0001370053-24-000027 | 10-Q | XBRL Viewer

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Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	27,316,644	26,597,000
Common stock, shares outstanding (in shares)	27,316,644	26,597,000

Equity Incentive Plans

3 Months Ended

Mar. 31, 2024

Share-Based Payment Arrangement [Abstract]

Equity Incentive Plans

2017 Equity Incentive Plan

In January 2017, our Board of Directors and stockholders approved and adopted the 2017 Equity Incentive Plan (the “2017 Plan”). Under the 2017 Plan, we may grant stock options, stock appreciation rights, restricted stock, restricted stock units and other awards to individuals who are then our employees, officers, directors or consultants. In addition, the number of shares of stock available for issuance under the 2017 Plan will be automatically increased each January 1, beginning on January 1, 2018, by 4% of the aggregate number of outstanding shares of our common stock as of the immediately preceding December 31 or such lesser number as determined by our Board of Directors. The 2017 Plan automatically increased by 1,063,871 shares as of January 1, 2024. As of March 31, 2024, 1,065,471 shares were available for future issuance.

Employee Stock Purchase Plan

In January 2017, our Board of Directors and stockholders approved and adopted the 2017 Employee Stock Purchase Plan (“ESPP”). In addition, the number shares of stock available for issuance under the ESPP will be automatically increased each January 1, beginning on January 1, 2018, by 1% of the aggregate number of outstanding shares of our common stock as of the immediately preceding December 31 or such lesser number as determined by our Board of Directors. The ESPP automatically increased by 265,967 shares as of January 1, 2024. As of March 31, 2024, 98,000 shares have been issued under the ESPP and 2,000,807 shares were available for future issuance.

Stock Options

Stock options granted to employees and non-employees generally vest over a four-year period while stock options granted to directors generally vest over a one year period. Each stock option award has a maximum term of 10 years from the date of grant, subject to earlier cancellation prior to vesting upon cessation of service to us. A summary of the activity related to stock option awards during the three months ended March 31, 2024 is as follows:


	Shares Subject to Options	Weighted-Average Exercise Price per Share		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2024	4,225,615	$	27.36	7.42	$	5,827
Granted	1,975,327	$	21.25
Exercised	(53,078)	$	15.29
Forfeitures and cancellations	(73,608)	$	44.19
Outstanding at March 31, 2024	6,074,256	$	25.28	8.14	$	9,356
Exercisable at March 31, 2024	2,452,748	$	29.36	6.51	$	5,322

Total cash received from the exercise of stock options was approximately $0.8 million during the three months ended March 31, 2024.

Time-Based Restricted Stock Units

Each Restricted Stock Unit (“RSU”) represents one equivalent share of our common stock to be issued after satisfying the applicable continued service-based vesting criteria over a specified period. The fair value of these RSUs is based on the closing price of our common stock on the date of the grant. We measure compensation expense over the expected vesting period on a

straight-line basis. The RSUs do not entitle the participants to the rights of holders of common stock, such as voting rights, until the shares are issued.


	Number of Restricted Stock Units	Weighted-Average Grant Date Fair Value		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2024	1,481,572	$	24.80	0.73	$	31,735
Granted	718,922	$	21.25
Vested	(1,014,242)	$	26.12
Forfeitures and cancellations	(1,950)	$	23.23
Outstanding at March 31, 2024	1,184,302	$	21.52	1.98	$	26,670
RSU expected to vest at March 31, 2024	1,184,302	$	21.52	1.98	$	26,670

Stock-Based Compensation Expense

We recognize stock-based compensation expense for awards issued to employees and non-employees over the requisite service period based on the estimated grant-date fair value of such awards. We record the expense for stock-based compensation awards subject to performance-based milestone vesting over the requisite service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the expected satisfaction of the performance conditions at each reporting date. The estimated fair values of stock option awards granted were determined on the date of grant using the Black-Scholes option valuation model with the following weighted-average assumptions:


	Three Months Ended March 31,

		2024	2023
Risk-free interest rate				3.9	%		3.7	%
Expected volatility				78.3	%		86.5	%
Expected dividend yield				—	%		—	%
Expected term (in years)				6.28			5.65
Weighted-average grant date fair value per share			$	15.12		$	16.88

We determine the appropriate risk-free interest rate, expected term for employee stock-based awards, contractual term for non-employee stock-based awards, and volatility assumptions. The weighted-average expected option term for employee and non-employee stock-based awards reflects the historical option term. Expected volatility incorporates the historical volatility of our stock price. The risk-free interest rate is based upon U.S. Treasury securities with remaining terms similar to the expected or contractual term of the stock-based payment awards. The assumed dividend yield is based on our expectation of not paying dividends in the foreseeable future.

Total non-cash stock-based compensation expense for all stock awards that was recognized in the consolidated statements of operations and comprehensive loss is as follows:


	Three Months Ended March 31,
(in thousands)		2024		2023
Research and development		$	3,454	$	2,770
General and administrative		6,677		6,090
Total		$	10,131	$	8,860

On March 21, 2022, we awarded our newly appointed Interim President and Chief Executive Officer RSUs for 887,043 shares of the Company’s common stock. The fair value of the award was recognized ratably to compensation expense over the stated 24-month requisite service period. During the three months ended March 31, 2024 and 2023, we recognized $2.6 million, and $2.9 million, respectively, of non-cash stock-based compensation cost related to the award.

At March 31, 2024, there was $56.0 million of unrecognized compensation cost related to unvested stock option awards, which is expected to be recognized over a remaining weighted-average vesting period of 3.08 years and $22.7 million of unrecognized cost related to unvested RSU awards, which is expected to be recognized over a period of 3.23 years and $0.1 million of unrecognized compensation cost related to the ESPP, which is expected to be recognized over a remaining weighted-average vesting period of 0.12 years

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and note disclosures normally included in annual financial statements prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) have been omitted. The accompanying unaudited consolidated financial statements include all known adjustments necessary for a fair presentation of the results of interim periods as required by U.S. GAAP. These adjustments consist primarily of normal recurring accruals and estimates that impact the carrying value of assets and liabilities. Operating results for the three months ended March 31, 2024 are not necessarily indicative of the results that may be expected for the year ending December 31, 2024. The financial statements should be read in conjunction with our audited financial statements for the year ended December 31, 2023 included in our Annual Report on Form 10-K.
Basis of Consolidation	Basis of Consolidation The accompanying consolidated financial statements include us and our wholly owned Australian subsidiary. All intercompany accounts and transactions have been eliminated in consolidation. We operate in one reportable segment, and our functional and reporting currency is the U.S. dollar.
Use of Estimates	Use of Estimates The preparation of the accompanying consolidated financial statements in conformity with U.S. GAAP requires our management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. We base our estimates and assumptions on historical experience when available and on various factors that we believe to be reasonable under the circumstances. Significant estimates relied upon in preparing these financial statements include estimates related to revenue recognition, accrued research and development expenses, stock-based compensation, and the liability related to the sale of future royalties. We evaluate our estimates and assumptions on an ongoing basis. Our actual results could differ from these estimates under different assumptions or conditions.
Net Loss Per Common Share	Net Loss Per Common Share Basic net loss per common share is computed by dividing net loss by the weighted-average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common equivalent shares outstanding for the period, as well as any dilutive effect from outstanding stock options and warrants using the treasury stock method. For each period presented, there is no difference in the number of shares used to calculate basic and diluted net loss per share.
Accounting Pronouncements and Recent Accounting Pronouncements Not Yet Adopted	Accounting Pronouncements We have implemented all new accounting pronouncements that are in effect and may have an impact on our consolidated financial statements. Unless otherwise discussed, we believe the impact of any recently issued and not yet effective pronouncements will not have a material impact on our consolidated financial statements. Recent Accounting Pronouncements Not Yet Adopted In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires enhanced disclosure of significant segment expenses on an annual and interim basis. The guidance will be effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning December 15, 2024, with early adoption permitted. Upon adoption, the guidance should be applied retrospectively to all prior periods presented in the financial statements. We are currently assessing the impact that this standard will have on our consolidated financial statements. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures Income Taxes, which improves the transparency of income tax disclosures by requiring consistent categories and greater disaggregation of information in the effective tax rate reconciliation and income taxes paid disaggregated by jurisdiction. It also includes certain other amendments to improve the effectiveness of income tax disclosures. This guidance will be effective for the annual periods beginning after December 15, 2024. Early adoption is permitted. Upon adoption, the guidance can be applied prospectively or retrospectively. We are currently assessing the impact that this standard will have on our consolidated financial statements.

Summary of Significant Accounting Policies - Narrative (Details)	3 Months Ended
	Mar. 31, 2024 segment
Accounting Policies [Abstract]
Number of reportable segments	1

Sale of Future Royalties - Narratives (Details) - USD ($)	1 Months Ended		3 Months Ended
	Sep. 30, 2022	Oct. 31, 2021	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Jan. 01, 2021
Liabilities Related To Sale Of Future Royalties [Line Items]
Liability related to sale of future royalties			$ 310,184,000		$ 310,807,000
Collaboration revenue			7,179,000	$ 1,374,000
Non-cash interest expense			6,317,000	4,336,000
Jemperli Royalty Monetization Agreement
Liabilities Related To Sale Of Future Royalties [Line Items]
Issuance costs related to the sale of future royalties		$ 400,000	$ 0
Net of proceeds		249,600,000
Effective interest rate			10.00%
Non-cash interest expense and amortization of issuance costs			$ 6,100,000	4,000,000
Non-cash interest expense			6,073,000
Jemperli Royalty Monetization Agreement \| Sagard
Liabilities Related To Sale Of Future Royalties [Line Items]
Proceeds from sale of future royalties		250,000,000
Royalties agreement, maximum annual royalty payout capacity		1,000,000,000
Royalties and milestones received			16,400,000
Liability related to sale of future royalties		250,000,000
Jemperli Royalty Monetization Agreement \| Sagard \| By the end of 2026
Liabilities Related To Sale Of Future Royalties [Line Items]
Royalties and milestones, agreement amount to be received		$ 312,500,000
Proceeds, contingent on annual sales milestones upfront percentage		125.00%
Jemperli Royalty Monetization Agreement \| Sagard \| During 2027
Liabilities Related To Sale Of Future Royalties [Line Items]
Royalties and milestones, agreement amount to be received		$ 337,500,000
Proceeds, contingent on annual sales milestones upfront percentage		135.00%
Jemperli Royalty Monetization Agreement \| Sagard \| At any time after 2027
Liabilities Related To Sale Of Future Royalties [Line Items]
Royalties and milestones, agreement amount to be received		$ 412,500,000
Proceeds, contingent on annual sales milestones upfront percentage		165.00%
Jemperli Royalty Monetization Agreement \| GSK
Liabilities Related To Sale Of Future Royalties [Line Items]
Collaboration revenue			$ 6,200,000	600,000
Zejula Royalty Monetization Agreement
Liabilities Related To Sale Of Future Royalties [Line Items]
Issuance costs related to the sale of future royalties	$ 200,000
Net of proceeds	34,800,000
Effective interest rate			2.90%
Non-cash interest expense			$ 223,000
Zejula Royalty Monetization Agreement \| GSK
Liabilities Related To Sale Of Future Royalties [Line Items]
Collaboration revenue			$ 1,000,000	800,000
Payment rate						1.00%
Settlement agreement rate						0.50%
Effective royalty rate			0.50%
Non-cash interest expense			$ 200,000	$ 400,000
Zejula Royalty Monetization Agreement \| DRI Healthcare Trust
Liabilities Related To Sale Of Future Royalties [Line Items]
Proceeds from sale of future royalties	35,000,000
Royalties and milestones, agreement amount to be received	10,000,000
Liability related to sale of future royalties	$ 35,000,000

Collaborative Research and Development Agreements - Narrative (Details) - USD ($)			1 Months Ended		3 Months Ended
	Nov. 24, 2023	Oct. 23, 2020	Dec. 31, 2023	Mar. 31, 2014	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Collaboration revenue					$ 7,179,000	$ 1,374,000
GSK \| GlaxoSmithKline Collaboration
Disaggregation of Revenue [Line Items]
Agreement term following first commercial sale or expiration of the last to expire patent		12 years
GSK \| GlaxoSmithKline Collaboration \| Minimum
Disaggregation of Revenue [Line Items]
Royalty percent on net sales				4.00%
GSK \| GlaxoSmithKline Collaboration \| Maximum
Disaggregation of Revenue [Line Items]
Royalty percent on net sales				8.00%
GSK \| Royalties
Disaggregation of Revenue [Line Items]
Collaboration revenue					7,200,000	1,400,000
GSK \| Royalty Agreement, Up To $1.0 billion \| Anti-PD-1 (Jemperli/Dostarlimab)
Disaggregation of Revenue [Line Items]
Royalty percent on net sales		8.00%
Net sales royalty		$ 1,000,000,000
GSK \| Royalty Agreement, Above $1.0 billion \| Minimum \| Anti-PD-1 (Jemperli/Dostarlimab)
Disaggregation of Revenue [Line Items]
Royalty percent on net sales		12.00%
GSK \| Royalty Agreement, Above $1.0 billion \| Maximum \| Anti-PD-1 (Jemperli/Dostarlimab)
Disaggregation of Revenue [Line Items]
Royalty percent on net sales		25.00%
Net sales royalty		$ 1,000,000,000
GSK \| Jemperli Royalty Monetization Agreement
Disaggregation of Revenue [Line Items]
Collaboration revenue					6,200,000	600,000
GSK \| Zejula Royalty Monetization Agreement
Disaggregation of Revenue [Line Items]
Collaboration revenue					1,000,000	800,000
GSK \| Zejula revenue prior to the Zejula Royalty Monetization Agreement
Disaggregation of Revenue [Line Items]
Collaboration revenue						$ 800,000
Centessa Pharmaceuticals (UK) Limited (Centessa) \| GlaxoSmithKline Collaboration
Disaggregation of Revenue [Line Items]
Potential future payments	$ 10,000,000				$ 10,000,000
Centessa Pharmaceuticals (UK) Limited (Centessa) \| GlaxoSmithKline Collaboration \| License Agreement, Centessa Pharmaceuticals (UK) Limited
Disaggregation of Revenue [Line Items]
Cash payment	4,000,000
Reimbursement	$ 3,000,000
Transaction costs incurred			$ 300,000
Total transferred			$ 7,300,000

Stockholders' Equity - Narrative (Details) - USD ($)	3 Months Ended
Stockholders' Equity - Narrative (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023	Jan. 31, 2023	Nov. 30, 2022
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	27,316,644	26,597,000
Common stock, shares outstanding (in shares)	27,316,644	26,597,000
Authorized repurchase amount			$ 50,000,000
stock repurchase plan, common stock par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Open Market Sales Agreement
Class of Stock [Line Items]
Aggregate offering of (up to)				$ 150,000,000
Shares sold (in shares)	0

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2024 shares
Trading Arrangements, by Individual
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Hollings C. Renton [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 14, 2024, Hollings C. Renton, a director of the Company, entered into a written plan for the sale of an aggregate 56,121 shares of common stock. The plan is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act and is scheduled to terminate no later than August 15, 2025.
Name	Hollings C. Renton
Title	a director of the Company
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 14, 2024
Arrangement Duration	519 days
Aggregate Available	56,121
Dennis M. Fenton [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On March 22, 2024, Dennis M. Fenton, a director of the Company, entered into a written plan for the sale of an aggregate 4,965 shares of common stock. The plan is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act and is scheduled to terminate no later than June 24, 2025.
Name	Dennis M. Fenton
Title	a director of the Company
Rule 10b5-1 Arrangement Adopted	false
Adoption Date	March 22, 2024
Arrangement Duration	459 days
Aggregate Available	4,965

Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	Collaboration Revenue [Member]	Collaboration Revenue [Member]
Collaboration revenue	$ 7,179	$ 1,374
Operating expenses:
Research and development	37,042	34,957
General and administrative	12,338	10,818
Total operating expenses	49,380	45,775
Loss from operations	(42,201)	(44,401)
Other (expense) income, net:
Interest income	4,584	4,486
Non-cash interest expense for the sale of future royalties	(6,317)	(4,336)
Other expense, net	(2)	(4)
Total other (expense) income, net	(1,735)	146
Net loss	(43,936)	(44,255)
Unrealized gain on available for sale securities	173	1,979
Comprehensive loss	$ (43,763)	$ (42,276)
Net loss per common share:
Basic (in dollars per share)	$ (1.64)	$ (1.58)
Diluted (in dollars per share)	$ (1.64)	$ (1.58)
Weighted-average number of shares outstanding:
Basic (in shares)	26,801	27,953
Diluted (in shares)	26,801	27,953

Stockholders' Equity - Schedule Of Stock Repurchase Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023
Equity [Abstract]
Total number of shares purchased (in shares)	2,124,214	534,790	1,589,424
Average price paid per share (in dollars per share)		$ 21.59	$ 24.19
Approximate dollar value of shares purchased (in dollars per share)	$ 50,000	$ 11,544	$ 38,456

Commitments and Contingencies

3 Months Ended

Mar. 31, 2024

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Operating Leases

On May 4, 2020, we entered into a lease agreement with Wateridge Property Owner, LP, with respect to facilities in the building at 10770 Wateridge Circle, San Diego, California 92121 (the “Lease Agreement”). Under the Lease Agreement, we agreed to lease approximately 45,000 square feet of space for a term of 124 months, beginning on April 5, 2021. The terms of the Lease Agreement provide us with an option to extend the term of the lease for an additional five years, as well as a one-time option to terminate the lease after seven years with the payment of a termination fee. The exercise of the lease option is at our sole discretion, which we currently do not anticipate exercising and as such was not recognized as part of the ROU asset and lease liability. The monthly base rent was initially $4.20 per rentable square foot and is increased by 3% annually. Under the Lease Agreement, we are also responsible for our pro rata share of real estate taxes, building insurance, maintenance, direct expenses, and utilities. Upon lease commencement, on April 5, 2021, we recognized an ROU asset of $20.6 million, with a corresponding lease liability of $20.7 million on the consolidated balance sheets. The ROU asset includes adjustments for prepayments, initial direct costs, and lease incentives. As of March 31, 2024, we have recorded $0.3 million as a security deposit in accordance with the terms of the Lease Agreement.

Our lease payments are fixed, and we recognize lease expense for leases on a straight-line basis over the lease term. Operating lease ROU assets and lease liabilities are recorded based on the present value of the future minimum lease payments over the lease term at commencement date. As our lease does not provide an implicit rate, we used our incremental borrowing rate based on the information available at the lease commencement date in determining the present value of future payments. The weighted-average discount rate used was 4.0% and the weighted-average remaining lease term is approximately 7.4 years.

The following non-cancellable office lease costs are included in our consolidated statements of cash flow (in thousands):


		Three Months Ended March 31,
Leases	Classification on the Cash Flow	2024		2023
Operating lease cost	Operating	$	619	$	619
Cash paid for amounts included in the measurement of lease liabilities	Operating	602		585

At March 31, 2024, the future minimum annual obligations for the Company’s operating lease liabilities are as follows (in thousands):


Years Ending December 31,
2024	$	1,855
2025	2,531
2026	2,607
2027	2,685
2028	2,766
Thereafter	7,788
Total minimum payments required	20,232
Less imputed interest	(2,844)
Total	$	17,388

Fair Value Measurements and Available for Sale Investments - Available-for-sale Investments (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2024	Jun. 30, 2023	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 316,860		$ 382,555
Gross Unrealized Gains	17		199
Gross Unrealized Losses	(434)		(789)
Total Fair Value	316,443		381,965
Short-term investments	300,970		354,939
Long-term investments	15,473		27,026
Agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	9,657		20,322
Gross Unrealized Gains	1		0
Gross Unrealized Losses	(24)		(69)
Total Fair Value	9,634		20,253
Short-term investments	9,600		20,300
Long-term investments	$ 0		0
Agency securities \| Minimum
Debt Securities, Available-for-sale [Line Items]
Remaining maturity (in years)	1 year	1 year
Agency securities \| Maximum
Debt Securities, Available-for-sale [Line Items]
Remaining maturity (in years)	2 years	2 years
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 247		246
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(1)		(2)
Total Fair Value	246		244
Short-term investments	200		200
Long-term investments	$ 0		0
Certificates of deposit \| Minimum
Debt Securities, Available-for-sale [Line Items]
Remaining maturity (in years)	1 year	1 year
Certificates of deposit \| Maximum
Debt Securities, Available-for-sale [Line Items]
Remaining maturity (in years)	2 years	2 years
Commercial and corporate obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 29,208		35,760
Gross Unrealized Gains	15		77
Gross Unrealized Losses	(19)		(83)
Total Fair Value	29,204		35,754
Short-term investments	28,600		25,800
Long-term investments	$ 600		10,000
Commercial and corporate obligations \| Minimum
Debt Securities, Available-for-sale [Line Items]
Remaining maturity (in years)	1 year	1 year
Commercial and corporate obligations \| Maximum
Debt Securities, Available-for-sale [Line Items]
Remaining maturity (in years)	2 years	2 years
U.S. Treasury Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 277,748		326,227
Gross Unrealized Gains	1		122
Gross Unrealized Losses	(390)		(635)
Total Fair Value	277,359		325,714
Short-term investments	262,500		308,600
Long-term investments	$ 14,900		$ 17,100
U.S. Treasury Securities \| Minimum
Debt Securities, Available-for-sale [Line Items]
Remaining maturity (in years)	1 year	1 year
U.S. Treasury Securities \| Maximum
Debt Securities, Available-for-sale [Line Items]
Remaining maturity (in years)	2 years	2 years

Description of the Business	3 Months Ended
Description of the Business	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business	Description of the Business AnaptysBio, Inc. (“we,” “us,” “our,” or the “Company”) was incorporated in the state of Delaware in November 2005. We are a clinical-stage biotechnology company focused on delivering innovative immunology therapeutics. We are developing immune cell modulating antibodies, including two wholly owned checkpoint agonists in clinical-stage development, for autoimmune and inflammatory diseases: rosnilimab, our PD-1 agonist in a Phase 2b trial for the treatment of moderate-to-severe rheumatoid arthritis (“RA”) and a Phase 2 trial for the treatment of moderate-to-severe ulcerative colitis (“UC”); and ANB032, our BTLA agonist, in a Phase 2b trial for the treatment of moderate-to-severe atopic dermatitis (“AD”). We also have other preclinical immune cell modulator candidates for the treatment of autoimmune and inflammatory diseases in our portfolio, including ANB033, an anti-CD122 antagonist antibody, and ANB101, a BDCA2 modulator antibody. In addition, we have developed two cytokine antagonists that we are exploring options for out-licensing: imsidolimab, our anti-IL-36R antibody, that has completed Phase 3 trials for the treatment of generalized pustular psoriasis (“GPP”), and etokimab, our anti-IL-33 antagonist that is Phase 2/3 ready. We have also discovered multiple therapeutic antibodies licensed to GlaxoSmithKline, Inc. (“GSK”) in a financial collaboration for immuno-oncology, including an anti-PD-1 antagonist antibody (Jemperli (dostarlimab-gxly) or “Jemperli”) and an anti-TIM-3 antagonist antibody (cobolimab, GSK4069889). We currently recognize revenue from milestones and royalties achieved under our immuno-oncology collaboration with GSK. Since our inception, we have devoted our primary effort to research and development activities. Our financial support has been provided primarily from the sale of our common stock, royalty monetizations, as well as through funds received under our collaborative research and development agreements. Going forward, as we continue our expansion, we may seek additional financing and/or strategic investments. However, there can be no assurance that any additional financing or strategic investments will be available to us on acceptable terms, if at all. If events or circumstances occur such that we do not obtain additional funding, we will most likely be required to reduce our plans and/or certain discretionary spending, which could have a material adverse effect on our ability to achieve our intended business objectives. AnaptysBio management believes our currently available resources will provide sufficient funds to enable us to meet our operating plans for at least the next twelve months from the issuance of our consolidated financial statements. The accompanying consolidated financial statements do not include any adjustments that might be necessary if we are unable to continue as a going concern.

Commitments and Contingencies - Narrative (Details) ft² in Thousands, $ in Thousands	May 04, 2020 ft² $ / ft²	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Apr. 05, 2021 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets		$ 15,732	$ 16,174
Lease liability		$ 17,388
Weighted-average discount rate		4.00%
Weighted average remaining lease term		7 years 4 months 24 days
Lease Agreement
Lessee, Lease, Description [Line Items]
Area of leased property (sqft) \| ft²	45
Lease term	124 months
Lease renewal term	5 years
Lease termination term	7 years
Monthly base rate (in dollars per sqft) \| $ / ft²	4.20
Increase in annual rent percentage	3.00%
Operating lease right-of-use assets				$ 20,600
Lease liability				$ 20,700
Security deposit		$ 300

Collaborative Research and Development Agreements (Tables)

3 Months Ended

Mar. 31, 2024

Revenue from Contract with Customer [Abstract]

Schedule of Milestones Achieved

Milestones under the GSK Agreement are as follows:

Anti-PD-1

(Jemperli/Dostarlimab)

Anti-TIM-3
(GSK4069889A/Cobolimab)

Milestone Event

Amount

Quarter Recognized

Amount

Quarter Recognized

Initiated in vivo toxicology studies using good laboratory practices (GLPs)

$1.0M

Q2'15

$1.0M

Q4'15

IND clearance from the FDA

$4.0M

Q1'16

$4.0M

Q2'16

Phase 2 clinical trial initiation

$3.0M

Q2'17

$3.0M

Q4'17

Phase 3 clinical trial initiation - first indication

$5.0M

Q3'18

$5.0M

Q4'22

Phase 3 clinical trial initiation - second indication

$5.0M

Q2'19

$5.0M

—

Filing of the first BLA(1) - first indication

$10.0M

Q1'20

$10.0M

—

Filing of the first MAA(2) - first indication

$5.0M

Q1'20

$5.0M

—

Filing of the first BLA - second indication

$10.0M

Q1'21

$10.0M

—

First BLA approval - first indication

$20.0M

Q2'21

$20.0M

—

First MAA approval - first indication

$10.0M

Q2'21

$10.0M

—

First BLA approval - second indication

$20.0M

Q3'21

$20.0M

—

Filing of the first MAA - second indication(3)

$5.0M

—

$5.0M

—

First MAA approval - second indication(3)

$10.0M

—

$10.0M

—

First commercial sales milestone(3)

$15.0M

—

$15.0M

—

Second commercial sales milestone(3)

$25.0M

—

$25.0M

—

Third commercial sales milestone(3)

$50.0M

—

$50.0M

—

Fourth commercial sales milestone

$75.0M

—

$75.0M

—

Milestones recognized through March 31, 2024

$93.0M

—

$13.0M

—

Milestones that may be recognized in the future

$180.0M

—

$260.0M

—

(1)Biologics License Application (“BLA”)

(2)Marketing Authorization Application (“MAA”)

(3)For Jemperli, the filing and approval of the first MAA for a second indication and first three commercial sales milestones are included as part of the royalty monetization agreement with Sagard (as defined below), see Note 5. Cash is generally received within 30 days of milestone achievement.

Balance Sheet Accounts and Supplemental Disclosures - Property and Equipment, net (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 8,313	$ 8,316
Less: accumulated depreciation and amortization	(6,359)	(6,218)
Total property and equipment, net	1,954	2,098
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	6,482	6,473
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,628	1,640
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 203	$ 203

Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2024

Accounting Policies [Abstract]

Schedule of Outstanding Potentially Dilutive Securities Excluded in the Calculation of Diluted Net Loss Per Share

The following table sets forth the weighted-average outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because to do so would be anti-dilutive (in common stock equivalent shares):


	Three Months Ended March 31,
(in thousands)		2024	2023

Options to purchase common stock		6,078	4,555

Restricted Stock Units		1,002	427
Total		7,080	4,982

Balance Sheet Accounts and Supplemental Disclosures

3 Months Ended

Mar. 31, 2024

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Accounts and Supplemental Disclosures

Property and Equipment, Net

Property and equipment, net consist of the following:


(in thousands)	March 31, 2024		December 31, 2023
Laboratory equipment	$	6,482	$	6,473
Office furniture and equipment	1,628		1,640
Leasehold improvements	203		203
Property and equipment, gross	8,313		8,316
Less: accumulated depreciation and amortization	(6,359)		(6,218)
Total property and equipment, net	$	1,954	$	2,098

Accrued Expenses

Accrued expenses consist of the following:


(in thousands)	March 31, 2024		December 31, 2023
Accrued compensation and related expenses	$	4,159	$	7,201
Accrued professional fees and other expenses	1,182		1,412
Accrued research, development and manufacturing expenses	20,106		21,898
Accrued for repurchases of common stock	456		456

Total accrued expenses	$	25,903	$	30,967

Subsequent Event	3 Months Ended
Subsequent Event	Mar. 31, 2024
Subsequent Events [Abstract]
Subsequent Events	Subsequent Event Amendment to Jemperli Royalty Monetization Agreement On May 8, 2024, we entered into an amendment to the Jemperli Royalty Monetization Agreement with Sagard (the “Amended Jemperli Royalty Monetization Agreement”) to monetize additional future Jemperli royalties under our GSK Agreement. Upon closing of the transaction, Sagard will pay us $50.0 million upfront in exchange for all Jemperli royalties payable to us under the GSK Agreement on annual global net sales. The aggregate Jemperli royalties and milestones to be received by Sagard under the Amended Jemperli Royalty Monetization Agreement has been increased to the following thresholds: an amount equal to $600.0 million, if received on or prior to March 31, 2031; or an amount equal to $675.0 million, if received on or after April 1, 2031. The Amended Jemperli Royalty Monetization Agreement will expire once Sagard receives either of the aggregate amounts resulting in us regaining all subsequent Jemperli royalties and milestones.

Sale of Future Royalties (Tables)

3 Months Ended

Mar. 31, 2024

Other Liabilities Disclosure [Abstract]

Schedule of Royalty Transaction Activity

The following table shows the activity within the liability account for the three months ended March 31, 2024:


(in thousands)	March 31, 2024
Liability related to sale of future Jemperli royalties and milestones – balance at 12/31/2023	$	278,090

Issuance costs related to the sale of future royalties	—
Amortization of issuance costs	14
Royalty and milestone payments to Sagard	(5,978)
Non-cash interest expense recognized	6,073
Liability related to sale of future royalties and milestones – ending balance	$	278,199

The following table shows the activity within the liability account for the three months ended March 31, 2024:


(in thousands)	March 31, 2024
Liability related to sale of future Zejula royalties and milestones – balance at 12/31/2023	$	32,717


Amortization of issuance costs	7
Royalty and milestone payments to DRI	(962)
Non-cash interest expense recognized	223
Liability related to sale of future royalties and milestones – ending balance	$	31,985

Fair Value Measurements and Available for Sale Investments

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Fair Value Measurements and Available for Sale Investments

Fair Value Measurements

Our financial instruments consist principally of cash, cash equivalents, short-term and long-term investments, receivables, and accounts payable. Certain of our financial assets and liabilities have been recorded at fair value in the consolidated balance sheet in accordance with the accounting standards for fair value measurements.

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants on the measurement date. Accounting guidance also establishes a fair value hierarchy that requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The standard describes three levels of inputs that may be used to measure fair value:

Level 1 – Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets.

Level 2 – Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted 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 related assets or liabilities; and

Level 3 – Unobservable inputs that are supported by little or no market activities, therefore requiring an entity to develop its own assumptions.

Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following table summarizes our assets and liabilities that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy:


	Fair Value Measurements at End of Period Using:
(in thousands)	Fair Value		Quoted Market Prices for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
At March 31, 2024
Money market funds(1)	$	42,780	$	42,780	$	—	$	—
Mutual funds(1)	6,293		6,293		—		—
U.S. Treasury securities(2)	277,359		277,359		—		—
Certificates of deposit(2)	246		—		246		—
Agency securities(2)	9,634		—		9,634		—
Commercial and corporate obligations(2)	29,204		—		29,204		—

At December 31, 2023
Money market funds(1)	$	27,789	$	27,789	$	—	$	—
Mutual funds(1)	6,286		6,286		—		—
U.S. Treasury securities(2)	325,714		325,714		—		—
Certificates of deposit(2)	244		—		244		—
Agency securities(2)	20,253		—		20,253		—
Commercial and corporate obligations(2)	35,754		—		35,754		—

(1) Included in cash and cash equivalents in the accompanying consolidated balance sheets.

(2) Included in short-term or long-term investments in the accompanying consolidated balance sheets depending on the respective maturity date.

The following methods and assumptions were used to estimate the fair value of our financial instruments for which it is practicable to estimate that value:

Marketable Securities. For fair values determined by Level 1 inputs, which utilize quoted prices in active markets for identical assets, the level of judgment required to estimate fair value is relatively low. For fair values determined by Level 2 inputs, which utilize quoted prices in less active markets for similar assets, the level of judgment required to estimate fair value is also considered relatively low.

Fair Value of Other Financial Instruments

The carrying amounts of certain of our financial instruments, including cash and cash equivalents, accounts payable, and accrued expenses approximate fair value due to their short-term nature.

Available for Sale Investments

We invest our excess cash in agency securities, debt instruments of financial institutions and corporations, commercial obligations, and U.S. Treasury securities, which we classify as available-for-sale investments. These investments are carried at fair value and are included in the tables above. The aggregate market value, cost basis, and gross unrealized gains and losses of available-for-sale investments by security type, classified in short-term and long-term investments as of March 31, 2024 are as follows:


(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Total Fair Value
Agency securities(1)	$	9,657	$	1	$	(24)	$	9,634

Certificates of deposit(2)	247		—		(1)		246
Commercial and corporate obligations(3)	29,208		15		(19)		29,204
U.S. Treasury securities(4)	277,748		1		(390)		277,359
Total available for sale investments	$	316,860	$	17	$	(434)	$	316,443

(1) Of our outstanding agency securities, $9.6 million have maturity dates of less than one year and $0.0 million have maturity dates between one to two years as of March 31, 2024.

(2) Of our outstanding certificates of deposit, $0.2 million have maturity dates of less than one year and $0.0 million have a maturity date of between one to two years as of March 31, 2024.

(3) Of our outstanding commercial and corporate obligations, $28.6 million have maturity dates of less than one year and $0.6 million have a maturity date of between one to two years as of March 31, 2024.

(4) Of our outstanding U.S. Treasury securities, $262.5 million have maturity dates of less than one year and $14.9 million have a maturity date of between one to two years as of March 31, 2024.

The aggregate market value, cost basis, and gross unrealized gains and losses of available for sale investments by security type, classified in short-term and long-term investments as of December 31, 2023 are as follows:


(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Total Fair Value
Agency securities(1)	$	20,322	$	—	$	(69)	$	20,253
Certificates of deposit(2)	246		—		(2)		244
Commercial and corporate obligations(3)	35,760		77		(83)		35,754
U.S. Treasury securities(4)	326,227		122		(635)		325,714
Total available for sale investments	$	382,555	$	199	$	(789)	$	381,965

(1) Of our outstanding agency securities, $20.3 million have maturity dates of less than one year and $0.0 million have a maturity date of between one to two years as of December 31, 2023.

(2) Of our outstanding certificates of deposit, $0.2 million have a maturity date of less than one year and $0.0 million have a maturity date of between one to two years as of December 31, 2023.

(3) Of our outstanding commercial and corporate obligations, $25.8 million have maturity dates of less than one year and $10.0 million have a maturity date of between one to two years as of December 31, 2023.

(4) Of our outstanding U.S. Treasury securities, $308.6 million have maturity dates of less than one year and $17.1 million have a maturity date of between one to two years as of December 31, 2023.

The following tables present gross unrealized losses and fair values for those investments that were in an unrealized loss position as of March 31, 2024 and December 31, 2023, aggregated by investment category and the length of time that individual securities have been in a continuous loss position:


	March 31, 2024
	Less than 12 Months				12 Months or Greater				Total
(in thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Agency securities	$	—	$	—	$	7,068	$	(24)	$	7,068	$	(24)
Commercial and corporate obligations	6,535		(9)		4,971		(9)		11,506		(18)
Certificates of deposit	—		—		246		(1)		246		(1)
U.S. Treasury Securities	197,715		(214)		59,916		(177)		257,631		(391)
Total	$	204,250	$	(223)	$	72,201	$	(211)	$	276,451	$	(434)


	December 31, 2023
	Less than 12 Months				12 Months or Greater				Total
(in thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Agency securities	$	2,530	$	(1)	$	17,723	$	(68)	$	20,253	$	(69)
Certificates of Deposit	—		—		244		(2)		244		(2)
Commercial and corporate obligations	5,160		(9)		15,200		(74)		20,360		(83)
U.S. Treasury Securities	98,840		(110)		99,000		(525)		197,840		(635)
Total	$	106,530	$	(120)	$	132,167	$	(669)	$	238,697	$	(789)

As of March 31, 2024 and December 31, 2023, unrealized losses on available-for-sale investments were $0.4 million and $0.8 million, respectively, with unrealized losses of $0.2 million, on available for sale investments that were in an unrealized loss position for greater than 12 months as of March 31, 2024. We do not intend to sell the investments and it is not more likely than not that we will be required to sell the investments before recovery of their amortized cost basis, accordingly, no allowance for credit losses was recorded.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Equity Incentive Plans - Time-based Restricted Stock Units (Details) - RSUs - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Number of Restricted Stock Units
Number of shares, beginning balance (in shares)	1,481,572
Granted (in shares)	718,922
Vested (in shares)	(1,014,242)
Forfeitures and cancellations (in shares)	(1,950)
Number of shares, ending balance (in shares)	1,184,302	1,481,572
Number of shares, Restricted stock units expected to vest (in shares)	1,184,302
Weighted-Average Grant Date Fair Value
Weighted average grant date fair value, beginning balance (in dollars per share)	$ 24.80
Granted (in dollars per share)	21.25
Vested (in dollars per share)	26.12
Cancelled (in dollars per share)	23.23
Weighted average grant date fair value, ending balance (in dollars per share)	21.52	$ 24.80
Number of shares, Restricted stock units expected to vest (in dollars per share)	$ 21.52
Weighted-Average Remaining Contractual Term and Aggregate Intrinsic Value
Weighted average remaining contractual term, other than options outstanding (in years)	1 year 11 months 23 days	8 months 23 days
Weighted average remaining contractual term, other than options vested and expected to vest (in years)	1 year 11 months 23 days
Aggregate intrinsic value, outstanding	$ 26,670	$ 31,735
Aggregate intrinsic value, restricted stock units expected to vest	$ 26,670

Fair Value Measurements and Available for Sale Investments - Schedule of Unrealized Loss and Fair Values in a Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair value	$ 204,250	$ 106,530
Less than 12 months, Gross unrealized losses	(223)	(120)
12 months or greater, Fair value	72,201	132,167
12 months or greater, Gross unrealized losses	(211)	(669)
Fair Value	276,451	238,697
Gross Unrealized Losses	(434)	(789)
Agency securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair value	0	2,530
Less than 12 months, Gross unrealized losses	0	(1)
12 months or greater, Fair value	7,068	17,723
12 months or greater, Gross unrealized losses	(24)	(68)
Fair Value	7,068	20,253
Gross Unrealized Losses	(24)	(69)
Commercial and corporate obligations
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair value	6,535	5,160
Less than 12 months, Gross unrealized losses	(9)	(9)
12 months or greater, Fair value	4,971	15,200
12 months or greater, Gross unrealized losses	(9)	(74)
Fair Value	11,506	20,360
Gross Unrealized Losses	(18)	(83)
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair value	0	0
Less than 12 months, Gross unrealized losses	0	0
12 months or greater, Fair value	246	244
12 months or greater, Gross unrealized losses	(1)	(2)
Fair Value	246	244
Gross Unrealized Losses	(1)	(2)
U.S. Treasury Securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair value	197,715	98,840
Less than 12 months, Gross unrealized losses	(214)	(110)
12 months or greater, Fair value	59,916	99,000
12 months or greater, Gross unrealized losses	(177)	(525)
Fair Value	257,631	197,840
Gross Unrealized Losses	$ (391)	$ (635)

Equity Incentive Plans - Allocation of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	$ 10,131	$ 8,860
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	3,454	2,770
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	$ 6,677	$ 6,090

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-1D

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
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-Subparagraph (c)(1)(i)
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (c)(1)(iv)(01)
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(02)
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(03)
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Paragraph 2
-Subparagraph (c)(1)(iv)(04)
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (c)(2)(i)
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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Reference 16: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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Reference 18: http://www.xbrl.org/2003/role/disclosureRef
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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Reference 20: http://www.xbrl.org/2003/role/disclosureRef
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Reference 24: http://www.xbrl.org/2003/role/disclosureRef
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Reference 25: http://www.xbrl.org/2003/role/disclosureRef
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Reference 26: http://www.xbrl.org/2003/role/disclosureRef
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Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(v)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

Summary of Significant Accounting Policies - Summary of Potentially Dilutive Securities (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Options to purchase common stock (in shares)	7,080	4,982
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Options to purchase common stock (in shares)	6,078	4,555
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Options to purchase common stock (in shares)	1,002	427

Fair Value Measurements and Available for Sale Investments (Tables)

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities that Require Fair Value Measurements on a Recurring Basis

The following table summarizes our assets and liabilities that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy:


	Fair Value Measurements at End of Period Using:
(in thousands)	Fair Value		Quoted Market Prices for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
At March 31, 2024
Money market funds(1)	$	42,780	$	42,780	$	—	$	—
Mutual funds(1)	6,293		6,293		—		—
U.S. Treasury securities(2)	277,359		277,359		—		—
Certificates of deposit(2)	246		—		246		—
Agency securities(2)	9,634		—		9,634		—
Commercial and corporate obligations(2)	29,204		—		29,204		—

At December 31, 2023
Money market funds(1)	$	27,789	$	27,789	$	—	$	—
Mutual funds(1)	6,286		6,286		—		—
U.S. Treasury securities(2)	325,714		325,714		—		—
Certificates of deposit(2)	244		—		244		—
Agency securities(2)	20,253		—		20,253		—
Commercial and corporate obligations(2)	35,754		—		35,754		—

(1) Included in cash and cash equivalents in the accompanying consolidated balance sheets.

(2) Included in short-term or long-term investments in the accompanying consolidated balance sheets depending on the respective maturity date.

Schedule of Available-for-sale Investments

The aggregate market value, cost basis, and gross unrealized gains and losses of available-for-sale investments by security type, classified in short-term and long-term investments as of March 31, 2024 are as follows:


(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Total Fair Value
Agency securities(1)	$	9,657	$	1	$	(24)	$	9,634

Certificates of deposit(2)	247		—		(1)		246
Commercial and corporate obligations(3)	29,208		15		(19)		29,204
U.S. Treasury securities(4)	277,748		1		(390)		277,359
Total available for sale investments	$	316,860	$	17	$	(434)	$	316,443

(1) Of our outstanding agency securities, $9.6 million have maturity dates of less than one year and $0.0 million have maturity dates between one to two years as of March 31, 2024.

(2) Of our outstanding certificates of deposit, $0.2 million have maturity dates of less than one year and $0.0 million have a maturity date of between one to two years as of March 31, 2024.

(4) Of our outstanding U.S. Treasury securities, $262.5 million have maturity dates of less than one year and $14.9 million have a maturity date of between one to two years as of March 31, 2024.


(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Total Fair Value
Agency securities(1)	$	20,322	$	—	$	(69)	$	20,253
Certificates of deposit(2)	246		—		(2)		244
Commercial and corporate obligations(3)	35,760		77		(83)		35,754
U.S. Treasury securities(4)	326,227		122		(635)		325,714
Total available for sale investments	$	382,555	$	199	$	(789)	$	381,965

(1) Of our outstanding agency securities, $20.3 million have maturity dates of less than one year and $0.0 million have a maturity date of between one to two years as of December 31, 2023.

(2) Of our outstanding certificates of deposit, $0.2 million have a maturity date of less than one year and $0.0 million have a maturity date of between one to two years as of December 31, 2023.

(4) Of our outstanding U.S. Treasury securities, $308.6 million have maturity dates of less than one year and $17.1 million have a maturity date of between one to two years as of December 31, 2023.

Schedule of Unrealized Loss and Fair Values in a Loss Position


	March 31, 2024
	Less than 12 Months				12 Months or Greater				Total
(in thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Agency securities	$	—	$	—	$	7,068	$	(24)	$	7,068	$	(24)
Commercial and corporate obligations	6,535		(9)		4,971		(9)		11,506		(18)
Certificates of deposit	—		—		246		(1)		246		(1)
U.S. Treasury Securities	197,715		(214)		59,916		(177)		257,631		(391)
Total	$	204,250	$	(223)	$	72,201	$	(211)	$	276,451	$	(434)


	December 31, 2023
	Less than 12 Months				12 Months or Greater				Total
(in thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Agency securities	$	2,530	$	(1)	$	17,723	$	(68)	$	20,253	$	(69)
Certificates of Deposit	—		—		244		(2)		244		(2)
Commercial and corporate obligations	5,160		(9)		15,200		(74)		20,360		(83)
U.S. Treasury Securities	98,840		(110)		99,000		(525)		197,840		(635)
Total	$	106,530	$	(120)	$	132,167	$	(669)	$	238,697	$	(789)

Balance Sheet Accounts and Supplemental Disclosures (Tables)

3 Months Ended

Mar. 31, 2024

Balance Sheet Related Disclosures [Abstract]

Schedule of Property and Equipment, Net

Property and equipment, net consist of the following:


(in thousands)	March 31, 2024		December 31, 2023
Laboratory equipment	$	6,482	$	6,473
Office furniture and equipment	1,628		1,640
Leasehold improvements	203		203
Property and equipment, gross	8,313		8,316
Less: accumulated depreciation and amortization	(6,359)		(6,218)
Total property and equipment, net	$	1,954	$	2,098

Schedule of Accrued Expenses

Accrued expenses consist of the following:


(in thousands)	March 31, 2024		December 31, 2023
Accrued compensation and related expenses	$	4,159	$	7,201
Accrued professional fees and other expenses	1,182		1,412
Accrued research, development and manufacturing expenses	20,106		21,898
Accrued for repurchases of common stock	456		456

Total accrued expenses	$	25,903	$	30,967

Stockholders' Equity

3 Months Ended

Mar. 31, 2024

Equity [Abstract]

Stockholders' Equity

Stockholders’ Equity

Common Stock

Of the 500,000,000 shares of common stock authorized, 27,316,644 shares were issued and outstanding as of March 31, 2024.

Stock Repurchase Program

In January 2023, our Board of Directors authorized a stock repurchase program (the “Repurchase Program”) to repurchase up to $50.0 million of our outstanding common stock, par value $0.001 per share. The Repurchase Program was completed in May 2023.

The following table presents the repurchase activity from January 1, 2023 through May 5, 2023, the end date of the Repurchase Program:


	Total number of shares purchased	Average price paid per share		Approximate dollar value of shares purchased (in thousands)
First Quarter 2023	1,589,424	$	24.19	$	38,456
Second Quarter 2023	534,790	21.59		11,544
Total	2,124,214			$	50,000

The repurchased common stock was subsequently retired after the repurchase and the par value of the shares was charged to common stock. The excess of the repurchase price over the par value was applied against additional paid in capital.

Open Market Sales Agreement

In November 2022, we entered into the Cowen Sales Agreement with Cowen, through which we may offer and sell shares of our common stock, having an aggregate offering of up to $150.0 million through Cowen as our sales agent. As of March 31, 2024, we had sold no shares under this agreement.

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Section 50
-Paragraph 13
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Publisher FASB
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Publisher FASB
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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-Section S99
-Paragraph 1
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-Publisher FASB
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
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-Section S99
-Paragraph 1
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Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org//505/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Paragraph 13
-Subparagraph (i)
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

+ Details

Equity Incentive Plans - Narrative (Details) $ in Thousands				3 Months Ended
Equity Incentive Plans - Narrative (Details) $ in Thousands	Jan. 01, 2024 shares	Mar. 21, 2022 shares	Jan. 01, 2018	Mar. 31, 2024 USD ($) shares	Mar. 31, 2023 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from stock options exercised \| $				$ 800
Non-cash stock-based compensation cost \| $				10,131	$ 8,860
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost \| $				$ 100
Weighted average period remaining for amortization of unrecognized compensation cost (in years)				1 month 13 days
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				4 years
Award expiration period				10 years
Unrecognized compensation cost \| $				$ 56,000
Weighted average period remaining for amortization of unrecognized compensation cost (in years)				3 years 29 days
Stock Options \| Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				1 year
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award equivalent shares				1
Granted (in shares)				718,922
Unrecognized compensation cost \| $				$ 22,700
Weighted average period remaining for amortization of unrecognized compensation cost (in years)				3 years 2 months 23 days
RSUs \| CEO \| Interim President and Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				24 months
Granted (in shares)		887,043
Non-cash stock-based compensation cost \| $				$ 2,600	$ 2,900
Equity Incentive Plan, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase in number of shares available for issuance percentage			4.00%
Capital shares reserved for future issuance, increase (in shares)	1,063,871
Shares reserved for future award grants (in shares)				1,065,471
Employee Stock Purchase Plan, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future award grants (in shares)				2,000,807
Employee Stock Purchase Plan, 2017 \| ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase in number of shares available for issuance percentage			1.00%
Capital shares reserved for future issuance, increase (in shares)	265,967
Issued under ESPP (in shares)				98,000

Collaborative Research and Development Agreements - Schedule of Milestone Achieved (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Mar. 31, 2020	Jun. 30, 2019	Sep. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2015
Disaggregation of Revenue [Line Items]
Collaboration revenue	$ 7,179	$ 1,374
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Initiated in vivo toxicology studies using good laboratory practices (GLPs)
Disaggregation of Revenue [Line Items]
Collaboration revenue															$ 1,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| IND clearance from the FDA
Disaggregation of Revenue [Line Items]
Collaboration revenue													$ 4,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Phase 2 clinical trial initiation
Disaggregation of Revenue [Line Items]
Collaboration revenue											$ 3,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Phase 3 clinical trial initiation - first indication
Disaggregation of Revenue [Line Items]
Collaboration revenue									$ 5,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Phase 3 clinical trial initiation - second indication
Disaggregation of Revenue [Line Items]
Collaboration revenue								$ 5,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Filing of the first BLA - first indication
Disaggregation of Revenue [Line Items]
Collaboration revenue							$ 10,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Filing of the first MAA - first indication
Disaggregation of Revenue [Line Items]
Collaboration revenue							$ 5,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Filing of the first BLA - second indication
Disaggregation of Revenue [Line Items]
Collaboration revenue						$ 10,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| First BLA approval - first indication
Disaggregation of Revenue [Line Items]
Collaboration revenue					$ 20,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| First MAA approval - first indication
Disaggregation of Revenue [Line Items]
Collaboration revenue					$ 10,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| First BLA approval - second indication
Disaggregation of Revenue [Line Items]
Collaboration revenue				$ 20,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Filing of the first MAA - second indication
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	5,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| First MAA approval - second indication
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	10,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| First commercial sales milestone
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	15,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Second commercial sales milestone
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	25,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Third commercial sales milestone
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	50,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Fourth commercial sales milestone
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	75,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Milestones recognized through March 31, 2024
Disaggregation of Revenue [Line Items]
Collaboration revenue	93,000
GSK \| Anti-PD-1 (Jemperli/Dostarlimab) \| Milestones that may be recognized in the future
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	180,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Initiated in vivo toxicology studies using good laboratory practices (GLPs)
Disaggregation of Revenue [Line Items]
Collaboration revenue														$ 1,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| IND clearance from the FDA
Disaggregation of Revenue [Line Items]
Collaboration revenue												$ 4,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Phase 2 clinical trial initiation
Disaggregation of Revenue [Line Items]
Collaboration revenue										$ 3,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Phase 3 clinical trial initiation - first indication
Disaggregation of Revenue [Line Items]
Collaboration revenue			$ 5,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Phase 3 clinical trial initiation - second indication
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	5,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Filing of the first BLA - first indication
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	10,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Filing of the first MAA - first indication
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	5,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Filing of the first BLA - second indication
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	10,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| First BLA approval - first indication
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	20,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| First MAA approval - first indication
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	10,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| First BLA approval - second indication
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	20,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Filing of the first MAA - second indication
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	5,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| First MAA approval - second indication
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	10,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| First commercial sales milestone
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	15,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Second commercial sales milestone
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	25,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Third commercial sales milestone
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	50,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Fourth commercial sales milestone
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	75,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Milestones recognized through March 31, 2024
Disaggregation of Revenue [Line Items]
Collaboration revenue	13,000
GSK \| Anti-TIM-3 (GSK4069889A/Cobolimab) \| Milestones that may be recognized in the future
Disaggregation of Revenue [Line Items]
Milestones that may be recognized in the future	$ 260,000

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2024

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and note disclosures normally included in annual financial statements prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) have been omitted. The accompanying unaudited consolidated financial statements include all known adjustments necessary for a fair presentation of the results of interim periods as required by U.S. GAAP. These adjustments consist primarily of normal recurring accruals and estimates that impact the carrying value of assets and liabilities. Operating results for the three months ended March 31, 2024 are not necessarily indicative of the results that may be expected for the year ending December 31, 2024. The financial statements should be read in conjunction with our audited financial statements for the year ended December 31, 2023 included in our Annual Report on Form 10-K.

Basis of Consolidation

The accompanying consolidated financial statements include us and our wholly owned Australian subsidiary. All intercompany accounts and transactions have been eliminated in consolidation. We operate in one reportable segment, and our functional and reporting currency is the U.S. dollar.

Use of Estimates

The preparation of the accompanying consolidated financial statements in conformity with U.S. GAAP requires our management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and reported amounts of revenues and expenses during

the reporting periods. Actual results could differ from those estimates. We base our estimates and assumptions on historical experience when available and on various factors that we believe to be reasonable under the circumstances. Significant estimates relied upon in preparing these financial statements include estimates related to revenue recognition, accrued research and development expenses, stock-based compensation, and the liability related to the sale of future royalties. We evaluate our estimates and assumptions on an ongoing basis. Our actual results could differ from these estimates under different assumptions or conditions.

Net Loss Per Common Share

Basic net loss per common share is computed by dividing net loss by the weighted-average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common equivalent shares outstanding for the period, as well as any dilutive effect from outstanding stock options and warrants using the treasury stock method. For each period presented, there is no difference in the number of shares used to calculate basic and diluted net loss per share.


	Three Months Ended March 31,
(in thousands)		2024	2023

Options to purchase common stock		6,078	4,555

Restricted Stock Units		1,002	427
Total		7,080	4,982

Accounting Pronouncements

We have implemented all new accounting pronouncements that are in effect and may have an impact on our consolidated financial statements. Unless otherwise discussed, we believe the impact of any recently issued and not yet effective pronouncements will not have a material impact on our consolidated financial statements.

Recent Accounting Pronouncements Not Yet Adopted

In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires enhanced disclosure of significant segment expenses on an annual and interim basis. The guidance will be effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning December 15, 2024, with early adoption permitted. Upon adoption, the guidance should be applied retrospectively to all prior periods presented in the financial statements. We are currently assessing the impact that this standard will have on our consolidated financial statements.

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures Income Taxes, which improves the transparency of income tax disclosures by requiring consistent categories and greater disaggregation of information in the effective tax rate reconciliation and income taxes paid disaggregated by jurisdiction. It also includes certain other amendments to improve the effectiveness of income tax disclosures. This guidance will be effective for the annual periods beginning after December 15, 2024. Early adoption is permitted. Upon adoption, the guidance can be applied prospectively or retrospectively. We are currently assessing the impact that this standard will have on our consolidated financial statements.

Sale of Future Royalties

3 Months Ended

Mar. 31, 2024

Other Liabilities Disclosure [Abstract]

Sale of Future Royalties

Jemperli Royalty Monetization Agreement

In October 2021, we signed a royalty monetization agreement (“Jemperli Royalty Monetization Agreement”) with Sagard Healthcare Royalty Partners, LP (“Sagard”). Under the terms of the Jemperli Royalty Monetization Agreement, we received $250.0 million in exchange for royalties and milestones payable to us under our GSK collaboration on annual global net sales of Jemperli below $1.0 billion starting in October 2021 (not including any combination products that contain both Jemperli and another Development Antibody (as defined in the Jemperli Royalty Monetization Agreement)). The aggregate Jemperli royalties and milestones to be received by Sagard under the Jemperli Royalty Monetization Agreement is capped at certain fixed multiples of the upfront payment based on time. Once Sagard receives an aggregate amount of either $312.5 million (125% of the upfront) by the end of 2026, $337.5 million (135% of the upfront) during 2027, or $412.5 million (165% of the upfront) at any time after 2027, the Jemperli Royalty Monetization Agreement will expire resulting in us regaining all subsequent Jemperli royalties and milestones. As of March 31, 2024, Sagard has received a total of $16.4 million in royalties and milestones.

The Jemperli Royalty Monetization Agreement includes a call option pursuant to which at any time after December 1, 2024, we may reacquire our interest in the specified royalties by paying Sagard (in cash) a specified amount as described in the Jemperli Royalty Monetization Agreement. The exercise of this call option is at our sole discretion, which we currently do not anticipate exercising.

The proceeds received from Sagard of $250.0 million were recorded as a liability, net of transaction costs of $0.4 million, which will be amortized over the estimated life of the arrangement using the effective interest rate method. The aggregate future estimated payments, less the $249.6 million, net of proceeds, will be recognized as non-cash interest expense over the life of the agreement. Royalty and milestone revenue will be recognized as earned on net sales of Jemperli, and these payments to Sagard will be recorded as a reduction of the liability when paid. As such payments are made to Sagard, the balance of the liability will be effectively repaid over the life of the Jemperli Royalty Monetization Agreement.

We estimate the effective interest rate used to record non-cash interest expense under the Jemperli Royalty Monetization Agreement based on the estimate of future royalty payments to be received by Sagard. As of March 31, 2024, the estimated effective rate under the agreement was 10.0%. Over the life of the arrangement, the actual effective interest rate will be affected by the amount and the timing of the royalty payments received by Sagard and changes in our forecasted royalties. At each reporting date, we will reassess our estimate of total future royalty payments to be received and if such payments are materially different than our original estimates, we will prospectively adjust the imputed interest rate and the related amortization of the royalty obligation.

We recognized Jemperli non-cash royalty revenue of approximately $6.2 million and $0.6 million during the three months ended March 31, 2024 and three months ended March 31, 2023, respectively, and non-cash interest expense of approximately $6.1 million and $4.0 million during the three months ended March 31, 2024 and three months ended March 31, 2023, respectively. The interest and amortization of issuance costs are reflected as non-cash interest expense for the sale of future royalties in the Consolidated Statements of Operations.

The following table shows the activity within the liability account for the three months ended March 31, 2024:


(in thousands)	March 31, 2024
Liability related to sale of future Jemperli royalties and milestones – balance at 12/31/2023	$	278,090

Issuance costs related to the sale of future royalties	—
Amortization of issuance costs	14
Royalty and milestone payments to Sagard	(5,978)
Non-cash interest expense recognized	6,073
Liability related to sale of future royalties and milestones – ending balance	$	278,199

On May 8, 2024, we entered into an amendment to the Jemperli Royalty Monetization Agreement with Sagard. For more information about this amendment, see Note 10 — Subsequent Event.

Zejula Royalty Monetization Agreement

In October 2020, in connection with Amendment No. 3 to the GSK Agreement, GSK agreed, under the terms of a settlement agreement (the “GSK Settlement Agreement”), to pay us a royalty on all GSK net sales of Zejula starting January 1, 2021. Under the GSK Settlement Agreement, the royalty is paid at a rate of 1.0% but is subject to reduction due to royalties paid to third parties, with a minimum royalty payable under the GSK Settlement Agreement of 0.5% of global net sales of Zejula. The current effective royalty rate is 0.5%.

In September 2022, we signed a purchase and sale agreement (the “Zejula Royalty Monetization Agreement”) with a wholly owned subsidiary of DRI to monetize all of our future royalties on global net sales of Zejula under the GSK Settlement Agreement. Under the terms of the Zejula Royalty Monetization Agreement, we received $35.0 million in exchange for all royalties payable by GSK to us under the GSK Settlement Agreement on global net sales of Zejula starting in July 2022. In addition, under the Zejula Royalty Monetization Agreement, we are entitled to receive an additional $10.0 million payment from DRI if Zejula is approved by the U.S. Food and Drug Administration for the treatment of endometrial cancer on or prior to December 31, 2025.

The proceeds received from DRI of $35.0 million were recorded as a liability, net of transaction costs of $0.2 million, which will be amortized over the estimated life of the arrangement using the effective interest rate method. Royalty revenue will be recognized as earned on net sales of Zejula, and these royalty payments to DRI will be recorded as a reduction of the liability when paid. The aggregate future estimated payments, less the $34.8 million, of net proceeds, will be recorded as non-cash interest expense over the life of the agreement. As such payments are made to DRI, the balance of the liability will be effectively repaid over the life of the Zejula Royalty Monetization Agreement.

We estimate the effective interest rate used to record non-cash interest expense under the Zejula Royalty Monetization Agreement based on the estimate of future royalty payments to be received by DRI. As of March 31, 2024, the estimated effective rate under the agreement was 2.9%. Over the life of the arrangement, the actual effective interest rate will be affected by the amount and the timing of the royalty payments received by DRI and the changes in our forecasted royalties. At each reporting date, we will reassess our estimate of total future royalty payments to be received and if such payments are materially different than our original estimates, we will prospectively adjust the imputed interest rate and the related amortization of the royalty obligation.

We recognized Zejula non-cash royalty revenue of approximately $1.0 million and $0.8 million during the three months ended March 31, 2024 and three months ended March 31, 2023, respectively, and non-cash interest expense of approximately $0.2 million and $0.4 million during the three months ended March 31, 2024 and three months ended March 31, 2023, respectively. The interest and amortization of issuance costs is reflected as non-cash interest expense for the sale of future royalties in the Consolidated Statements of Operations.

The following table shows the activity within the liability account for the three months ended March 31, 2024:


(in thousands)	March 31, 2024
Liability related to sale of future Zejula royalties and milestones – balance at 12/31/2023	$	32,717


Amortization of issuance costs	7
Royalty and milestone payments to DRI	(962)
Non-cash interest expense recognized	223
Liability related to sale of future royalties and milestones – ending balance	$	31,985

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (43,936)	$ (44,255)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	163	166
Stock-based compensation	10,131	8,860
Accretion/amortization of investments, net	(2,968)	(2,191)
Amortization of right-of-use assets – operating	442	427
Non-cash interest expense	6,317	4,336
Changes in operating assets and liabilities:
Receivables from collaborative partners	(238)	(104)
Prepaid expenses and other assets	(1,566)	51
Accounts payable and other liabilities	(5,172)	8,533
Operating lease liabilities	(426)	(391)
Net cash used in operating activities	(37,253)	(24,568)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of investments	(58,997)	(48,555)
Sales and maturities of investments	127,640	134,126
Purchases of property and equipment	(27)	(175)
Net cash provided by investing activities	68,616	85,396
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	811	1,265
Repurchase and retirements of common stock	0	(37,526)
Payment for net share settlement of equity awards	(7,504)	0
Repayment of liability for sale of future royalties	(6,940)	(1,270)
Payments for debt issuance costs	0	(43)
Net cash used in financing activities	(13,633)	(37,574)
Net increase in cash and cash equivalents	17,730	23,254
Cash and cash equivalents, beginning of period	35,965	71,308
Cash and cash equivalents, end of period	53,695	94,562
Non-cash investing and financing activities:
Amounts accrued for property and equipment	0	38
Amounts accrued for repurchases of common stock	0	1,290
Receivable related to issuance of common stock, upon exercise of stock options	$ 0	$ (43)

Equity Incentive Plans (Tables)

3 Months Ended

Mar. 31, 2024

Share-Based Payment Arrangement [Abstract]

Schedule of Activity Related to Stock Option Awards

A summary of the activity related to stock option awards during the three months ended March 31, 2024 is as follows:


	Shares Subject to Options	Weighted-Average Exercise Price per Share		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2024	4,225,615	$	27.36	7.42	$	5,827
Granted	1,975,327	$	21.25
Exercised	(53,078)	$	15.29
Forfeitures and cancellations	(73,608)	$	44.19
Outstanding at March 31, 2024	6,074,256	$	25.28	8.14	$	9,356
Exercisable at March 31, 2024	2,452,748	$	29.36	6.51	$	5,322

Schedule of Time-based Restricted Stock Units Activity


	Number of Restricted Stock Units	Weighted-Average Grant Date Fair Value		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2024	1,481,572	$	24.80	0.73	$	31,735
Granted	718,922	$	21.25
Vested	(1,014,242)	$	26.12
Forfeitures and cancellations	(1,950)	$	23.23
Outstanding at March 31, 2024	1,184,302	$	21.52	1.98	$	26,670
RSU expected to vest at March 31, 2024	1,184,302	$	21.52	1.98	$	26,670

Schedule of Weighted Average Assumptions used to Estimate Fair Value

The estimated fair values of stock option awards granted were determined on the date of grant using the Black-Scholes option valuation model with the following weighted-average assumptions:


	Three Months Ended March 31,

		2024	2023
Risk-free interest rate				3.9	%		3.7	%
Expected volatility				78.3	%		86.5	%
Expected dividend yield				—	%		—	%
Expected term (in years)				6.28			5.65
Weighted-average grant date fair value per share			$	15.12		$	16.88

Schedule of Non-cash Stock-based Compensation Expense

Total non-cash stock-based compensation expense for all stock awards that was recognized in the consolidated statements of operations and comprehensive loss is as follows:


	Three Months Ended March 31,
(in thousands)		2024		2023
Research and development		$	3,454	$	2,770
General and administrative		6,677		6,090
Total		$	10,131	$	8,860

Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2024

Commitments and Contingencies Disclosure [Abstract]

Schedule of Costs in Cash Flow Statement

The following non-cancellable office lease costs are included in our consolidated statements of cash flow (in thousands):


		Three Months Ended March 31,
Leases	Classification on the Cash Flow	2024		2023
Operating lease cost	Operating	$	619	$	619
Cash paid for amounts included in the measurement of lease liabilities	Operating	602		585

Schedule of Future Minimum Annual Obligations

At March 31, 2024, the future minimum annual obligations for the Company’s operating lease liabilities are as follows (in thousands):


Years Ending December 31,
2024	$	1,855
2025	2,531
2026	2,607
2027	2,685
2028	2,766
Thereafter	7,788
Total minimum payments required	20,232
Less imputed interest	(2,844)
Total	$	17,388

Fair Value Measurements and Available for Sale Investments - Narratives (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Unrealized losses on available-for-sale	$ 434,000	$ 789,000
Unrealized losses on available for sale investments in unrealized loss position for greater than 12 months	211,000	$ 669,000
Allowance for credit losses	$ 0

Consolidated Statement of Stockholders’ Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Stockholders' equity, beginning balance (in shares) at Dec. 31, 2022		28,513,000
Stockholders' equity, beginning balance at Dec. 31, 2022	$ 262,103	$ 29	$ 717,797	$ (5,246)	$ (450,477)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from exercises of options and employee stock purchase plan (in shares)		55,000
Issuance of common stock from exercises of options and employee stock purchase plan	1,222		1,222
Issuance of common stock upon vesting of restricted stock units (in shares)		39,000
Repurchases and retirements of common stock (in shares)		(1,589,000)
Repurchases and retirements of common stock	(38,816)	$ (2)	(38,814)
Stock-based compensation	8,860		8,860
Comprehensive gain, net	1,979			1,979
Net loss	(44,255)				(44,255)
Stockholders' equity, ending balance (in shares) at Mar. 31, 2023		27,018,000
Stockholders' equity, ending balance at Mar. 31, 2023	$ 191,093	$ 27	689,065	(3,267)	(494,732)
Stockholders' equity, beginning balance (in shares) at Dec. 31, 2023	26,597,000	26,597,000
Stockholders' equity, beginning balance at Dec. 31, 2023	$ 88,103	$ 27	702,969	(797)	(614,096)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from exercises of options and employee stock purchase plan (in shares)		53,000
Issuance of common stock from exercises of options and employee stock purchase plan	811		811
Issuance of common stock upon vesting of restricted stock units (in shares)		1,014,000
Tax withholding related to vesting of restricted stock units (in shares)		(347,000)
Net share settlement of restricted stock units	(7,504)		(7,504)
Stock-based compensation	10,131		10,131
Comprehensive gain, net	173			173
Net loss	$ (43,936)				(43,936)
Stockholders' equity, ending balance (in shares) at Mar. 31, 2024	27,316,644	27,317,000
Stockholders' equity, ending balance at Mar. 31, 2024	$ 47,778	$ 27	$ 706,407	$ (624)	$ (658,032)

Balance Sheet Accounts and Supplemental Disclosures - Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Balance Sheet Related Disclosures [Abstract]
Accrued compensation and related expenses	$ 4,159	$ 7,201
Accrued professional fees and other expenses	1,182	1,412
Accrued research, development and manufacturing expenses	20,106	21,898
Accrued for repurchases of common stock	456	456
Total accrued expenses	$ 25,903	$ 30,967

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net loss	$ (43,936)	$ (44,255)

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/exampleRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Equity Incentive Plans - Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Shares Subject to Options
Stock options outstanding, beginning balance (in shares)	4,225,615
Granted (in shares)	1,975,327
Exercised (in shares)	(53,078)
Forfeitures and cancellations (in shares)	(73,608)
Stock options outstanding, ending balance (in shares)	6,074,256	4,225,615
Shares subject to options, exercisable, ending balance (in shares)	2,452,748
Weighted-Average Exercise Price per Share
Stock options outstanding, beginning balance (in dollars per share)	$ 27.36
Granted (in dollars per share)	21.25
Exercised (in dollars per share)	15.29
Forfeitures and cancellations (in dollars per share)	44.19
Stock options outstanding, ending balance (in dollars per share)	25.28	$ 27.36
Weighted-average exercise price per share, Stock options exercisable, ending balance (in dollars per share)	$ 29.36
Weighted-Average Remaining Contractual Term and Aggregate Intrinsic Value
Weighted average remaining contractual term, options outstanding (in years)	8 years 1 month 20 days	7 years 5 months 1 day
Weighted average remaining contractual term, options exercisable (in years)	6 years 6 months 3 days
Aggregate intrinsic value, options outstanding	$ 9,356	$ 5,827
Aggregate intrinsic value, options exercisable	$ 5,322

Collaborative Research and Development Agreements

3 Months Ended

Mar. 31, 2024

Revenue from Contract with Customer [Abstract]

Collaborative Research and Development Agreements

GSK Collaboration

In March 2014, we entered into a Collaboration and Exclusive License Agreement with GSK (the “GSK Agreement”) with TESARO, Inc. (“Tesaro”), an oncology-focused biopharmaceutical company now a part of GSK (Tesaro and GSK are hereinafter referred to, collectively, as “GSK”). Currently, under the GSK Agreement, GSK is developing Jemperli as a monotherapy for various solid tumor indications. In addition, GSK is developing dostarlimab in combination with additional therapies under the collaboration, including with another development program from the GSK Agreement: cobolimab, an anti-TIM-3 antibody, in 2L NSCLC. In October 2023, Amendment No. 5 to the GSK Agreement was agreed by both parties to terminate the anti-LAG-3 antagonist antibody development program under the GSK Agreement. In accordance with the GSK Agreement and the amendment, we have regained full global rights to the anti-LAG-3 antagonist antibody development program.

For each remaining development program under the GSK Agreement, we are eligible to receive milestone payments if certain preclinical and clinical trial events are achieved by GSK, if certain U.S. and European regulatory submissions and approvals in multiple indications are achieved, and upon the achievement of specified levels of annual worldwide net sales. We will also be eligible to receive tiered 4-8% royalties related to worldwide net sales of products developed under the collaboration. On October 23, 2020, Amendment No. 3 to the GSK Agreement (the “Amendment”) was agreed to by both parties to permit GSK to conduct development and commercialization in combination with any third-party molecules of Zejula, an oral, once-daily poly (ADP-ribose) polymerase (PARP) inhibitor (“Zejula”). Under the Amendment, we were granted increased royalties upon sales of Jemperli, equal to 8% of Net Sales (as defined in the GSK Agreement) below $1.0 billion and from 12% up to 25% of Net Sales above $1.0 billion. Unless earlier terminated by either party upon specified circumstances, the GSK Agreement will terminate, with respect to each specific developed product, upon the later of the 12th anniversary of the first commercial sale of the product or the expiration of the last to expire of any patent.

We assessed these arrangements in accordance with ASC 606 and concluded that the contract counterparty, GSK, is a customer. We identified the following material promises under the GSK Agreement: (1) the licenses under certain patent rights and transfer of certain development and regulatory information, (2) research and development (“R&D”) services, and (3) joint

steering committee meetings. We considered the research and discovery capabilities of GSK for these specific programs and the fact that the discovery and optimization of these antibodies is proprietary and could not, at the time of contract inception, be provided by other vendors, to conclude that the license does not have stand-alone functionality and is therefore not distinct. Additionally, we determined that the joint steering committee participation would not have been provided without the R&D services and GSK Agreement. Based on these assessments, we identified all services to be interrelated and therefore concluded that the promises should be combined into a single performance obligation at the inception of the arrangement.

As of March 31, 2024, the transaction price for the GSK Agreement and Amendments includes the upfront payment, research reimbursement revenue and milestones and royalties earned to date, which are allocated in their entirety to the single performance obligation.

We recognized $7.2 million in royalty revenue during the three months ended March 31, 2024 related to GSK’s net sales of Jemperli and Zejula during the period, which we estimate based on either GSK’s prior sales experience or actuals. Of the royalty revenue recognized during the three months ended March 31, 2024, $6.2 million is Jemperli non-cash revenue related to the Jemperli Royalty Monetization Agreement and $1.0 million is Zejula non-cash revenue related to the Zejula Royalty Monetization Agreement, each of such agreements as described in Note 5. We recognized $1.4 million in royalty revenue during the three months ended March 31, 2023, related to GSK’s net sales of Zejula and Jemperli during the period based on GSK’s prior sales experience or actuals. Of the royalty revenue recognized during the three months ended March 31, 2023, $0.6 million is Jemperli non-cash revenue related to the Jemperli Royalty Monetization Agreement and $0.8 million is Zejula non-cash revenue related to the Zejula Royalty Monetization Agreement. GSK reports sales information to us on a one quarter lag and differences between actual and estimated royalty revenues will be adjusted in the following quarter. All royalty revenue related to Zejula global net sales starting July 2022 will be paid directly to a wholly owned subsidiary of DRI Healthcare Trust (“DRI”) pursuant to the Zejula Royalty Monetization Agreement, as described in Note 5.

No clinical milestones were recognized during the three months ended March 31, 2024 and 2023. No other future clinical or regulatory milestones have been included in the transaction price, as all milestone amounts were subject to the revenue constraint. As part of the constraint evaluation, we considered numerous factors including the fact that the receipt of milestones is outside of our control and contingent upon success in future clinical trials, an outcome that is difficult to predict, and GSK’s efforts. Any consideration related to sales-based milestones, including royalties, will be recognized when the related sales occur as they were determined to relate predominantly to the intellectual property license granted to GSK and therefore have also been excluded from the transaction price. We will re-evaluate the variable transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur.

Milestones under the GSK Agreement are as follows:

Anti-PD-1

(Jemperli/Dostarlimab)

Anti-TIM-3
(GSK4069889A/Cobolimab)

Milestone Event

Amount

Quarter Recognized

Amount

Quarter Recognized

Initiated in vivo toxicology studies using good laboratory practices (GLPs)

$1.0M

Q2'15

$1.0M

Q4'15

IND clearance from the FDA

$4.0M

Q1'16

$4.0M

Q2'16

Phase 2 clinical trial initiation

$3.0M

Q2'17

$3.0M

Q4'17

Phase 3 clinical trial initiation - first indication

$5.0M

Q3'18

$5.0M

Q4'22

Phase 3 clinical trial initiation - second indication

$5.0M

Q2'19

$5.0M

—

Filing of the first BLA(1) - first indication

$10.0M

Q1'20

$10.0M

—

Filing of the first MAA(2) - first indication

$5.0M

Q1'20

$5.0M

—

Filing of the first BLA - second indication

$10.0M

Q1'21

$10.0M

—

First BLA approval - first indication

$20.0M

Q2'21

$20.0M

—

First MAA approval - first indication

$10.0M

Q2'21

$10.0M

—

First BLA approval - second indication

$20.0M

Q3'21

$20.0M

—

Filing of the first MAA - second indication(3)

$5.0M

—

$5.0M

—

First MAA approval - second indication(3)

$10.0M

—

$10.0M

—

First commercial sales milestone(3)

$15.0M

—

$15.0M

—

Second commercial sales milestone(3)

$25.0M

—

$25.0M

—

Third commercial sales milestone(3)

$50.0M

—

$50.0M

—

Fourth commercial sales milestone

$75.0M

—

$75.0M

—

Milestones recognized through March 31, 2024

$93.0M

—

$13.0M

—

Milestones that may be recognized in the future

$180.0M

—

$260.0M

—

(1)Biologics License Application (“BLA”)

(2)Marketing Authorization Application (“MAA”)

Centessa

On November 24, 2023, we entered into an exclusive license agreement (as amended, the “Centessa Agreement”) with Centessa Pharmaceuticals (UK) Limited (“Centessa”), pursuant to which we acquired the exclusive global development and commercialization rights to a blood dendritic cell antigen 2 (BDCA2) modulator antibody portfolio, including lead asset CBS004 (renamed ANB101), CBS008 (renamed ANB102) and the related family of backup antibodies, for the treatment of autoimmune and inflammatory diseases.

In connection with the Centessa Agreement, we paid Centessa an upfront cash payment of $4.0 million and an additional cash payment of $3.0 million as reimbursement to Centessa for manufacturing costs incurred. There were $0.3 million in transaction costs incurred. The total transaction amount of $7.3 million was expensed as in-process research and development and classified as an operating activity in the statement of cash flows. We accounted for the transaction as an asset acquisition as the set of acquired assets did not constitute a business.

Under the terms of the agreement, Centessa may be entitled to receive potential future payments of up to $10.0 million upon the achievement of a certain event-based milestone and would be entitled to receive on a product-by-product and country-by-country basis, a royalty of low single digits on annual net sales of any product in the territory in each calendar year. As of

March 31, 2024, achievement of the milestone is not probable and, therefore, we have not recognized a liability for the associated $10.0 million contingent consideration.

Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2024

Equity [Abstract]

Schedule of Repurchase Activity

The following table presents the repurchase activity from January 1, 2023 through May 5, 2023, the end date of the Repurchase Program:


	Total number of shares purchased	Average price paid per share		Approximate dollar value of shares purchased (in thousands)
First Quarter 2023	1,589,424	$	24.19	$	38,456
Second Quarter 2023	534,790	21.59		11,544
Total	2,124,214			$	50,000

Cover Page - shares	3 Months Ended
Cover Page - shares	Mar. 31, 2024	May 06, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-37985
Entity Registrant Name	ANAPTYSBIO, INC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-3828755
Entity Address, Address Line One	10770 Wateridge Circle
Entity Address, Address Line Two	Suite 210
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	362-6295
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	ANAB
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		27,318,644
Entity Central Index Key	0001370053
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

Commitments and Contingencies - Schedule of Future Minimum Annual Obligations (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2024	$ 1,855
2025	2,531
2026	2,607
2027	2,685
2028	2,766
Thereafter	7,788
Total minimum payments required	20,232
Less imputed interest	(2,844)
Total	$ 17,388

Subsequent Event (Details) - Jemperli Royalty Monetization Agreement - Sagard - USD ($)		1 Months Ended
	May 08, 2024	Oct. 31, 2021
Subsequent Event [Line Items]
Proceeds from sale of future royalties		$ 250,000,000
Subsequent event
Subsequent Event [Line Items]
Proceeds from sale of future royalties	$ 50,000,000
Subsequent event \| Received on or prior to March 31, 2031
Subsequent Event [Line Items]
Upfront payment	600,000,000
Subsequent event \| Received on or after April 1, 2031
Subsequent Event [Line Items]
Upfront payment	$ 675,000,000

Commitments and Contingencies - Costs Included in Cash Flow Statement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 619	$ 619
Cash paid for amounts included in the measurement of lease liabilities	$ 602	$ 585

Equity Incentive Plans - Summary of Weighted Average Assumptions used to Estimate Fair Value (Details) - Stock Options - $ / shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	3.90%	3.70%
Expected volatility	78.30%	86.50%
Expected dividend yield	0.00%	0.00%
Expected term (in years)	6 years 3 months 10 days	5 years 7 months 24 days
Weighted average grant date fair value per share (in dollars per share)	$ 15.12	$ 16.88

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Sale of Future Royalties - Schedule of Royalty Transaction Activity (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Sep. 30, 2022	Oct. 31, 2021	Mar. 31, 2024	Mar. 31, 2023
Liabilities Related To Sale Of Future Royalties [Roll Forward]
Royalty and milestone payments			$ (6,940)	$ (1,270)
Non-cash interest expense recognized			6,317	$ 4,336
Jemperli Royalty Monetization Agreement
Liabilities Related To Sale Of Future Royalties [Roll Forward]
Beginning balance			278,090
Issuance costs related to the sale of future royalties		$ 400	0
Amortization of issuance costs			14
Royalty and milestone payments			(5,978)
Non-cash interest expense recognized			6,073
Ending balance			278,199
Zejula Royalty Monetization Agreement
Liabilities Related To Sale Of Future Royalties [Roll Forward]
Beginning balance			32,717
Issuance costs related to the sale of future royalties	$ 200
Amortization of issuance costs			7
Royalty and milestone payments			(962)
Non-cash interest expense recognized			223
Ending balance			$ 31,985

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 53,695	$ 35,965
Receivables from collaborative partners	7,089	6,851
Short-term investments	300,970	354,939
Prepaid expenses and other current assets	10,666	9,080
Total current assets	372,420	406,835
Property and equipment, net	1,954	2,098
Operating lease right-of-use assets	15,732	16,174
Long-term investments	15,473	27,026
Other long-term assets	256	256
Total assets	405,835	452,389
Current liabilities:
Accounts payable	4,582	4,698
Accrued expenses	25,903	30,967
Current portion of operating lease liability	1,813	1,777
Total current liabilities	32,298	37,442
Liability related to sale of future royalties	310,184	310,807
Operating lease liability, net of current portion	15,575	16,037
Stockholders’ equity:
Preferred stock, $0.001 par value, 10,000 shares authorized and no shares, issued or outstanding at March 31, 2024 and December 31, 2023, respectively	0	0
Common stock, $0.001 par value, 500,000 shares authorized, 27,317 shares and 26,597 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively	27	27
Additional paid in capital	706,407	702,969
Accumulated other comprehensive loss	(624)	(797)
Accumulated deficit	(658,032)	(614,096)
Total stockholders’ equity	47,778	88,103
Total liabilities and stockholders’ equity	$ 405,835	$ 452,389

Fair Value Measurements and Available for Sale Investments - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	$ 316,443	$ 381,965
U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	277,359	325,714
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	246	244
Agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	9,634	20,253
Commercial and corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	29,204	35,754
Recurring \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	42,780	27,789
Recurring \| Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	6,293	6,286
Recurring \| U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	277,359	325,714
Recurring \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	246	244
Recurring \| Agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	9,634	20,253
Recurring \| Commercial and corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	29,204	35,754
Recurring \| Quoted Market Prices for Identical Assets (Level 1) \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	42,780	27,789
Recurring \| Quoted Market Prices for Identical Assets (Level 1) \| Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	6,293	6,286
Recurring \| Quoted Market Prices for Identical Assets (Level 1) \| U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	277,359	325,714
Recurring \| Quoted Market Prices for Identical Assets (Level 1) \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring \| Quoted Market Prices for Identical Assets (Level 1) \| Agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring \| Quoted Market Prices for Identical Assets (Level 1) \| Commercial and corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring \| Significant Other Observable Inputs (Level 2) \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	0	0
Recurring \| Significant Other Observable Inputs (Level 2) \| Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	0	0
Recurring \| Significant Other Observable Inputs (Level 2) \| U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring \| Significant Other Observable Inputs (Level 2) \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	246	244
Recurring \| Significant Other Observable Inputs (Level 2) \| Agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	9,634	20,253
Recurring \| Significant Other Observable Inputs (Level 2) \| Commercial and corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	29,204	35,754
Recurring \| Significant Unobservable Inputs (Level 3) \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	0	0
Recurring \| Significant Unobservable Inputs (Level 3) \| Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value	0	0
Recurring \| Significant Unobservable Inputs (Level 3) \| U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring \| Significant Unobservable Inputs (Level 3) \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring \| Significant Unobservable Inputs (Level 3) \| Agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	0	0
Recurring \| Significant Unobservable Inputs (Level 3) \| Commercial and corporate obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, debt securities	$ 0	$ 0