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Condensed Consolidated Financial Statement Details - Schedule of Liability Related to Sale of Potential Future Royalties (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Liabilities related to the sales of future royalties, net – beginning balance			$ 112,625
Non-cash royalty revenue			(32,298)	$ (32,693)
Non-cash interest expense	$ 6,408	$ 6,152	11,939	$ 12,557
Amortization of transaction costs			240
Proceeds from the Amendment			15,000
Liabilities related to the sales of future royalties, net – ending balance	107,506		107,506
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			24,217
Non-cash royalty revenue			(14,104)
Non-cash interest expense			3,488
Amortization of transaction costs			0
Proceeds from the Amendment			0
Liabilities related to the sales of future royalties, net – ending balance	13,601		13,601
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			88,408
Non-cash royalty revenue			(18,194)
Non-cash interest expense			8,451
Amortization of transaction costs			240
Proceeds from the Amendment			15,000
Liabilities related to the sales of future royalties, net – ending balance	$ 93,905		$ 93,905

Organization and Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization

We are a clinical stage, research-based drug discovery biopharmaceutical company headquartered in San Francisco, California and incorporated in Delaware, focused on discovering and developing innovative medicines in the field of immunotherapy. Within this growing field, we direct our efforts toward creating new immunomodulatory agents that selectively induce, amplify, attenuate or prevent immune responses in order to achieve desired therapeutic outcomes. Our pipeline of clinical-stage and preclinical-stage immunomodulatory agents targets the treatment of autoimmune diseases (e.g. rezpegaldesleukin and NKTR-0165, respectively) and cancer (e.g. NKTR-255).

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 June 30, 2024, we had approximately $290.6 million in cash and investments in marketable securities.

Financing Transactions

During the six months ended June 30, 2024, we entered into the following transactions:

•

On February 12, 2024, for total cash consideration paid of $3.0 million, we repurchased from Bristol Myers Squibb Company (BMS) 8.3 million shares of Nektar's common stock that were previously sold to BMS, which we report as treasury stock on our Condensed Consolidated Balance Sheets. See Note 6 for additional information.

•

On March 4, 2024, we entered into a Securities Purchase Agreement with TCG Crossover Fund II, L.P. (TCG), pursuant to which we issued a pre-funded warrant to TCG to purchase 25,000,000 shares of Nektar’s common stock for gross proceeds of $30.0 million (or a purchase price of $1.20 per share of common stock that can be issued upon exercise of the pre-funded warrant). On May 28, 2024, we filed with the SEC a registration statement on Form S-3 (file no. 333-279760) registering for the resale of up to 25,000,000 shares of Nektar’s common stock upon exercise of the pre-funded warrant issued to TCG pursuant to the Securities Purchase Agreement. The registration statement became effective on June 5, 2024. See Note 5 for additional information.

•

On March 4, 2024, for total cash consideration received of $15.0 million, we entered into an amendment (the Amendment) with entities managed by Healthcare Royalty Management, LLC (collectively, HCR) to remove the cap on royalties previously sold to HCR under a Purchase and Sale Agreement (the 2020 Purchase and Sale Agreement). See Note 3 for additional information.

Restructuring Plans

In April 2022, we announced the termination of the bempegaldesleukin program and a new strategic reorganization and cost restructuring plan (together, the 2022 Restructuring Plan), pursuant to which we completed an approximate 70% reduction of our workforce during 2022. We also decided to seek a sublease for certain of our leased premises in San Francisco, CA, including all of our office space on Third St. and portions of our office and laboratory space on Mission Bay Blvd. South.

In April 2023, we announced Eli Lilly and Company's (Lilly) decision to terminate our license agreement (the Lilly Agreement) for the development of rezpegaldesleukin, as well as 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%. In addition, under the 2023 Restructuring Plan, we decided to seek a sublease for 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 regained full rights to rezpegaldesleukin from Lilly, and we initiated a Phase 2b study of rezpegaldesleukin in patients with moderate-to-severe atopic dermatitis in October 2023 and a Phase 2b study of rezpegaldesleukin in patients with severe-to-very severe alopecia areata in March 2024. We will also explore other auto-immune indications for the development of rezpegaldesleukin.

We have incurred significant costs resulting from the 2022 and 2023 Restructuring Plans. See Note 7 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 income (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 income (loss) to the statements of operations during the three and six months ended June 30, 2024 and 2023 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, 2023 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, 2023 filed with the SEC on March 5, 2024. 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 not experienced credit losses from our accounts receivable. We have not recorded reserves for credit losses for the three and six months ended June 30, 2024 and 2023, nor have recorded such an allowance as of June 30, 2024 or December 31, 2023.

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.

Treasury Stock

We record treasury stock activities under the cost method. Treasury stock is included in authorized and issued shares but excluded from outstanding shares. The re-issuance of treasury stock is accounted for on a first in, first-out basis and any differences between the cost of treasury stock and the re-issuance proceeds are charged or credited to additional paid-in capital.

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; and

•

contract termination costs for costs incurred when we cancel the contract in accordance with its terms, or for 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 7 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 8 for additional information regarding the impairment charges we recorded during the three months ended March 31, 2023 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 7 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, including the pre-funded warrant, during the periods presented. Shares of common stock into which the pre-funded warrant may be exercised are considered outstanding for the purposes of computing basic net loss per share because the shares may be issued for little or no consideration, are fully vested and are exercisable after the original issuance date. For the three and six months ended June 30, 2024 and 2023, 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 June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Potentially dilutive securities		26,396		21,317		26,685		22,049

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.

As of June 30, 2024 and December 31, 2023, we recorded aggregate provisions of $3.1 million and $2.0 million, respectively, for the net realizable value of our batches. Our manufacturing agreement with UCB Pharma (UCB) provides for a fixed selling price which we had negotiated in exchange for a higher royalty rate. Accordingly, when evaluating the net realizable value of our inventory for UCB, we include the negotiated increase of the royalties in our analysis, and the aggregate revenue has historically been greater than our manufacturing cost. Due to the decreases in the royalty rate for 2024 and 2025 as a result of a settlement agreement with UCB, the aggregate revenue is expected to be less than our manufacturing cost for these years, and therefore we recorded a provision for net realizable value. On July 31, 2024, we entered into an extension agreement with UCB that increases the selling price of the reagent beginning in 2025. At the increased selling price, beginning in 2025, we no longer expect the aggregate revenue to be less than our manufacturing costs.

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (52,363)	$ (51,122)	$ (89,165)	$ (188,140)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Condensed Consolidated Financial Statement Details - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Accrued compensation	$ 8,715	$ 5,553
Accrued research and development expenses	11,060	10,118
Accrued contract termination costs	3,357	3,020
Other accrued expenses	6,382	3,471
Total accrued expenses	$ 29,514	$ 22,162

Organization and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)				1 Months Ended			3 Months Ended		6 Months Ended
	May 28, 2024	Mar. 04, 2024	Feb. 12, 2024	Mar. 31, 2024	Jun. 30, 2023	Apr. 30, 2022	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Organization And Summary Of Significant Accounting Policies [Line Items]
Cash and investments in marketable securities							$ 290,640,000		$ 290,640,000		$ 329,441,000
Proceeds from issuance of pre-funded warrant									30,000,000	$ 0
Accounts receivable, credit loss expense (reversal)							$ 0	$ 0	$ 0	$ 0
Bristol Myers Squibb Company
Organization And Summary Of Significant Accounting Policies [Line Items]
Sale of stock repurchased cash consideration			$ 3,000,000
Sale of stock shares repurchased			8,300,000
Securities Purchase Agreement \| TCG Crossover Fund II, L.P.
Organization And Summary Of Significant Accounting Policies [Line Items]
Proceeds from issuance of pre-funded warrant		$ 30,000,000		$ 30,000,000
Effective date of warrant	Jun. 05, 2024
2020 Purchase and Sale Agreement
Organization And Summary Of Significant Accounting Policies [Line Items]
Amount exchanged to remove cap on royalties		$ 15,000,000
Pre-Funded Warrant \| Securities Purchase Agreement \| TCG Crossover Fund II, L.P.
Organization And Summary Of Significant Accounting Policies [Line Items]
Number of warrants issued to be purchase common shares		25,000,000		25,000,000
Shares issued, price per share		$ 1.2		$ 1.2
Pre-Funded Warrant \| Securities Purchase Agreement \| TCG Crossover Fund II, L.P. \| Maximum
Organization And Summary Of Significant Accounting Policies [Line Items]
Resale of common stock issuable upon exercise of warrant	25,000,000
Employee Severance \| 2022 Restructuring Plan
Organization And Summary Of Significant Accounting Policies [Line Items]
Workforce termination, percentage						70.00%
Employee Severance \| 2023 Restructuring Plan
Organization And Summary Of Significant Accounting Policies [Line Items]
Workforce termination, percentage					60.00%

Organization and Summary of Significant Accounting Policies - Weighted Average Outstanding Stock Options (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Stock Options, RSUs And PSUs
Organization And Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities (in shares)	26,396	21,317	26,685	22,049

License and Collaboration Agreements - Additional Information (Details) - USD ($)			1 Months Ended	3 Months Ended		6 Months Ended
	Feb. 12, 2024	Jul. 23, 2017	Apr. 30, 2018	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue, excluding assessed tax				$ 23,489,000	$ 20,499,000	$ 45,128,000	$ 42,093,000
Non-cash royalty revenue related to the sales of future royalties
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue, excluding assessed tax				16,790,000	$ 15,832,000	32,298,000	$ 32,693,000
Bristol Myers Squibb Company
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Sale of stock shares repurchased	8,300,000
Sale of stock repurchased cash consideration	$ 3,000,000
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
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		75.00%
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
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Sale of stock shares repurchased	8,300,000
Sale of stock repurchased cash consideration	$ 3,000,000
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		25.00%
Nektar's \| Bristol Myers Squibb Collaboration Agreement \| Nektar 214
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
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

Impairement of Goodwill (Additional Information) (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Additional impairment charges on remaining long-lived assets				$ 0
Impairment of goodwill	$ 0	$ 0	$ (76,500,000)	$ 0	$ (76,501,000)

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash flows from operating activities:
Net loss	$ (89,165)	$ (188,140)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash royalty revenue related to the sales of future royalties	(32,298)	(32,693)
Non-cash interest expense on liabilities related to the sales of future royalties	11,939	12,557
Stock-based compensation	11,418	17,985
Depreciation and amortization	3,066	4,468
Deferred income tax expense	19	(1,839)
Impairment of right-of-use assets and property, plant and equipment	8,329	26,455
Impairment of goodwill	0	76,501
Provision for net realizable value of inventory	2,567	1,252
Amortization of premiums (discounts), net and other non-cash transactions	(5,647)	(8,150)
Changes in operating assets and liabilities:
Accounts receivable	9	4,646
Inventory	(931)	(2,739)
Operating leases, net	(4,196)	(3,717)
Other assets	1,817	7,902
Accounts payable	(3,266)	(9,997)
Accrued expenses	10,749	(7,929)
Net cash used in operating activities	(85,590)	(103,438)
Cash flows from investing activities:
Purchases of investments	(173,504)	(249,724)
Maturities of investments	210,087	316,088
Purchases of property, plant and equipment	(343)	(595)
Net cash provided by investing activities	36,240	65,769
Cash flows from financing activities:
Proceeds from shares issued under equity compensation plans	22	18
Proceeds from issuance of pre-funded warrant	30,000	0
Proceeds from sale of future royalties	15,000	0
Repurchase of common stock from Bristol-Myers Squibb	(3,000)	0
Net cash provided by financing activities	42,022	18
Effect of foreign exchange rates on cash and cash equivalents	(9)	152
Net increase (decrease) in cash and cash equivalents	(7,337)	(37,499)
Cash and cash equivalents at beginning of period	35,277	88,227
Cash and cash equivalents at end of period	$ 27,940	$ 50,728

Condensed Consolidated Financial Statement Details - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	$ 102,891	$ 105,015
Less: accumulated depreciation	(88,428)	(86,898)
Depreciable property, plant and equipment, net	14,463	18,117
Construction in process	724	739
Property, plant and equipment, net	15,187	18,856
Building and leasehold improvements
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	41,867	43,184
Computer equipment and computer software
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	22,118	22,438
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	23,980	24,315
Laboratory equipment
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	14,385	14,537
Furniture, fixtures and other
Property, Plant and Equipment [Line Items]
Depreciable property, plant and equipment at cost	$ 541	$ 541

Restructuring, Impairment and Costs of Terminated Program - Summary of Restructuring Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Restructuring and Related Activities [Abstract]
Clinical trial expense, other third-party and employee costs for the wind down of the bempegaldesleukin program	$ 0	$ 1,356	$ 0	$ 2,954
Severance and benefit expense	0	1,943	0	7,426
Impairment of other property, plant and equipment	8,329	13,255	8,329	26,455
Contract termination and other restructuring costs	4,960	0	5,935	912
Restructuring, impairment and other costs of terminated program	$ 13,289	$ 16,554	$ 14,264	$ 37,747

Cover Page - shares	6 Months Ended
Cover Page - shares	Jun. 30, 2024	Aug. 02, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2024
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	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		184,079,479
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Entity Central Index Key	0000906709
Current Fiscal Year End Date	--12-31

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenue:
Total revenue	$ 23,489	$ 20,499	$ 45,128	$ 42,093
Operating costs and expenses:
Cost of goods sold	9,740	6,994	18,274	14,054
Research and development	29,724	29,681	57,132	60,150
General and administrative	20,510	17,869	40,659	38,950
Restructuring, impairment and costs of terminated program	13,289	16,554	14,264	37,747
Impairment of goodwill	0	0	0	76,501
Total operating costs and expenses	73,263	71,098	130,329	227,402
Loss from operations	(49,774)	(50,599)	(85,201)	(185,309)
Non-operating income (expense):
Non-cash interest expense on liabilities related to the sales of future royalties	(6,408)	(6,152)	(11,939)	(12,557)
Interest income	3,901	4,846	8,121	9,181
Other income (expense), net	(36)	736	(135)	435
Total non-operating income (expense), net	(2,543)	(570)	(3,953)	(2,941)
Loss before provision for income taxes	(52,317)	(51,169)	(89,154)	(188,250)
Provision (benefit) for income taxes	46	(47)	11	(110)
Net loss	$ (52,363)	$ (51,122)	$ (89,165)	$ (188,140)
Basic net loss per share (in dollars per share)	$ (0.25)	$ (0.27)	$ (0.44)	$ (0.99)
Diluted net loss per share (in dollars per share)	$ (0.25)	$ (0.27)	$ (0.44)	$ (0.99)
Weighted average shares outstanding used in computing basic net loss per share (in shares)	208,828	189,656	201,787	189,268
Weighted average shares outstanding used in computing diluted net loss per share (in shares)	208,828	189,656	201,787	189,268
Product sales
Revenue:
Total revenue	$ 6,640	$ 4,658	$ 12,674	$ 9,376
Non-cash royalty revenue related to the sales of future royalties
Revenue:
Total revenue	16,790	15,832	32,298	32,693
License, collaboration and other revenue
Revenue:
Total revenue	$ 59	$ 9	$ 156	$ 24

Cash and Investments in Marketable Securities

6 Months Ended

Jun. 30, 2024

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
	June 30, 2024		December 31, 2023
Cash and cash equivalents	$	27,940	$	35,277
Short-term investments		243,295		268,339
Long-term investments		19,405		25,825
Total cash and investments in marketable securities	$	290,640	$	329,441

Our portfolio of cash and investments in marketable securities includes (in thousands):


		June 30, 2024									December 31, 2023
	Fair Value Hierarchy Level	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Fair Value
Corporate notes and bonds	2	$	88,822	$	3	$	(258	)	$	88,567	$	38,882
Corporate commercial paper	2		166,404		—		(257	)		166,147		255,241
Obligations of U.S. government agencies	2		3,482		—		(3	)		3,479		—
Available-for-sale investments		$	258,708	$	3	$	(518	)	$	258,193	$	294,123
Money market funds	1									8,059		2,359
Certificates of deposit	2									14,020		15,116
Cash	N/A									10,368		17,843
Total cash and investments in marketable securities									$	290,640	$	329,441

For the three and six months ended June 30, 2024 and 2023, there were no transfers between Level 1 and Level 2 of the fair value hierarchy. At December 31, 2023, our gross unrealized gains and losses were insignificant.

Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2024

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 June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Cost of goods sold	$	525	$	801	$	1,158	$	1,613
Research and development		2,047		3,759		4,327		7,905
General and administrative		2,846		3,406		5,933		8,467
Total stock-based compensation	$	5,418	$	7,966	$	11,418	$	17,985

Condensed Consolidated Financial Statement Details - Schedule of Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other current assets	$ 8,292	$ 9,779
Prepaid research and development expenses
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other current assets	4,214	4,325
Interest and Other Non-trade Receivables
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other current assets	1,703	1,047
Other prepaid expenses
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other current assets	$ 2,375	$ 4,407

Condensed Consolidated Financial Statement Details - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 126,705	$ 130,987	$ 240,865	$ 366,638
Ending balance	79,688	126,705	196,958	240,865
Accumulated Other Comprehensive Income
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(403)	80	(5,681)	(6,907)
Ending balance	(494)	(403)	(6,450)	(5,681)
Foreign currency translation
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	22	30	(4,992)	(5,131)
Adjustments	(1)	(8)	13	139
Reclassification adjustments to income			(1,026)
Ending balance	21	22	(6,005)	(4,992)
Available-for-sale securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(425)	50	(689)	(1,776)
Adjustments	(90)	(475)	244	1,087
Ending balance	$ (515)	$ (425)	$ (445)	$ (689)

- Definition

Amount of equity (deficit) attributable to parent. Excludes temporary equity and equity attributable to noncontrolling interest.

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Reference 12: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 13: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

Restructuring, Impairment and Costs of Terminated Program - Narrative (Details) - USD ($)	1 Months Ended		3 Months Ended					6 Months Ended		12 Months Ended
	Jun. 30, 2023	Apr. 30, 2022	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges				$ 0					$ 24,755,000
Third St. Facility
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges			$ 4,400,000			$ 6,200,000
2022 Restructuring Plan \| Mission Bay Facility
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges						$ 7,100,000
2023 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges							$ 1,700,000
2023 Restructuring Plan \| Mission Bay Facility
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges			3,900,000		$ 9,100,000		$ 11,500,000
Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Contract termination and other costs included in accrued expenses			$ 3,400,000					$ 3,400,000		$ 3,000,000
Measurement Input, Market Participant Subtenant Borrowing Rate
Restructuring Cost and Reserve [Line Items]
Operating lease, measurement input							7.90%
Sublease income, measurement input			6.20%			8.50%
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring, impairment, and costs of terminated program						$ 1,943,000	$ 5,483,000	0
Payments during the period						6,624,000	3,299,000	196,000
Employee Severance \| 2022 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Workforce termination, percentage		70.00%
Restructuring, impairment, and costs of terminated program						0	0	0
Payments during the period						0	3,299,000	0
Employee Severance \| 2023 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Workforce termination, percentage	60.00%
Restructuring, impairment, and costs of terminated program						1,943,000	5,483,000	0		$ 7,900,000
Payments during the period				$ 200,000		$ 6,624,000	$ 0	$ 196,000

Pre-Funded Warrant

6 Months Ended

Jun. 30, 2024

Equity [Abstract]

Pre-Funded Warrant

Note 5 — Pre-Funded Warrant

In March 2024, we issued a pre-funded warrant to purchase an aggregate of 25,000,000 shares of our common stock to TCG at a price of $1.20 per share for gross proceeds of $30.0 million. Transaction costs were immaterial. The pre-funded warrant has an exercise price of $0.0001 per share and may be exercised at any time after the original issuance date. TCG may not exercise the warrant if TCG, together with its affiliates, would beneficially own more than 9.99% of the number of shares of our common stock outstanding immediately after giving effect to such exercise. TCG may increase or decrease this percentage not in excess of 19.99% by providing at least 61 days’ prior notice to the Company. As of June 30, 2024, the warrant has not been exercised. On May 28, 2024, we filed with the SEC a registration statement on Form S-3 (file no. 333-279760) registering for resale of up to 25,000,000 shares of our common stock issuable upon exercise of the pre-funded warrant. The registration statement became effective on June 5, 2024.

We classified the pre-funded warrant as a component of permanent equity in our Condensed Consolidated Balance Sheets as it is a freestanding financial instrument that was immediately exercisable, does not embody an obligation for the Company to repurchase its own shares and permits the holder to receive a fixed number of shares of common stock upon exercise. All of the shares underlying the pre-funded warrant have been included in the weighted-average number of shares of common stock used to calculate net loss per share attributable to common stockholders because the shares may be issued for little or no consideration, are fully vested and are exercisable after the original issuance date of the pre-funded warrant.

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Shares	Treasury Stock	Capital in Excess of Par Value	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2022		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
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)	(187,683)
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)
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)
Beginning balance (in shares) at Dec. 31, 2023	191,384	191,384
Beginning balance at Dec. 31, 2023	$ 130,987	$ 19		3,608,137	80	(3,477,249)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under equity compensation plans (in shares)		525
Shares issued under equity compensation plans	3			3
Stock-based compensation	6,000			6,000
Repurchase of common stock from Bristol-Myers Squibb (in shares)		(8,285)	8,285
Repurchase of common stock from Bristol-Myers Squibb	(3,000)		$ (3,000)
Issuance of prefunded warrant	30,000			30,000
Comprehensive income (loss)	(37,285)				(483)	(36,802)
Ending balance (in shares) at Mar. 31, 2024		183,624	8,285
Ending balance at Mar. 31, 2024	$ 126,705	$ 19	$ (3,000)	3,644,140	(403)	(3,514,051)
Beginning balance (in shares) at Dec. 31, 2023	191,384	191,384
Beginning balance at Dec. 31, 2023	$ 130,987	$ 19		3,608,137	80	(3,477,249)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	$ (89,739)
Ending balance (in shares) at Jun. 30, 2024	184,061	184,061	8,285
Ending balance at Jun. 30, 2024	$ 79,688	$ 19	$ (3,000)	3,649,577	(494)	(3,566,414)
Beginning balance (in shares) at Mar. 31, 2024		183,624	8,285
Beginning balance at Mar. 31, 2024	126,705	$ 19	$ (3,000)	3,644,140	(403)	(3,514,051)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under equity compensation plans (in shares)		437
Shares issued under equity compensation plans	19			19
Stock-based compensation	5,418			5,418
Comprehensive income (loss)	$ (52,454)				(91)	(52,363)
Ending balance (in shares) at Jun. 30, 2024	184,061	184,061	8,285
Ending balance at Jun. 30, 2024	$ 79,688	$ 19	$ (3,000)	$ 3,649,577	$ (494)	$ (3,566,414)

Commitments and Contingencies - Additional Information (Details) - USD ($)	Jun. 30, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Liability for litigation	$ 0	$ 0

Cash and Investments in Marketable Securities - Cash and Investments in Marketable Securities, Including Cash Equivalents (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Estimated Fair Value at
Cash and cash equivalents	$ 27,940	$ 35,277
Short-term investments	243,295	268,339
Long-term investments	19,405	25,825
Total cash and investments in marketable securities	$ 290,640	$ 329,441

Restructuring, Impairment and Costs of Terminated Program (Tables)

6 Months Ended

Jun. 30, 2024

Restructuring and Related Activities [Abstract]

Schedule of Restructuring, Impairment and Other Costs of Terminated Program

Restructuring, impairment and costs of terminated program includes the following (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Clinical trial expense, other third-party and employee costs for the wind down of the bempegaldesleukin program	$	—	$	1,356	$	—	$	2,954
Severance and benefit expense		—		1,943		—		7,426
Impairment of right-of-use assets and property, plant and equipment		8,329		13,255		8,329		26,455
Contract termination and other restructuring costs		4,960		—		5,935		912
Restructuring, impairment and other costs of terminated program	$	13,289	$	16,554	$	14,264	$	37,747

The following table provides details regarding the severance and benefit expense for the three and six months ended June 30, 2024 pursuant to the 2023 Restructuring Plan and a reconciliation of the severance and benefits liability for the three and six months ended June 30, 2023 pursuant to the 2022 and 2023 Restructuring Plans, which we report within accrued expenses on our Condensed Consolidated Balance Sheet (in thousands):


	Six Months Ended June 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

	Six Months Ended June 30, 2024
	2023 Restructuring Plan			2022 Restructuring Plan			Total
Liability balance as of December 31, 2023	$	196		$	—		$	196
Expense recognized during the period		—			—			—
Payments during the period		(196	)		—			(196	)
Liability balance as of June 30, 2024	$	—		$	—		$	—

The following is a reconciliation of the impairment charges we recorded for the three and six months ended June 30, 2024 and 2023, including the net book values of the sublease assets before the impairment and the fair values of the sublease assets (in thousands):


	Three and Six Months Ended June 30, 2024
	Property, Plant and Equipment			Operating Lease Right-of-Use Assets			Total
Net book value of impaired facilities before write-off	$	1,897		$	12,506		$	14,403
Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy		(855	)		(5,219	)		(6,074	)
Total impairment of right-of-use assets and property, plant and equipment	$	1,042		$	7,287		$	8,329


	Three Months Ended June 30, 2023
	Property, Plant and Equipment			Operating Lease Right-of-Use Assets			Total
Net book value of impaired facilities before write-off	$	2,092		$	16,392		$	18,484
Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy		(529	)		(4,700	)		(5,229	)
Total impairment of right-of-use assets and property, plant and equipment	$	1,563		$	11,692		$	13,255


	Six Months Ended June 30, 2023
	Property, Plant and Equipment			Operating Lease Right-of-Use Assets			Total
Net book value of impaired facilities before write-off	$	7,206		$	44,826		$	52,032
Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy		(3,843	)		(23,434	)		(27,277	)
Impairment expense for facilities		3,363			21,392			24,755
Impairment of other property, plant and equipment		1,700			—			1,700
Total impairment of right-of-use assets and property, plant and equipment	$	5,063		$	21,392		$	26,455

The following are reconciliations of the contract termination and other costs for three and six months ended June 30, 2024 and 2023. As of June 30, 2024 and December 31, 2023, we report $3.4 million and $3.0 million, respectively, within accrued expenses and the remaining within other long-term liabilities on our Condensed Consolidated Balance Sheets.


	For the Six Months Ended June 30,
	2024			2023
Liability balances as of December 31, 2023 and December 31, 2022, respectively	$	5,542		$	7,710
Expense recognized during the period		975			912
Payments during the period		(928	)		(1,129	)
Liability balances as of March 31, 2024 and March 31, 2023, respectively	$	5,589		$	7,493
Expense recognized during the period		4,960			-
Payments during the period		(887	)		(1,264	)
Liability balances as of June 30, 2024 and June 30, 2023, respectively	$	9,662		$	6,229

Organization and Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2024

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 June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Potentially dilutive securities		26,396		21,317		26,685		22,049

Condensed Consolidated Financial Statement Details

6 Months Ended

Jun. 30, 2024

Inventory Disclosure [Abstract]

Condensed Consolidated Financial Statement Details

Note 3 — Condensed Consolidated Financial Statement Details

Inventory

Inventory consists of the following (in thousands):


	June 30, 2024		December 31, 2023
Raw materials	$	1,719	$	1,861
Work-in-process		10,590		12,880
Finished goods		2,156		1,360
Total inventory, net	$	14,465	$	16,101

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.

Other Current Assets

Other current assets consist of the following (in thousands):


	June 30, 2024		December 31, 2023
Prepaid research and development expenses	$	4,214	$	4,325
Interest and other non-trade receivables		1,703		1,047
Other prepaid expenses		2,375		4,407
Total other current assets	$	8,292	$	9,779

Property, Plant and Equipment

Property, plant and equipment consists of the following (in thousands):


	June 30, 2024			December 31, 2023
Building and leasehold improvements	$	41,867		$	43,184
Computer equipment and computer software		22,118			22,438
Manufacturing equipment		23,980			24,315
Laboratory equipment		14,385			14,537
Furniture, fixtures and other		541			541
Depreciable property, plant and equipment at cost		102,891			105,015
Less: accumulated depreciation		(88,428	)		(86,898	)
Depreciable property, plant and equipment, net		14,463			18,117
Construction in process		724			739
Property, plant and equipment, net	$	15,187		$	18,856

Due to the weakening lease markets during the three months ended June 30, 2024, we recorded additional non-cash impairment charges of $1.0 million for property, plant and equipment for the three months ended June 30, 2024, which we report in restructuring, impairment and costs of terminated program in our Condensed Consolidated Statement of Operations. See Note 7 for additional information.

Accrued Expenses

Accrued expenses consist of the following (in thousands):


	June 30, 2024		December 31, 2023
Accrued compensation	$	8,715	$	5,553
Accrued research and development expenses		11,060		10,118
Accrued contract termination costs		3,357		3,020
Other accrued expenses		6,382		3,471
Total accrued expenses	$	29,514	$	22,162

Liabilities Related to the Sales of Future Royalties

In 2012 and 2020, we sold to RPI Finance Trust (RPI) and 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 June 30, 2024, our imputed interest rates for the arrangements with RPI and HCR were 35% and 19%, respectively.

The original 2020 Purchase and Sale Agreement was to expire -- and wherein the right to receive royalties would revert to us -- if HCR received aggregate royalties of $210.0 million on or prior to December 31, 2025 (the 2025 Threshold), or, if the 2025 Threshold was not achieved by December 31, 2025, when HCR received aggregate royalties of $240.0 million. On March 4, 2024, Nektar and HCR amended the original 2020 Purchase and Sale Agreement (the Amendment), pursuant to which the parties agreed to remove our reversionary rights in the royalties in exchange for a $15.0 million payment from HCR. Accordingly, HCR will receive all future royalties of the products, and none of these royalties will return to Nektar. We concluded that we should account for the Amendment as a modification of the existing arrangement, and therefore recorded the $15.0 million proceeds as an increase to the liability.

The following is a reconciliation of the changes in our liabilities related to the sales of future royalties for the six months ended June 30, 2024 (in thousands):


	Six Months Ended June 30, 2024
	2012 Purchase and Sale Agreement			2020 Purchase and Sale Agreement			Total
Liabilities related to the sales of future royalties, net – beginning balance	$	24,217		$	88,408		$	112,625
Non-cash royalty revenue		(14,104	)		(18,194	)		(32,298	)
Non-cash interest expense		3,488			8,451			11,939
Amortization of transaction costs		—			240			240
Proceeds from the Amendment		—			15,000			15,000
Liabilities related to the sales of future royalties, net – ending balance	$	13,601		$	93,905		$	107,506

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, 2023	$	30		$	50		$	80
Foreign currency translation adjustments		(8	)		—			(8	)
Unrealized gain on available-for-sale securities		—			(475	)		(475	)
Balance at March 31, 2024	$	22		$	(425	)	$	(403	)
Foreign currency translation adjustments		(1	)		—			(1	)
Unrealized gain on available-for-sale securities		—			(90	)		(90	)
Balance at June 30, 2024	$	21		$	(515	)	$	(494	)


	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	)

The reclassification from accumulated other comprehensive loss relates to the closure of one of our foreign subsidiaries and has been included within other income (expense), net in our Condensed Consolidated Statement of Operations.

Cash and Investments in Marketable Securities - Portfolio of Cash and Investments in Marketable Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash	$ 10,368	$ 17,843
Total cash and investments in marketable securities	290,640	329,441
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	258,708
Gross Unrealized Gains	3
Gross Unrealized Losses	(518)
Fair Value	258,193	294,123
Level 2 \| Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	88,822
Gross Unrealized Gains	3
Gross Unrealized Losses	(258)
Fair Value	88,567	38,882
Level 2 \| Corporate commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	166,404
Gross Unrealized Gains	0
Gross Unrealized Losses	(257)
Fair Value	166,147	255,241
Level 2 \| Obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	3,482
Gross Unrealized Gains	0
Gross Unrealized Losses	(3)
Fair Value	3,479	0
Level 2 \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	14,020	15,116
Level 1 \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	$ 8,059	$ 2,359

Condensed Consolidated Financial Statement Details - Schedule of Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Raw materials	$ 1,719	$ 1,861
Work-in-process	10,590	12,880
Finished goods	2,156	1,360
Total inventory, net	$ 14,465	$ 16,101

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2024	Dec. 31, 2023
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)	192,346,000	191,384,000
Common stock, shares outstanding (in shares)	184,061,000	191,384,000
Treasury Stock, Common, Shares	8,285,000	0

Restructuring, Impairment and Costs of Terminated Program - Sublease Information (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Restructuring Cost and Reserve [Line Items]
Impairment expense for facilities		$ 0			$ 24,755,000
Impairment of other property, plant and equipment					1,700,000
Total impairment of right-of-use assets and property, plant and equipment	$ 8,329,000		$ 13,255,000	$ 8,329,000	26,455,000
Reported Value Measurement
Restructuring Cost and Reserve [Line Items]
Property, plant and equipment and operating lease right-of-use assets		14,403,000				$ 14,403,000	$ 18,484,000	$ 52,032,000
Property, Plant and Equipment
Restructuring Cost and Reserve [Line Items]
Impairment expense for facilities					3,363,000
Impairment of other property, plant and equipment					1,700,000
Total impairment of right-of-use assets and property, plant and equipment	1,042,000		1,563,000	1,042,000	5,063,000
Property, Plant and Equipment \| Reported Value Measurement
Restructuring Cost and Reserve [Line Items]
Property, plant and equipment and operating lease right-of-use assets		1,897,000				1,897,000	2,092,000	7,206,000
Operating Lease Right-of-Use Assets
Restructuring Cost and Reserve [Line Items]
Impairment expense for facilities					21,392,000
Total impairment of right-of-use assets and property, plant and equipment	$ 7,287,000		$ 11,692,000	$ 7,287,000	$ 21,392,000
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		12,506,000				12,506,000	16,392,000	44,826,000
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		(6,074,000)				(6,074,000)	(5,229,000)	(27,277,000)
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		(855,000)				(855,000)	(529,000)	(3,843,000)
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		$ (5,219,000)				$ (5,219,000)	$ (4,700,000)	$ (23,434,000)

Condensed Consolidated Financial Statement Details - Narrative (Details) $ in Thousands			3 Months Ended		6 Months Ended
	Mar. 04, 2024 USD ($)	Dec. 16, 2020 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Goodwill [Line Items]
Impairment of other property, plant and equipment			$ 8,329	$ 13,255	$ 8,329	$ 26,455
2012 Purchase and Sale Agreement
Goodwill [Line Items]
Royalties liability discount rate			0.35		0.35
2020 Purchase and Sale Agreement
Goodwill [Line Items]
Royalties liability discount rate			0.19		0.19
Payment of transaction related to purchase and sale agreement		$ 210,000
Payment of transaction related to purchase and sale agreement if threshold is not achieved		$ 240,000
Amount exchanged to remove cap on royalties	$ 15,000
Proceeds from sale of royalty rights					$ 15,000
UCB Pharma Manufacturing Agreement
Goodwill [Line Items]
Net realizable value of assets			$ 3,100		$ 3,100		$ 2,000
Sublease of Laboratory and Office Space
Goodwill [Line Items]
Impairment of other property, plant and equipment			$ 1,000

Pre-Funded Warrant - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	6 Months Ended
	May 28, 2024	Mar. 04, 2024	Mar. 31, 2024	Jun. 30, 2024	Jun. 30, 2023
Subsidiary, Sale of Stock [Line Items]
Proceeds from issuance of pre-funded warrant				$ 30,000	$ 0
Pre-Funded Warrant
Subsidiary, Sale of Stock [Line Items]
Exercise price of warrants			$ 0.0001
Securities Purchase Agreement \| TCG Crossover Fund II, L.P.
Subsidiary, Sale of Stock [Line Items]
Proceeds from issuance of pre-funded warrant		$ 30,000	$ 30,000
Warrant exercised prior notice period			61 days
Effective date of warrant	Jun. 05, 2024
Securities Purchase Agreement \| TCG Crossover Fund II, L.P. \| Maximum
Subsidiary, Sale of Stock [Line Items]
Percentage of number of shares of warrant exercised			19.99%
Securities Purchase Agreement \| TCG Crossover Fund II, L.P. \| Pre-Funded Warrant
Subsidiary, Sale of Stock [Line Items]
Number of warrants issued to be purchase common shares		25,000,000	25,000,000
Shares issued, price per share		$ 1.2	$ 1.2
Securities Purchase Agreement \| TCG Crossover Fund II, L.P. \| Pre-Funded Warrant \| Maximum
Subsidiary, Sale of Stock [Line Items]
Resale of common stock issuable upon exercise of warrant	25,000,000
Affiliates \| Securities Purchase Agreement \| TCG Crossover Fund II, L.P. \| Maximum
Subsidiary, Sale of Stock [Line Items]
Percentage of number of shares of warrant exercised			9.99%

Organization and Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2024

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

Financing Transactions

During the six months ended June 30, 2024, we entered into the following transactions:

•

Restructuring Plans

We have incurred significant costs resulting from the 2022 and 2023 Restructuring Plans. See Note 7 for additional information on the effect on our Condensed Consolidated Financial Statements.

Basis of Presentation and Principles of Consolidation

Use of Estimates

Significant Concentrations

Treasury Stock

Restructuring

•

See Note 7 for additional information on the severance expense that we recognized for employees terminated in connection with our reductions-in-force.

Impairment of Goodwill

See Note 8 for additional information regarding the impairment charges we recorded during the three months ended March 31, 2023 in connection with our goodwill.

Long-Lived Asset Impairment

See Note 7 for additional information regarding the impairment charges we recorded in connection with our leased facilities and certain property and equipment.

Net Loss per Share


	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Potentially dilutive securities		26,396		21,317		26,685		22,049

Cash and Investments in Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2024

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
	June 30, 2024		December 31, 2023
Cash and cash equivalents	$	27,940	$	35,277
Short-term investments		243,295		268,339
Long-term investments		19,405		25,825
Total cash and investments in marketable securities	$	290,640	$	329,441

Schedule of Portfolio of Cash and Investments in Marketable Securities

Our portfolio of cash and investments in marketable securities includes (in thousands):


		June 30, 2024									December 31, 2023
	Fair Value Hierarchy Level	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Fair Value
Corporate notes and bonds	2	$	88,822	$	3	$	(258	)	$	88,567	$	38,882
Corporate commercial paper	2		166,404		—		(257	)		166,147		255,241
Obligations of U.S. government agencies	2		3,482		—		(3	)		3,479		—
Available-for-sale investments		$	258,708	$	3	$	(518	)	$	258,193	$	294,123
Money market funds	1									8,059		2,359
Certificates of deposit	2									14,020		15,116
Cash	N/A									10,368		17,843
Total cash and investments in marketable securities									$	290,640	$	329,441

Condensed Consolidated Financial Statement Details (Tables)

6 Months Ended

Jun. 30, 2024

Inventory Disclosure [Abstract]

Schedule of Inventory

Inventory consists of the following (in thousands):


	June 30, 2024		December 31, 2023
Raw materials	$	1,719	$	1,861
Work-in-process		10,590		12,880
Finished goods		2,156		1,360
Total inventory, net	$	14,465	$	16,101

Schedule of Other Current Assets

Other current assets consist of the following (in thousands):


	June 30, 2024		December 31, 2023
Prepaid research and development expenses	$	4,214	$	4,325
Interest and other non-trade receivables		1,703		1,047
Other prepaid expenses		2,375		4,407
Total other current assets	$	8,292	$	9,779

Schedule of Property, Plant and Equipment

Property, plant and equipment consists of the following (in thousands):


	June 30, 2024			December 31, 2023
Building and leasehold improvements	$	41,867		$	43,184
Computer equipment and computer software		22,118			22,438
Manufacturing equipment		23,980			24,315
Laboratory equipment		14,385			14,537
Furniture, fixtures and other		541			541
Depreciable property, plant and equipment at cost		102,891			105,015
Less: accumulated depreciation		(88,428	)		(86,898	)
Depreciable property, plant and equipment, net		14,463			18,117
Construction in process		724			739
Property, plant and equipment, net	$	15,187		$	18,856

Schedule of Accrued Expenses

Accrued expenses consist of the following (in thousands):


	June 30, 2024		December 31, 2023
Accrued compensation	$	8,715	$	5,553
Accrued research and development expenses		11,060		10,118
Accrued contract termination costs		3,357		3,020
Other accrued expenses		6,382		3,471
Total accrued expenses	$	29,514	$	22,162

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 six months ended June 30, 2024 (in thousands):


	Six Months Ended June 30, 2024
	2012 Purchase and Sale Agreement			2020 Purchase and Sale Agreement			Total
Liabilities related to the sales of future royalties, net – beginning balance	$	24,217		$	88,408		$	112,625
Non-cash royalty revenue		(14,104	)		(18,194	)		(32,298	)
Non-cash interest expense		3,488			8,451			11,939
Amortization of transaction costs		—			240			240
Proceeds from the Amendment		—			15,000			15,000
Liabilities related to the sales of future royalties, net – ending balance	$	13,601		$	93,905		$	107,506

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, 2023	$	30		$	50		$	80
Foreign currency translation adjustments		(8	)		—			(8	)
Unrealized gain on available-for-sale securities		—			(475	)		(475	)
Balance at March 31, 2024	$	22		$	(425	)	$	(403	)
Foreign currency translation adjustments		(1	)		—			(1	)
Unrealized gain on available-for-sale securities		—			(90	)		(90	)
Balance at June 30, 2024	$	21		$	(515	)	$	(494	)


	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	)

Impairment of Goodwill

6 Months Ended

Jun. 30, 2024

Goodwill and Intangible Assets Disclosure [Abstract]

Impairment of Goodwill

Note 8 — Impairment of Goodwill

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.

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 sublease assets, for which we recognized significant impairment charges during 2022 and 2023, including for the three months ended March 31, 2023, are independent of our entity-wide group. See Note 7 for additional information regarding impairment charges that we have recorded for our sublease assets, as well as certain property, plant and equipment that we subsequently sold.

We next evaluated our remaining long-lived assets for impairment and performed a recoverability test using the undiscounted cash flows approach. We did not recognize any additional impairment charges on the remaining long-lived assets.

Finally, 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 which we reported as impairment of goodwill in our Condensed Consolidated Statements of Operations for the three months ended March 31, 2023. We had previously recognized goodwill primarily from our acquisitions of Shearwater Corp. and Aerogen, Inc. in 2001 and 2005, respectively.

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of Comprehensive Income [Abstract]
Net loss	$ (52,363)	$ (51,122)	$ (89,165)	$ (188,140)
Other comprehensive income (loss):
Net unrealized gain (loss) on available-for-sale securities	(90)	244	(565)	1,331
Net foreign currency translation gain (loss)	(1)	(1,013)	(9)	(874)
Other comprehensive income (loss)	(91)	(769)	(574)	457
Comprehensive loss	$ (52,454)	$ (51,891)	$ (89,739)	$ (187,683)

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(19))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
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-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482765/220-10-50-4

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482765/220-10-50-5

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section S99
-Paragraph 2
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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-Section S99
-Paragraph 1
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-1A

+ Details

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 5,418	$ 7,966	$ 11,418	$ 17,985
Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	525	801	1,158	1,613
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	2,047	3,759	4,327	7,905
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 2,846	$ 3,406	$ 5,933	$ 8,467

Restructuring, Impairment and Costs of Terminated Program - Restructuring Reserve Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended	12 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Dec. 31, 2023
Employee Severance
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance		$ 196	$ 5,483	$ 3,299	$ 196	$ 3,299
Expense recognized during the period			1,943	5,483	0
Payments during the period			(6,624)	(3,299)	(196)
Restructuring reserve, ending balance	$ 0		802	5,483	0	196
Employee Severance \| 2023 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance		196	5,483	0	196	0
Expense recognized during the period			1,943	5,483	0	7,900
Payments during the period		(200)	(6,624)	0	(196)
Restructuring reserve, ending balance	0		802	5,483	0	196
Employee Severance \| 2022 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance		0	0	3,299	0	3,299
Expense recognized during the period			0	0	0
Payments during the period			0	(3,299)	0
Restructuring reserve, ending balance	0		0	0	0	0
Contract Termination and Other Costs \| Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	5,589	5,542	7,493	7,710	5,542	7,710
Expense recognized during the period	4,960	975	0	912
Payments during the period	(887)	(928)	(1,264)	(1,129)
Restructuring reserve, ending balance	$ 9,662	$ 5,589	$ 6,229	$ 7,493	$ 9,662	$ 5,542

License and Collaboration Agreements

6 Months Ended

Jun. 30, 2024

License And Collaboration Agreements [Abstract]

License and Collaboration Agreements

Note 6 — 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 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 April 23, 2023, we received from Lilly a notice of at-will termination of the Lilly Agreement. We have regained full rights to rezpegaldesleukin from Lilly, and the Lilly Agreement subsequently terminated. Following the return of our rights to develop rezpegaldesleukin, we bear all costs of development. We initiated a Phase 2b study of rezpegaldesleukin in patients with moderate-to-severe atopic dermatitis in October 2023 and a Phase 2b study of rezpegaldesleukin in patients with severe-to-very severe alopecia areata in March 2024. We will also explore other auto-immune indications for the development of rezpegaldesleukin.

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 shared 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.

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.

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. On February 12, 2024, we repurchased the 8.3 million shares previously sold to BMS for total cash consideration of $3.0 million.

We determined that the BMS Collaboration Agreement falls within the scope of ASC 808. Based on the cost sharing percentages described above, we recognize the net reimbursement to (from) BMS as an increase (decrease) to the applicable expense. As discussed in Note 7, 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. For the three and six months ended June 30, 2024, such amounts are immaterial and are included in research and development expense.

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 $15.8 million and $32.7 million for the three and six months ended June 30, 2023, respectively, and $16.8 million and $32.3 million for the three and six months ended June 30, 2024, 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 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.

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 27,940	$ 35,277
Short-term investments	243,295	268,339
Accounts receivable	1,196	1,205
Inventory, net	14,465	16,101
Other current assets	8,292	9,779
Total current assets	295,188	330,701
Long-term investments	19,405	25,825
Property, plant and equipment, net	15,187	18,856
Operating lease right-of-use assets	9,240	18,007
Other assets	4,314	4,644
Total assets	343,334	398,033
Current liabilities:
Accounts payable	6,475	9,848
Accrued expenses	29,514	22,162
Operating lease liabilities, current portion	21,337	19,259
Total current liabilities	57,326	51,269
Operating lease liabilities, less current portion	90,763	98,517
Liabilities related to the sales of future royalties, net	107,506	112,625
Other long-term liabilities	8,051	4,635
Total liabilities	263,646	267,046
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.0001 par value; 10,000 shares authorized; no shares designated or outstanding at June 30, 2024 or December 31, 2023, respectively	0	0
Common stock, $0.0001 par value; 300,000 shares authorized; 192,346 shares and 191,384 shares issued at June 30, 2024 and December 31, 2023, respectively; 184,061 shares and 191,384 shares outstanding at June 30, 2024 and December 31, 2023, respectively;	19	19
Capital in excess of par value	3,649,577	3,608,137
Treasury stock, at cost; 8,285 shares as of June 30, 2024 and none as of December 31, 2023, respectively	(3,000)	0
Accumulated other comprehensive income (loss)	(494)	80
Accumulated deficit	(3,566,414)	(3,477,249)
Total stockholders’ equity	79,688	130,987
Total liabilities and stockholders’ equity	$ 343,334	$ 398,033

Restructuring, Impairment and Costs of Terminated Program

6 Months Ended

Jun. 30, 2024

Restructuring and Related Activities [Abstract]

Restructuring, Impairment and Costs of Terminated Program

Note 7 — 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.

Restructuring, impairment and costs of terminated program includes the following (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Clinical trial expense, other third-party and employee costs for the wind down of the bempegaldesleukin program	$	—	$	1,356	$	—	$	2,954
Severance and benefit expense		—		1,943		—		7,426
Impairment of right-of-use assets and property, plant and equipment		8,329		13,255		8,329		26,455
Contract termination and other restructuring costs		4,960		—		5,935		912
Restructuring, impairment and other costs of terminated program	$	13,289	$	16,554	$	14,264	$	37,747

Wind Down of the Bempegaldesleukin Program

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, following our announcement to terminate the program, 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. For the three and six months ended June 30, 2024, such amounts are immaterial and are included in research and development expense.

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 all expense in 2022 and paid the final liability of $3.3 million in the three months ended March 31, 2023.

For the 2023 Restructuring Plan, we recognized $7.9 million in total expense in 2023 for the 2023 Restructuring Plan and paid the final liability of $0.2 million in the three months ended March 31, 2024.

We do not expect to recognize any additional severance and benefits expense for the 2022 and 2023 Restructuring Plans.


	Six Months Ended June 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

	Six Months Ended June 30, 2024
	2023 Restructuring Plan			2022 Restructuring Plan			Total
Liability balance as of December 31, 2023	$	196		$	—		$	196
Expense recognized during the period		—			—			—
Payments during the period		(196	)		—			(196	)
Liability balance as of June 30, 2024	$	—		$	—		$	—

Impairment of Long-Lived Assets

As a result of our 2022 and 2023 Restructuring Plans, we decided to seek a sublease for all of our leased spaces on Third Street and Mission Bay Blvd. South (the Third Street Facility and the Mission Bay Facility, respectively). Accordingly, we evaluate each space for impairment when management decides to sublease the respective space and at each reporting date thereafter, as facts and circumstances change. The significant assumptions in our impairment analysis relate to sublease income, including the length of time to enter into a sublease, sublease rental payments, free rent periods, tenant improvement allowances and broker commissions. When available, we use sublease negotiations or agreements, but in the absence of such information, we develop our own subjective estimates based on current real estate trends and market conditions. Accordingly, our estimates are subject to significant risk, and the terms of sublease agreements, if any, and the resulting amount and timing of sublease income, if ever realized, may be materially different than our estimates.

As part of our evaluation of each sublease space, we separately compare the estimated undiscounted sublease income, as described above, 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). If such sublease income exceeds the net book value of the sublease assets, we do not record an impairment charge. Otherwise, we record an impairment charge by reducing the net book value of the sublease 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.

During the three months ended March 31, 2023, we recorded an initial impairment charge of $11.5 million for our remaining office and laboratory leased space in our Mission Bay Facility, when we initially decided to sublease the space under the 2023 Restructuring Plan. We also recorded an additional impairment charge of $1.7 million for certain excess laboratory equipment which we subsequently sold in 2023. As the life sciences lease market has continued to deteriorate in the San Francisco Bay Area, we recorded additional non-cash impairment charges of $9.1 million in the three months ended September 30, 2023, and $3.9 million in the three months ended June 30, 2024, for this space.

During the three months ended June 30, 2023, we recorded a non-cash impairment charge of $7.1 million for other sublease assets in our Mission Bay Facility that we sought to sublease under the 2022 Restructuring Plan. Due to the worsening office lease market, for the three months ended June 30, 2024 and 2023, we recorded non-cash impairment charges of $4.4 million and $6.2 million, respectively, for our sublease assets at our Third Street Facility.

For these impairment charges, we developed our estimates of sublease income based on market participant assumptions as described above, and we discounted the sublease income using the estimated borrowing rate of a market participant subtenant,

which we estimated to be 7.9% for the three months ended March 31, 2023, 8.5% for the three months ended June 30, 2023 and 6.2% for the three months ended June 30, 2024. We recorded no impairment charges for the three months ended March 31, 2024.


	Three and Six Months Ended June 30, 2024
	Property, Plant and Equipment			Operating Lease Right-of-Use Assets			Total
Net book value of impaired facilities before write-off	$	1,897		$	12,506		$	14,403
Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy		(855	)		(5,219	)		(6,074	)
Total impairment of right-of-use assets and property, plant and equipment	$	1,042		$	7,287		$	8,329


	Three Months Ended June 30, 2023
	Property, Plant and Equipment			Operating Lease Right-of-Use Assets			Total
Net book value of impaired facilities before write-off	$	2,092		$	16,392		$	18,484
Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy		(529	)		(4,700	)		(5,229	)
Total impairment of right-of-use assets and property, plant and equipment	$	1,563		$	11,692		$	13,255


	Six Months Ended June 30, 2023
	Property, Plant and Equipment			Operating Lease Right-of-Use Assets			Total
Net book value of impaired facilities before write-off	$	7,206		$	44,826		$	52,032
Less: Fair value of impaired facilities — Level 3 of Fair Value Hierarchy		(3,843	)		(23,434	)		(27,277	)
Impairment expense for facilities		3,363			21,392			24,755
Impairment of other property, plant and equipment		1,700			—			1,700
Total impairment of right-of-use assets and property, plant and equipment	$	5,063		$	21,392		$	26,455

Contract Termination and Other Costs

We have incurred significant contract termination costs in connection with our Restructuring Plans. Because we adjust this liability at fair value at each reporting date, we continue to recognize expense as our estimates change until settlement.


	For the Six Months Ended June 30,
	2024			2023
Liability balances as of December 31, 2023 and December 31, 2022, respectively	$	5,542		$	7,710
Expense recognized during the period		975			912
Payments during the period		(928	)		(1,129	)
Liability balances as of March 31, 2024 and March 31, 2023, respectively	$	5,589		$	7,493
Expense recognized during the period		4,960			-
Payments during the period		(887	)		(1,264	)
Liability balances as of June 30, 2024 and June 30, 2023, respectively	$	9,662		$	6,229

Commitments and Contingencies

6 Months Ended

Jun. 30, 2024

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 each reporting date 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 (the Court) against Lilly alleging, among other claims, breach of contract and breach of implied covenant of good faith and fair dealing (the Complaint), in connection with our collaboration with Lilly. Following the denial of its motion to dismiss the Complaint entirely, Lilly filed an answer that included counterclaims against us alleging breach of specified confidentiality provisions and defamation. The case is proceeding.

We have recorded no liability for any litigation matters in our Condensed Consolidated Balance Sheets at either June 30, 2024 or December 31, 2023.

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.

Stock-Based Compensation

6 Months Ended

Jun. 30, 2024

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

Note 9 — Stock-Based Compensation

We recognized total stock-based compensation expense in our Condensed Consolidated Statements of Operations as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Cost of goods sold	$	525	$	801	$	1,158	$	1,613
Research and development		2,047		3,759		4,327		7,905
General and administrative		2,846		3,406		5,933		8,467
Total stock-based compensation	$	5,418	$	7,966	$	11,418	$	17,985