ARCUS BIOSCIENCES, INC., 10-Q filed on 10/28/2025
Quarterly Report
v3.25.3
Cover - shares
9 Months Ended
Sep. 30, 2025
Oct. 23, 2025
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 30, 2025  
Document Transition Report false  
Entity File Number 001-38419  
Entity Registrant Name Arcus Biosciences, Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 47-3898435  
Entity Address, Address Line One 3928 Point Eden Way  
Entity Address, City or Town Hayward  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 94545  
City Area Code 510  
Local Phone Number 694-6200  
Title of 12(b) Security Common Stock, Par Value $0.0001 Per Share  
Trading Symbol RCUS  
Security Exchange Name NYSE  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   107,973,536
Entity Central Index Key 0001724521  
Current Fiscal Year End Date --12-31  
Amendment Flag false  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q3  
v3.25.3
Condensed Consolidated Statements of Operations - USD ($)
shares in Millions, $ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Revenues:        
Total revenues $ 26 $ 48 $ 214 $ 232
Operating expenses:        
Research and development (Includes $13, ($2), $19 and ($32) from a related party) 141 123 402 347
General and administrative (Includes $3, $—, $5, and $— from a related party) 27 30 84 92
Impairment of long-lived assets 0 0 0 20
Total operating expenses 168 153 486 459
Loss from operations (142) (105) (272) (227)
Non-operating income (expense):        
Interest and other income, net 10 14 31 40
Interest expense (3) (1) (6) (2)
Total non-operating income, net 7 13 25 38
Loss before income taxes (135) (92) (247) (189)
Income tax expense 0 0 0 0
Net loss $ (135) $ (92) $ (247) $ (189)
Net loss per share:        
Basic (in dollars per share) $ (1.27) $ (1.00) $ (2.39) $ (2.11)
Diluted (in dollars per share) $ (1.27) $ (1.00) $ (2.39) $ (2.11)
Shares used to compute net loss per share:        
Basic (in shares) 106.5 91.4 103.7 89.6
Diluted (in shares) 106.5 91.4 103.7 89.6
License and Development Services Revenue        
Revenues:        
Total revenues $ 20 $ 41 $ 192 $ 204
Other Collaboration Revenue        
Revenues:        
Total revenues $ 6 $ 7 $ 22 $ 28
v3.25.3
Condensed Consolidated Statements of Operations (Parenthetical) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Revenue $ 26 $ 48 $ 214 $ 232
General and administrative expense 27 30 84 92
Related Party        
Research and development expense, net of recoveries 13 (2) 19 (32)
General and administrative expense 3 0 5 0
License and Development Services Revenue        
Revenue 20 41 192 204
License and Development Services Revenue | Related Party        
Revenue 20 23 192 179
Other Collaboration Revenue        
Revenue 6 7 22 28
Other Collaboration Revenue | Related Party        
Revenue $ 6 $ 7 $ 22 $ 28
v3.25.3
Condensed Consolidated Statements of Comprehensive Loss - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Income Statement [Abstract]        
Net loss $ (135) $ (92) $ (247) $ (189)
Other comprehensive income 0 2 0 1
Comprehensive loss $ (135) $ (90) $ (247) $ (188)
v3.25.3
Condensed Consolidated Balance Sheets - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Current assets:    
Cash and cash equivalents $ 238 $ 150
Marketable securities 593 828
Receivable from collaboration partners ($— and $6 from a related party) 11 20
Prepaid expenses and other current assets 15 18
Total current assets 857 1,016
Long-term marketable securities 10 14
Property and equipment, net 42 47
Other noncurrent assets 65 73
Total assets 974 1,150
Current liabilities:    
Accounts payable ($29 and $— to a related party) 42 18
Deferred revenue ($52 and $85 to a related party) 52 85
Other current liabilities 141 123
Total current liabilities 235 226
Deferred revenue, noncurrent ($53 and $234 to a related party) 53 234
Long-term debt 98 48
Other noncurrent liabilities 152 157
Commitments
Stockholders’ equity:    
Common stock and additional paid-in capital: $0.0001 par value per share; 400.0 shares authorized; 107.1 shares in 2025 and 92.2 shares in 2024 issued and outstanding 1,815 1,617
Accumulated deficit (1,379) (1,132)
Total stockholders’ equity 436 485
Total liabilities and stockholders’ equity $ 974 $ 1,150
v3.25.3
Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)
shares in Millions, $ in Millions
Sep. 30, 2025
Dec. 31, 2024
Receivable from collaboration partners, current $ 11 $ 20
Accounts payable, current 42 18
Deferred revenue, current 52 85
Deferred revenue, noncurrent $ 53 $ 234
Common stock, par value (in dollars per share) $ 0.0001 $ 0.0001
Common stock, shares authorized (in shares) 400.0 400.0
Common stock, shares issued (in shares) 107.1 92.2
Common stock, shares outstanding (in shares) 107.1 92.2
Related Party    
Receivable from collaboration partners, current $ 0 $ 6
Accounts payable, current 29 0
Deferred revenue, current 52 85
Deferred revenue, noncurrent $ 53 $ 234
v3.25.3
Condensed Consolidated Statements of Stockholders' Equity - USD ($)
shares in Millions, $ in Millions
Total
Equity Award Programs
Common Stock
Common Stock
Equity Award Programs
Common stock and additional paid-in capital
Common stock and additional paid-in capital
Equity Award Programs
Accumulated deficit
Accumulated other comprehensive income (loss)
Beginning balance, shares at Dec. 31, 2023     75.5          
Beginning balance at Dec. 31, 2023 $ 462       $ 1,311   $ (849) $ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Issuance of common stock (in shares)     15.2 0.2        
Issuance of common stock 228 $ 2     228 $ 2    
Stock-based compensation 20       20      
Other comprehensive (loss) income (1)             (1)
Net (loss) income (4)           (4)  
Ending balance, shares at Mar. 31, 2024     90.9          
Ending balance at Mar. 31, 2024 707       1,561   (853) (1)
Beginning balance, shares at Dec. 31, 2023     75.5          
Beginning balance at Dec. 31, 2023 462       1,311   (849) 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Net (loss) income (189)              
Ending balance, shares at Sep. 30, 2024     91.5          
Ending balance at Sep. 30, 2024 565       1,602   (1,038) 1
Beginning balance, shares at Mar. 31, 2024     90.9          
Beginning balance at Mar. 31, 2024 707       1,561   (853) (1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Issuance of common stock (in shares)       0.4        
Issuance of common stock   1       1    
Stock-based compensation 20       20      
Net (loss) income (93)           (93)  
Ending balance, shares at Jun. 30, 2024     91.3          
Ending balance at Jun. 30, 2024 635       1,582   (946) (1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Issuance of common stock (in shares)       0.2        
Issuance of common stock   1       1    
Stock-based compensation 19       19      
Other comprehensive (loss) income 2             2
Net (loss) income (92)           (92)  
Ending balance, shares at Sep. 30, 2024     91.5          
Ending balance at Sep. 30, 2024 $ 565       1,602   (1,038) 1
Beginning balance, shares at Dec. 31, 2024 92.2   92.2          
Beginning balance at Dec. 31, 2024 $ 485       1,617   (1,132) 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Issuance of common stock (in shares)     13.6 0.1        
Issuance of common stock 142 0     142      
Stock-based compensation 16       16      
Net (loss) income (112)           (112)  
Ending balance, shares at Mar. 31, 2025     105.9          
Ending balance at Mar. 31, 2025 $ 531       1,775   (1,244) 0
Beginning balance, shares at Dec. 31, 2024 92.2   92.2          
Beginning balance at Dec. 31, 2024 $ 485       1,617   (1,132) 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Net (loss) income $ (247)              
Ending balance, shares at Sep. 30, 2025 107.1   107.1          
Ending balance at Sep. 30, 2025 $ 436       1,815   (1,379) 0
Beginning balance, shares at Mar. 31, 2025     105.9          
Beginning balance at Mar. 31, 2025 531       1,775   (1,244) 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Issuance of common stock (in shares)       0.5        
Issuance of common stock   $ 3       $ 3    
Stock-based compensation 15       15      
Net (loss) income 0              
Ending balance, shares at Jun. 30, 2025     106.4          
Ending balance at Jun. 30, 2025 549       1,793   (1,244) 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]                
Issuance of common stock (in shares)     0.7          
Issuance of common stock 8       8      
Stock-based compensation 14       14      
Net (loss) income $ (135)           (135)  
Ending balance, shares at Sep. 30, 2025 107.1   107.1          
Ending balance at Sep. 30, 2025 $ 436       $ 1,815   $ (1,379) $ 0
v3.25.3
Condensed Consolidated Statements of Cash Flows - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Cash flow from operating activities    
Net loss $ (247) $ (189)
Adjustments to reconcile net loss to net cash used in operating activities:    
Stock-based compensation expense 45 59
Depreciation and amortization 7 7
Noncash lease expense 5 5
Impairment of long-lived assets 0 20
Amortization of discounts on marketable securities (10) (19)
Other items, net 2 2
Changes in operating assets and liabilities:    
Receivable from collaboration partners ($6 and $18 from a related party) 9 32
Other assets ($— and $6 from a related party) 5 16
Accounts payable ($29 and $— to a related party) 24 (2)
Deferred revenue (($214) and ($20) to a related party) (214) (14)
Other liabilities 12 13
Net cash used in operating activities (362) (70)
Cash flow from investing activities    
Purchases of marketable securities (679) (871)
Proceeds from maturities of marketable securities 858 726
Proceeds from sales of marketable securities 70 15
Purchases of property and equipment (1) (5)
Net cash provided by (used in) investing activities 248 (135)
Cash flow from financing activities    
Proceeds from issuance of common stock ($14 and $228 from a related party) 150 228
Proceeds from debt issuances, net 49 47
Proceeds from issuance of common stock pursuant to equity award plans 3 6
Payments of employee taxes related to net settlement of equity awards 0 (2)
Net cash provided by financing activities 202 279
Net increase in cash, cash equivalents and restricted cash 88 74
Cash, cash equivalents and restricted cash at beginning of period 153 130
Cash, cash equivalents and restricted cash at end of period $ 241 $ 204
v3.25.3
Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Receivable from collaboration partners $ 9 $ 32
Other assets (5) (16)
Accounts payable 24 (2)
Deferred revenue (214) (14)
Proceeds from issuance of common stock 150 228
Related Party    
Receivable from collaboration partners 6 18
Other assets 0 6
Accounts payable 29 0
Deferred revenue (214) (20)
Proceeds from issuance of common stock $ 14 $ 228
v3.25.3
Organization, Liquidity and Capital Resources
9 Months Ended
Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Organization, Liquidity and Capital Resources Organization, liquidity and capital resources
Organization
Arcus Biosciences, Inc. (referred to as "Arcus," "we," "our," "us," or the "Company") is a clinical-stage biopharmaceutical company focused on creating best-in-class therapies. Using our robust and highly efficient drug discovery capability, we have created a significant portfolio of investigational products which are in clinical development, with our most advanced molecule, an anti-TIGIT antibody, now in multiple Phase 3 registrational studies targeting lung and gastrointestinal ("GI") cancers. Our deep portfolio of novel small molecules and enabling antibodies allows us to create highly differentiated therapies, which we are developing to treat multiple large indications.
We operate and manage our business as one reportable and operating segment, which is the business of developing and commercializing highly differentiated therapies that have a meaningful impact on patients. See Note 15, Business segment, for more information.
Liquidity and Capital Resources
As of September 30, 2025, we had cash, cash equivalents and marketable securities of $841 million, which we believe will be sufficient to fund our planned operations for a period of at least twelve months following the date of filing of this report.
v3.25.3
Summary of Significant Accounting Policies
9 Months Ended
Sep. 30, 2025
Accounting Policies [Abstract]  
Summary of Significant Accounting Policies Summary of significant accounting policies
Basis of Presentation
These interim financial statements should be read in conjunction with the audited Consolidated Financial Statements and the related notes thereto for the year ended December 31, 2024 included in our Annual Report on Form 10-K filed with the Securities and Exchange Commission ("SEC") on February 25, 2025. There have been no significant changes to our summary of significant accounting policies as disclosed in that filing.
These interim financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") for interim financial information and include all normal and recurring adjustments that management believes are necessary for a fair presentation of the periods presented. The Condensed Consolidated Balance Sheet as of December 31, 2024 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements.
Operating results for the three and nine months ended September 30, 2025 are not necessarily indicative of the results that may be expected for the year ending December 31, 2025 or for any future period.
Use of Estimates
The preparation of the Condensed Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosures. We base our estimates on historical experience and on various market-specific and other relevant assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Estimates are assessed and updated each period to reflect current information. Actual results may differ materially from those estimates.
Recent Accounting Pronouncements
In December 2023, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires disclosure of disaggregated income taxes paid, prescribes standard categories for the components of the effective tax rate reconciliation, and modifies other income tax-related disclosures. The standard will become effective for the fiscal year ending December 31, 2025, with early adoption permitted. We plan to adopt this guidance beginning with our 2025 Annual Report to be filed in early 2026. We are currently assessing the potential impact of the new standard on our Notes to our Consolidated Financial Statements.
In November 2024, the FASB issued ASU 2024-03 — Income Statement — Reporting Comprehensive Income — Expense Disaggregation Disclosures (Subtopic 220-40) — Disaggregation of Income Statement Expenses. This ASU requires disclosure, in the notes to financial statements, of specified information about certain costs and expenses. We plan to adopt this guidance beginning with our 2027 Annual Report to be filed in early 2028 and all quarterly and Annual Reports thereafter. We expect the adoption of this standard to result in increased disclosures in our Notes to our Consolidated Financial Statements.
In September 2025, the FASB issued ASU 2025-07 — Derivatives and Hedging (Topic 815) and Revenue from Contracts with Customers (Topic 606): Derivatives Scope Refinements and Scope Clarification for Share-Based Noncash Consideration from a Customer in a Revenue Contract. This ASU refines the scope of the guidance on derivatives in Topic 815 and clarifies the guidance on share-based payments from a customer in ASC 606. The standard will become effective for the fiscal year ending December 31, 2027, with early adoption permitted. We are currently assessing the potential impact of this new standard on our Consolidated Financial Statements.
v3.25.3
Related Party - Gilead Sciences, Inc.
9 Months Ended
Sep. 30, 2025
Related Party Transactions [Abstract]  
Related Party - Gilead Sciences, Inc. Related party - Gilead Sciences, Inc.
In 2020, we and Gilead entered into an Option, License and Collaboration Agreement (the "Gilead Collaboration Agreement"), Common Stock Purchase Agreement (the "Stock Purchase Agreement"), and Investor Rights Agreement (the "Investor Rights Agreement").
The Gilead Collaboration Agreement was amended in 2021 (the "First Gilead Collaboration Agreement Amendment"), in 2023 (the "Second Gilead Collaboration Agreement Amendment"), in the first quarter 2024 (the "Third Gilead Collaboration Agreement Amendment") and in the second quarter 2024 (the "Fourth Gilead Collaboration Agreement Amendment").
The Stock Purchase Agreement was amended in 2021 (the "First Stock Purchase Agreement Amendment"), in 2023 (the "Second Stock Purchase Agreement Amendment"), and was amended and restated in the first quarter 2024 (the "Third Stock Purchase Agreement Amendment"). Gilead’s right to purchase shares under the Third Stock Purchase Agreement Amendment expired in July 2025.
The Investor Rights Agreement was amended in 2022 (the "First Investor Rights Agreement Amendment") and was amended and restated in the first quarter 2024 (the "Second Investor Rights Agreement Amendment").
We refer to these agreements collectively as the Gilead Agreements.
Stock Purchase and Investor Rights Agreements
In the first quarter 2024, under the Third Stock Purchase Agreement Amendment, Gilead purchased 15.2 million shares of our common stock for total gross proceeds of $320 million, of which $87 million was determined to be a premium on the purchase of common stock and allocated to the performance obligations created by the Third Gilead Collaboration Agreement Amendment.
In the first quarter 2025, through our underwritten offering, Gilead purchased 1.4 million shares of our common stock for total gross proceeds of $15 million.
Gilead had the right under the Stock Purchase Agreement and the related amendments, which expired in July 2025, to purchase up to a maximum of 35% of the Company’s then-outstanding voting common stock, at a purchase price equal to the greater of a 20% premium to market (based on a trailing five-day average closing price at option exercise) or the $33.54 initial purchase price. Based on the value of our common stock at each contract closing, the right to purchase additional shares had no value. Under the Investor Rights Agreement entered into in 2020 and subsequent amendments, Gilead has: the right to designate three members of our board of directors; registration rights for shares that it purchases; and had pro rata participation rights in certain future financings that expired in July 2025. Gilead has exercised its rights to appoint all three board members and we have registered all shares purchased to date.
As of September 30, 2025, Gilead held approximately 29.3% of our outstanding common stock arising from purchases in our public offerings and under the Stock Purchase Agreement and related amendments.
Collaboration Agreements
In 2020, we entered into the Gilead Collaboration Agreement, which gave Gilead an exclusive license to develop and commercialize zimberelimab (the anti PD-1 program) in certain markets and time-limited options to acquire exclusive licenses to develop and commercialize any of our then-current and future clinical programs arising during the 10-year collaboration term, contingent upon $100 million option continuation payments payable on each of the second, fourth, sixth and eighth anniversaries of the agreement. Upon closing of the transaction in 2020, Gilead made an upfront payment of $175 million.
In 2021, we entered into the First Gilead Collaboration Agreement Amendment pursuant to which Gilead exercised its option to three programs—providing Gilead with exclusive licenses to develop and commercialize domvanalimab and AB308 (collectively, the anti-TIGIT program), etrumadenant (the adenosine receptor antagonist program) and quemliclustat (the CD73 program), in certain markets—for a total payment of $725 million that was received in 2022. The amendment also (i) provided for a slight reduction in the royalties for these three programs, such that Gilead will pay us tiered royalties as a percentage of revenues ranging from the mid-teens to the low twenties; and (ii) removed the $100 million option continuation payment that was otherwise due on the second anniversary of the Gilead Collaboration Agreement. With respect to domvanalimab, we are also eligible to receive up to $500 million in potential U.S. regulatory approval milestones.
Gilead's option to acquire exclusive licenses to develop and commercialize any of our clinical programs arising during the collaboration term, on a program-by-program basis, will expire after a prescribed period following the achievement of a clinical development milestone in such program and our delivery to Gilead of the requisite data package. Gilead may exercise its option to any program at any time prior to expiration of the option and will pay Arcus an option fee of $150 million per program.
For each program that Gilead opts in to, both companies will co-develop and equally share global development costs, subject to certain opt-out rights that we have, caps on our spending and related subsequent adjustments, and certain other exceptions. For each program, provided we have not exercised our opt-out rights, we have the option to co-promote in the U.S. with equal sharing of related profits and losses. Gilead has the right to exclusively commercialize outside of the U.S., subject to the rights of our existing partners in any territories and will pay us tiered royalties as a percentage of revenues ranging from the high teens to the low twenties.
Under the First Gilead Collaboration Agreement Amendment, Gilead also has option rights to two oncology research programs for which we will lead discovery and early development activities. With respect to these two research programs, Gilead has the right to exercise its option, on a program-by-program basis, either (i) upon our completion of certain investigational new drug ("IND")-enabling activities for an option payment of $60 million or (ii) following the achievement of a clinical development milestone for an option payment of $150 million.
In 2023, we entered into the Second Gilead Collaboration Agreement Amendment pursuant to which we expanded our collaboration to provide Gilead with options to license up to four jointly selected research-stage programs that target inflammatory diseases for which we will lead discovery and early development activities. We will receive an upfront payment of $17.5 million for each initiated program and Gilead will have an option to license each program at two separate, prespecified time points. For the first two research programs, Gilead has the right, on a program-by-program basis, either (i) to exercise its option upon our completion of certain IND-enabling activities for an option payment of $45 million or (ii) to extend its option and exercise it following the achievement of a clinical development milestone for an option payment of $150 million. If Gilead exercises its option at the earlier time point for the first two programs, we would be eligible to receive up to $375 million in regulatory and commercial milestone payments as well as tiered royalties for each optioned program. For any other program option exercise by Gilead, the parties would have rights to co-develop and share global development costs and to co-promote and share profits in the U.S. for that program. We received a total upfront payment of $35 million for an initial two research programs in 2023. Gilead’s options to the other two research programs, as amended under the Fourth Gilead Collaboration Agreement Amendment expired in May 2025.
In the first quarter 2024, we entered into the Third Gilead Collaboration Agreement Amendment. The Third Gilead Collaboration Agreement Amendment, among other things, (i) required Gilead to pay the $100 million option continuation payment due on the fourth anniversary of the Gilead Collaboration Agreement, which was received in the third quarter 2024 (ii) provides that we will operationalize and fund the Phase 3 PRISM-1 study evaluating quemliclustat in pancreatic cancer subject to Gilead's right to reinstate the study as part of the parties' joint development activities upon regulatory approval, (iii) provides that we will solely fund our share of PACIFIC-8, subject to Gilead’s right to reinstate PACIFIC-8 as part of the parties’ joint development activities for the TIGIT Program in the first quarter 2026, and (iv) provides that we will fund certain other activities. All other terms of the existing collaboration agreements, remain unchanged.
As of September 30, 2025, Gilead has licenses to domvanalimab, AB308, quemliclustat and zimberelimab. In the second quarter 2025, Gilead returned its license to the adenosine receptor antagonist program, which includes etrumadenant. In the first quarter 2025, Gilead's time-limited exclusive option rights to our HIF-2α program, which includes casdatifan, expired.
For the three and nine months ended September 30, 2025, under the Gilead Agreements we recognized revenue of $26 million and $214 million, respectively, and for the three and nine months ended September 30, 2024, we recognized revenue of $30 million and $207 million, respectively. For the three and nine months ended September 30, 2025, we recognized net expense to Gilead of $16 million and $24 million, respectively, and for the three and nine months ended September 30, 2024, we recognized net reimbursements from Gilead of $2 million and $32 million, respectively, in Operating expense, allocated between R&D and General and Administrative ("G&A") based upon the activity that generated the net expense or reimbursement.
At September 30, 2025, we had a net payable to Gilead of $29 million, recorded in Accounts payable on our Condensed Consolidated Balance Sheets. At December 31, 2024, we had a net receivable from Gilead of $6 million, recorded in Receivable from collaboration partners on our Condensed Consolidated Balance Sheets.
For a more detailed discussion on revenues recognized under the Gilead Agreements, see Note 5, Revenues, for more information.
v3.25.3
License and Collaborations
9 Months Ended
Sep. 30, 2025
License and Collaboration Agreements [Abstract]  
License and Collaborations License and collaborations
We enter into licensing agreements, strategic collaborations and other similar arrangements with third parties for the development and commercialization of certain investigational products. These arrangements: may be collaborative and involve two or more parties who are active participants in the operating activities of the collaboration and are exposed to significant risks and rewards depending on the commercial success of the activities; are performed with no guarantee of either technological or commercial success; and are each unique in nature. Such arrangements may include: non-refundable upfront payments; payments for options to acquire certain rights; potential development and regulatory milestone payments and/or sales-based milestone payments; royalty payments; revenue or profit-sharing arrangements; expense reimbursements; and cost-sharing arrangements.
Operating expenses for costs incurred pursuant to these arrangements are reported in their respective expense line items in the Condensed Consolidated Statements of Operations, net of any payments due to or reimbursements due from our collaboration partners, with such reimbursements being recognized at the time the party becomes obligated to pay.
Our significant arrangements are discussed below. For a more detailed discussion on revenues recognized under these arrangements, see Note 5, Revenues.
Gilead Collaboration
See Note 3, Related party - Gilead Sciences, Inc., for more information.
Taiho Collaboration
In 2017, we entered into an agreement with Taiho Pharmaceutical Co., Ltd ("Taiho") under which we granted them exclusive options to programs arising over a five-year period which ended in September 2022 for an upfront payment of $35 million. Upon exercising their option to a program, Taiho would obtain exclusive development and commercialization rights to investigational products under the program to Japan and certain other Asian countries (excluding China) (the "Taiho Territory").
For each option to a program that Taiho exercises, except for casdatifan (the HIF-2α program) see below, they will be obligated to make a payment of $3 million to $15 million, depending on the development stage of the optioned program. Upon exercise, Taiho is solely responsible for continued development and commercialization in the Taiho Territory, unless they opt to participate in a global study, in which case they would become obligated to reimburse us for their portion of the global study costs. In addition, for each optioned program we would be eligible to receive clinical and regulatory milestones of up to $130 million and commercial milestone payments of up to $145 million with the achievement of certain sales thresholds in the Taiho Territory. We will also receive royalties ranging from high single-digits to mid-teens on net sales of licensed products in the Taiho Territory. Royalties will be payable by product and country commencing on the first commercial sale and ending upon the later of: (a) 10 years; and (b) expiration of the last-to-expire valid claim of our patents covering the manufacture, use or sale.
As of September 30, 2025, Taiho has licenses for the Taiho Territory to (i) etrumadenant (the adenosine receptor antagonist program); (ii) zimberelimab (the anti PD-1 program); (iii) domvanalimab and AB308 (the anti-TIGIT program); and (iv) quemliclustat (the CD73 program), for which Taiho exercised its option and made an option payment of $15 million in the third quarter 2024.
In October 2025, Taiho exercised its option for casdatifan (the HIF-2α program) for the Taiho Territory, for an option payment of $15 million, payable in the fourth quarter 2025. We and Taiho concurrently entered into the Second Amendment where we will lead development for two indications in Japan and we may also be eligible to receive clinical and regulatory milestones of up to $172 million, commercial milestone payments of up to $145 million with the achievement of certain sales thresholds in the Taiho Territory and royalties ranging from high single-digits to mid-teens on net sales of the licensed product in the Taiho Territory. We will be responsible for the global study costs.
In 2022, Taiho opted to participate in two global Phase 3 trials of domvanalimab and zimberelimab combinations, STAR-121 and STAR-221, and became obligated to reimburse us for their portion of the global study costs, and to make milestone payments contingent upon successfully satisfying the related clinical milestones. The clinical milestones for domvanalimab and zimberelimab for the STAR-221 study were met in 2023, and Taiho became obligated to pay us $28 million which has been fully received. The clinical milestones for domvanalimab and zimberelimab for the STAR-121 study were met in the first quarter 2024 and Taiho became obligated to pay us $26 million, of which $16 million was received in the first quarter 2024 and the remaining $10 million was received in the first quarter 2025. In the third quarter 2024, Taiho opted to participate in the global Phase 3 trial of quemliclustat, PRISM-1, and became obligated to reimburse us for their portion of the global study costs and in the first quarter 2025, Taiho dosed their first patient in Japan for PRISM-1, and became obligated to make milestone payments totaling $19 million of which $12 million was received in the first quarter 2025 and the remaining $7 million is due in the first quarter 2026. Due to the nature of this arrangement, these clinical milestones were determined to be advance cost sharing payments for a portion of the related global study Research and Development ("R&D") costs under the collaboration and are deferred and recognized as a reduction in R&D expense as the related global studies are performed, calculated as an estimated percentage of completion based on the estimated total effort for the programs.
We recognized net reimbursements including amortization of advance cost sharing payments from Taiho for the three months ended September 30, 2025 and 2024 of $7 million and $3 million, respectively, and for the nine months ended September 30, 2025 and 2024 of $24 million and $10 million, respectively, recognized as a reduction in R&D expense. For the three and nine months ended September 30, 2024, we recognized revenue of $18 million and $25 million, respectively under this arrangement.
At September 30, 2025 and December 31, 2024, we had $11 million and $14 million, respectively, related to these agreements recorded in Receivable from collaboration partners on our Condensed Consolidated Balance Sheets. At September 30, 2025 and December 31, 2024, we had liabilities of $42 million and $36 million, respectively related to certain advance cost sharing payments under this arrangement recorded in Other liabilities, allocated between current and noncurrent based on the expected timing of future recognition.
AstraZeneca Collaboration
In 2020, we entered into a collaboration with AstraZeneca to evaluate domvanalimab, our investigational anti-TIGIT antibody, in combination with AstraZeneca’s durvalumab in a registrational Phase 3 clinical trial in patients with unresectable Stage 3 non-small cell lung cancer ("NSCLC"), known as the PACIFIC-8 trial. The terms of this agreement were amended in the first quarter 2024.
Under the collaboration, as amended, each company will retain existing rights to their respective molecules and any future commercial economics. AstraZeneca will conduct the trial, and each company will supply their respective investigational product to support the trial. We may incur milestones of up to $24 million upon the achievement of certain clinical trial progress milestones or under certain circumstances if the agreement is terminated early and we will reimburse AstraZeneca annually for a portion of the trial costs. The portion of the costs that we consider to be unavoidable are accrued as incurred and milestones that are deemed probable of occurring are accrued in advance of the achievement of the milestone.
Prior to January 2024, the PACIFIC-8 trial formed part of the Arcus and Gilead joint development program for domvanalimab and our portion of the trial costs were shared with Gilead. At December 31, 2023, we had recognized amounts due from Gilead for these shared costs of $6 million, recorded in Other noncurrent assets on our Consolidated Balance Sheet. Under the Third Gilead Collaboration Agreement Amendment, we agreed to solely fund our share of PACIFIC-8, subject to Gilead’s right to reinstate PACIFIC-8 as part of the parties’ joint development activities for the TIGIT Program in the first quarter 2026. For the nine months ended September 30, 2024, we incurred $6 million under the Third Gilead Collaboration Agreement as R&D expense, reflecting our additional share of costs previously shared with Gilead.
We recognized R&D expense for the three months ended September 30, 2025 and 2024 of $7 million and $4 million, respectively, and for the nine months ended September 30, 2025 and 2024 of $16 million and $10 million, respectively under this arrangement.
At September 30, 2025 and December 31, 2024, we recognized a total liability of $28 million and $26 million, respectively, related to our obligation to AstraZeneca, recorded in Other current liabilities and Other noncurrent liabilities on our Condensed Consolidated Balance Sheets based on the expected timing of payment.
WuXi Biologics License - anti-PD-1
In 2017, we entered into an agreement with WuXi Biologics Ireland Limited ("WuXi Biologics") which, as amended, provides us with exclusive rights to (i) develop, use and manufacture products that include an anti-PD-1 antibody, including zimberelimab, worldwide and (ii) commercialize any such products worldwide, except in Greater China. As of September 30, 2025, under this arrangement, we may incur (i) additional regulatory milestone payments of up to $50 million and commercialization milestone payments of up to $375 million, (ii) tiered royalties that range from the high single-digits to low teens on net sales of the licensed products and (iii) fees related to any sublicenses.
We did not have any milestones or royalties due under this arrangement for the three and nine months ended September 30, 2025 and 2024.
WuXi Biologics License - anti-CD39
In 2020, we entered into an agreement with WuXi Biologics, under which we obtained the exclusive worldwide license to develop and commercialize anti-CD39 antibodies discovered under this arrangement. As of September 30, 2025, we may incur additional clinical and regulatory milestone payments of up to $14 million and royalty payments in the low single digits on net sales of the licensed products under this agreement.
We did not have any milestones or royalties due under this arrangement for the three and nine months ended September 30, 2025 and 2024.
Abmuno License
In 2016, we entered into an agreement (the "Abmuno Agreement") with Abmuno Therapeutics LLC ("Abmuno"), under which we obtained the exclusive worldwide license to develop, use, manufacture, and commercialize products that include an anti-TIGIT antibody, including domvanalimab. As of September 30, 2025, under this arrangement we may incur additional clinical, regulatory and commercialization milestone payments of up to $88 million.
We did not have any milestones due under this arrangement for the three and nine months ended September 30, 2025 and 2024.
v3.25.3
Revenues
9 Months Ended
Sep. 30, 2025
Revenue from Contract with Customer [Abstract]  
Revenues Revenues
The following table summarizes our revenues by collaboration, category of revenue, and the method of recognition (in millions):
Three Months Ended September 30,Nine Months Ended September 30,
Over timePoint in time2025202420252024
Gilead collaboration      
License and R&D services* $23 $25 $200 $185 
Access rights* 14 22 
Taiho collaboration      
License revenue*— 15 — 15 
Other*— — 10 
Total revenues  $26 $48 $214 $232 
Total revenues from collaborations$20 $41 $192 $204 
Total revenues from a customer$$$22 $28 
Revenues from Gilead accounted for 100% and 63% of Total revenues for the three months ended September 30, 2025 and 2024, respectively and 100% and 89% of Total revenues for the nine months ended September 30, 2025 and 2024, respectively.
The following table summarizes the revenue recognized as a result of changes in the deferred revenue balance (in millions):
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Revenue recognized from amounts in deferred revenue at the beginning of the period$26 $33 $214 $212 
We had $105 million and $319 million of deferred revenue remaining on our Condensed Consolidated Balance Sheets at September 30, 2025 and December 31, 2024, respectively, allocated between current and noncurrent based on the expected timing of future recognition.
Revenue from the Gilead Collaboration
In the first quarter 2025, we decided to pause future development of etrumadenant. In June 2025, Gilead terminated its rights to etrumadenant (the adenosine receptor antagonist program). We determined that this was a significant reduction in the scope of the arrangement, which met the accounting definition of a contract modification. As a result, we accounted for this as both a modification of the existing contract and the creation of a new contract. Under the applicable accounting rules for such contract modifications, we did not adjust the accounting for completed performance obligations that were distinct from the modified goods or services. Accordingly, we allocated the updated transaction price of $256 million, which was comprised of the deferred revenue remaining as of the modification date, to the remaining unsatisfied and partially satisfied performance obligations and updated the measure of progress as of the modification date, which resulted in a cumulative catch-up to revenue of $143 million. This cumulative catch-up reduced net loss per share, basic and diluted, in the nine months ended September 30, 2025 by $1.38. See Note 3, Related party - Gilead Sciences, Inc., for more information.
The following table summarizes the allocation of the updated transaction price to the remaining unsatisfied and partially satisfied performance obligations (in millions):
Allocation to performance obligationsDistinctCombinedAmount
License and R&D services*$192 
R&D services*17
Access rights and option continuation periods*30
Rights to certain studies*17
Total allocated transaction price$256 
We account for these performance obligations as follows:
License and R&D Services - Etrumadenant, Quemliclustat and Domvanalimab
Under the Gilead Collaboration Agreement, Gilead obtained options to the exclusive rights: to our adenosine receptor antagonist program, etrumadenant; to our CD73 program, quemliclustat; and to our anti-TIGIT program, domvanalimab and AB308. Effective December 2021, under the First Gilead Collaboration Agreement Amendment, Gilead exercised these options and obtained exclusive licenses to these programs for a total non-refundable payment totaling $725 million.
We determined the standalone selling price of each license using a discounted cash flow method and the R&D services for each program, using an expected cost-plus margin approach. For domvanalimab, we determined that the license was distinct based on an evaluation of the delivery of the license, noting that the program was in the later stages of development and the ongoing R&D services do not significantly modify or customize the related intellectual property. For etrumadenant and quemliclustat programs, we determined that the license and R&D services were combined at the inception of the agreement based on an evaluation of the delivery of the license, due to the early stage of the technology and the specialized nature of our know-how. We recognize the amounts allocated to R&D services for domvanalimab and the combined license and R&D for etrumadenant and quemliclustat as each performance obligation is satisfied, calculated as an estimated percentage of completion based on management's estimated total effort for each program.
Effective June 2025, these performance obligations were partially satisfied and we allocated the updated transaction price to these performance obligations based on their standalone selling prices and adjusted revenue based on an updated measure of progress, which resulted in a cumulative catch-up of revenue of $143 million.
For the three and nine months ended September 30, 2025, we recognized revenue of $20 million and $192 million respectively, (including the cumulative catch-up due to Gilead's termination of its rights to etrumadenant). For the three and nine months ended September 30, 2024, we recognized revenue of $23 million and $179 million (including the cumulative catch-up due to the Third Gilead Collaboration Agreement Amendment executed in the first quarter 2024), respectively. This was recognized within License and development services revenue in our Condensed Consolidated Statements of Operations.
Access Rights and Option Continuation Periods
Under the Gilead Collaboration Agreement entered into in 2020 and related amendments, Gilead has exclusive access to our current programs as well as future programs for a period of ten years, contingent upon option continuation payments totaling $300 million, consisting of a $100 million payment on each of the fourth (paid in July 2024), sixth, and eighth anniversaries of the Gilead Collaboration Agreement.
The standalone selling price of the ongoing R&D pipeline access and the option continuation material rights were determined using an expected cost-plus margin approach, with the option continuation material rights probability-adjusted for the likelihood of exercise. We use a time-elapsed input method to measure progress toward satisfying the access rights performance obligation, which is the method we believe most faithfully depicts our performance in transferring the promised services during the time period in which Gilead has access to our R&D pipeline. Accordingly, the revenue allocated to the initial four-year access rights performance obligation was recognized using this input method over the remaining period through July 2024, and for the fourth anniversary access rights continuation, over the two-year period commencing July 2024. For the remaining access rights option continuation periods commencing on the sixth, and eighth anniversaries of the agreement, if Gilead elects to exercise their option, we will recognize the revenue allocated to that option together with the $100 million continuation payment over the new minimum access period or immediately if the option lapses.
For the three and nine months ended September 30, 2025, we recognized revenue of $3 million and $14 million respectively. For the three and nine months ended September 30, 2024, we recognized revenue of $5 million and $22 million, respectively. This was recognized within Other collaboration revenue in our Condensed Consolidated Statements of Operations.
Rights to Certain Studies
Effective January 2024, under the Third Gilead Collaboration Agreement Amendment, we will solely fund certain studies, but Gilead retains exclusive rights to reinstate into the collaboration each study at specified time-points for a payment.
We have determined that these are material rights and we estimated the standalone selling price of these performance obligations using a discounted cash flow method probability-adjusted for the likelihood of exercise. We will recognize the amount allocated to each right if and when the related study is reinstated into the parties' co-development plans or if the option lapses.
As of September 30, 2025, we have $17 million of deferred revenue on our Condensed Consolidated Balance Sheet related to these performance obligations.
R&D Services - Inflammation Programs
In May 2023, we entered into the Second Gilead Collaboration Agreement Amendment pursuant to which we expanded our collaboration to provide Gilead with options to license up to four jointly selected research-stage programs that target inflammatory diseases for which we will lead discovery and early development activities, see Note 3, Related party - Gilead Sciences, Inc., for more information. In 2023, we received a total upfront payment of $35 million for an initial two jointly selected research-stage programs. We determined that the Second Gilead Collaboration Agreement Amendment represented a separate contract.
We determined that we have two separate distinct performance obligations to perform R&D services for Gilead related to discovery and early development activities for each research program for which they have made an upfront payment and, at the amendment closing date, we allocated the transaction price of $35 million equally to the two performance obligations created by this amendment based upon there standalone selling prices. The standalone selling prices of these obligations were determined using an expected cost-plus margin approach. We recognize the amounts allocated to these services as the performance obligation is satisfied, calculated as an estimated percentage of completion based on management's estimated total effort for the program. The options to acquire additional licenses or services did not result in additional performance obligations because they did not provide a material right at contract inception, primarily due to the very early stages of the programs.
For the three and nine months ended September 30, 2025, we recognized revenue of $3 million and $8 million respectively. For the three and nine months ended September 30, 2024, we recognized revenue of $2 million and $6 million, respectively. This was recognized in Other collaboration revenue in our Condensed Consolidated Statements of Operations.
v3.25.3
Income Taxes
9 Months Ended
Sep. 30, 2025
Income Tax Disclosure [Abstract]  
Income Taxes Income taxes
The income tax provision or benefit for interim periods is determined using an estimate of our annual effective tax rate, adjusted for discrete items, if any, that are taken into consideration in the relevant period. Each quarter, we update the estimate of the annual effective tax rate, and if the estimated tax rate changes, we record a cumulative adjustment to the provision or benefit.
The One Big Beautiful Bill Act of 2025 ("OBBBA") was enacted on July 4, 2025. The OBBBA contains several changes to corporate taxation, including permanent repeal of the requirement to capitalize domestic research and experimental expenditures for federal income tax purposes for taxable years beginning after December 31, 2024. The OBBBA does not materially impact the Company's effective tax rate or cash flows in the current fiscal year.
We did not record a provision for income taxes for the three and nine months ended September 30, 2025 and 2024 because of forecasted full year net operating losses ("NOLs"), which consider the timing of recognition of deferred revenue for tax purposes and the effects of the option to capitalize and amortize U.S. R&D expenses as allowed by the OBBBA. The effective tax rate differs from the U.S. statutory tax rate primarily due to the valuation allowances on our deferred tax assets and state income taxes.
As of September 30, 2025 and December 31, 2024, we have provided a valuation allowance against U.S. federal and state deferred tax assets. We continue to evaluate the realizability of deferred tax assets and the related valuation allowance. If our assessment of the deferred tax assets or the corresponding valuation allowance were to change, we would record the related adjustment to income during the period in which we make the determination.
We recognize interest and penalties associated with uncertain tax benefits as part of the income tax provision. To date, we have not recognized any interest and penalties, nor have we accrued for or made payments for interest and penalties.
We have not been audited by the Internal Revenue Service, any state, or foreign tax authority. We are subject to taxation in the U.S. and in Australia. Due to NOLs and research credit carryforwards, all of our tax years, from 2015 to 2024, remain open to U.S. federal and California state tax examinations. In addition, our fiscal years from 2020 to 2024 are open to examination in Australia.
v3.25.3
Net Loss Per Share
9 Months Ended
Sep. 30, 2025
Earnings Per Share [Abstract]  
Net Loss Per Share Net loss per share
The following table summarizes potentially dilutive securities excluded from the computation of diluted net loss per share calculations because they would have been antidilutive (in millions):
September 30, 2025September 30, 2024
Common stock options issued and outstanding17.315.5
Restricted stock units issued3.93.0
Employee stock purchase plan shares0.20.2
Total potential dilutive securities21.418.7
We have also excluded the effect of Gilead’s right to purchase additional shares of our common stock which expired in July 2025, from the calculation as these rights had no intrinsic value at September 30, 2024.
v3.25.3
Stock-Based Compensation
9 Months Ended
Sep. 30, 2025
Share-Based Payment Arrangement [Abstract]  
Stock-Based Compensation Stock-based compensation
Stock-based Compensation Expense
The following table reflects the components of stock-based compensation expense recognized in our Condensed Consolidated Statements of Operations (in millions):
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Research and development$$$23 $29 
General and administrative10 22 30 
Total stock-based compensation$14 $19 $45 $59 
v3.25.3
Cash, Cash Equivalents and Marketable Securities
9 Months Ended
Sep. 30, 2025
Cash, Cash Equivalents and Marketable Securities [Abstract]  
Cash, Cash Equivalents and Marketable Securities Cash, cash equivalents and marketable securities
The following table summarizes the amortized cost, gross unrealized gains and losses and the fair value of our cash, cash equivalents and marketable securities, all of which are considered available for sale, by type of securities (in millions):
Types of securities as of September 30, 2025
Amortized
Cost
Unrealized
Gain
Unrealized
Loss
Fair
Value
Money market funds$171 $— $— $171 
U.S. treasury securities246 — — 246 
Corporate securities and commercial paper406 — — 406 
Certificate of deposit18 — — 18 
Total cash, cash equivalents and marketable securities$841 $— $— $841 
Types of securities as of December 31, 2024
Amortized
Cost
Unrealized
Gain
Unrealized
Loss
Fair
Value
Money market funds$120 $— $— $120 
U.S. treasury securities251 — — 251 
Corporate securities and commercial paper592 — — 592 
U.S. government agency securities— — 
Certificate of deposit24 — — 24 
Total cash, cash equivalents and marketable securities$992 $— $— $992 
The following table summarizes the fair values of our cash, cash equivalents and marketable securities by location in the Condensed Consolidated Balance Sheets and contractual maturity (in millions):
Location in Condensed Consolidated Balance SheetsContractual MaturitySeptember 30, 2025December 31, 2024
Cash and cash equivalents$238 $150 
Marketable securitiesWithin one year593 828 
Long-term marketable securitiesBetween one and three years10 14 
Total cash, cash equivalents and marketable securities $841 $992 
Realized gains or losses recognized on the sale of available-for-sale marketable securities were not material for the three and nine months ended September 30, 2025 and 2024 and are included in Interest and other income, net, in the Condensed Consolidated Statements of Operations. The cost of a security sold is determined using the specific-identification method.
We limit the credit risk associated with our investments by placing them with banks and institutions we believe are highly credit worthy and investing in highly rated investments. We held a total of 21 and 54 positions in securities which were in unrealized loss positions as of September 30, 2025 and December 31, 2024, respectively, which were immaterial individually and in aggregate. We do not intend to sell our securities with unrealized loss positions and have concluded we will not be required to sell the securities before recovery of the amortized cost for the investment at maturity. No credit related losses have been recognized for any of the periods presented.
The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the Condensed Consolidated Balance Sheets to the total shown in the Condensed Consolidated Statements of Cash Flows (in millions):
As of September 30,
20252024
Cash and cash equivalents$238 $201 
Restricted cash (included in Other noncurrent assets)
Total cash, cash equivalents and restricted cash$241 $204 
Restricted cash at September 30, 2025 and 2024 represents cash balances held as security in connection with our facility lease agreements.
v3.25.3
Condensed Consolidated Balance Sheet Components
9 Months Ended
Sep. 30, 2025
Balance Sheet Related Disclosures [Abstract]  
Condensed Consolidated Balance Sheet Components Condensed consolidated balance sheet components
Prepaid Expenses and Other Current Assets
Prepaid expenses and other current assets consisted of the following (in millions):
September 30, 2025December 31, 2024
Prepaid expenses and other assets$12 $13 
Accrued interest receivable
Total prepaid expenses and other current assets$15 $18 
Other Current Liabilities
Other current liabilities consisted of the following (in millions):
September 30, 2025December 31, 2024
Accrued research and development$84 $65 
Accrued personnel expenses28 31 
Current portion of lease liabilities13 12 
Other16 15 
Total other current liabilities$141 $123 
v3.25.3
Long-Term Debt
9 Months Ended
Sep. 30, 2025
Debt Disclosure [Abstract]  
Long-Term Debt Long-term debt
The following table summarizes our borrowings (in millions):
September 30, 2025December 31, 2024
Long-term debt, non-current (Contractual maturity 2029)$100 $50 
Unamortized discounts, issuance costs and payment-in-kind interest, net
(2)(2)
Total long-term debt$98 $48 
On August 27, 2024, we and Hercules Capital, Inc. ("Hercules") entered into a loan and security agreement (the "Hercules Agreement"), under which Hercules agreed to lend us up to $250 million in term loans in various tranches subject to minimum draw requirements for each tranche. Under the terms of this agreement, $50 million was drawn at closing and $50 million was drawn in the second quarter 2025, with an additional $50 million committed and fully available at our sole option in minimum increments of $25 million. A second tranche of $100 million will be available subject to future approval by Hercules.
The term loans have an interest only period for the first 48 months from the agreement date and bear cash interest at a rate equal to the greater of (i) 10.45% or (ii) the prime rate plus 1.95%. The agreement allows us to defer up to 2.0% of the cash interest as payment-in-kind interest which is added to the principal at a 1.10 multiple and effective July 1, 2025, we have elected the maximum payment-in-kind deferral.
The aggregate future minimum payments due under the Hercules Agreement, including principal payments, payment-in-kind interest incurred to date, and the end of term charge, are as follows (in millions):
Maturity DateAmount
2028$30 
202978 
Total payments$108 
During the three and nine months ended September 30, 2025, we recognized $4 million and $7 million of interest expense, respectively. During the three and nine months ended September 30, 2024, we recognized $1 million of interest expense. The effective interest rate of the debt, including payment-in-kind interest, amortization of the debt discount, and issuance costs, was 13.08% commencing with the quarter ended September 30, 2025 compared to 13.39% for the quarters ended March 31, 2025 and prior.
v3.25.3
Leases
9 Months Ended
Sep. 30, 2025
Leases [Abstract]  
Leases Leases
The following table summarizes our cash and non-cash information related to our operating leases (in millions):
Nine Months Ended September 30,
20252024
Cash paid for amounts included in measurement of lease liabilities$13 $12 
In the first quarter 2024, we evaluated our plans for a portion of our office space that we expected to sublease, and identified indicators of impairment to certain right-of-use assets associated with the leased space where the asset value was determined to be non-recoverable based upon a discounted cash flow analysis, resulting in an impairment charge of $20 million for the three months ended March 31, 2024 and the nine months ended September 30, 2024.
As of September 30, 2025 and December 31, 2024, we have provided deposits for letters of credit totaling $3 million to secure our obligations under our leases, which are included in Other noncurrent assets on the Condensed Consolidated Balance Sheets.
v3.25.3
Stockholders' Equity
9 Months Ended
Sep. 30, 2025
Stockholders' Equity Note [Abstract]  
Stockholders' Equity Stockholders' equity
Common Stock
Gilead Stock Purchase Agreement
In the first quarter 2024, under the Third Stock Purchase Agreement Amendment, Gilead purchased 15.2 million shares of our common stock at a price of $21.00 per share for total gross proceeds of $320 million. Of the $320 million equity investment, $87 million was determined to be a premium on the purchase of common stock and allocated to the performance obligations created by the Third Gilead Collaboration Agreement Amendment, see Note 5, Revenues, for more information. Net proceeds from Gilead's equity investment were $228 million after allocating the premium and deducting direct offering expenses of $5 million.
Underwritten Offering
In the first quarter 2025, we sold through an underwritten offering, 13.6 million shares of our common stock at a price per share of $11.00, for total gross proceeds of approximately $150 million, before deducting underwriting discounts, commissions and offering expenses. As part of this underwritten offering, Gilead purchased 1.4 million shares of our common stock for total gross proceeds of $15 million.
At-the-Market Facility
In the third quarter 2025, we issued and sold under our equity distribution agreement 0.6 million shares of our common stock for total gross and net proceeds of $8 million.
v3.25.3
Fair Value Measurements
9 Months Ended
Sep. 30, 2025
Fair Value Disclosures [Abstract]  
Fair Value Measurements Fair value measurements
We determine the fair value of financial and non-financial assets and liabilities using the fair value hierarchy, which establishes three levels of inputs that may be used to measure fair value, as follows:
Level 1 inputs include unadjusted quoted prices in active markets for identical assets or liabilities;
Level 2 inputs include observable inputs other than Level 1 inputs, such as quoted prices for similar assets or liabilities; quoted prices for identical or similar assets or liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the asset or liability; and
Level 3 inputs include unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the underlying asset or liability. Our Level 3 assets and liabilities include those whose fair value measurements are determined using pricing models, discounted cash flow methodologies or similar valuation techniques and significant management judgment or estimation.
Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement.
The following tables summarize the types of assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy (in millions):
Fair value measurement as of September 30, 2025Level 1Level 2Level 3Total
Assets
Money market funds$171 $— $— $171 
U.S. treasury securities— 246 — 246 
Corporate securities and commercial paper— 406 — 406 
Certificate of deposit— 18 — 18 
Total assets measured at fair value$171 $670 $— $841 
Fair value measurement as of December 31, 2024Level 1Level 2Level 3Total
Assets
Money market funds$120 $— $— $120 
U.S. treasury securities— 251 — 251 
Corporate securities and commercial paper— 592 — 592 
U.S. government agency obligations— — 
Certificate of deposit— 24 — 24 
Total assets measured at fair value$120 $872 $— $992 
Liabilities    
Liability for sale of future royalties$— $— $21 $21 
Total liabilities measured at fair value$— $— $21 $21 
Liability for sale of future royalties
In 2021, we entered into an agreement with BVF Partners L.P. ("BVF"), under which BVF funded the discovery and development of compounds for the treatment of inflammatory diseases (the "BVF Program") for $15 million in non-refundable payments. In return, we were obligated to: perform R&D activities in the BVF Program; make contingent payments upon the achievement of certain clinical and regulatory milestones; and pay mid- to high-single digit royalties on any net product sales generated by this program. We account for the BVF agreement as a liability primarily because at the time the agreement was entered into we had significant continuing involvement in generating the cash flows due to BVF.
During the first quarter 2025, new preclinical information led to the decision to discontinue the BVF Program which decreased the likelihood of achieving regulatory and commercial success. These changes in assumptions are accounted for prospectively, resulting in the amortization of the net carrying amount of the liability to the initial carrying amount of $15 million using an imputed effective interest rate of negative 6.1%, on the unamortized portion of the liability, which will be applied until there is a change in future cash flow expectations or the debt is legally extinguished. The imputed effective interest for periods shown prior to first quarter 2025 was 10.1%. Changes in this liability related to interest accretion are recognized in Non-operating income (expense) in the Condensed Consolidated Statements of Operations. The liability for sale of future royalties is reflected at the unamortized carrying amount and thus is no longer considered to be at fair value commencing the first quarter 2025, with the estimated fair value being immaterial.
The liability is reported in Other noncurrent liabilities in the Condensed Consolidated Balance Sheets and changes were as follows (in millions):
Nine Months Ended September 30,
20252024
Beginning balance$21 $19 
Interest accretion— 
Ending balance$21 $21 
Long-term debt
As of September 30, 2025, the estimated fair value of our long-term debt approximated the carrying amount. The fair value of the long-term debt was estimated for disclosure purposes only and was determined based on other inputs that are observable, and thus categorized as Level 2 in the fair value hierarchy.
v3.25.3
Business Segment
9 Months Ended
Sep. 30, 2025
Segment Reporting [Abstract]  
Business Segment Business segment
We operate and manage our business as one reportable and operating segment, which is the business of developing and commercializing highly differentiated therapies that have a meaningful impact on patients. Our chief operating decision maker ("CODM") is the Chief Executive Officer, who decides how to allocate resources and assesses segment performance based on the net loss reported in the Condensed Consolidated Statements of Operations.
The table below is a summary of the segment net loss, including significant segment expenses (in millions):
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Total revenues26 48 214 232 
Less:
Late-stage development programs (1)
78 69 207 196 
Early-stage development and preclinical programs (2)
33 34 113 92 
Compensation and personnel costs59 62 187 190 
Depreciation and amortization
Impairment of long-lived assets— — — 20 
Interest income, net(7)(13)(25)(38)
Income tax expense— — — — 
Other segment items (3)
24 23 71 68 
Partnership reimbursements(28)(37)(99)(114)
Segment and Consolidated net loss$(135)$(92)$(247)$(189)
(1) R&D expenses incurred related to a Phase 3 clinical program intended to result in registration of a new product. This includes all unallocated program-level expense not directly attributable to a specific clinical trial once a molecule enters into one or more Phase 3 clinical trials.
(2) R&D expenses incurred for activities ranging from early-stage development and preclinical to Phase 2 clinical trials. This includes all unallocated program-level expense not directly attributable to a specific clinical trial unless the related program has entered into one or more Phase 3 clinical trials.
(3) Other segment items includes non-allocated program costs and other G&A costs.
Total segment assets at September 30, 2025 and 2024 were $1.0 billion and $1.3 billion, respectively.
v3.25.3
Insider Trading Arrangements
3 Months Ended
Sep. 30, 2025
shares
Trading Arrangements, by Individual  
Material Terms of Trading Arrangement
The adoption, modification or termination of contracts, instructions or written plans for the purchase or sale of our securities by our Section 16 officers and directors for the three months ended September 30, 2025, which are intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act, were as follows:
Name and TitleActionDateTotal Shares to be SoldExpiration Date
Robert C. Goeltz II
Chief Financial Officer
AdoptionSeptember 10, 202550,138January 29, 2027
Juan Jaen
President
AdoptionAugust 8, 2025265,993November 13, 2026
Non-Rule 10b5-1 Arrangement Adopted false
Rule 10b5-1 Arrangement Terminated false
Non-Rule 10b5-1 Arrangement Terminated false
Robert C. Goeltz II [Member]  
Trading Arrangements, by Individual  
Name Robert C. Goeltz II
Title Chief Financial Officer
Rule 10b5-1 Arrangement Adopted true
Adoption Date September 10, 2025
Expiration Date January 29, 2027
Arrangement Duration 506 days
Aggregate Available 50,138
Juan Jaen [Member]  
Trading Arrangements, by Individual  
Name Juan Jaen
Title President
Rule 10b5-1 Arrangement Adopted true
Adoption Date August 8, 2025
Expiration Date November 13, 2026
Arrangement Duration 462 days
Aggregate Available 265,993
v3.25.3
Summary of Significant Accounting Policies (Policies)
9 Months Ended
Sep. 30, 2025
Accounting Policies [Abstract]  
Basis of Presentation
Basis of Presentation
These interim financial statements should be read in conjunction with the audited Consolidated Financial Statements and the related notes thereto for the year ended December 31, 2024 included in our Annual Report on Form 10-K filed with the Securities and Exchange Commission ("SEC") on February 25, 2025. There have been no significant changes to our summary of significant accounting policies as disclosed in that filing.
These interim financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") for interim financial information and include all normal and recurring adjustments that management believes are necessary for a fair presentation of the periods presented. The Condensed Consolidated Balance Sheet as of December 31, 2024 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements.
Operating results for the three and nine months ended September 30, 2025 are not necessarily indicative of the results that may be expected for the year ending December 31, 2025 or for any future period.
Use of Estimates
Use of Estimates
The preparation of the Condensed Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosures. We base our estimates on historical experience and on various market-specific and other relevant assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Estimates are assessed and updated each period to reflect current information. Actual results may differ materially from those estimates.
Recent Accounting Pronouncements
Recent Accounting Pronouncements
In December 2023, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires disclosure of disaggregated income taxes paid, prescribes standard categories for the components of the effective tax rate reconciliation, and modifies other income tax-related disclosures. The standard will become effective for the fiscal year ending December 31, 2025, with early adoption permitted. We plan to adopt this guidance beginning with our 2025 Annual Report to be filed in early 2026. We are currently assessing the potential impact of the new standard on our Notes to our Consolidated Financial Statements.
In November 2024, the FASB issued ASU 2024-03 — Income Statement — Reporting Comprehensive Income — Expense Disaggregation Disclosures (Subtopic 220-40) — Disaggregation of Income Statement Expenses. This ASU requires disclosure, in the notes to financial statements, of specified information about certain costs and expenses. We plan to adopt this guidance beginning with our 2027 Annual Report to be filed in early 2028 and all quarterly and Annual Reports thereafter. We expect the adoption of this standard to result in increased disclosures in our Notes to our Consolidated Financial Statements.
In September 2025, the FASB issued ASU 2025-07 — Derivatives and Hedging (Topic 815) and Revenue from Contracts with Customers (Topic 606): Derivatives Scope Refinements and Scope Clarification for Share-Based Noncash Consideration from a Customer in a Revenue Contract. This ASU refines the scope of the guidance on derivatives in Topic 815 and clarifies the guidance on share-based payments from a customer in ASC 606. The standard will become effective for the fiscal year ending December 31, 2027, with early adoption permitted. We are currently assessing the potential impact of this new standard on our Consolidated Financial Statements.
v3.25.3
Revenues (Tables)
9 Months Ended
Sep. 30, 2025
Revenue from Contract with Customer [Abstract]  
Summary of Revenues by Collaboration, Category of Revenue and Method of Recognition
The following table summarizes our revenues by collaboration, category of revenue, and the method of recognition (in millions):
Three Months Ended September 30,Nine Months Ended September 30,
Over timePoint in time2025202420252024
Gilead collaboration      
License and R&D services* $23 $25 $200 $185 
Access rights* 14 22 
Taiho collaboration      
License revenue*— 15 — 15 
Other*— — 10 
Total revenues  $26 $48 $214 $232 
Total revenues from collaborations$20 $41 $192 $204 
Total revenues from a customer$$$22 $28 
Summary of Revenue Recognized as a Result of Changes in Deferred Revenue
The following table summarizes the revenue recognized as a result of changes in the deferred revenue balance (in millions):
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Revenue recognized from amounts in deferred revenue at the beginning of the period$26 $33 $214 $212 
Summary of Transaction Price and Allocation of Transaction Price to the Performance Obligations
The following table summarizes the allocation of the updated transaction price to the remaining unsatisfied and partially satisfied performance obligations (in millions):
Allocation to performance obligationsDistinctCombinedAmount
License and R&D services*$192 
R&D services*17
Access rights and option continuation periods*30
Rights to certain studies*17
Total allocated transaction price$256 
v3.25.3
Net Loss Per Share (Tables)
9 Months Ended
Sep. 30, 2025
Earnings Per Share [Abstract]  
Summary of Outstanding Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share
The following table summarizes potentially dilutive securities excluded from the computation of diluted net loss per share calculations because they would have been antidilutive (in millions):
September 30, 2025September 30, 2024
Common stock options issued and outstanding17.315.5
Restricted stock units issued3.93.0
Employee stock purchase plan shares0.20.2
Total potential dilutive securities21.418.7
v3.25.3
Stock-Based Compensation (Tables)
9 Months Ended
Sep. 30, 2025
Share-Based Payment Arrangement [Abstract]  
Summary of Stock-Based Compensation Expense
The following table reflects the components of stock-based compensation expense recognized in our Condensed Consolidated Statements of Operations (in millions):
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Research and development$$$23 $29 
General and administrative10 22 30 
Total stock-based compensation$14 $19 $45 $59 
v3.25.3
Cash, Cash Equivalents and Marketable Securities (Tables)
9 Months Ended
Sep. 30, 2025
Cash, Cash Equivalents and Marketable Securities [Abstract]  
Summary of Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Our Cash, Cash Equivalents and Marketable Securities
The following table summarizes the amortized cost, gross unrealized gains and losses and the fair value of our cash, cash equivalents and marketable securities, all of which are considered available for sale, by type of securities (in millions):
Types of securities as of September 30, 2025
Amortized
Cost
Unrealized
Gain
Unrealized
Loss
Fair
Value
Money market funds$171 $— $— $171 
U.S. treasury securities246 — — 246 
Corporate securities and commercial paper406 — — 406 
Certificate of deposit18 — — 18 
Total cash, cash equivalents and marketable securities$841 $— $— $841 
Types of securities as of December 31, 2024
Amortized
Cost
Unrealized
Gain
Unrealized
Loss
Fair
Value
Money market funds$120 $— $— $120 
U.S. treasury securities251 — — 251 
Corporate securities and commercial paper592 — — 592 
U.S. government agency securities— — 
Certificate of deposit24 — — 24 
Total cash, cash equivalents and marketable securities$992 $— $— $992 
Summary of Fair Values of Our Cash, Cash Equivalents and Marketable Securities
The following table summarizes the fair values of our cash, cash equivalents and marketable securities by location in the Condensed Consolidated Balance Sheets and contractual maturity (in millions):
Location in Condensed Consolidated Balance SheetsContractual MaturitySeptember 30, 2025December 31, 2024
Cash and cash equivalents$238 $150 
Marketable securitiesWithin one year593 828 
Long-term marketable securitiesBetween one and three years10 14 
Total cash, cash equivalents and marketable securities $841 $992 
Summary of Cash, Cash Equivalents and Restricted Cash
The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the Condensed Consolidated Balance Sheets to the total shown in the Condensed Consolidated Statements of Cash Flows (in millions):
As of September 30,
20252024
Cash and cash equivalents$238 $201 
Restricted cash (included in Other noncurrent assets)
Total cash, cash equivalents and restricted cash$241 $204 
Summary of Cash and Cash Equivalents
The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the Condensed Consolidated Balance Sheets to the total shown in the Condensed Consolidated Statements of Cash Flows (in millions):
As of September 30,
20252024
Cash and cash equivalents$238 $201 
Restricted cash (included in Other noncurrent assets)
Total cash, cash equivalents and restricted cash$241 $204 
v3.25.3
Condensed Consolidated Balance Sheet Components (Tables)
9 Months Ended
Sep. 30, 2025
Balance Sheet Related Disclosures [Abstract]  
Summary of Prepaid and Other Current Assets
Prepaid expenses and other current assets consisted of the following (in millions):
September 30, 2025December 31, 2024
Prepaid expenses and other assets$12 $13 
Accrued interest receivable
Total prepaid expenses and other current assets$15 $18 
Summary of Other Current Liabilities
Other current liabilities consisted of the following (in millions):
September 30, 2025December 31, 2024
Accrued research and development$84 $65 
Accrued personnel expenses28 31 
Current portion of lease liabilities13 12 
Other16 15 
Total other current liabilities$141 $123 
v3.25.3
Long-Term Debt (Tables)
9 Months Ended
Sep. 30, 2025
Debt Disclosure [Abstract]  
Summary of Long-Term Debt Instruments
The following table summarizes our borrowings (in millions):
September 30, 2025December 31, 2024
Long-term debt, non-current (Contractual maturity 2029)$100 $50 
Unamortized discounts, issuance costs and payment-in-kind interest, net
(2)(2)
Total long-term debt$98 $48 
Summary of Maturities of Long-Term Debt
The aggregate future minimum payments due under the Hercules Agreement, including principal payments, payment-in-kind interest incurred to date, and the end of term charge, are as follows (in millions):
Maturity DateAmount
2028$30 
202978 
Total payments$108 
v3.25.3
Leases (Tables)
9 Months Ended
Sep. 30, 2025
Leases [Abstract]  
Summary of Cash and Non-cash Information Related to Operating Leases
The following table summarizes our cash and non-cash information related to our operating leases (in millions):
Nine Months Ended September 30,
20252024
Cash paid for amounts included in measurement of lease liabilities$13 $12 
v3.25.3
Fair Value Measurements (Tables)
9 Months Ended
Sep. 30, 2025
Fair Value Disclosures [Abstract]  
Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis
The following tables summarize the types of assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy (in millions):
Fair value measurement as of September 30, 2025Level 1Level 2Level 3Total
Assets
Money market funds$171 $— $— $171 
U.S. treasury securities— 246 — 246 
Corporate securities and commercial paper— 406 — 406 
Certificate of deposit— 18 — 18 
Total assets measured at fair value$171 $670 $— $841 
Fair value measurement as of December 31, 2024Level 1Level 2Level 3Total
Assets
Money market funds$120 $— $— $120 
U.S. treasury securities— 251 — 251 
Corporate securities and commercial paper— 592 — 592 
U.S. government agency obligations— — 
Certificate of deposit— 24 — 24 
Total assets measured at fair value$120 $872 $— $992 
Liabilities    
Liability for sale of future royalties$— $— $21 $21 
Total liabilities measured at fair value$— $— $21 $21 
Summary of Changes of Liabilities for Sale of Future Royalties
The liability is reported in Other noncurrent liabilities in the Condensed Consolidated Balance Sheets and changes were as follows (in millions):
Nine Months Ended September 30,
20252024
Beginning balance$21 $19 
Interest accretion— 
Ending balance$21 $21 
v3.25.3
Business Segment (Tables)
9 Months Ended
Sep. 30, 2025
Segment Reporting [Abstract]  
Summary of Segment Reporting Information
The table below is a summary of the segment net loss, including significant segment expenses (in millions):
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
Total revenues26 48 214 232 
Less:
Late-stage development programs (1)
78 69 207 196 
Early-stage development and preclinical programs (2)
33 34 113 92 
Compensation and personnel costs59 62 187 190 
Depreciation and amortization
Impairment of long-lived assets— — — 20 
Interest income, net(7)(13)(25)(38)
Income tax expense— — — — 
Other segment items (3)
24 23 71 68 
Partnership reimbursements(28)(37)(99)(114)
Segment and Consolidated net loss$(135)$(92)$(247)$(189)
(1) R&D expenses incurred related to a Phase 3 clinical program intended to result in registration of a new product. This includes all unallocated program-level expense not directly attributable to a specific clinical trial once a molecule enters into one or more Phase 3 clinical trials.
(2) R&D expenses incurred for activities ranging from early-stage development and preclinical to Phase 2 clinical trials. This includes all unallocated program-level expense not directly attributable to a specific clinical trial unless the related program has entered into one or more Phase 3 clinical trials.
(3) Other segment items includes non-allocated program costs and other G&A costs.
v3.25.3
Organization, Liquidity and Capital Resources - Additional Information (Details)
$ in Millions
9 Months Ended
Sep. 30, 2025
USD ($)
segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Number of reportable segments 1
Number of operating segments 1
Cash and investments | $ $ 841
v3.25.3
Related Party - Gilead Sciences, Inc. (Details)
$ / shares in Units, shares in Millions, $ in Millions
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2025
USD ($)
$ / shares
Mar. 31, 2025
USD ($)
shares
Sep. 30, 2024
USD ($)
Mar. 31, 2024
USD ($)
shares
Sep. 30, 2025
USD ($)
member
$ / shares
Sep. 30, 2024
USD ($)
Dec. 31, 2023
USD ($)
program
Dec. 31, 2021
USD ($)
program
Dec. 31, 2020
USD ($)
Dec. 31, 2024
USD ($)
Related Party Transaction [Line Items]                    
Sale of stock, consideration received on transaction   $ 150.0                
Number of programs, eligible to receive regulatory and commercial milestone payments | program             4      
Revenue recognized from amounts in deferred revenue at the beginning of the period $ 26.0   $ 33.0   $ 214.0 $ 212.0        
Accounts payable, current 42.0       42.0         $ 18.0
Receivable from collaboration partners, current $ 11.0       $ 11.0         20.0
Gilead                    
Related Party Transaction [Line Items]                    
Sale of stock, consideration received on transaction   $ 15.0                
Gilead                    
Related Party Transaction [Line Items]                    
Sale of stock, number of shares acquired in transaction (in shares) | shares   1.4                
Related Party                    
Related Party Transaction [Line Items]                    
Percentage of outstanding common stock held 29.30%       29.30%          
Accounts payable, current $ 29.0       $ 29.0         0.0
Receivable from collaboration partners, current 0.0       0.0         $ 6.0
Related Party | Research and Development                    
Related Party Transaction [Line Items]                    
Reimbursement from related party for shared costs $ 16.0   (2.0)   $ 24.0 (32.0)        
Purchase Agreement | Related Party                    
Related Party Transaction [Line Items]                    
Common stock shares issued (in shares) | shares       15.2            
Funds received for stock purchase agreement       $ 320.0            
Purchase price of common stock allocation to performance obligation       87.0            
Percentage of premium purchase price of common stock         20.00%          
Trailing days average closing price         5 days          
Weighted average closing price of our common stock on grant date (in dollars per share) | $ / shares $ 33.54       $ 33.54          
Number of board members | member         3          
Purchase Agreement | Related Party | Maximum                    
Related Party Transaction [Line Items]                    
Right to purchase additional outstanding voting common stock percentage 35.00%       35.00%          
Gilead Collaboration Agreement                    
Related Party Transaction [Line Items]                    
Option payment upon completion of certain IND-enabling activities               $ 60.0    
Option payment upon achievement of certain development milestones               150.0    
Gilead Collaboration Agreement | Related Party                    
Related Party Transaction [Line Items]                    
Collaboration term for current and future clinical programs                 10 years  
Option continuation payment due upon second anniversary of agreement                 $ 100.0  
Option continuation payment due upon fourth anniversary of agreement       $ 100.0         100.0  
Option continuation payment due upon sixth anniversary of agreement                 100.0  
Option continuation payment due upon eighth anniversary of agreement                 100.0  
Upfront cash payment                 $ 175.0  
Option fee per program for all other programs entering clinical development to exercise option               $ 150.0    
Number of research programs | program               2    
Revenue recognized from amounts in deferred revenue at the beginning of the period $ 26.0   $ 30.0   $ 214.0 $ 207.0        
Gilead Collaboration Agreement | Related Party | Maximum                    
Related Party Transaction [Line Items]                    
Potential regulatory approval milestones payment receivable related to domvanalimab               $ 500.0    
Amended Gilead Collaboration Agreement                    
Related Party Transaction [Line Items]                    
Number of exercise option to programs | program               3    
Option payments received               $ 725.0    
Removal of option continuation payment under agreement               $ 100.0    
Option payment upon achievement of certain development milestones             $ 150.0      
Number of programs, eligible to receive regulatory and commercial milestone payments | program             2      
Amended Gilead Collaboration Agreement | Related Party                    
Related Party Transaction [Line Items]                    
Upfront cash payment             $ 17.5      
Number of research programs | program             2      
Option payment upon completion of certain IND-enabling activities             $ 45.0      
Total upfront cash payment             35.0      
Amended Gilead Collaboration Agreement | Related Party | Maximum                    
Related Party Transaction [Line Items]                    
Regulatory and commercial milestone payments received             $ 375.0      
v3.25.3
License and Collaborations (Details) - USD ($)
$ in Millions
1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
Oct. 31, 2025
Mar. 31, 2026
Dec. 31, 2025
Sep. 30, 2025
Mar. 31, 2025
Sep. 30, 2024
Mar. 31, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2023
Dec. 31, 2020
Dec. 31, 2017
Dec. 31, 2024
License And Collaboration Agreements [Line Items]                          
Total revenues       $ 6   $ 7   $ 22 $ 28        
Receivable from collaboration partners, current       11       11         $ 20
Other noncurrent assets       65       65         73
Other current liabilities       141       141         123
Other noncurrent liabilities       152       152         157
Taiho Collaboration Agreement                          
License And Collaboration Agreements [Line Items]                          
Milestone payments           19              
Milestone payments, received         $ 12                
Receivable from collaboration partners, current       11       11         14
Other liabilities       42       42         36
Taiho Collaboration Agreement | Forecast                          
License And Collaboration Agreements [Line Items]                          
Milestone payments, received   $ 7                      
AstraZeneca Agreement                          
License And Collaboration Agreements [Line Items]                          
Milestone payments                     $ 24    
Development cost recorded within research and development expenses       7   4   16 10        
Other current liabilities       28       28          
Other noncurrent liabilities                         $ 26
Gilead Collaboration Agreement                          
License And Collaboration Agreements [Line Items]                          
Other noncurrent assets                   $ 6      
Development cost recorded within research and development expenses                 6        
Taiho Pharmaceutical Co., Ltd | Taiho Agreement                          
License And Collaboration Agreements [Line Items]                          
Option period                       5 years  
Non refundable and non creditable cash payments                       $ 35  
Payment for option exercise           15              
Royalties payable term                       10 years  
Reimbursement of research and development expense       7   3   24 10        
Total revenues           18     25        
Taiho Pharmaceutical Co., Ltd | Taiho Agreement | Forecast                          
License And Collaboration Agreements [Line Items]                          
Payment for option exercise     $ 15                    
Taiho Pharmaceutical Co., Ltd | Taiho Agreement | Minimum                          
License And Collaboration Agreements [Line Items]                          
Payment for option exercise                       $ 3  
Taiho Pharmaceutical Co., Ltd | Taiho Agreement | Maximum                          
License And Collaboration Agreements [Line Items]                          
Payment for option exercise                       15  
Additional clinical and regulatory milestone payments receivable                       130  
Contingent milestone payments receivable                       $ 145  
Taiho Pharmaceutical Co., Ltd | Taiho Agreement | Maximum | Subsequent Event                          
License And Collaboration Agreements [Line Items]                          
Additional clinical and regulatory milestone payments receivable $ 172                        
Contingent milestone payments receivable $ 145                        
STAR-221 Development Activities | Taiho Collaboration Agreement                          
License And Collaboration Agreements [Line Items]                          
Milestone payments                   $ 28      
STAR-121 Development Activities | Taiho Collaboration Agreement                          
License And Collaboration Agreements [Line Items]                          
Milestone payments             $ 26            
Milestone payments, received         $ 10   $ 16            
WuXi Biologics License Agreement | anti-PD-1                          
License And Collaboration Agreements [Line Items]                          
Development milestone expense       0   0   0 0        
WuXi Biologics License Agreement | anti-CD39                          
License And Collaboration Agreements [Line Items]                          
Development milestone expense       0   0   0 0        
WuXi Biologics License Agreement | Maximum | anti-PD-1                          
License And Collaboration Agreements [Line Items]                          
Clinical regulatory milestone payments               50          
Clinical, regulatory and commercialization milestone payments               375          
WuXi Biologics License Agreement | Maximum | anti-CD39                          
License And Collaboration Agreements [Line Items]                          
Additional clinical, regulatory and commercialization milestone payments               14          
Abmuno License Agreement                          
License And Collaboration Agreements [Line Items]                          
Development milestone expense       $ 0   $ 0   0 $ 0        
Additional clinical, regulatory and commercialization milestone payments               $ 88          
v3.25.3
Revenues - Summary of Revenues by Collaboration, Category of Revenue and Method of Recognition (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
License And Collaboration Agreements [Line Items]        
Total revenues $ 26 $ 48 $ 214 $ 232
Total revenues from collaborations 20 41 192 204
Total revenues from a customer 6 7 22 28
License and R&D services | Gilead collaboration | Over time        
License And Collaboration Agreements [Line Items]        
Total revenues 23 25 200 185
Access rights | Gilead collaboration | Over time        
License And Collaboration Agreements [Line Items]        
Total revenues 3 5 14 22
License revenue | Taiho collaboration | Point in time        
License And Collaboration Agreements [Line Items]        
Total revenues 0 15 0 15
Other | Taiho collaboration | Over time        
License And Collaboration Agreements [Line Items]        
Total revenues $ 0 $ 3 $ 0 $ 10
v3.25.3
Revenues - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Millions
1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
Jun. 30, 2025
Dec. 31, 2021
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2020
Dec. 31, 2024
Dec. 31, 2023
Disaggregation of Revenue [Line Items]                  
Contract with customer, liability     $ 105   $ 105     $ 319  
Deferred revenue, transaction price $ 256   256   $ 256        
Contract with customer, liability, cumulative catch-up adjustment to revenue, change in measure of progress and change in estimate of transaction price $ 143                
Contract with customer, liability, cumulative catch-up adjustment to revenue, earnings per share, diluted (in dollars per share)         $ 1.38        
Contract with customer, liability, cumulative catch-up adjustment to revenue, earnings per share, basic (in dollars per share)         $ 1.38        
Deferred revenue, non-refundable payment   $ 725              
Total revenues     26 $ 48 $ 214 $ 232      
Access rights and option continuation periods                  
Disaggregation of Revenue [Line Items]                  
Total revenues     3 5 14 22      
Gilead | R&D services                  
Disaggregation of Revenue [Line Items]                  
Total revenues     20 23 192 179      
Gilead | Access rights and option continuation periods                  
Disaggregation of Revenue [Line Items]                  
Current and future programs exclusive access period             10 years    
Contingent milestone payments receivable             $ 300    
Option continuation payment receivable upon sixth anniversary of agreement             $ 100    
Gilead | Rights to certain studies                  
Disaggregation of Revenue [Line Items]                  
Contract with customer, liability     17   17        
Gilead | R&D Activities for Inflammation Programs                  
Disaggregation of Revenue [Line Items]                  
Total revenues     $ 3 $ 2 $ 8 $ 6      
Gilead | Revenue Benchmark | Customer Concentration Risk                  
Disaggregation of Revenue [Line Items]                  
Percentage of revenues     100.00% 63.00% 100.00% 89.00%      
STAR-221 Development Activities | Taiho Collaboration Agreement                  
Disaggregation of Revenue [Line Items]                  
Contract with customer, liability                 $ 35
v3.25.3
Revenues - Summary of Revenue Recognized as a Result of Changes in Deferred Revenue (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Revenue from Contract with Customer [Abstract]        
Revenue recognized from amounts in deferred revenue at the beginning of the period $ 26 $ 33 $ 214 $ 212
v3.25.3
Revenues - Summary of Transaction Price and Allocation of Transaction Price to the Performance Obligations (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Jun. 30, 2025
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]    
Total allocated transaction price $ 256 $ 256
License and R&D services    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]    
Total allocated transaction price 192  
R&D services    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]    
Total allocated transaction price 17  
Access rights and option continuation periods    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]    
Total allocated transaction price 30  
Rights to certain studies    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]    
Total allocated transaction price $ 17  
v3.25.3
Net Loss Per Share - Summary of Outstanding Potentially Dilutive Securities Excluded from Computation of Diluted Net Income (Loss) per Share (Details) - shares
shares in Millions
9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]    
Antidilutive securities excluded from computation of diluted net loss per share (in shares) 21.4 18.7
Common stock options issued and outstanding    
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]    
Antidilutive securities excluded from computation of diluted net loss per share (in shares) 17.3 15.5
Restricted stock units issued    
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]    
Antidilutive securities excluded from computation of diluted net loss per share (in shares) 3.9 3.0
Employee stock purchase plan shares    
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]    
Antidilutive securities excluded from computation of diluted net loss per share (in shares) 0.2 0.2
v3.25.3
Stock-Based Compensation (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]        
Total stock-based compensation $ 14 $ 19 $ 45 $ 59
Research and development        
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]        
Total stock-based compensation 7 9 23 29
General and administrative        
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]        
Total stock-based compensation $ 7 $ 10 $ 22 $ 30
v3.25.3
Cash, Cash Equivalents and Marketable Securities - Summary of Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Our Cash, Cash Equivalents and Marketable Securities (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Debt Securities, Available-for-Sale [Line Items]    
Amortized Cost $ 841 $ 992
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value 841 992
Money market funds    
Debt Securities, Available-for-Sale [Line Items]    
Amortized Cost 171 120
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value 171 120
U.S. treasury securities    
Debt Securities, Available-for-Sale [Line Items]    
Amortized Cost 246 251
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value 246 251
Corporate securities and commercial paper    
Debt Securities, Available-for-Sale [Line Items]    
Amortized Cost 406 592
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value 406 592
U.S. government agency securities    
Debt Securities, Available-for-Sale [Line Items]    
Amortized Cost   5
Unrealized Gain   0
Unrealized Loss   0
Fair Value   5
Certificate of deposit    
Debt Securities, Available-for-Sale [Line Items]    
Amortized Cost 18 24
Unrealized Gain 0 0
Unrealized Loss 0 0
Fair Value $ 18 $ 24
v3.25.3
Cash, Cash Equivalents and Marketable Securities - Summary of Fair Values of Our Cash, Cash Equivalents and Marketable Securities (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Cash, Cash Equivalents and Marketable Securities [Abstract]    
Cash and cash equivalents $ 238 $ 150
Marketable securities 593 828
Long-term marketable securities 10 14
Total cash, cash equivalents and marketable securities $ 841 $ 992
v3.25.3
Cash, Cash Equivalents and Marketable Securities - Additional Information (Details)
3 Months Ended 9 Months Ended
Sep. 30, 2025
USD ($)
position
Sep. 30, 2024
USD ($)
Sep. 30, 2025
USD ($)
position
Sep. 30, 2024
USD ($)
Dec. 31, 2024
position
Cash, Cash Equivalents and Marketable Securities [Abstract]          
Number of positions in securities in unrealized loss | position 21   21   54
Credit related losses | $ $ 0 $ 0 $ 0 $ 0  
v3.25.3
Cash, Cash Equivalents and Marketable Securities - Summary of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Sep. 30, 2024
Dec. 31, 2023
Cash, Cash Equivalents and Marketable Securities [Abstract]        
Cash and cash equivalents $ 238 $ 150 $ 201  
Restricted cash (included in Other noncurrent assets) 3   3  
Total cash, cash equivalents and restricted cash $ 241 $ 153 $ 204 $ 130
Restricted Cash, Noncurrent, Statement of Financial Position [Extensible Enumeration] Other noncurrent assets   Other noncurrent assets  
v3.25.3
Condensed Consolidated Balance Sheet Components - Summary of Prepaid and Other Current Assets (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Balance Sheet Related Disclosures [Abstract]    
Prepaid expenses and other assets $ 12 $ 13
Accrued interest receivable 3 5
Total prepaid expenses and other current assets $ 15 $ 18
v3.25.3
Condensed Consolidated Balance Sheet Components - Summary of Other Current Liabilities (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Balance Sheet Related Disclosures [Abstract]    
Accrued research and development $ 84 $ 65
Accrued personnel expenses 28 31
Current portion of lease liabilities 13 12
Other 16 15
Total other current liabilities $ 141 $ 123
v3.25.3
Long-Term Debt - Summary of Long-Term Debt Instruments (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Debt Disclosure [Abstract]    
Long-term debt, non-current (Contractual maturity 2029) $ 100 $ 50
Unamortized discounts, issuance costs and payment-in-kind interest, net (2) (2)
Total long-term debt $ 98 $ 48
v3.25.3
Long-Term Debt - Additional Information (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Aug. 27, 2024
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Jun. 30, 2025
Mar. 31, 2025
Debt Instrument [Line Items]              
Interest expense, debt   $ 4 $ 1 $ 7 $ 1    
Debt instrument, interest rate, effective percentage   13.08%   13.08%     13.39%
Hercules Agreement | Secured Debt              
Debt Instrument [Line Items]              
Debt instrument, face amount $ 250            
Proceeds from issuance of secured debt 50            
Debt Instrument, additional committed amount 50         $ 50  
Debt Instrument, minimum increments amount 25            
Debt instrument, face amount, contingently available $ 100            
Debt instrument, periodic payment, interest, term 48 months            
Debt instrument, interest rate, stated percentage 10.45%            
Debt Instrument, variable interest rate, Type [Extensible Enumeration] Prime Rate [Member]            
Debt instrument, basis spread on variable rate 1.95%            
Debt instrument, payment in kind 2.00%            
Debt instrument, payment in kind, principal 110.00%            
v3.25.3
Long-Term Debt - Summary of Maturities of Long-Term Debt (Details) - Hercules Agreement
$ in Millions
Sep. 30, 2025
USD ($)
Debt Instrument [Line Items]  
2028 $ 30
2029 78
Total payments $ 108
v3.25.3
Leases - Summary of Cash and Non-cash Information Related to Operating Leases (Details) - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Leases [Abstract]    
Cash paid for amounts included in measurement of lease liabilities $ 13 $ 12
v3.25.3
Leases - Additional Information (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Mar. 31, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2024
Leases [Abstract]            
Impairment of long-lived assets $ 0 $ 0 $ 20 $ 0 $ 20  
Deposits for letters of credit $ 3     $ 3   $ 3
v3.25.3
Stockholders' Equity (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
3 Months Ended
Sep. 30, 2025
Mar. 31, 2025
Mar. 31, 2024
Class of Stock [Line Items]      
Common stock share value $ 8 $ 142 $ 228
Sale of stock, number of shares issued in transaction (in shares)   13.6  
Sale of stock, price per share (in dollars per share)   $ 11.00  
Sale of stock, consideration received on transaction   $ 150  
At-the-Market Facility      
Class of Stock [Line Items]      
Sale of stock, number of shares issued in transaction (in shares) 0.6    
Sale of stock, consideration received on transaction $ 8    
Third Stock Purchase Agreement Amendment      
Class of Stock [Line Items]      
Contract with customer, asset, before allowance for credit loss     228
Capitalized contract cost, gross     $ 5
Gilead      
Class of Stock [Line Items]      
Sale of stock, consideration received on transaction   $ 15  
Gilead | Third Stock Purchase Agreement Amendment      
Class of Stock [Line Items]      
Common stock shares issued (in shares)     15.2
Shares issued, price per share (in dollars per share)     $ 21.00
Common stock share value     $ 320
Premiums earned, net     $ 87
Gilead      
Class of Stock [Line Items]      
Sale of stock, number of shares acquired in transaction (in shares)   1.4  
v3.25.3
Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value On Recurring Basis - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total assets measured at fair value $ 841 $ 992
Total liabilities measured at fair value   21
Money market funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 171 120
U.S. treasury securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 246 251
Corporate securities and commercial paper    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 406 592
U.S. government agency securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments   5
Certificate of deposit    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 18 24
Liability for sale of future royalties    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total liabilities measured at fair value   21
Level 1    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total assets measured at fair value 171 120
Total liabilities measured at fair value   0
Level 1 | Money market funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 171 120
Level 1 | U.S. treasury securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 0 0
Level 1 | Corporate securities and commercial paper    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 0 0
Level 1 | U.S. government agency securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments   0
Level 1 | Certificate of deposit    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 0 0
Level 1 | Liability for sale of future royalties    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total liabilities measured at fair value   0
Level 2    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total assets measured at fair value 670 872
Total liabilities measured at fair value   0
Level 2 | Money market funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 0 0
Level 2 | U.S. treasury securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 246 251
Level 2 | Corporate securities and commercial paper    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 406 592
Level 2 | U.S. government agency securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments   5
Level 2 | Certificate of deposit    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 18 24
Level 2 | Liability for sale of future royalties    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total liabilities measured at fair value   0
Level 3    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total assets measured at fair value 0 0
Total liabilities measured at fair value   21
Level 3 | Money market funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 0 0
Level 3 | U.S. treasury securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 0 0
Level 3 | Corporate securities and commercial paper    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments 0 0
Level 3 | U.S. government agency securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments   0
Level 3 | Certificate of deposit    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash, cash equivalents, and short-term investments $ 0 0
Level 3 | Liability for sale of future royalties    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total liabilities measured at fair value   $ 21
v3.25.3
Fair Value Measurements - Additional Information (Details) - BVF Partners L.P. - BVF Agreement - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2025
Dec. 31, 2024
Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]      
Non-refundable payments received     $ 15
Liabilities, fair value disclosure, imputed interest rate (6.10%) 10.10%  
v3.25.3
Fair Value Measurements - Summary of Changes of Liabilities for Sale of Future Royalties (Details) - BVF Partners L.P. - BVF Agreement - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning balance $ 21 $ 19
Interest accretion 0 2
Ending balance $ 21 $ 21
v3.25.3
Business Segment - Additional Information (Details)
$ in Millions
9 Months Ended
Sep. 30, 2025
USD ($)
segment
Dec. 31, 2024
USD ($)
Sep. 30, 2024
USD ($)
Segment Reporting, Asset Reconciling Item [Line Items]      
Number of reportable segments | segment 1    
Number of operating segments | segment 1    
Assets | $ $ 974 $ 1,150  
Reportable segment      
Segment Reporting, Asset Reconciling Item [Line Items]      
Assets | $ $ 1,000   $ 1,300
v3.25.3
Business Segment - Summary of Segment Reporting Information (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Jun. 30, 2025
Mar. 31, 2025
Sep. 30, 2024
Jun. 30, 2024
Mar. 31, 2024
Sep. 30, 2025
Sep. 30, 2024
Segment Reporting, Asset Reconciling Item [Line Items]                
Total revenues $ 26     $ 48     $ 214 $ 232
Less:                
Impairment of long-lived assets 0     0   $ 20 0 20
Income tax expense 0     0     0 0
Net loss (135) $ 0 $ (112) (92) $ (93) $ (4) (247) (189)
Reportable segment                
Segment Reporting, Asset Reconciling Item [Line Items]                
Total revenues 26     48     214 232
Less:                
Late-stage development programs 78     69     207 196
Early-stage development and preclinical programs 33     34     113 92
Compensation and personnel costs 59     62     187 190
Depreciation and amortization 2     2     7 7
Impairment of long-lived assets 0     0     0 20
Interest income, net (7)     (13)     (25) (38)
Income tax expense 0     0     0 0
Other segment items 24     23     71 68
Partnership reimbursements (28)     (37)     (99) (114)
Net loss $ (135)     $ (92)     $ (247) $ (189)