleukin (previously referred to as NKTR-358) On July 23, 2017, we entered into a worldwide license agreement (the Lilly Agreement) with Eli Lilly and Company (Lilly) to co-develop rezpegaldesleukin, a novel immunological drug candidate that we invented, pursuant to which we received an initial payment of $ 150.0 million and were eligible for up to $ 250.0 million in additional development and regulatory milestones. The Lilly Agreement provided that, during Phase 1B and Phase 2 development, we shared development costs wherein 75 % of the costs were borne by Lilly and 25 % of the costs were borne by us. On February 23, 2023, we announced the topline data from the Phase 2 study (Phase 2 Lupus Study) of rezpegaldesleukin in adult patients with systemic lupus erythematosus (SLE). Although the Phase 2 Lupus Study did not meet its primary endpoint, patients who received the middle dose within the modified intent-to-treat population, defined as all patients who were randomized and received at least one dose of rezpegaldesleukin, demonstrated improvement in SLEDAI-2K score as compared to placebo. Nonetheless, Lilly notified us that it does not intend to advance rezpegaldesleukin into Phase 3 development for SLE. On April 23, 2023, we received from Lilly a notice of at-will termination of the Lilly Agreement. On April 27, 2023, we announced that we would regain full rights to rezpegaldesleukin from Lilly, and the Lilly Agreement had subsequently terminated. Following the return of our rights to develop rezpegaldesleukin, we bear all costs of development. We have initiated a Phase 2b study of rezpegaldesleukin in patients with moderate-to-severe atopic dermatitis, and we are planning to initiate in late 2023 or early 2024 a new Phase 2b study of rezpegaldesleukin in patients with alopecia areata. We will also explore other auto-immune indications for the development of rezpegaldesleukin. On August 7, 2023, we announced that the interim efficacy data previously generated by Lilly for rezpegaldesleukin that were presented at the EADV conference in September 2022 were incorrectly calculated by Lilly. The erroneous interim data were reported in connection with the Phase 1b study of rezpegaldesleukin in adult patients with atopic dermatitis (Phase 1b AD Study) and the Phase 1b study of rezpegaldesleukin in adult patients with psoriasis. We reported the new and corrected data from the Phase 1b AD Study of rezpegaldesleukin. On October 13, 2023, we announced final efficacy data from the Phase 1b AD Study at the 2023 EADV conference. The final data from the study demonstrated rezpegaldesleukin resulted in dose-dependent improvements in EASI, validated investigated global assessment (vIGA), body surface area (BSA), and itch numeric rating scale (NRS) over twelve weeks of treatment compared to placebo, which were sustained post-treatment over an additional thirty-six weeks. Bristol-Myers Squibb Company (BMS) : Bempegaldesleukin, also referred to as NKTR-214 Effective April 3, 2018, we entered into a Strategic Collaboration Agreement (the BMS Collaboration Agreement) and a Share Purchase Agreement with BMS. Pursuant to the BMS Collaboration Agreement, we and BMS jointly developed bempegaldesleukin in combination with BMS’ Opdivo ® . The parties share the internal and external development costs for bempegaldesleukin in combination regimens based on each party’s relative ownership interest in the compounds included in the regimens. In accordance with the agreement, the parties share development costs for bempegaldesleukin in combination with Opdivo ® , 67.5 % of costs to BMS and 32.5 % to Nektar. The parties also shared costs for the manufacturing and pre-commercial costs of bempegaldesleukin, 35 % of the costs to BMS and 65 % to Nektar. Upon the effective date of the BMS Collaboration Agreement in April 2018, BMS paid us a non-refundable upfront cash payment of $ 1.0 billion and purchased 8,284,600 shares of our common stock pursuant to the Share Purchase Agreement for total additional cash consideration of $ 850.0 million. In 2020, we received additional non-refundable milestone payments of $ 50.0 million. As discussed in Note 1, in April 2022, we announced that BMS and we decided to discontinue all development of bempegaldesleukin in combination with Opdivo ® . On September 6, 2023, BMS and we terminated the BMS Collaboration Agreement, and pursuant to the surviving provisions of the BMS Collaboration Agreement, we and BMS continue our efforts to wind down the bempegaldesleukin program, and the cost sharing provisions continue to remain in effect as the parties wind down the studies. We determined that the BMS Collaboration Agreement falls within the scope of ASC 808. Based on the cost sharing percentages described above, we recognized BMS’ reimbursement of our expenses as a reduction of research and development expense and our reimbursement of BMS’ expenses as research and development expense. As discussed in Note 6, beginning in the second quarter of 2022, we began reporting clinical trial, other third-party costs and employee costs for the wind down of the bempegaldesleukin program in restructuring, impairment and costs of terminated program. Accordingly, during the three and nine months ended September 30, 2022, we recorded $ 8.3 million and $ 16.7 million , as a reduction of such expense for the net reimbursement from BMS. During the nine months ended September 30, 2022 , we recorded $ 24.9 million as a reduction of research and development expense for the net reimbursement from BMS recorded in the three months ended March 31, 2022. The net reimb ursement payable to BMS for the three and nine months ended September 30, 2023 was not significant. SFJ Pharmaceuticals On February 12, 2021, we entered into a Co-Development Agreement (the SFJ Agreement) with SFJ Pharmaceuticals XII, L.P., a SFJ Pharmaceuticals Group company (SFJ), pursuant to which SFJ would pay up to $ 150.0 million to support a Phase 2/3 study of bempegaldesleukin in combination with Keytruda ® (pembrolizumab) in metastatic or unresectable recurrent squamous cell carcinoma of the head and neck (the SCCHN Clinical Trial). SFJ had primary responsibility for the clinical trial management of the SCCHN Clinical Trial, and we were the sponsor of the SCCHN Clinical Trial. The SFJ Agreement provided for us to pay up to $ 637.5 million in Success Payments in the event of FDA approval of bempegaldesleukin in up to three indications. We accounted for the SFJ Agreement as a derivative liability, which we remeasured to fair value at each reporting date. We recorded increases to the liability for non-cash research and development expense as SFJ conducted the SCCHN Clinical Trial and for cash receipts from SFJ to us to support our internal costs of conducting the trial. We presented the gain (loss) from the remeasurement as change in fair value of development derivative liability in our Condensed Consolidated Statements of Operations. At March 31, 2022, due to the negative results of the metastatic melanoma trial and initial discussions with SFJ, we concluded that it was remote that SFJ and we would continue the SCCHN Clinical Trial. Accordingly, the fair value of the development derivative liability was reduced to zero as of March 31, 2022, and we recognized a corresponding gain in change in fair value of development derivative liability. In April 2022, we announced that SFJ and we agreed to discontinue the SCCHN Clinical Trial. Accordingly, SFJ will not be entitled to any Success Payments, and SFJ has the responsibility to wind down the SCCHN Clinical Trial at its sole cost. SFJ has no right to seek reimbursement from us for any costs incurred for the SCCHN Clinical Trial. The following table presents the change in the derivative liability for the nine months ended September 30, 2022: Fair Value Nine Months Ended September 30, 2022 Fair value at beginning of period 3 $ 27,726 Non-cash research and development expense 4,951 Cash receipts from SFJ 750 Change in the fair value of development derivative liability ( 33,427 ) Fair value at end of period 3 $ — Other We have other collaboration agreements that have resulted in commercialized products for our collaborations partners. Under these agreements, we may sell our proprietary PEGylation materials for use in these products, and we are entitled to receive royalties based on net sales of these products as well as sales milestones. As discussed in Note 3, we have sold our rights to receive royalties from these other collaboration agreements. Our non-cash royalty revenue, which totaled $ 18.3 million and $ 52.2 million for the three and nine months ended September 30, 2022, respectively, and totaled $ 18.2 million and $ 50.9 million for three and nine months ended September 30, 2023, respectively, represents revenue for granting licenses which we had satisfied in prior periods. Additionally, we have a collaboration agreement for a product under development, under which we are entitled to up to a total of $ 40.0 million of regulatory milestones, as well as sales milestones upon achievement of annual sales targets and royalties based on net sales of commercialized products, if any. However, given the current phase of development of the potential product under this collaboration agreement, we cannot estimate the probability or timing of achieving these milestones, and, therefore, have excluded all development milestones from the transaction price for this agreement.

Restructuring, Impairment and C

Restructuring, Impairment and Costs of Terminated Program, and Impairment of Goodwill	9 Months Ended
	Sep. 30, 2023
Restructuring and Related Activities [Abstract]
Restructuring, Impairment and Costs of Terminated Program, and Impairment of Goodwill	Note 6 — Restructuring, Impairment and Costs of Terminated Program, and Impairment of Goodwill Restructuring, Impairment and Costs of Terminated Program In connection with our 2022 and 2023 Restructuring Plans, we report the following costs in restructuring, impairment and costs of terminated program: • Clinical trial expense, other third-party costs and employee costs for the wind down of the bempegaldesleukin program, net of the reimbursement from BMS, initiated in 2022; • Severance and related benefit costs pursuant to the 2022 and 2023 Restructuring Plans; • Non-cash impairment of right-of-use assets and property, plant and equipment; and • Contract termination and other costs associated with these plans. In prior periods through March 31, 2022, we reported the clinical trial costs, other third-party costs and employee costs related to the bempegaldesleukin program primarily in research and development expense. Beginning in the second quarter of 2022, we began reporting clinical trial, other third-party costs and employee costs for the wind down of the bempegaldesleukin program in restructuring, impairment and costs of terminated program. 2022 Restructuring Plan As discussed in Note 1, because our registrational trials in bempegaldesleukin did not meet their primary endpoints, we decided to discontinue all development of bempegaldesleukin and wind down the clinical trials studying bempegaldesleukin. In April 2022, we announced the 2022 Restructuring Plan pursuant to which we completed an approximate 70 % reduction of our workforce during 2022. We also sold our research facility in India in December 2022 and decided to sublease certain of our leased premises in San Francisco, CA, including all of our office leased space on Third St. and portions of our office and laboratory space on Mission Bay Blvd. South. Restructuring, impairment and other costs of terminated program pertaining to the 2022 Restructuring Plan includes the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Clinical trial expense, other third-party and employee costs for the wind down of the bempegaldesleukin program $ 652 $ 8,530 $ 3,606 $ 28,938 Severance and benefits expense — 2,077 — 29,827 Impairment of right-of-use assets and property, plant and equipment 1,467 1,200 14,728 58,521 Contract termination and other restructuring costs — 5,023 878 7,064 Restructuring, impairment and costs of terminated program $ 2,119 $ 16,830 $ 19,212 $ 124,350 The clinical trial expense, other third-party and employee costs for the wind down of the bempegaldesleukin program for the three and nine months ended September 30, 2022 includes reductions of $ 8.3 million and $ 16.7 million, respectively, for the net reimbursement from BMS. The net reimbursement payable to BMS for the three and nine months ended September 30, 2023 was not significant. Non-cash impairment charges of lease assets pertaining to the 2022 Restructuring Plan include the following (in thousands): Three-months Ended Sublease Spaces June 30, 2022 September 30, 2022 December 31, 2022 March 31, 2023 June 30, 2023 September 30, 2023 Total Mission Bay Blvd. South $ 3,000 $ 1,200 $ 361 $ — $ 7,055 $ 1,467 $ 13,083 Third St 49,200 — 12,000 — 6,200 — 67,400 Total impairment of lease assets $ 52,200 $ 1,200 $ 12,361 $ — $ 13,255 $ 1,467 $ 80,483 • T he non-cash impairment charges for the three months ended June 30, 2022 for our office lease on Third St. reflects our initial estimates of sublease income. As the San Francisco office lease market has continued to deteriorate over the past year, we have recognized additional non-cash impairment charges for the Third St. space in the three months ended December 31, 2022, and in the three months ended June 30, 2023. • The non-cash impairment charges for the three months ended June 30, 2022 for our office and laboratory space on Mission Bay Blvd. South reflects our initial estimates of sublease income. As the life sciences lease market has deteriorated during 2023, we recorded additional non-cash impairment charges in the three months ended June 30, 2023 and in the three months ended September 30, 2023. Through September 30, 2023 , we have recognized $ 11.8 million cumulatively for contract termination and other costs for the 2022 Restructuring Plan. 2023 Restructuring Plan As discussed in Note 1, pursuant to plans approved by our Board in March 2023, we announced the 2023 Restructuring Plan to further reduce our San Francisco-based workforce by approximately 60 %, which was substantially completed by June 30, 2023. In addition, under the 2023 Restructuring Plan, we decided to sublease our remaining office and laboratory space on Mission Bay Blvd. South, which we had not planned to sublease pursuant to the 2022 Restructuring Plan. Restructuring, impairment and other costs of terminated program pertaining to the 2023 Restructuring Plan includes the following (in thousands): Three Months Ended September 30, 2023 Nine Months Ended September 30, 2023 Severance and benefit expense $ 535 $ 7,961 Impairment of right-of-use assets and property, plant and equipment 8,706 21,900 Contract termination and other restructuring costs — 34 Restructuring, impairment and costs of terminated program $ 9,241 $ 29,895 As further described below, the impairment charge in the nine months ended September 30, 2023, includes $ 20.6 million for the impairment of our remaining office and laboratory space on Mission Bay Blvd. South that we are currently seeking to sublease. We recorded an impairment charge of $ 11.5 million in the three months ended March 31, 2023, based on our initial estimates of sublease income. As the life sciences lease market has deteriorated during 2023, including a significant increase in available sublease space in San Francisco, California, we recorded an additional impairment charge of $ 9.1 million in the three months ended September 30, 2023 for this space. Severance and Benefit Expense Employees affected by the reduction in force under the 2022 and 2023 Restructuring Plans are entitled to receive severance payments and certain Company funded benefits. The restructuring charges are recorded at fair value. For the 2022 Restructuring Plan, we recognized severance and benefit expense in full for employees who had no requirements for future service upon approval of the 2022 Restructuring Plan by the Board in April 2022. We recognized severance and benefit expense for employees who were required to render services to receive their severance and benefits ratably over the service period. This service period began on the communication date in April 2022 and was completed for all employees during 2022. We recognized $ 30.9 million in total severance and benefit expense during 2022 and paid the remaining liability of $ 3.3 million in January 2023. For the 2023 Restructuring Plan, we recognized a liability of $ 5.5 million of severance and benefit expense as of March 31, 2023, reflecting severance and benefits which the employees had vested into and for which payment was probable and reasonably estimable as of March 31, 2023. During the three months ended June 30, 2023, we recognized an additional $ 1.9 million of severance and benefit expense. We do not expect to recognize significant severance expense for the remainder of 2023. The following table provides details regarding the severance and benefit expense for the three and nine months ended September 30, 2023 pursuant to the 2023 Restructuring Plan and a reconciliation of the severance and benefits liability for the three and nine months ended September 30, 2023 pursuant to the 2022 and 2023 Restructuring Plans, which we report within accrued expenses on our Condensed Consolidated Balance Sheet (in thousands): Nine Months Ended September 30, 2023 2023 Restructuring Plan 2022 Restructuring Plan Total Liability balance as of December 31, 2022 $ — $ 3,299 $ 3,299 Expense recognized during the period 5,483 — 5,483 Payments during the period — ( 3,299 ) ( 3,299 ) Liability balance as of March 31, 2023 $ 5,483 $ — $ 5,483 Expense recognized during the period 1,943 — 1,943 Payments during the period ( 6,624 ) — ( 6,624 ) Liability balance as of June 30, 2023 $ 802 $ — $ 802 Expense recognized during the period 535 — 535 Payments during the period ( 887 ) — ( 887 ) Liability balance as of September 30, 2023 $ 450 $ — $ 450 Impairment of Long-Lived Assets and Goodwill In connection with our 2022 Restructuring Plan, we consolidated our operations by exiting all of the office space from our leased facility at 360 Third St. and certain laboratory and office spaces at our leased facility at 455 Mission Bay Blvd. South, both in San Francisco, CA. We have sought to sublease these spaces. We also terminated all research and development activities at our owned facility in India, which we sold in December 2022. As a result of these plans, we reviewed each of our excess spaces for impairment during the three months ended June 30, 2022. As part of our impairment evaluation of each excess space, we separately compared the estimated undiscounted income for each sublease to the net book value of the related long-term assets, which include right-of-use assets and certain property, plant and equipment, primarily for leasehold improvements (collectively, sublease assets). We estimated sublease income using market participant assumptions, including the length of time to enter into a sublease and sublease payments, tenant improvement allowances and broker commissions, which we evaluated using current real estate trends and market conditions. If such income exceeded the net book value of the related assets, we did not record an impairment charge. Otherwise, we recorded an impairment charge by reducing the net book value of the assets to their estimated fair value, which we determined by discounting the estimated sublease income using the estimated borrowing rate of a market participant subtenant, which we estimated to be 6.4 %. Additionally, we recorded an impairment expense primarily for software which we planned to abandon and certain excess equipment based on the estimated income from selling such assets. We recorded impairment charges as follows (in thousands): Nine months ended September 30, 2022 Property, Plant and Equipment Operating Lease Right-of-Use Assets Total Net book value of impaired facilities before write-off $ 16,348 $ 74,191 $ 90,539 Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy ( 6,976 ) ( 30,162 ) ( 37,138 ) Impairment expense for facilities 9,372 44,029 53,401 Impairment of other property, plant and equipment 5,120 — 5,120 Total impairment of right-of-use assets and property, plant and equipment $ 14,492 $ 44,029 $ 58,521 In the three months ended September 30, 2022, we recorded an impairment charge of $ 1.2 million for a right-of-use asset based on changes to sublease negotiations during such period . During the three months ended March 31, 2023, our stock price and resulting market capitalization experienced a significant, sustained decline. Accordingly, we assessed our long-lived assets, including our property, plant and equipment, right-of-use assets and goodwill, for impairment. We had previously recognized goodwill primarily from our acquisitions of Shearwater Corp. and Aerogen, Inc. in 2001 and 2005, respectively. Accordingly, in accordance with ASC 350-20 Goodwill and ASC 820-10 Fair Value Measurement , we measured the fair value of our reporting unit utilizing both income and market approaches for our entity-wide asset impairment analysis. Based on this analysis, we wrote off all of our goodwill, resulting in a non-cash impairment charge of $ 76.5 million during the three months ended March 31, 2023, which we reported as impairment of goodwill in our Condensed Consolidated Statements of Operations for the nine months ended September 30, 2023. As part of our long-lived asset impairment analysis, we first assessed which long-lived assets have identifiable cash flows that are largely independent of the cash flows of other groups of assets. We concluded that the long-lived assets associated with our leased spaces we had previously decided to sublease under our 2022 Restructuring Plan continue to have cash flows that are independent of our entity-wide group. We concluded that these sublease assets, for which we had recognized impairment charges during 2022, were recoverable based on estimated sublease income, and therefore we did not record any impairment charges for these long-lived assets for the three months ended March 31, 2023. During the three months ended March 31, 2023, we next evaluated our remaining long-lived assets for impairment and performed a recoverability test using the undiscounted cash flows approach. We concluded that our net assets were not recoverable within the remaining useful lives. Accordingly, we estimated the fair value of each asset or asset group based on discounted future cash flows of the asset or asset group using a discount rate commensurate with the related risk. For the operating lease asset related to our Mission Bay facility, we estimated the fair value based on market participant assumptions related to sublease income as described above, including the length of time to enter into a sublease and sublease payments, tenant improvement allowances and broker commissions. We discounted the sublease income at rate of 7.9 %, reflecting the estimated borrowing rate of a market participant subtenant. As a result of this analysis, we recorded a non-cash impairment charge of $ 11.5 million. We also recorded an additional non-cash impairment charge of $ 1.7 million for certain laboratory equipment in the three months ended Mach 31, 2023, which we sold in the three months ended September 30, 2023 and recognized an immaterial gain, resulting in a net impairment of $ 1.3 million for the nine months ended September 30, 2023. During the three months ended June 30, 2023, due to the weakening life sciences sublease market, we recorded a non-cash impairment charge of $ 7.1 million for our lease assets at our Mission Bay facility, and due to the continued depression of the office lease market, we recorded an impairment charge of $ 6.2 million for our lease assets at our Third. St. facility, based on market participant assumptions related to sublease income, discounted at a rate of 8.5 %. We had decided to sublease both of these spaces under the 2022 Restructuring Plan. During the three months ended September 30, 2023, due to the continued weakening of the life sciences sublease market, we recorded additional non-cash impairment charges of $ 10.6 million for our lease assets at our Mission Bay facility based on market participant assumptions related to sublease income, discounted at a rate of 8.7 %. We report the aggregate non-cash impairment charge of $ 10.2 million and $ 36.6 million for the three and nine months ended September 30, 2023 , respectively, in restructuring, impairment and costs of terminated program in our Condensed Consolidated Statement of Operations. The following table presents a reconciliation of the non-cash impairment charges we recorded for these long-lived assets for the three and nine months ended September 30, 2023 (in thousands): Three Months Ended September 30, 2023 Property, Plant and Equipment Operating Lease Right-of-Use Assets Total Net book value of impaired facilities before write-off $ 3,050 $ 18,830 $ 21,880 Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy ( 1,650 ) ( 9,663 ) ( 11,313 ) Total impairment of right-of-use assets and property, plant and equipment $ 1,400 $ 9,167 $ 10,567 (Gain) on sale or disposal of property, plant and equipment, net ( 394 ) — ( 394 ) Total impairment of right-of-use assets and property, plant and equipment $ 1,006 $ 9,167 $ 10,173 Nine Months Ended September 30, 2023 Property, Plant and Equipment Operating Lease Right-of-Use Assets Total Net book value of impaired facilities before write-off $ 10,257 $ 63,656 $ 73,913 Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy ( 5,486 ) ( 33,098 ) ( 38,584 ) Impairment expense for facilities 4,771 30,558 35,329 Impairment of other property, plant and equipment 1,299 — 1,299 Total impairment of right-of-use assets and property, plant and equipment $ 6,070 $ 30,558 $ 36,628

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Note 7 — Stock-Based Compensation On June 8, 2023, the stockholders of Nektar approved an amendment to the Amended and Restated 2017 Performance Incentive Plan to increase the aggregate number of shares of Common Stock authorized for issuance thereunder by 12,000,000 shares. We recognized total stock-based compensation expense in our Condensed Consolidated Statements of Operations as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Cost of goods sold $ 841 $ 720 $ 2,454 $ 2,037 Research and development 3,202 5,422 11,107 22,215 General and administrative 4,106 5,369 12,573 18,401 Restructuring, impairment and other costs of terminated program — 1,007 — 1,929 Total stock-based compensation $ 8,149 $ 12,518 $ 26,134 $ 44,582

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization We are a research-based biopharmaceutical company headquartered in San Francisco, California and incorporated in Delaware. We (individually or with a partner) are developing a pipeline of drug candidates that utilize our advanced polymer conjugate technology platforms, which are designed to enable the development of new molecular entities that target known mechanisms of action. Our research and development pipeline of new investigational drugs includes investigational treatments in the field of immunotherapy. Our research and development activities have required significant ongoing investment to date and are expected to continue to require significant investment. As a result, we expect to continue to incur substantial losses and negative cash flows from operations in the future. We have financed our operations primarily through cash generated from licensing, collaboration and manufacturing agreements and financing transactions. As of September 30, 2023, we had approximately $ 372.7 million in cash and investments in marketable securities.
Results of Clinical Trial Programs and the Restructuring Plans	Results of Clinical Trial Programs and the Restructuring Plans In March and April 2022, we announced that our registrational trials of bempegaldesleukin in combination with Opdivo ® in metastatic melanoma, renal cell carcinoma and locally advanced or metastatic urothelial cancer under our Strategic Collaboration Agreement (BMS Collaboration Agreement) with Bristol-Myers Squibb Company (BMS) did not meet their primary endpoints. Based on these results, in April 2022, we announced our decisions to discontinue all development of bempegaldesleukin in combination with checkpoint inhibitors, including these trials, our registrational trial in adjuvant melanoma under our BMS Collaboration Agreement, and our Phase 2/3 study of bempegaldesleukin in combination with Keytruda ® in squamous cell cancer of the head and neck under our Co-Development Agreement with SFJ Pharmaceuticals. See Note 5 for additional information regarding our BMS Collaboration Agreement and Co-Development Agreement with SFJ Pharmaceuticals. On September 6, 2023, BMS and we terminated the BMS Collaboration Agreement, however, we continue our efforts to wind down the bempegaldesleukin program following the same cost sharing provisions provided for in the BMS Collaboration Agreement. In April 2022, we also announced new strategic reorganization and cost restructuring plans (together, the 2022 Restructuring Plan), pursuant to which we completed an approximate 70 % reduction of our workforce during 2022 and sold our research facility in India in December 2022. We also decided to sublease certain of our leased premises in San Francisco, CA, including all of our office leased space on Third St. and portions of our office and laboratory space on Mission Bay Blvd. South. On February 23, 2023, we announced the topline data from the Phase 2 study of rezpegaldesleukin in adult patients with systemic lupus erythematosus (SLE) (Phase 2 Lupus Study) under our collaboration agreement with Eli Lilly and Company (Lilly). Lilly subsequently notified us that it did not intend to advance rezpegaldesleukin into Phase 3 development for SLE. On April 27, 2023, we announced that we would be regaining the full rights to rezpegaldesleukin from Lilly, and the collaboration agreement has subsequently terminated. We have initiated a Phase 2b study of rezpegaldesleukin in patients with moderate-to-severe atopic dermatitis, and we are planning to initiate in late 2023 or in early 2024 a new Phase 2b study of rezpegaldesleukin in patients with alopecia areata. We will also explore other auto-immune indications for the development of rezpegaldesleukin. On August 7, 2023, we announced that the interim efficacy data previously generated by Lilly for rezpegaldesleukin that were presented at the European Academy of Dermatology and Venereolgy (EADV) conference in September 2022 were incorrectly calculated by Lilly. The erroneous interim data were reported in connection with the Phase 1b study of rezpegaldesleukin in adult patients with atopic dermatitis (Phase 1b AD Study) and the Phase 1b study of rezpegaldesleukin in adult patients with psoriasis. We reported the new and corrected data from the Phase 1b AD Study of rezpegaldesleukin. On October 13, 2023, we announced final efficacy data from the Phase 1b AD Study at the 2023 EADV conference. The final data from the study demonstrated rezpegaldesleukin resulted in dose-dependent improvements in EASI, validated investigated global assessment (vIGA), body surface area (BSA), and itch numeric rating scale (NRS) over twelve weeks of treatment compared to placebo, which were sustained post-treatment over an additional thirty-six weeks. Pursuant to plans approved by our Board of Directors (the Board) on March 29, 2023, we announced on April 17, 2023, a new strategic reprioritization and cost restructuring plan (the 2023 Restructuring Plan). Under the 2023 Restructuring Plan, we reduced our San Francisco-based workforce by approximately 60 %, which was substantially completed by June 2023. In addition, under the 2023 Restructuring Plan, we decided to sublease our remaining office and laboratory space on Mission Bay Blvd. South which we had not planned to sublease pursuant to the 2022 Restructuring Plan. We have incurred significant costs resulting from the 2022 and 2023 Restructuring Plans. See Note 6 for additional information on the effect on our Condensed Consolidated Financial Statements.
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation Our Condensed Consolidated Financial Statements include the financial position, results of operations and cash flows of Nektar Therapeutics and our wholly-owned subsidiaries. We have eliminated all intercompany accounts and transactions in consolidation. We prepared our Condensed Consolidated Financial Statements following the requirements of the Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, we may condense or omit certain footnotes or other financial information that are normally required by U.S. generally accepted accounting principles (GAAP) for annual periods. In the opinion of management, these financial statements include all normal and recurring adjustments that we consider necessary for the fair presentation of our financial position and operating results. Our Condensed Consolidated Financial Statements are denominated in U.S. dollars. Accordingly, changes in exchange rates between the applicable foreign currency and the U.S. dollar will affect the translation of each foreign subsidiary’s financial results into U.S. dollars for purposes of reporting our consolidated financial results. We include translation gains and losses in accumulated other comprehensive loss in the stockholders’ equity section of our Condensed Consolidated Balance Sheets. Our comprehensive loss consists of our net loss plus our foreign currency translation gains and losses and unrealized gains and losses on available-for-sale securities. There were no significant reclassifications out of accumulated other comprehensive loss to the statements of operations during the three and nine months ended September 30, 2023 and 2022 except as otherwise disclosed below in Note 3. The accompanying Condensed Consolidated Financial Statements are unaudited. The Condensed Consolidated Balance Sheet data as of December 31, 2022 was derived from the audited consolidated financial statements which are included in our Annual Report on Form 10-K for the year ended December 31, 2022 filed with the SEC on February 28, 2023. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and the accompanying notes to those financial statements. Revenue, expenses, assets, and liabilities can vary during each quarter of the year. The results and trends in these interim Condensed Consolidated Financial Statements are not necessarily indicative of the results to be expected for the full year or any other period.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Accounting estimates and assumptions are inherently uncertain. Actual results could differ materially from those estimates and assumptions. As appropriate, we assess estimates each period, update them to reflect current information, and generally reflect any changes in estimates in the period first identified.
Significant Concentrations	Significant Concentrations Our customers are primarily pharmaceutical companies that are located in the U.S. and Europe and with whom we have multi-year arrangements. Our accounts receivable balance contains billed and unbilled trade receivables from product sales, milestones (to the extent that they have been achieved and are due from the counterparty), and other contingent payments, as well as reimbursable costs from collaborative research and development agreements. We generally do not require collateral from our customers. We perform a regular review of our customers’ credit risk and payment histories, including payments made after period end. Historically, we have no t experienced credit losses from our accounts receivable. We have not recorded reserves for credit losses for the three and nine months ended September 30, 2023 and 2022, nor have recorded such an allowance as of September 30, 2023 or December 31, 2022. We are dependent on our suppliers and contract manufacturers to provide raw materials and drugs of appropriate quality and reliability and to meet applicable contract and regulatory requirements. In certain cases, we rely on single sources of supply of one or more critical materials. Consequently, in the event that supplies are delayed or interrupted for any reason, our ability to develop and produce our drug candidates or our ability to meet our supply obligations could be significantly impaired, which could have a material adverse effect on our business, financial condition and results of operations. For our available-for-sale securities, we have significant concentrations of issuers in the banking and financial services industries. While our investment policy requires that we only invest in highly-rated securities and limit our exposure to any single issuer, various factors may materially affect the financial condition of issuers. Additionally, pursuant to our investment policy, we may sell securities before maturity if the issuer’s credit rating has been downgraded below our minimum credit rating requirements, which may result in a loss on the sale. Accordingly, if various factors result in downgrades below our minimum credit rating requirements and if we decide to sell these securities, we may experience losses on such sales.
Restructuring	Restructuring We recognize restructuring charges related to reorganization plans that have been committed to by management when liabilities have been incurred. In connection with these activities, we record restructuring charges at fair value for: • contractual or other employee termination benefits provided that the obligations result from services already rendered based on rights that vest or accumulated when the payment of benefits becomes probable and the amount can be reasonably estimated, • one-time employee termination benefits on the communication date from management to the employees provided that management has committed to a plan of termination, the plan identifies the employees and their expected termination dates, the details of termination benefits are complete, and it is unlikely that changes to the plan will be made or the plan will be withdrawn, • contract termination costs when we cancel the contract in accordance with its terms, and • costs to be incurred over the remaining contract term without economic benefit to us at the cease-use date. For one-time employee terminations benefits, we recognize the liability in full on the communication date when future services are not required or amortize the liability ratably over the service period, if required. The fair value of termination benefits reflects our estimates of expected utilization of certain Company-funded post-employment benefits. See Note 6 for additional information on the severance expense that we recognized for employees terminated in connection with our reductions-in-force.
Impairment of Goodwill	Impairment of Goodwill Goodwill is assessed for impairment on an annual basis and whenever events and circumstances indicate that it may be impaired. Factors that may indicate potential impairment and trigger an impairment test include, but are not limited to, current economic, market and geopolitical conditions, including a significant, sustained decline in our stock price and market capitalization compared to the net book value; an adverse change in legal factors, business climate or operational performance of the business; or significant changes in the ability of the reporting unit to generate positive cash flows for our strategic business objectives. If the carrying value of the reporting unit, including goodwill, exceeds the reporting unit’s fair value, we will recognize a goodwill impairment loss, and we will write down goodwill such that the carrying value of the reporting unit equals its fair value, provided that we cannot reduce goodwill below zero. See Note 6 for additional information regarding the impairment charges we recorded in connection with our goodwill.
Long-Lived Asset Impairment	Long-Lived Asset Impairment We assess the impairment of long-lived assets whenever events or changes in business circumstances indicate that the carrying amounts of the assets may not be fully recoverable. In the case of property, plant and equipment and right-of-use assets for our leases, we determine whether there has been an impairment by comparing the carrying value of the asset to the anticipated undiscounted net cash flows associated with the asset. If such cash flows are less than the carrying value, we write down the asset to its fair value, which may be measured as anticipated net cash flows associated with the asset, discounted at a rate that we believe a market participant would utilize to reflect the risks associated with the cash flows, such as credit risk. See Note 6 for additional information regarding the impairment charges we recorded in connection with our leased facilities and certain property and equipment.
Net Loss per Share	Net Loss per Share For all periods presented in the Condensed Consolidated Statements of Operations, the net loss available to common stockholders is equal to the reported net loss. We calculate basic net loss per share based on the weighted-average number of common shares outstanding during the periods presented. For the three and nine months ended September 30, 2023 and 2022 , basic and diluted net loss per share are the same due to our net losses and the requirement to exclude potentially dilutive securities which would have an antidilutive effect on net loss per share.
Inventory	We value inventory at the lower of cost or net realizable value, and we write down defective or excess inventory to net realizable value based on historical experience or projected usage. We expense inventory related to our research and development activities as manufactured by us or when purchased.

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	We excluded shares underlying the weighted average outstanding stock options, restricted stock units (RSUs) and performance stock units (PSUs), as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Potentially dilutive securities 17,476 19,575 20,513 20,809

Cash and Investments in Marke_2

Cash and Investments in Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Schedule of Cash and Investments in Marketable Securities, Including Cash Equivalents	Cash and investments in marketable securities, including cash equivalents, are as follows (in thousands): Estimated Fair Value at September 30, 2023 December 31, 2022 Cash and cash equivalents $ 64,921 $ 88,227 Short-term investments 307,737 416,750 Total cash and investments in marketable securities $ 372,658 $ 504,977
Schedule of Portfolio of Cash and Investments in Marketable Securities	Our portfolio of cash and investments in marketable securities includes (in thousands): September 30, 2023 December 31, 2022 Fair Value Hierarchy Level Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fair Value Corporate notes and bonds 2 $ 11,251 $ — $ ( 20 ) $ 11,231 $ 83,522 Corporate commercial paper 2 294,184 — ( 229 ) 293,955 344,204 Available-for-sale investments $ 305,435 $ — $ ( 249 ) $ 305,186 $ 427,726 Money market funds 1 46,858 47,054 Certificates of deposit 2 15,186 21,399 Cash N/A 5,428 8,798 Total cash and investments in marketable securities $ 372,658 $ 504,977

Condensed Consolidated Financ_2

Condensed Consolidated Financial Statement Details (Tables)	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventory consists of the following (in thousands): September 30, 2023 December 31, 2022 Raw materials $ 1,918 $ 2,575 Work-in-process 12,291 10,749 Finished goods 921 5,878 Total inventory, net $ 15,130 $ 19,202
Schedule of Other Current Assets	Other current assets consist of the following (in thousands): September 30, 2023 December 31, 2022 Prepaid research and development expenses $ 2,014 $ 7,398 Non-trade receivables and other 1,226 2,423 Other prepaid expenses 5,793 5,987 Total other current assets $ 9,033 $ 15,808
Schedule of Property, Plant and Equipment	Property, plant and equipment consists of the following (in thousands): September 30, 2023 December 31, 2022 Building and leasehold improvements $ 42,641 $ 74,889 Computer equipment and computer software 24,586 26,205 Manufacturing equipment 25,352 25,052 Laboratory equipment 14,592 24,243 Furniture, fixtures and other 533 4,263 Depreciable property, plant and equipment at cost 107,704 154,652 Less: accumulated depreciation ( 88,243 ) ( 124,731 ) Depreciable property, plant and equipment, net 19,461 29,921 Construction in process 488 2,530 Property, plant and equipment, net $ 19,949 $ 32,451
Schedule of Goodwill	The following is a reconciliation of the changes in our goodwill for the nine months ended September 30, 2023 (in thousands): Nine months ended September 30, 2023 Goodwill – beginning balance $ 76,501 Impairment of goodwill ( 76,501 ) Goodwill – ending balance $ —
Schedule of Accrued Expenses	Accrued expenses consist of the following (in thousands): September 30, 2023 December 31, 2022 Accrued compensation $ 11,477 $ 9,582 Accrued clinical trial expenses 4,236 12,262 Liability to collaboration partners 4,444 3,808 Accrued contract termination costs 2,624 3,902 Other accrued expenses 6,948 7,003 Total accrued expenses $ 29,729 $ 36,557
Schedule of Liability Related to Sale of Potential Future Royalties	The following is a reconciliation of the changes in our liabilities related to the sales of future royalties for the nine months ended September 30, 2023 (in thousands): Nine Months Ended September 30, 2023 2012 Purchase and Sale Agreement 2020 Purchase and Sale Agreement Total Liabilities related to the sales of future royalties, net – beginning balance $ 55,167 $ 100,211 $ 155,378 Non-cash royalty revenue ( 28,035 ) ( 22,825 ) ( 50,860 ) Non-cash interest expense 3,551 14,916 18,467 Amortization of transaction costs — 625 625 Liabilities related to the sales of future royalties, net – ending balance $ 30,683 $ 92,927 $ 123,610
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table summarizes the changes in accumulated other comprehensive income (loss) by component (in thousands): Foreign currency translation Available-for-sale securities Accumulated Other Comprehensive Income Balance at December 31, 2022 $ ( 5,131 ) $ ( 1,776 ) $ ( 6,907 ) Foreign currency translation adjustments 139 — 139 Unrealized gain on available-for-sale securities — 1,087 1,087 Balance at March 31, 2023 $ ( 4,992 ) $ ( 689 ) $ ( 5,681 ) Foreign currency translation adjustments 13 — 13 Unrealized gain on available-for-sale securities — 244 244 Reclassification adjustments to income ( 1,026 ) — ( 1,026 ) Balance at June 30, 2023 $ ( 6,005 ) $ ( 445 ) $ ( 6,450 ) Foreign currency translation adjustments ( 98 ) — ( 98 ) Unrealized gain on available-for-sale securities — 196 196 Balance at September 30, 2023 $ ( 6,103 ) $ ( 249 ) $ ( 6,352 )

License and Collaboration Agr_2

License and Collaboration Agreements (Tables)	9 Months Ended
	Sep. 30, 2023
License And Collaboration Agreements [Abstract]
Schedule of Derivative Liabilities at Fair Value	The following table presents the change in the derivative liability for the nine months ended September 30, 2022: Fair Value Nine Months Ended September 30, 2022 Fair value at beginning of period 3 $ 27,726 Non-cash research and development expense 4,951 Cash receipts from SFJ 750 Change in the fair value of development derivative liability ( 33,427 ) Fair value at end of period 3 $ —

Restructuring, Impairment and_2

Restructuring, Impairment and Costs of Terminated Program, and Impairment of Goodwill (Tables)	9 Months Ended
	Sep. 30, 2023
Restructuring and Related Activities [Abstract]
Schedule of Restructuring, Impairment and Other Costs of Terminated Program	Restructuring, impairment and other costs of terminated program pertaining to the 2022 Restructuring Plan includes the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Clinical trial expense, other third-party and employee costs for the wind down of the bempegaldesleukin program $ 652 $ 8,530 $ 3,606 $ 28,938 Severance and benefits expense — 2,077 — 29,827 Impairment of right-of-use assets and property, plant and equipment 1,467 1,200 14,728 58,521 Contract termination and other restructuring costs — 5,023 878 7,064 Restructuring, impairment and costs of terminated program $ 2,119 $ 16,830 $ 19,212 $ 124,350 Non-cash impairment charges of lease assets pertaining to the 2022 Restructuring Plan include the following (in thousands): Three-months Ended Sublease Spaces June 30, 2022 September 30, 2022 December 31, 2022 March 31, 2023 June 30, 2023 September 30, 2023 Total Mission Bay Blvd. South $ 3,000 $ 1,200 $ 361 $ — $ 7,055 $ 1,467 $ 13,083 Third St 49,200 — 12,000 — 6,200 — 67,400 Total impairment of lease assets $ 52,200 $ 1,200 $ 12,361 $ — $ 13,255 $ 1,467 $ 80,483 T Restructuring, impairment and other costs of terminated program pertaining to the 2023 Restructuring Plan includes the following (in thousands): Three Months Ended September 30, 2023 Nine Months Ended September 30, 2023 Severance and benefit expense $ 535 $ 7,961 Impairment of right-of-use assets and property, plant and equipment 8,706 21,900 Contract termination and other restructuring costs — 34 Restructuring, impairment and costs of terminated program $ 9,241 $ 29,895 The following table provides details regarding the severance and benefit expense for the three and nine months ended September 30, 2023 pursuant to the 2023 Restructuring Plan and a reconciliation of the severance and benefits liability for the three and nine months ended September 30, 2023 pursuant to the 2022 and 2023 Restructuring Plans, which we report within accrued expenses on our Condensed Consolidated Balance Sheet (in thousands): Nine Months Ended September 30, 2023 2023 Restructuring Plan 2022 Restructuring Plan Total Liability balance as of December 31, 2022 $ — $ 3,299 $ 3,299 Expense recognized during the period 5,483 — 5,483 Payments during the period — ( 3,299 ) ( 3,299 ) Liability balance as of March 31, 2023 $ 5,483 $ — $ 5,483 Expense recognized during the period 1,943 — 1,943 Payments during the period ( 6,624 ) — ( 6,624 ) Liability balance as of June 30, 2023 $ 802 $ — $ 802 Expense recognized during the period 535 — 535 Payments during the period ( 887 ) — ( 887 ) Liability balance as of September 30, 2023 $ 450 $ — $ 450 Additionally, we recorded an impairment expense primarily for software which we planned to abandon and certain excess equipment based on the estimated income from selling such assets. We recorded impairment charges as follows (in thousands): Nine months ended September 30, 2022 Property, Plant and Equipment Operating Lease Right-of-Use Assets Total Net book value of impaired facilities before write-off $ 16,348 $ 74,191 $ 90,539 Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy ( 6,976 ) ( 30,162 ) ( 37,138 ) Impairment expense for facilities 9,372 44,029 53,401 Impairment of other property, plant and equipment 5,120 — 5,120 Total impairment of right-of-use assets and property, plant and equipment $ 14,492 $ 44,029 $ 58,521 The following table presents a reconciliation of the non-cash impairment charges we recorded for these long-lived assets for the three and nine months ended September 30, 2023 (in thousands): Three Months Ended September 30, 2023 Property, Plant and Equipment Operating Lease Right-of-Use Assets Total Net book value of impaired facilities before write-off $ 3,050 $ 18,830 $ 21,880 Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy ( 1,650 ) ( 9,663 ) ( 11,313 ) Total impairment of right-of-use assets and property, plant and equipment $ 1,400 $ 9,167 $ 10,567 (Gain) on sale or disposal of property, plant and equipment, net ( 394 ) — ( 394 ) Total impairment of right-of-use assets and property, plant and equipment $ 1,006 $ 9,167 $ 10,173 Nine Months Ended September 30, 2023 Property, Plant and Equipment Operating Lease Right-of-Use Assets Total Net book value of impaired facilities before write-off $ 10,257 $ 63,656 $ 73,913 Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy ( 5,486 ) ( 33,098 ) ( 38,584 ) Impairment expense for facilities 4,771 30,558 35,329 Impairment of other property, plant and equipment 1,299 — 1,299 Total impairment of right-of-use assets and property, plant and equipment $ 6,070 $ 30,558 $ 36,628

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Stock-Based Compensation Expense	We recognized total stock-based compensation expense in our Condensed Consolidated Statements of Operations as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Cost of goods sold $ 841 $ 720 $ 2,454 $ 2,037 Research and development 3,202 5,422 11,107 22,215 General and administrative 4,106 5,369 12,573 18,401 Restructuring, impairment and other costs of terminated program — 1,007 — 1,929 Total stock-based compensation $ 8,149 $ 12,518 $ 26,134 $ 44,582

Organization and Summary of S_4

Organization and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	Jun. 30, 2023	Apr. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Organization And Summary Of Significant Accounting Policies [Line Items]
Cash and investments in marketable securities			$ 372,658,000		$ 372,658,000		$ 504,977,000
Accounts receivable, credit loss expense (reversal)			$ 0	$ 0	$ 0	$ 0
Employee Severance | 2022 Restructuring Plan
Organization And Summary Of Significant Accounting Policies [Line Items]
Workforce termination, percentage		70%
Employee Severance | 2023 Restructuring Plan
Organization And Summary Of Significant Accounting Policies [Line Items]
Workforce termination, percentage	60%

Organization and Summary of S_5

Organization and Summary of Significant Accounting Policies - Weighted Average Outstanding Stock Options (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Stock Options, RSUs And PSUs
Organization And Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities (in shares)	17,476	19,575	20,513	20,809

Cash and Investments in Marke_3

Cash and Investments in Marketable Securities - Cash and Investments in Marketable Securities, Including Cash Equivalents (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Estimated Fair Value at
Cash and cash equivalents	$ 64,921	$ 88,227
Short-term investments	307,737	416,750
Total cash and investments in marketable securities	$ 372,658	$ 504,977

Cash and Investments in Marke_4

Cash and Investments in Marketable Securities - Portfolio of Cash and Investments in Marketable Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gross Unrealized Losses		$ (1,800)
Cash	$ 5,428	8,798
Total cash and investments in marketable securities	372,658	504,977
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	305,435
Gross Unrealized Gains	0
Gross Unrealized Losses	(249)
Fair Value	305,186	427,726
Level 2 | Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	11,251
Gross Unrealized Gains	0
Gross Unrealized Losses	(20)
Fair Value	11,231	83,522
Level 2 | Corporate commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	294,184
Gross Unrealized Gains	0
Gross Unrealized Losses	(229)
Fair Value	293,955	344,204
Level 2 | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	15,186	21,399
Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	$ 46,858	$ 47,054

Cash and Investments in Marke_5

Cash and Investments in Marketable Securities - Additional Information (Detail) $ in Millions	Dec. 31, 2022 USD ($)
Fair Value Disclosures [Abstract]
Gross unrealized losses	$ 1.8

Condensed Consolidated Financ_3

Condensed Consolidated Financial Statement Details - Schedule of Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Raw materials	$ 1,918	$ 2,575
Work-in-process	12,291	10,749
Finished goods	921	5,878
Total inventory, net	$ 15,130	$ 19,202

Condensed Consolidated Financ_4

Condensed Consolidated Financial Statement Details - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	$ 107,704	$ 154,652
Less: accumulated depreciation	(88,243)	(124,731)
Depreciable property, plant and equipment, net	19,461	29,921
Construction in process	488	2,530
Property, plant and equipment, net	19,949	32,451
Building and leasehold improvements
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	42,641	74,889
Computer equipment and computer software
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	24,586	26,205
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	25,352	25,052
Laboratory equipment
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	14,592	24,243
Furniture, fixtures and other
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	$ 533	$ 4,263

Condensed Consolidated Financ_5

Condensed Consolidated Financial Statement Details - Narrative (Details) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)
Goodwill [Line Items]
Provision for inventory obsolescence				$ 4,444
Impairment of other property, plant and equipment	$ 10,173			36,628	$ 58,521
Impairment of goodwill	$ 0	$ 76,500	$ 0	$ 76,501	$ 0
2012 Purchase and Sale Agreement
Goodwill [Line Items]
Royalties liability discount rate	0.10			0.10
2020 Purchase and Sale Agreement
Goodwill [Line Items]
Royalties liability discount rate	0.20			0.20
Huntsville, Alabama Manufacturing Facility
Goodwill [Line Items]
Provision for inventory obsolescence	$ 3,700
Sublease of Laboratory and Office Space
Goodwill [Line Items]
Impairment of other property, plant and equipment				$ 6,100

Condensed Consolidated Financ_6

Condensed Consolidated Financial Statement Details - Schedule of Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Goodwill [Roll Forward]
Goodwill – beginning balance		$ 76,501		$ 76,501
Impairment of goodwill	$ 0	$ (76,500)	$ 0	(76,501)	$ 0
Goodwill – ending balance	$ 0			$ 0

Condensed Consolidated Financ_7

Condensed Consolidated Financial Statement Details - Schedule of Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other current assets	$ 9,033	$ 15,808
Prepaid research and development expenses
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other current assets	2,014	7,398
Non-trade receivables and other
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other current assets	1,226	2,423
Other prepaid expenses
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other current assets	$ 5,793	$ 5,987

Condensed Consolidated Financ_8

Condensed Consolidated Financial Statement Details - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Accrued compensation	$ 11,477	$ 9,582
Accrued clinical trial expenses	4,236	12,262
Liability to collaboration partners	4,444	3,808
Accrued contract termination costs	2,624	3,902
Other accrued expenses	6,948	7,003
Total accrued expenses	$ 29,729	$ 36,557

Condensed Consolidated Financ_9

Condensed Consolidated Financial Statement Details - Schedule of Liability Related to Sale of Potential Future Royalties (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Liabilities related to the sales of future royalties, net – beginning balance			$ 155,378
Non-cash royalty revenue			(50,860)	$ (52,167)
Non-cash interest expense	$ 5,910	$ 6,953	18,467	$ 21,710
Amortization of transaction costs			625
Liabilities related to the sales of future royalties, net – ending balance	123,610		123,610
2012 Purchase and Sale Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Liabilities related to the sales of future royalties, net – beginning balance			55,167
Non-cash royalty revenue			(28,035)
Non-cash interest expense			3,551
Amortization of transaction costs			0
Liabilities related to the sales of future royalties, net – ending balance	30,683		30,683
2020 Purchase and Sale Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Liabilities related to the sales of future royalties, net – beginning balance			100,211
Non-cash royalty revenue			(22,825)
Non-cash interest expense			14,916
Amortization of transaction costs			625
Liabilities related to the sales of future royalties, net – ending balance	$ 92,927		$ 92,927

Condensed Consolidated Finan_10

Condensed Consolidated Financial Statement Details - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 196,958	$ 240,865	$ 366,638
Ending balance	159,368	196,958	240,865
Accumulated Other Comprehensive Loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(6,450)	(5,681)	(6,907)
Ending balance	(6,352)	(6,450)	(5,681)
Foreign currency translation
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(6,005)	(4,992)	(5,131)
Adjustments	(98)	13	139
Reclassification adjustments to income		(1,026)
Ending balance	(6,103)	(6,005)	(4,992)
Available-for-sale securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(445)	(689)	(1,776)
Adjustments	196	244	1,087
Ending balance	$ (249)	$ (445)	$ (689)

Commitments and Contingencies (

Commitments and Contingencies (Detail) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Liability for litigation	$ 0	$ 0

License and Collaboration Agr_3

License and Collaboration Agreements - Additional Information (Details) - USD ($)				1 Months Ended	3 Months Ended			9 Months Ended
	Feb. 12, 2021	Apr. 03, 2018	Jul. 23, 2017	Apr. 30, 2018	Sep. 30, 2023	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Derivative liability							$ 0
Revenue, excluding assessed tax					$ 24,144,000	$ 23,625,000		$ 66,237,000	$ 70,032,000
SFJ
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Committed funding (up to)	$ 150,000,000
Success payments (up to)	$ 637,500,000
Non-cash royalty revenue related to the sales of future royalties
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue, excluding assessed tax					18,167,000	18,342,000		50,860,000	52,167,000
Bristol Myers Squibb Company | Purchase Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Shares issued (in shares)				8,284,600
Sale of stock consideration received				$ 850,000,000
Bristol Myers Squibb Company | Nektar 214 | Research and Development Expense
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reimbursement of expenses						$ 8,300,000	$ 24,900,000		$ 16,700,000
Other Partner
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential future additional payments for development milestones					$ 40,000,000			$ 40,000,000
Nektar-358 | Eli Lilly
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of sharing in Phase 2 development costs			75%
Nektar-358 | Maximum | Eli Lilly And Company
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential future additional development and regulatory milestones (up to)			$ 250,000,000
Bristol Myers Squibb Collaboration Agreement | Bristol Myers Squibb Company | Nektar 214
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of sharing production costs		35%
Bristol Myers Squibb Collaboration Agreement | Bristol Myers Squibb Company | Nektar 214 | Opdivo
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of sharing development costs		67.50%
Nektar's | Nektar-358
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Received upfront and milestone payment			$ 150,000,000
Percentage of sharing in Phase 2 development costs			25%
Nektar's | Bristol Myers Squibb Collaboration Agreement | Nektar 214
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of sharing production costs		65%
Upfront and milestone payments received from license agreements				$ 1,000,000,000
Nektar's | Bristol Myers Squibb Collaboration Agreement | Nektar 214 | Milestone One
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential future additional payments for development milestones										$ 50,000,000
Nektar's | Bristol Myers Squibb Collaboration Agreement | Nektar 214 | Opdivo
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of sharing development costs		32.50%

License and Collaboration Agr_4

License and Collaboration Agreements - Fair Value of Derivative Liabilities (Details) - Fair Value, Level 3 - Development Derivative Liability $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period	$ 27,726
Non-cash research and development expense	4,951
Cash receipts from SFJ	750
Change in the fair value of development derivative liability	(33,427)
Fair value at end of period	$ 0

Restructuring, Impairment and_3

Restructuring, Impairment and Costs of Terminated Program, and Impairment of Goodwill - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended							9 Months Ended		12 Months Ended	21 Months Ended
	Jun. 30, 2023	Jan. 31, 2023	Apr. 30, 2022	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Sep. 30, 2023
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges				$ (10,567)							$ (35,329)	$ (53,401)
Impairment of other property, plant and equipment						$ 1,700					1,299	5,120
Gain on net impairment											1,300
Impairment of goodwill				0		76,500		$ 0			76,501	0
Nektar 214 | Research and Development Expense | Bristol Myers Squibb Company
Restructuring Cost and Reserve [Line Items]
Reimbursement of expenses								8,300		$ 24,900		16,700
2022 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges				(1,467)	$ (13,255)	0	$ (12,361)	(1,200)	$ (52,200)			(80,483)
Contract termination and other restructuring costs				0				5,023			878	$ 7,064		$ 11,800
2023 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges				10,200		11,500					36,600
Contract termination and other restructuring costs				0							34
2023 Restructuring Plan | Third St. Facility
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges					6,200
2023 Restructuring Plan | Mission Bay Facility
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges				10,600	$ 7,100
2023 Restructuring Plan | Life Sciences Lease Market
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges				$ 9,100
2023 Restructuring Plan | Property, Plant and Equipment
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges								$ 1,200
2023 Restructuring Plan | Office and Laboratory Space | Mission Bay Facility
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges						$ 11,500					$ 20,600
Measurement Input, Market Participant Subtenant Borrowing Rate
Restructuring Cost and Reserve [Line Items]
Operating lease, measurement input						7.90%			6.40%
Measurement Input, Market Participant Subtenant Borrowing Rate | 2023 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Sublease income, measurement input				8.70%	8.50%
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring, impairment, and costs of terminated program				$ 535	$ 1,943	$ 5,483
Payments during the period		$ 3,300		887	6,624	3,299
Employee Severance | 2022 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Workforce termination, percentage			70%
Restructuring, impairment, and costs of terminated program				0	0	0
Payments during the period				0	0	3,299
Employee Severance | 2023 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Workforce termination, percentage	60%
Restructuring, impairment, and costs of terminated program				535	1,943	5,483							$ 30,900
Payments during the period				$ 887	$ 6,624	$ 0

Restructuring, Impairment and_4

Restructuring, Impairment and Costs of Terminated Program, and Impairment of Goodwill - Summary of Restructuring Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		21 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023
Restructuring Cost and Reserve [Line Items]
Impairment of other property, plant and equipment	$ 10,173		$ 36,628	$ 58,521
Restructuring, impairment and costs of terminated program	11,360	$ 16,830	49,107	124,350
2022 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Clinical trial expense, other third-party and employee costs for the wind down of the bempegaldesleukin program	652	8,530	3,606	28,938
Severance and benefit expense	0	2,077	0	29,827
Impairment of other property, plant and equipment	1,467	1,200	14,728	58,521
Contract termination and other restructuring costs	0	5,023	878	7,064	$ 11,800
Restructuring, impairment and costs of terminated program	2,119	$ 16,830	19,212	$ 124,350
2023 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Severance and benefit expense	535		7,961
Impairment of other property, plant and equipment	8,706		21,900
Contract termination and other restructuring costs	0		34
Restructuring, impairment and costs of terminated program	$ 9,241		$ 29,895

Restructuring, Impairment and_5

Restructuring, Impairment and Costs of Terminated Program, and Impairment of Goodwill - Non-cash Impairment Charges Pertaining 2022 Restructuring Plan (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Restructuring Cost and Reserve [Line Items]
Total impairment of lease assets	$ 10,567						$ 35,329	$ 53,401
2022 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Total impairment of lease assets	1,467	$ 13,255	$ 0	$ 12,361	$ 1,200	$ 52,200		80,483
Mission Bay Blvd. South | 2022 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Total impairment of lease assets	1,467	7,055	0	361	1,200	3,000		13,083
Third St | 2022 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Total impairment of lease assets	$ 0	$ 6,200	$ 0	$ 12,000	$ 0	$ 49,200		$ 67,400

Restructuring, Impairment and_6

Restructuring, Impairment and Costs of Terminated Program, and Impairment of Goodwill - Restructuring Reserve Rollforward (Details) - Employee Severance - USD ($) $ in Thousands	1 Months Ended	3 Months Ended			12 Months Ended
	Jan. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	$ 3,299	$ 802	$ 5,483	$ 3,299
Expense recognized during the period		535	1,943	5,483
Payments during the period	(3,300)	(887)	(6,624)	(3,299)
Restructuring reserve, ending balance		450	802	5,483	$ 3,299
2023 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	0	802	5,483	0
Expense recognized during the period		535	1,943	5,483	30,900
Payments during the period		(887)	(6,624)	0
Restructuring reserve, ending balance		450	802	5,483	0
2022 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	$ 3,299	0	0	3,299
Expense recognized during the period		0	0	0
Payments during the period		0	0	(3,299)
Restructuring reserve, ending balance		$ 0	$ 0	$ 0	$ 3,299

Restructuring, Impairment and_7

Restructuring, Impairment and Costs of Terminated Program, and Impairment of Goodwill - Sublease Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2023	Dec. 31, 2022
Restructuring Cost and Reserve [Line Items]
Impairment expense for facilities	$ (10,567)		$ (35,329)	$ (53,401)
(Gain) on sale or disposal of property, plant and equipment, net	(394)
Impairment of other property, plant and equipment		$ 1,700	1,299	5,120
Impairment of other property, plant and equipment	10,173		36,628	58,521
Reported Value Measurement
Restructuring Cost and Reserve [Line Items]
Property, plant and equipment and operating lease right-of-use assets				90,539	$ 21,880	$ 73,913
Property, Plant and Equipment
Restructuring Cost and Reserve [Line Items]
Impairment expense for facilities	1,400		4,771	9,372
(Gain) on sale or disposal of property, plant and equipment, net	(394)
Impairment of other property, plant and equipment			1,299	5,120
Impairment of other property, plant and equipment	1,006		6,070	14,492
Property, Plant and Equipment | Reported Value Measurement
Restructuring Cost and Reserve [Line Items]
Property, plant and equipment and operating lease right-of-use assets				16,348	3,050	10,257
Operating Lease Right-of-Use Assets
Restructuring Cost and Reserve [Line Items]
Impairment expense for facilities	9,167		30,558	44,029
(Gain) on sale or disposal of property, plant and equipment, net	0
Impairment of other property, plant and equipment			0	0
Impairment of other property, plant and equipment	$ 9,167		$ 30,558	44,029
Operating Lease Right-of-Use Assets | Reported Value Measurement
Restructuring Cost and Reserve [Line Items]
Property, plant and equipment and operating lease right-of-use assets				74,191	18,830	63,656
Fair Value, Level 3 | Estimate of Fair Value Measurement
Restructuring Cost and Reserve [Line Items]
Property, plant and equipment and operating lease right-of-use assets				37,138	11,313	38,584
Fair Value, Level 3 | Property, Plant and Equipment | Estimate of Fair Value Measurement
Restructuring Cost and Reserve [Line Items]
Property, plant and equipment and operating lease right-of-use assets				6,976	1,650	5,486
Fair Value, Level 3 | Operating Lease Right-of-Use Assets | Estimate of Fair Value Measurement
Restructuring Cost and Reserve [Line Items]
Property, plant and equipment and operating lease right-of-use assets				$ 30,162	$ 9,663	$ 33,098

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail)	Jun. 08, 2023 shares
2017 Performance Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares authorized (in shares)	12,000,000

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 8,149	$ 12,518	$ 26,134	$ 44,582
Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	841	720	2,454	2,037
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	3,202	5,422	11,107	22,215
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	4,106	5,369	12,573	18,401
Restructuring, impairment and other costs of terminated program
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 0	$ 1,007	$ 0	$ 1,929