RAPT Therapeutics (RAPT) 10-K 6 Mar 25 2024 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Mar. 03, 2025	Jun. 28, 2024
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Trading Symbol	RAPT
Entity Registrant Name	RAPT THERAPEUTICS, INC.
Entity Central Index Key	0001673772
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Document Financial Statement Error Correction	false
Entity File Number	001-38997
Entity Tax Identification Number	47-3313701
Entity Address, Address Line One	561 Eccles Avenue
Entity Address, City or Town	South San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	650
Local Phone Number	489-9000
Entity Common Stock, Shares Outstanding		132,006,828
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Annual Report	true
Document Transition Report	false
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
ICFR Auditor Attestation Flag	false
Entity Public Float			$ 75
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	San Mateo, California
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the Registrant’s Definitive Proxy Statement for the 2025 Annual Meeting of Stockholders to be filed with the U.S. Securities and Exchange Commission pursuant to Regulation 14A within 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K are incorporated by reference in Part III, Items 10-14 of this Annual Report on Form 10-K.
Auditor Opinion	Opinion on the Financial Statements We have audited the accompanying balance sheets of RAPT Therapeutics, Inc. (the Company) as of December 31, 2024 and 2023, the related statements of operations and comprehensive loss , stockholders' equity and cash flows for each of the two years in the period ended December 31, 2024, and the related notes (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the two years in the period ended December 31, 2024, in conformity with U.S. generally accepted accounting principles.

BALANCE SHEETS

BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 169,735	$ 47,478
Marketable securities	61,320	111,384
Prepaid expenses and other current assets	4,181	2,920
Total current assets	235,236	161,782
Property and equipment, net	1,367	2,448
Operating lease right-of-use assets	3,333	5,228
Other assets	389	3,871
Total assets	240,325	173,329
Current liabilities:
Accounts payable	1,275	5,176
Accrued expenses	9,597	14,103
License fees payable	35,000
Operating lease liabilities, current	2,422	2,448
Other current liabilities	57	109
Total current liabilities	48,351	21,836
Operating lease liabilities, non-current	2,070	4,458
Total liabilities	50,421	26,294
Commitments (see note 6)
Stockholders' equity:
Preferred stock, $0.0001 par value: 50,000,000 shares authorized; no shares issued and outstanding at December 31, 2024 and 2023
Common stock, $0.0001 par value; 500,000,000 shares authorized; 132,006,828 and 34,398,312 shares issued and outstanding at December 31, 2024 and 2023, respectively	13	3
Additional paid-in capital	804,388	631,611
Accumulated other comprehensive income	50	103
Accumulated deficit	(614,547)	(484,682)
Total stockholders' equity	189,904	147,035
Total liabilities and stockholders' equity	$ 240,325	$ 173,329

BALANCE SHEETS (Parenthetical)

BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	132,006,828	34,398,312
Common stock, shares outstanding	132,006,828	34,398,312

STATEMENTS OF OPERATIONS AND CO

STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Operating expenses:
Research and development	$ 107,217	$ 101,002
General and administrative	28,884	26,060
Total operating expenses	136,101	127,062
Loss from operations	(136,101)	(127,062)
Other income, net	6,236	10,264
Net loss	(129,865)	(116,798)
Other comprehensive income (loss):
Foreign currency translation loss	0	(655)
Unrealized (loss) gain on marketable securities	(53)	784
Total comprehensive loss	$ (129,918)	$ (116,669)
Net loss per share, basic	$ (3.19)	$ (3.05)
Net loss per share, diluted	$ (3.19)	$ (3.05)
Weighted average number of shares used in computing net loss per share, basic	40,761,143	38,338,161
Weighted average number of shares used in computing net loss per share, diluted	40,761,143	38,338,161

STATEMENTS OF STOCKHOLDERS' EQU

STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	At The Market	Common Stock	Common Stock At The Market	Additional Paid-In Capital	Additional Paid-In Capital At The Market	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2022	$ 245,166		$ 3		$ 613,073		$ (367,884)	$ (26)
Beginning balance, shares at Dec. 31, 2022			34,254,314
Issuances of common stock under employee stock plans	1,447				1,447
Issuances of common stock under employee stock plans, shares			143,998
Stock-based compensation	17,091				17,091
Foreign currency translation loss	(655)							(655)
Unrealized gain (loss) on marketable securities	784							784
Net Income (Loss)	(116,798)						(116,798)
Ending balance at Dec. 31, 2023	$ 147,035		$ 3		631,611		(484,682)	103
Ending balance, shares at Dec. 31, 2023	34,398,312		34,398,312
Issuance of common stock and pre-funded warrants in a private placement, net of issuance costs	$ 143,050		$ 10		143,040
Issuance of common stock and pre-funded warrants in a private placement, net of issuance costs, shares			100,000,000
Exchange of common stock for pre-funded warrants			(2,951,425)
Issuance of common stock from of net issuance costs		$ 8,957				$ 8,957
Issuance of common stock from net of issuance costs, shares				365,316
Issuances of common stock under employee stock plans	845				845
Issuances of common stock under employee stock plans, shares			194,625
Stock-based compensation	19,935				19,935
Foreign currency translation loss	0
Unrealized gain (loss) on marketable securities	(53)							(53)
Net Income (Loss)	(129,865)						(129,865)
Ending balance at Dec. 31, 2024	$ 189,904		$ 13		$ 804,388		$ (614,547)	$ 50
Ending balance, shares at Dec. 31, 2024	132,006,828		132,006,828

STATEMENTS OF STOCKHOLDERS' E_2

STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)
Statement of Stockholders' Equity [Abstract]
Common stock and pre-funded warrants, issuance costs	$ 6.9

STATEMENTS OF CASH FLOWS

STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Operating activities
Net loss	$ (129,865)	$ (116,798)
Adjustments to reconcile net loss to net cash used in operating activities:
Accretion of discounts on marketable securities	(2,813)	(5,736)
Depreciation and amortization	1,203	1,216
Stock-based compensation expense	19,935	17,091
Loss on foreign currency translation	0	(655)
Non-cash operating lease expense	2,336	2,335
Changes in operating assets and liabilities:
Prepaid expenses and other assets	2,221	871
Accounts payable, accrued expenses and other current liabilities	(8,459)	7,335
License fees payable	35,000	0
Operating lease liabilities	(2,855)	(2,707)
Net cash used in operating activities	(83,297)	(97,048)
Investing activities
Purchase of marketable securities	(82,218)	(161,497)
Proceeds from maturities of marketable securities	135,042	266,755
Purchase of property and equipment	(122)	(1,125)
Net cash provided by investing activities	52,702	104,133
Financing activities
Proceeds from sale of common stock and pre-funded warrants in a private placement, net of issuance costs	143,050	0
Proceeds from issuances of common stock in "at-the-market" offerings, net of issuance costs	8,957	0
Proceeds from issuance of common stock under employee stock plans	845	1,447
Net cash provided by financing activities	152,852	1,447
Net increase in cash and cash equivalents	122,257	8,532
Cash and cash equivalents at beginning of period	47,478	38,946
Cash and cash equivalents at end of period	$ 169,735	$ 47,478

Cybersecurity Risk Management,

Cybersecurity Risk Management, Strategy and Governance	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Item 1C. Cybers ecurity Risk management and strategy We have implemented and maintain various information security processes designed to identify, assess and manage material risks from cybersecurity threats to our critical computer networks, third-party hosted services, communications systems, hardware, software and critical data, including intellectual property, clinical trial data, and other confidential information that is proprietary, strategic or competitive in nature (“Information Systems and Data”). Our information security function, led by our Director of Information Technology, helps identify, assess and manage the Company’s cybersecurity threats and risks. Our Director of Information Technology helps to identify and assess risks from cybersecurity threats by monitoring and evaluating our threat environment using various methods including, for example, monitoring provided by a third-party security operations center, deploying manual and third-party service provider automated tools in certain environments, subscribing to reports and services that identify cybersecurity threats (and analyzing such reports), conducting scans of certain environments, evaluating our industry’s risk profile and threats reported to us, conducting internal audits and threat assessments for certain threats, conducting vulnerability assessments using third-party tools to identify vulnerabilities, engaging third parties to conduct threat assessments, using external intelligence feeds and monitoring the dark web. Depending on the environment and system, we implement and maintain various technical, physical and organizational measures, processes, standards and policies designed to manage and mitigate material risks from cybersecurity threats to our Information Systems and Data including, for example: incident response plans and policies; vulnerability management policy; disaster recovery and business continuity plans; risk assessments; encryption of certain data; network security controls and data segregation for certain systems; access controls; physical security controls; asset management, tracking, and disposal; systems monitoring for certain systems; employee training; penetration testing of certain environments and cybersecurity insurance. Our assessment and management of material risks from cybersecurity threats are taken into account as part of the Company’s risk management processes. For example, our Director of Information Technology works with management to help mitigate cybersecurity threats that are more likely to lead to a material impact to our business. We use third-party service providers to assist us from time to time to identify, assess and manage material risks from cybersecurity threats, including for example professional services firms (including legal counsel), threat intelligence service providers, cybersecurity consultants and software providers, managed cybersecurity service providers, penetration testing firms, dark web monitoring services, forensic investigators and endpoint detection and response vendors. We use third-party service providers to perform a variety of functions throughout our business, such as application providers, hosting companies, contract research organizations, contract manufacturing organizations, distributors and supply chain resources. Depending on the nature of the services provided, the sensitivity of the Information Systems and Data at issue, and the identity of the provider, we may utilize various vendor management processes that may include reviews of security assessments or certifications and contractual measures. For a description of the risks from cybersecurity threats that may materially affect the Company and how they may do so, see our risk factors under Part 1. Item 1A. Risk Factors in this Annual Report on Form 10-K, including “ If our information technology systems or those of the third parties whom we work with, or our data, are or were compromised, we could experience adverse consequences resulting from such compromise, including but not limited to regulatory investigations or actions, litigation, fines and penalties, disruptions of our business operations, reputational harm, loss of revenue or profits and other adverse consequences.” Governance Our board of directors addresses the Company’s cybersecurity risk management as part of its general oversight function. The board of directors’ audit committee is responsible for overseeing the Company’s cybersecurity risk management processes, including oversight and mitigation of risks from cybersecurity threats. We also have a Corporate Information Security Steering Committee (“CISSC”), which includes several members of senior management, including the Chief Financial Officer (“CFO”) and General Counsel. The CISSC oversees corporate information security initiatives and the Company’s responses to cybersecurity incidents, and reports to the board of directors on certain of the Company’s corporate security programs and investments. Our cybersecurity risk assessment and management processes are implemented and maintained by certain Company management, including our Director of Information Technology, Gio Hernandez, who has over 15 years of experience in information security. Mr. Hernandez reports to our CFO, Rodney Young, who has approximately 20 years of experience supervising the information technology function. Mr. Hernandez is responsible for hiring appropriate personnel, helping to develop the Company’s cybersecurity risk management strategy and communicating key priorities to relevant personnel. Mr. Hernandez is also responsible for helping prepare for cybersecurity incidents, approving cybersecurity processes and reviewing security assessments and other security-related reports. Mr. Young is responsible for approving cybersecurity-related budgets. Our cybersecurity incident response and vulnerability management policies are designed to escalate certain cybersecurity incidents to members of senior management depending on the circumstances, including our CFO and Chief Executive Officer. Senior management through the CISSC works with the Company’s incident response team to help the Company mitigate and remediate cybersecurity incidents of which they are notified. In addition, the Company’s incident response and vulnerability management policies include reporting to the audit committee of the board of directors for certain cybersecurity incidents. The audit committee receives periodic reports from management concerning the Company’s significant cybersecurity threats and risk and the processes the Company has implemented to address them. The audit committee also has access to various reports, summaries or presentations related to cybersecurity threats, risk and mitigation.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	Governance Our board of directors addresses the Company’s cybersecurity risk management as part of its general oversight function. The board of directors’ audit committee is responsible for overseeing the Company’s cybersecurity risk management processes, including oversight and mitigation of risks from cybersecurity threats. We also have a Corporate Information Security Steering Committee (“CISSC”), which includes several members of senior management, including the Chief Financial Officer (“CFO”) and General Counsel. The CISSC oversees corporate information security initiatives and the Company’s responses to cybersecurity incidents, and reports to the board of directors on certain of the Company’s corporate security programs and investments. Our cybersecurity risk assessment and management processes are implemented and maintained by certain Company management, including our Director of Information Technology, Gio Hernandez, who has over 15 years of experience in information security. Mr. Hernandez reports to our CFO, Rodney Young, who has approximately 20 years of experience supervising the information technology function. Mr. Hernandez is responsible for hiring appropriate personnel, helping to develop the Company’s cybersecurity risk management strategy and communicating key priorities to relevant personnel. Mr. Hernandez is also responsible for helping prepare for cybersecurity incidents, approving cybersecurity processes and reviewing security assessments and other security-related reports. Mr. Young is responsible for approving cybersecurity-related budgets. Our cybersecurity incident response and vulnerability management policies are designed to escalate certain cybersecurity incidents to members of senior management depending on the circumstances, including our CFO and Chief Executive Officer. Senior management through the CISSC works with the Company’s incident response team to help the Company mitigate and remediate cybersecurity incidents of which they are notified. In addition, the Company’s incident response and vulnerability management policies include reporting to the audit committee of the board of directors for certain cybersecurity incidents. The audit committee receives periodic reports from management concerning the Company’s significant cybersecurity threats and risk and the processes the Company has implemented to address them. The audit committee also has access to various reports, summaries or presentations related to cybersecurity threats, risk and mitigation.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	Our board of directors addresses the Company’s cybersecurity risk management as part of its general oversight function. The board of directors’ audit committee is responsible for overseeing the Company’s cybersecurity risk management processes, including oversight and mitigation of risks from cybersecurity threats.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	The audit committee receives periodic reports from management concerning the Company’s significant cybersecurity threats and risk and the processes the Company has implemented to address them. The audit committee also has access to various reports, summaries or presentations related to cybersecurity threats, risk and mitigation.
Cybersecurity Risk Role of Management [Text Block]	We also have a Corporate Information Security Steering Committee (“CISSC”), which includes several members of senior management, including the Chief Financial Officer (“CFO”) and General Counsel. The CISSC oversees corporate information security initiatives and the Company’s responses to cybersecurity incidents, and reports to the board of directors on certain of the Company’s corporate security programs and investments. Our cybersecurity risk assessment and management processes are implemented and maintained by certain Company management, including our Director of Information Technology, Gio Hernandez, who has over 15 years of experience in information security. Mr. Hernandez reports to our CFO, Rodney Young, who has approximately 20 years of experience supervising the information technology function. Mr. Hernandez is responsible for hiring appropriate personnel, helping to develop the Company’s cybersecurity risk management strategy and communicating key priorities to relevant personnel. Mr. Hernandez is also responsible for helping prepare for cybersecurity incidents, approving cybersecurity processes and reviewing security assessments and other security-related reports. Mr. Young is responsible for approving cybersecurity-related budgets. Our cybersecurity incident response and vulnerability management policies are designed to escalate certain cybersecurity incidents to members of senior management depending on the circumstances, including our CFO and Chief Executive Officer. Senior management through the CISSC works with the Company’s incident response team to help the Company mitigate and remediate cybersecurity incidents of which they are notified. In addition, the Company’s incident response and vulnerability management policies include reporting to the audit committee of the board of directors for certain cybersecurity incidents.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	We also have a Corporate Information Security Steering Committee (“CISSC”), which includes several members of senior management, including the Chief Financial Officer (“CFO”) and General Counsel. The CISSC oversees corporate information security initiatives and the Company’s responses to cybersecurity incidents, and reports to the board of directors on certain of the Company’s corporate security programs and investments.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	Director of Information Technology, Gio Hernandez, who has over 15 years of experience in information security. Mr. Hernandez reports to our CFO, Rodney Young, who has approximately 20 years of experience supervising the information technology function.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	Our cybersecurity incident response and vulnerability management policies are designed to escalate certain cybersecurity incidents to members of senior management depending on the circumstances, including our CFO and Chief Executive Officer. Senior management through the CISSC works with the Company’s incident response team to help the Company mitigate and remediate cybersecurity incidents of which they are notified. In addition, the Company’s incident response and vulnerability management policies include reporting to the audit committee of the board of directors for certain cybersecurity incidents.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (129,865)	$ (116,798)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Organization

Organization	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1. Organization Description of the Business RAPT Therapeutics, Inc. (“RAPT” or the “Company”) is a clinical-stage immunology-based biopharmaceutical company focused on discovering, developing and commercializing novel therapies for patients living with inflammatory and immunological diseases. The Company's lead drug candidate, RPT904, is a half-life extended monoclonal antibody designed to bind free human immunoglobulin E (“IgE”), a key driver of several allergic diseases. The Company’s oncology drug candidate, tivumecirnon, is an oral small-molecule C-C motif chemokine receptor 4 (“CCR4”) antagonist designed to selectively inhibit the migration of immunosuppressive regulatory T cells into tumors. In November 2024, the Company ceased development of zelnecirnon, its small molecule CCR4 antagonist for inflammatory disease. The Company is currently pursuing different novel CCR4 antagonists, which it believes may have improved safety margins. The Company is located in South San Francisco, California. Liquidity and Management Plans The accompanying financial statements have been prepared assuming that the Company will continue as a going concern. Since inception, the Company has incurred net losses and negative cash flows from operations. During the year ended December 31, 2024, the Company incurred a net loss of $ 129.9 million and used $ 83.3 million of cash in operations. At December 31, 2024, the Company had cash and cash equivalents and marketable securities of $ 231.1 million and working capital of $ 186.9 million. In July, 2024, the Company's board of directors approved a reduction of the Company's workforce to conserve cash resources. The workforce reduction impacted 47 people, or approximately 40 % of the Company's headcount. All employees affected by the workforce reduction were eligible to receive, among other things, severance payments and paid COBRA premiums for a specified time period post-termination. The Company incurred $ 0.9 million in restructuring charges in connection with the workforce reduction, consisting of cash-based expenses related to employee severance payments, benefits and related costs. The Company completed the workforce reduction and all cash payments related to the restructuring during the year ended December 31, 2024. As of December 31, 2024, there were no accrued expenses associated with this workforce reduction. Management plans to continue to incur substantial costs in order to conduct research and development activities and additional capital will be needed to undertake these activities. The Company intends to raise such capital through the issuance of additional equity, borrowings and strategic alliances with other companies. However, if such arrangements are not available at adequate levels or on acceptable terms, the Company would be required to significantly reduce operating expenses and delay or reduce the scope of or eliminate some of its development programs. Management believes that the Company’s current cash and cash equivalents and marketable securities will provide sufficient funds to enable the Company to meet its obligations for at least 12 months from the filing date of this Annual Report on Form 10-K. The Company’s evaluation was based on the facts known as of the date of filing of this Annual Report on Form 10-K.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and include the accounts of the Company. The Company was an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”) until December 31, 2024. Use of Estimates The preparation of the financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, management evaluates its critical accounting policies or estimates related to revenue recognition, clinical trial accruals, fair value of assets and liabilities and stock-based compensation. The Company bases its estimates on historical experience and market-specific or other relevant assumptions that it believes are reasonable under the circumstances. The amounts of assets and liabilities reported in the Company’s balance sheets and the amounts of expenses and revenue reported for each of the periods presented are affected by estimates and assumptions. Actual results could differ from such estimates or assumptions. Concentration of Credit Risk and Other Risks and Uncertainties The Company is subject to a number of risks similar to other biopharmaceutical companies in the early stage, including, but not limited to, the need to obtain adequate additional funding, possible failure of preclinical testing or clinical trials, the need to obtain marketing approval for its product candidates, competitors developing new technological innovations, the need to successfully commercialize and gain market acceptance of the Company’s products and protection of proprietary technology. If the Company does not successfully obtain regulatory approval, commercialize or partner any of its product candidates, it will be unable to generate revenue from product sales or achieve profitability. Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents and marketable securities. Substantially all the Company’s cash is held by two financial institutions. Such deposits may, at times, exceed federally insured limits. The Company invests its cash equivalents in highly rated money market funds and short-term marketable securities comprising commercial paper, corporate bonds and U.S. government agency securities. Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the chief operating decision maker (“CODM”), in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its chief executive officer , Brian Wong, M.D., Ph.D. Based on the information used by the CODM to allocate resources, the Company has determined it operates in one segment. The CODM assesses performance for the Company’s operating segment and decides how to allocate resources based on the Company’s cash runway and net loss that also is reported on the statements of operations and comprehensive loss as net loss. Net loss is used to monitor budget versus actual results. The measure of segment assets is reported on the balance sheets as total assets. As of December 31, 2024 and 2023, all of the Company’s property and equipment was maintained in the U.S. Fair Value of Financial Instruments The carrying amount of the Company’s financial instruments, including certain prepaid and accrued expenses, approximates fair value due to their short-term maturities. Cash Equivalents The Company considers all highly liquid investments with original maturities of 90 days or less from the date of purchase to be cash equivalents. Marketable Securities Marketable securities primarily consist of commercial paper, corporate debt securities and U.S. government agency securities. The Company has classified its marketable securities as available-for-sale and may sell these securities prior to their stated maturities. The Company views these marketable securities as available to support current operations and classifies marketable securities with maturities beyond 12 months as current assets. The Company’s marketable securities are carried at estimated fair value, which is derived from independent pricing sources based on quoted prices in active markets for similar securities. Unrealized gains and losses are reported as a component of accumulated other comprehensive income (loss). The cost of marketable securities is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in other income, net on the statements of operations. All of the Company's available-for-sale investments are subject to a periodic impairment review. For each available-for-sale investment whose fair value is below its amortized cost, the Company determines if the impairment is a result of a credit-related loss or other factors using both quantitative and qualitative factors, including the length of time and extent to which the market value has been less than amortized cost, the financial condition and near-term prospects of the issuer and the Company’s intent and ability to retain its investment in the issuer for a period of time sufficient to allow for any anticipated recovery in market value. If the impairment is a result of a credit-related loss, the Company recognizes an allowance for credit losses. If the impairment is not a result of a credit loss, the Company recognizes the loss in other comprehensive loss. Property and Equipment Property and equipment consist of computer equipment, laboratory equipment, leasehold improvements and furniture and fixtures, and is recorded at cost, less accumulated depreciation and amortization. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the respective assets, generally three to five years . Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the improvements. Depreciation and amortization begin at the time the asset is placed in service. Maintenance and repairs are charged to expense as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation and amortization are removed from the balance sheet and the resulting gain or loss is reflected in the results of operations. Impairment of Long-Lived Assets The Company evaluates its long-lived assets for impairment annually or more frequently whenever events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. Recoverability of these assets is measured by comparing the carrying amount of each asset to the future undiscounted cash flows the asset is expected to generate over its remaining life. If the asset is considered to be impaired, the amount of any impairment is measured as the difference between the carrying value and the fair value of the impaired asset. For the years ended December 31, 2024 and 2023 , the Company did no t record any impairment losses on long-lived assets. Leases At inception of a contract, the Company determines whether an arrangement is or contains a lease. For all leases, the Company determines the classification as either operating leases or financing leases. Operating leases are included in operating lease right-of-use (“ROU”) assets and operating lease liabilities in the Company’s balance sheets. Lease recognition occurs at the commencement date and lease liability amounts are based on the present value of lease payments over the lease term. The lease term may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. The Company uses an implicit rate when readily available, or its incremental borrowing rate based on the information available at lease commencement date, in determining the present value of lease payments. ROU assets represent the Company's right to use underlying assets for the lease term and operating lease liabilities represent the Company's obligation to make lease payments under the lease. ROU assets also include any lease payments made prior to the commencement date and exclude lease incentives received. Operating lease expense is recognized on a straight-line basis over the lease term. Lease agreements with both lease and nonlease components are generally accounted for together as a single lease component . Research and Development Costs Research and development costs are expensed as incurred. Research and development costs consist primarily of salaries and benefits of research and development personnel, costs related to research activities, preclinical studies, clinical trials, drug manufacturing and allocated overhead and facility-related expenses. Amounts incurred in connection with license agreements, such as upfront license and milestone fees are also included in research and development expense. The Company accounts for non-refundable advance payments for goods or services that will be used in future research and development activities as expenses when the goods have been received or when the service has been performed rather than when the payment is made. Clinical trial costs are a component of research and development expenses. The Company expenses costs for its clinical trial activities performed by third parties, including clinical research organizations (“CROs”) and other service providers, as they are incurred, based upon estimates of the work completed over the life of the individual study in accordance with associated agreements. The Company uses information it receives from internal personnel and outside service providers to estimate the clinical trial costs incurred. Stock-Based Compensation The Company determines employee, non-employee and director stock-based compensation expense for all stock-based awards based on their grant date fair value using the Black-Scholes option-pricing model. For stock-based awards with service conditions only, stock-based compensation expense is recognized over the requisite service period using the straight-line method. Forfeitures are recognized as they occur. The fair value of restricted stock awards granted is determined based on the stock price on the date of grant. The estimated fair value is amortized as compensation expense over the service period of the award. Foreign Currency Transactions The Company is subject to foreign currency risk with respect to its clinical contracts denominated in currencies other than the U.S. dollar. Payments on contracts denominated in foreign currencies are made at the spot rate on the day of payment. The cumulative adjustment resulting from the translation of financial statements to the reporting currency is recorded in other comprehensive income (loss). Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period such tax rate changes are enacted. The Company recognizes the effect of income tax positions only if those positions are more likely than not to be sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely to be realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. Valuation allowances are established when necessary to reduce deferred tax assets to amounts more likely than not to be realized. Interest and penalties related to unrecognized tax benefits are recognized as a component of income tax expense. Comprehensive Loss Comprehensive loss includes net loss and certain changes in stockholders’ deficit that are excluded from net loss, primarily unrealized gains and losses from marketable securities and foreign currency translation adjustments. Net Loss Per Share Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding during the period, without consideration of potential dilutive securities. Diluted net loss per common share is computed by dividing the net loss by the sum of the weighted average number of common shares outstanding during the period plus the number of potential dilutive securities outstanding during the period calculated in accordance with the treasury stock method. Diluted net loss per share is the same as basic net loss per share since the effect of potentially dilutive securities is anti-dilutive. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies and adopted by the Company as of the specified effective date. Under the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), the Company meets the definition of an emerging growth company and has elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which provides updates to qualitative and quantitative reportable segment disclosure requirements, including enhanced disclosures about significant segment expenses and increased interim disclosure requirements, among others. ASU No. 2023-07 is effective for fiscal years beginning after December 15, 2023, and interim periods in fiscal years beginning after December 15, 2024. The amendments in this ASU should be applied retrospectively to all prior periods presented in the financial statements. The Company retrospectively adopted ASU 2023-07 on January 1, 2024 and will adopt it for its interim reporting starting with the quarter ending March 31, 2025 . The adoption of ASU 2023-07 did no t have a material impact on the Company’s financial statements. Recent Accounting Pronouncements Not Yet Adopted In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (“ASU 2024-03”). ASU 2024-03 requires disaggregated disclosures of certain categories of expenses in the notes to the financial statements that are included in expense line items on the face of the income statement in annual and interim periods. ASU 2024-03 is effective for annual periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027. The Company is currently evaluating the impact of this guidance on its financial statements and related disclosures. In December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures, which requires disclosure of disaggregated income taxes paid, prescribes standard categories for the components of the effective tax rate reconciliation, and modifies other income tax-related disclosures. ASU No. 2023-09 is effective for fiscal years beginning after December 15, 2024 and allows for adoption on a prospective basis, with a retrospective option. Early adoption is permitted. The Company is currently evaluating the impact of this standard on the income tax disclosures within the financial statements.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements Fair value accounting is applied for all financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis (at least annually). Financial instruments include cash and cash equivalents, marketable securities, accounts payable and accrued expenses that approximate fair value due to their relatively short maturities. Assets and liabilities recorded at fair value on a recurring basis in the balance sheet are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1—Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; 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 significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data. The Company estimates the fair values of investments in corporate debt securities, commercial paper and U.S. government agency securities using valuations obtained from third-party pricing services. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, issuer credit spreads, benchmark securities, prepayment/default projections based on historical data and other observable inputs. Cash equivalents and marketable securities, all of which are classified as available-for-sale securities and measured at fair value on a recurring basis, consisted of the following (in thousands): As of December 31, 2024 Fair Value Amortized Unrealized Unrealized Fair Financial assets: Money market funds Level 1 $ 152,776 $ — $ — $ 152,776 Corporate debt Level 2 17,772 21 ( 3 ) 17,790 Asset-backed securities Level 2 3,820 5 — 3,825 Commercial paper Level 2 16,795 — — 16,795 U.S. government agency securities Level 2 39,743 27 — 39,770 Subtotal 230,906 53 ( 3 ) 230,956 Less: Cash equivalents ( 169,636 ) — — ( 169,636 ) Marketable securities $ 61,270 $ 53 $ ( 3 ) $ 61,320 As of December 31, 2023 Fair Value Amortized Unrealized Unrealized Fair Financial assets: Money market funds Level 1 $ 10,869 $ — $ — $ 10,869 Corporate debt Level 2 19,531 37 ( 9 ) 19,559 Asset-backed securities Level 2 5,242 7 ( 4 ) 5,245 Commercial paper Level 2 59,828 7 ( 8 ) 59,827 U.S. government agency securities Level 2 63,206 91 ( 18 ) 63,279 Subtotal 158,676 142 ( 39 ) 158,779 Less: Cash equivalents ( 47,395 ) — — ( 47,395 ) Marketable securities $ 111,281 $ 142 $ ( 39 ) $ 111,384 As of December 31, 2024 , the unrealized losses on the Company’s securities that were in an unrealized loss position were caused by interest rate changes and were not attributable to credit losses. The Company does not intend to sell the securities that are in an unrealized loss position and the Company believes it is more likely than not that the investments will be held until recovery of the amortized cost bases. The Company did no t record an allowance for credit losses or other impairment charges related to its marketable securities as of December 31, 2024 and 2023. The following table presents the remaining contractual maturities of the Company’s marketable securities as of December 31, 2024 (in thousands): December 31, 2024 Maturing in one year or less $ 61,320 Maturing after one year through five years — Total $ 61,320

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Property and Equipment	4. Property and Equipment Property and equipment consisted of the following (in thousands): December 31, December 31, 2024 2023 Laboratory equipment $ 7,035 $ 7,399 Leasehold improvements 3,295 3,295 Computer equipment 706 727 Furniture and fixtures 411 394 Total property and equipment 11,448 11,815 Less accumulated depreciation and amortization ( 10,081 ) ( 9,367 ) Property and equipment, net $ 1,367 $ 2,448 Depreciation and amortization expenses were $ 1.2 million for each of the years ended December 31, 2024 and 2023 , respectively.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2024
Payables and Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses consisted of the following (in thousands): December 31, December 31, 2024 2023 Accrued research and development expenses $ 1,239 $ 7,281 Accrued compensation 6,723 6,303 Accrued professional and consulting services 1,493 341 Other 142 178 Total accrued expenses $ 9,597 $ 14,103

Commitments

Commitments	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments	6. Commitments The Company enters into contracts in the normal course of business with CROs for preclinical studies and clinical trials. These agreements provide for notice of termination by either party and are, therefore, cancelable contracts. From time to time, the Company may be subject to various legal proceedings and claims arising in the ordinary course of business. The Company assesses contingencies to determine the degree of probability and range of possible loss for potential accrual in its financial statements. An estimated loss contingency is accrued in the financial statements if it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. The Company is not subject to any current pending legal matters or claims and no contingency losses were accrued at either December 31, 2024 and 2023. Leases In May 2015, the Company entered into an operating lease for 30,376 square feet of laboratory and office facilities in South San Francisco, California. In April 2018, the Company amended the lease agreement to include an additional 6,378 square feet of laboratory and office space increasing the total leased premises to 36,754 square feet. The lease amendment extended the lease term to November 2026 and contained scheduled rent increases over the lease term and an option for the Company to extend the lease for an additional five-year term. In November 2022, the Company entered into an operating lease for 13,232 square feet of office facilities in South San Francisco, California, which expires in July 2025 . The lease agreement contained an option to extend the lease for an additional six-month term. Cash paid for amounts included in the measurement of operating lease liabilities for the year ended December 31, 2024 was $ 2.9 million and was included in net cash used in operating activities in the Company’s statements of cash flows. As of December 31, 2024 , the weighted-average remaining lease term and discount rate for the Company’s operating leases was 1.72 years and 8.21 %, respectively. The following table summarizes maturities of operating lease liabilities as of December 31, 2024 (in thousands): 2025 $ 2,662 2026 2,137 Thereafter — Total future undiscounted lease payments 4,799 Less: Imputed interest ( 307 ) Total Lease Liabilities $ 4,492 The following table summarizes the supplemental balance sheet information related to operating leases at December 31, 2024 (in thousands): Operating leases December 31, December 31, 2024 2023 Operating lease right-of-use assets $ 3,333 $ 5,228 Operating lease liabilities, current 2,422 2,448 Operating lease liabilities, non-current 2,070 4,458 Total operating lease liabilities $ 4,492 $ 6,906 For each of the years ended December 31, 2024 and 2023 , the Company incurred $ 2.3 million of lease expense included in operating expenses in the statement of operations in relation to operating leases. Variable lease expense was insignificant for the years ended December 31, 2024 and 2023 . Rent expense was $ 3.1 million and $ 2.9 million in the years ended December 31, 2024 and 2023, respectively. The Company does not have any financing lease agreements as of December 31, 2024 .

License and Collaboration Agree

License and Collaboration Agreements	12 Months Ended
	Dec. 31, 2024
Collaboration Agreements [Abstract]
License and Collaboration Agreements	7. License and Collaboration Agreements License Agreement with Shanghai Jemincare Pharmaceutical Co., Ltd. In December 2024, the Company entered into a license agreement (the “Jemincare License Agreement”) with Shanghai Jemincare Pharmaceutical Co., Ltd., a company incorporated in the People’s Republic of China (“Jemincare”), and a subsidiary of Jiangxi Jemincare Group Co., Ltd. Under the Jemincare License Agreement and subject to certain rights, Jemincare granted the Company: (1) the exclusive and sublicensable rights to develop, manufacture, commercialize and otherwise exploit Jemincare’s anti-IgE monoclonal antibody JYB1904/RPT904 (together with certain related molecules, the “Licensed Molecules”) throughout the world, except mainland China, Hong Kong, Macau and Taiwan (together, the “Jemincare Territory”) for any and all uses; (2) the non-exclusive and sublicensable rights to develop the Licensed Molecules in the Jemincare Territory solely for the purposes of exploiting the Licensed Molecules outside of the Jemincare Territory; and (3) the non-exclusive and sublicensable rights to manufacture the Licensed Molecules in the Jemincare Territory solely for the purposes of exercising the Company’s rights in the foregoing (1) and (2). As consideration for the rights granted, the Company paid Jemincare a $ 35.0 million upfront license fee, and could pay up to an additional $ 672.5 million in milestone payments, as well as tiered royalty payments (at percentages ranging from high single-digit to low double-digit) on future net sales. Those additional milestone payments include $ 1.5 million contingent upon the completion of manufacturing technology transfer, up to $ 226.0 million contingent upon the achievement of specified development and regulatory milestone events, and up to $ 445.0 million contingent upon the achievement of specified commercial milestone events. As of December 31, 2024, the Company accrued the upfront license fee of $ 35.0 million as research and development expense. The Company paid the upfront license fee in January 2025. Under the Jemincare License Agreement, royalty payments will be payable on a product-by-product and country-by-country basis during the period commencing on the first commercial sale and continuing until the later of: (a) the 10-year anniversary of the date of such first commercial sale; (b) the expiration of the relevant patent claims; and (c) the expiration of the relevant regulatory exclusivity (the “Jemincare Royalty Term”). Subject to a certain floor, the Company’s royalty payments will be reduced by specified percentages for patent expiration, biosimilar entry, payments for third party intellectual property, compulsory sublicenses or drug pricing programs. Clinical Trial Collaboration and Supply Agreement with Merck In November 2018, the Company entered into a clinical trial collaboration and supply agreement with an affiliate of Merck (known as MSD outside the United States and Canada) under which the Company conducted a clinical trial evaluating tivumecirnon in combination with pembrolizumab (KEYTRUDA ® ), Merck’s anti-PD-1 therapy, in patients with advanced cancers. The Company is the sponsor of the clinical trial, and Merck supplied pembrolizumab for use in the clinical trial. In March 2022 and February 2024, the Company and Merck amended the agreement to provide for additional supply of pembrolizumab.

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Common Stock	8. Common Stock The holders of the Company’s common stock have one vote for each share of common stock held by them. Holders of shares of the Company’s common stock are entitled to dividends when, as and if declared by the board of directors. No dividends had been declared as of December 31, 2024 or December 31, 2023. The Company had reserved the following shares of common stock, on an as-converted basis, for future issuance as follows: Year Ended December 31, 2024 2023 Options issued and outstanding under the 2019 Equity Incentive Plan and 5,005,320 4,099,947 Restricted stock units issued and outstanding under the 2019 Equity — 13,500 Shares available for future grants under the 2019 Equity Incentive Plan 3,489,005 3,032,820 Pre-funded warrants issued and outstanding 83,403,425 4,000,000 Shares reserved under the 2019 Employee Stock Purchase Plan 492,307 410,522 Total 92,390,057 11,556,789 In December 2024, the Company sold through a private placement to a select group of accredited investors 100,000,000 shares of common stock at a price of $ 0.85 per share and pre-funded warrants to purchase up to 76,452,000 shares of common stock at a purchase price of $ 0.8499 per pre-funded warrant, resulting in net proceeds of $ 143.0 million, after deducting offering expenses (the “Private Placement”). Also in December 2024, the Company entered into an exchange agreement with The Column Group II, LP and certain of its affiliated funds (collectively, the “TCG Funds”), pursuant to which the TCG Funds agreed to exchange an aggregate of 2,951,425 shares of Common Stock for pre-funded warrants (the “Exchange Warrants”) to purchase up to 2,951,425 shares of Common Stock (the “Exchange”). The material terms of the Exchange Warrants are identical to the pre-funded warrants issued in the Private Placement and the accounting impact of the exchange was deemed immaterial. In August 2023, the Company filed with the SEC, and the SEC declared effective, a shelf registration statement on Form S-3 related to the sale and issuance of up to $ 450 million of the Company’s securities, including up to $ 150 million of shares of common stock that may be offered and sold from time to time in one or more “at-the-market” offerings pursuant to a Controlled Equity Offering SM Sales Agreement (the “ATM Sales Agreement”) with Cantor Fitzgerald & Co. (“Cantor”) and Leerink Partners LLC. The ATM Sales Agreement replaced the Controlled Equity Offering SM Sales Agreement, dated November 4, 2020, by and among the Company, Cantor and Stifel, Nicolaus & Company, Incorporated. During the year ended December 31, 2024 , the Company sold 365,316 shares of common stock in “at-the-market offerings” under the ATM Sales Agreement, for net proceeds of $ 9.0 million, after deducting sales agent commissions and other offering related costs. No shares were sold under the ATM Sales Agreement or the Prior ATM Sales Agreement during the year ended December 31, 2023. As of the date of filing of this Annual Report there were up to $ 140.6 million shares of common stock available for future issuance under the ATM Sales Agreement. In May 2022, through a private placement financing, the Company issued pre-funded warrants to purchase an aggregate of 4,000,000 shares of the Company’s common stock. Each pre-funded warrant has an exercise price of $ 0.0001 per share. The purchase price per pre-funded warrant was $ 12.4999 (representing the $ 12.50 per share closing price of the common stock on May 24, 2022, less the exercise price of $ 0.0001 per pre-funded warrant). The private placement financing of the pre-funded warrants resulted in net proceeds of $ 49.8 million, after deducting offering expenses. All pre-funded warrants, including Exchange Warrants were classified as a component of permanent equity in the Company’s balance sheet as they are freestanding financial instruments that are immediately exercisable, do not embody an obligation for the Company to repurchase its shares and permit the holders to receive a fixed number of shares of common stock upon exercise.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation	9. Stock-Based Compensation Stock Option Plan In 2015, the Company adopted the FLX Bio, Inc. 2015 Stock Plan (the “2015 Plan”). In November 2019, the Company’s board of directors adopted the 2019 Equity Incentive Plan (the “2019 Plan” and collectively with the 2015 Plan, the “Option Plans”). Upon the effectiveness of the 2019 Plan, the 2015 Plan terminated and no further grants may be made thereunder. However, the 2015 Plan will continue to govern the terms and conditions of the outstanding awards previously granted thereunder. In addition, the number of shares reserved for issuance under the 2019 Plan automatically increases on January 1 of each year beginning January 1, 2020 by a number equal to (i) 4 % of the shares of common stock outstanding on the last business day of the prior fiscal year or (ii) the number of shares determined by the Company’s board of directors. As of January 1, 2024 , an additional 1,375,932 shares of common stock were reserved for issuance pursuant to the automatic increase to the authorized shares under the 2019 Plan. The Option Plans provide for the granting of incentive and non-statutory stock options and restricted shares of common stock options to eligible employees, officers, directors, advisors and consultants. Terms of the stock option agreements, including vesting requirements, are determined by the board of directors, subject to the provisions of the Options Plans. Options granted generally vest over four years and expire no later than ten years from the date of grant. As a private company, the estimated fair value of the Company’s underlying common stock was determined by the board of directors. Following its initial public offering, the fair value of the Company’s common stock is based on the closing price of its common stock on the date of grant. Employee Stock Purchase Plan In October 2019, the Company adopted the 2019 Employee Stock Purchase Plan (the “2019 ESPP”). The Company reserved 240,336 shares of common stock pursuant to purchase rights to be granted to the Company’s employees. The 2019 ESPP provides that the number of shares reserved and available for issuance automatically increases on January 1 of each calendar year, beginning January 1, 2020, by the lesser of (1) 1.0 % of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, (2) 240,336 shares or (3) a number determined by the board of directors that is less than (1) and (2). As of January 1, 2024 , 240,336 shares of common stock were authorized for issuance pursuant to the annual automatic increase to the authorized shares under the 2019 ESPP. Under the 2019 ESPP, eligible employees are granted rights to purchase shares of common stock, which can be funded through payroll deductions that cannot exceed 15 % of each employee’s compensation. The 2019 ESPP generally provides for a 24 -month offering period, which includes four six-month purchase periods. At the end of each purchase period, eligible employees are permitted to purchase shares of common stock at 85 % of the lower of fair market value at the beginning of the offering period or fair market value at the end of the purchase period. During the years ended December 31, 2024 and 2023 , employees purchased 158,551 shares at weighted average price of $ 4.91 and 87,671 shares at a weighted average exercise price of $ 12.34 , respectively. The 2019 ESPP is considered a compensatory plan and the Company recorded stock-based compensation expense of $ 1.1 million and $ 1.3 million for the years ended December 31, 2024 and 2023, respectively. Stock Options Stock option activity under the 2019 Plan is set forth below for the year ended December 31, 2024: Weighted Average Average Remaining Aggregate Number of Exercise Contractual Intrinsic Shares Price Per Term Value Outstanding Share (Years) (in thousands) Balances at December 31, 2023 4,099,947 $ 21.00 7.6 $ 23,206 Stock options granted 1,648,459 21.74 Stock options exercised ( 14,374 ) 4.67 Stock options forfeited ( 728,712 ) 23.36 Balances at December 31, 2024 5,005,320 $ 20.94 7.2 $ 1 Vested and expected to vest at December 31, 2024 5,005,320 20.94 7.2 $ 1 Exercisable at December 31, 2024 3,224,884 19.65 6.5 — The aggregate intrinsic values of options outstanding, exercisable, vested and expected to vest were calculated as the difference between the exercise price of the underlying awards and the quoted price of the Company’s common stock for options that were in-the-money as of December 31, 2024. The options granted in the years ended December 31, 2024 and 2023 had a weighted average per share grant-date fair value of $ 17.48 and $ 20.20 , respectively, and a total grant date fair value of $ 28.8 million and $ 24.6 million, respectively. The aggregate intrinsic value of stock options exercised in the years ended December 31, 2024 and 2023 was $ 0.1 million and $ 0.7 million, respectively. Cash received from stock option exercises were $ 67,000 and $ 0.5 million for the years ended December 31, 2024 and 2023, respectively. The Company issues new shares of common stock upon exercise of options. In connection with these exercises, there was no tax benefit realized by the Company due to its current loss position. The aggregate fair value of options that vested in the years ended December 31, 2024 and 2023 was $ 18.8 million and $ 15.2 million, respectively. Restricted Stock Units Restricted Stock Units (“RSU”) activity under the 2019 Plan is set forth below for the year ended December 31, 2024: Weighted Average Number of Grant Date Shares Fair Value Outstanding Per Share Balances at December 31, 2023 13,500 $ 44.66 RSUs granted — — RSUs vested and settled ( 13,500 ) 44.66 RSUs forfeited — — Balances at December 31, 2024 — $ — Employee stock option valuation In determining the fair value of the options granted, the Company uses the Black-Scholes option-pricing model and assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment to determine. Expected term The expected term represents the period that the Company’s options granted are expected to be outstanding and is determined using the simplified method (based on the mid-point between the vesting date and the end of the contractual term). The Company has very limited historical information to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior for its stock option grants. Expected volatility Since the Company recently became a public company and has only a limited trading history for its common stock, the expected volatility was estimated based on the average historical volatility for comparable publicly traded biopharmaceutical companies and our historical volatility over a period, where available, equal to the expected term of the stock option grants. The comparable companies were chosen based on their similar size, life cycle stage or area of specialty. Risk-free interest rate The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of the options. Expected dividend The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero . The assumptions used to value employee and non-employee stock option awards granted under the Option Plans during the years ended December 31, 2024 and 2023, using the Black-Scholes option pricing model, were as follows: For the Year 2024 2023 Fair value $ 1.16 - $ 24.75 $ 11.25 - $ 23.70 Expected term (in years) 5.88 - 6.06 5.87 - 6.06 Volatility 99.6 % - 110.7 % 94.9 % - 97.8 % Risk-free interest rate 3.93 % - 4.64 % 3.46 % - 4.71 % Dividend yield — — Employee stock purchase plan The fair value of the rights granted to employees under the 2019 ESPP was estimated using a Black-Scholes option-pricing model with the following valuation assumptions: For the Year 2024 2023 Fair value $ 0.91 - $ 5.90 $ 4.79 - $ 12.12 Expected term (in years) 0.50 - 2.00 0.50 - 2.00 Volatility 95.6 % - 165.3 % 64.3 % - 93.2 % Risk-free interest rate 4.21 % - 5.53 % 4.14 % - 5.51 % Dividend yield — — Stock-based compensation expense Total stock-based compensation expense recognized for stock options and RSUs granted to both employees and non-employees and for the employee stock purchase plan was as follows (in thousands): For the Year 2024 2023 Research and development $ 9,203 $ 7,941 General and administrative 10,732 9,150 Total stock-based compensation expense $ 19,935 $ 17,091 As of December 31, 2024 , unrecognized stock-based compensation cost related to outstanding unvested stock options that are expected to vest was $ 32.7 million. This unrecognized stock-based compensation cost is expected to be recognized over 2.4 years. Repricing of stock options On November 12, 2024, the Compensation Committee (the “Committee”) of the Board of Directors of the Company approved an option repricing, which was effective on November 13, 2024 (the “Effective Date”). The repricing generally applies to options to purchase shares of the Company’s common stock that: (i) were granted under the Company’s 2019 Plan; (ii) as of the Effective Date, are held by the Company’s then-current employees and consultants (subject to the caveat below) (each, an “Eligible Participant”); and (iii) have an exercise price per share greater than $ 8.00 (the “Eligible Options”). The Eligible Options include options held by certain of the Company's executive officers. Options held by non-employee members of the Board were not eligible for the repricing program. As of the Effective Date, the Eligible Options were immediately repriced such that the exercise price per share for such options was reduced to the closing price of the Company’s common stock per share on the Effective Date, subject to certain retention requirements outlined below. The closing price of the Company’s common stock per share on the Effective Date was $ 1.57 , which became the reduced exercise price per share for the Eligible Options. If an employee exercises Eligible Options in advance of the end of the retention period as described below, the employee will be required to pay a premium exercise price equal to the original exercise price per share of the Eligible Options. There were no changes to the number of shares underlying the Eligible Options or to the vesting schedules or expiration dates of the Eligible Options. In order to exercise the Eligible Options at the reduced exercise price, holders of the Eligible Options are required to remain in service with the Company through the end of the relevant retention period. The retention period begins on the Effective Date and ends on the earliest of the following: (i) the date 12 months following the Effective Date; (ii) a Change in Control (as defined in the 2019 Plan) if the Eligible Options are not assumed or continued by the successor or acquiror entity (or its parent company) in such Change in Control or substituted for a similar award of the successor or acquiror entity (or its parent company); or (iii) the option holder’s termination of Continuous Service (as defined in the 2019 Plan) (a) due to such individual’s death or disability, (b) by the Company (or successor entity in a Change in Control) other than for Cause (as defined in the applicable 2019 Plan) or (c) due to such option holder’s resignation on or following a Change in Control under certain circumstances. As of the Effective Date, the total number of shares underlying all Eligible Options was 3.9 million shares. The effect of the repricing resulted in total incremental stock-based compensation expense of $ 1.6 million, $ 0.5 million of which will be recognized on a straight-line basis through the end of the retention period, while the remaining $ 1.1 million will be recognized on a straight-line basis over the original vesting period for those options that vest after the end of the retention period. The incremental stock-based compensation expense was calculated using the Monte Carlo option-pricing model. For the year ended December 31, 2024, the Company recognized incremental stock-based compensation expense totaling $ 0.1 million associated with the option repricing, which is included in general and administrative and research and development expense on the statement of operations.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes The following table presents domestic and foreign components of income (loss) before income taxes for the periods presented (in thousands): December 31, 2024 2023 United States $ ( 129,865 ) $ ( 116,798 ) Foreign — — $ ( 129,865 ) $ ( 116,798 ) A reconciliation of the statutory U.S. federal rate and effective rate is as follows: December 31, 2024 2023 Federal tax 21.0 % 21.0 % State tax — — Stock-based compensation ( 1.4 ) ( 0.9 ) Research and development tax credit 1.9 2.4 Foreign losses not benefited — — Global intangible low-taxed income — — Change in valuation allowance ( 21.5 ) ( 22.4 ) Other — ( 0.1 ) Income tax expense — % — % The Company has incurred net operating losses for all periods since inception. The Company has not reflected any benefit of such net operating loss carryforwards in the accompanying financial statements. The Company has established a full valuation allowance against its deferred tax assets due to the uncertainty surrounding the realization of such assets. The components of the Company’s deferred tax assets and liabilities are as follows (in thousands): December 31, 2024 2023 Deferred tax assets: Net operating loss carryforwards $ 67,565 $ 58,248 Federal and state research and development tax credits 15,086 12,601 Accrued liabilities and reserves 1,355 1,234 Stock-based compensation 8,588 6,238 Depreciation and amortization 8,036 689 Lease liability 944 1,450 Research and development capitalized expenditures 33,708 27,290 Gross deferred tax assets 135,282 107,750 Valuation allowance ( 134,582 ) ( 106,652 ) Deferred tax liabilities: Right of use asset ( 700 ) ( 1,098 ) Other — — Gross deferred tax liabilities ( 700 ) ( 1,098 ) Net deferred taxes $ — $ — In accordance with the 2017 Tax Act, research and experimentation (R&E) expenses under Internal Revenue Code Section 174 are required to be capitalized beginning in 2022. R&E expenses are required to be amortized over a period of 5 years for domestic expenses and 15 years for foreign expenses. As a result of this provision of the 2017 Tax Act, deferred tax assets related to capitalized research expenses increased by $ 6.4 million and $ 15.5 million during the years ended December 31, 2024 and 2023, respectively. Realization of deferred tax assets is dependent upon future taxable income, if any. The Company has established a valuation allowance to offset deferred tax assets as of December 31, 2024 and 2023 , due to the uncertainty of realizing future tax benefits from its net operating loss carryforwards and other deferred tax assets. The valuation allowance increased by approximately $ 27.9 million and $ 26.2 million during the years ended December 31, 2024 and 2023, respectively. The increase in the valuation allowance is mainly related to the capitalization of research and development expenses under Internal Revenue Code ("IRC") Section 174, capitalization of the Jemincare upfront fee as an intangible under IRC Section 197 and an increase in net operating loss carryforwards incurred during the respective taxable years. As of December 31, 2024 and 2023 , the Company had federal net operating loss carryforwards of approximately $ 317.6 million and $ 273.3 million, respectively. The federal net operating loss carryforwards generated during and after fiscal 2018 are carried forward indefinitely, while all others, along with the federal tax credit carryforwards, expire in years beginning in 2035 . As of December 31, 2024 and 2023 , the Company had state net operating loss carryforwards of approximately $ 12.1 million, which begin to expire in 2035 and are available to offset future taxable income. As of December 31, 2024 and 2023 , the Company had federal research and development tax credit carryforwards of approximately $ 12.4 million and $ 10.2 million, respectively. As of December 31, 2024 and 2023 , the Company had state research and development tax credit carryforwards of approximately $ 9.9 million and $ 8.4 million, respectively. Moreover, as of December 31, 2024 , the Company recorded federal and state reserves of approximately $ 3.1 million and $ 2.5 million, respectively, as uncertain tax positions. If not utilized, the federal credit carryforwards will begin expiring in 2035. The state credits carry forward indefinitely. Federal and state laws impose substantial restrictions on the utilization of net operating loss and tax credit carryforwards in the event of an ownership change for tax purposes, as defined in Section 382 of the Internal Revenue Code. As a result of such ownership changes, the Company’s ability to realize the potential future benefit of tax losses and tax credits that existed at the time of the ownership change may be significantly reduced. The Company’s deferred tax asset and related valuation allowance would be reduced as a result. The Company has not yet performed a Section 382 study to determine the amount of reduction, if any. The annual limitation may result in the expiration of net operating losses and credits before utilization. Under the 2017 Tax Act as modified by the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) the carryforward period of net operating losses generated from 2018 forward is indefinite but the ability to deduct such federal net operating losses is limited to 80% of taxable income; however, the carryforward period for net operating losses generated prior to 2018 remains 20 years. Therefore, the annual limitation may still result in the expiration of certain net operating losses and tax credit carryforwards before their utilization. In February 2022, California Senate Bill 113 “SB 113” was signed into law. SB 113 lifted the limitation for California NOL and Credit utilization disallowed by California Assembly Bill 85. In June 2024, California Senate Bill 167 (“SB 167”) was signed into law, which suspends the NOL utilization for companies whose California taxable income exceeds $1 million and limits R&D credit utilization to $5 million. Given the Company’s loss position, SB113 and SB167 did not impact the Company's tax provision. The Company will continue to monitor possible California net operating loss and credit limitation in future periods. Tax benefits from uncertain tax positions are recognized when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on the technical merits. The amount recognized is measured as the largest amount of tax benefit that is greater than 50 percent likely of being realized upon effective settlement. A reconciliation of the beginning and ending amounts of unrecognized tax benefits for the years ended December 31, 2024 and 2023 resulting primarily from research and development tax credits claimed for both U.S. and foreign operations on the Company’s annual tax returns were as follows (in thousands): December 31, 2024 2023 Balance at beginning of year $ 4,674 $ 3,663 Additions on tax positions related to prior years — ( 3 ) Additions on tax positions related to current year 905 1,014 Balance at end of year $ 5,579 $ 4,674 The Company does not expect that its uncertain tax positions will materially change in the next 12 months. The reversal of uncertain tax benefits would not impact the Company’s effective tax rate as the Company continues to maintain a full valuation allowance against its deferred tax assets. In accordance with ASC 740, the Company would classify interest and penalties related to uncertain tax positions in income tax expense, if applicable. There was no interest expense or penalties related to unrecognized tax benefits through December 31, 2024. The Company files income tax returns with varying statutes of limitations in the United States and various states. The Company is not currently under examination by income tax authorities in federal, state or other jurisdictions. All tax returns remain open for examination by federal and state authorities. The tax years from inception in 2015 forward remain open to examination due to the carryover of unused net operating losses and tax credits. The Inflation Reduction Act of 2022 was signed into law in August 2022 and contained several tax provisions to curb inflation by reducing the deficit, lowering prescription drug prices, investing into domestic energy production while promoting clean energy, and introduced the topic of corporate alternative minimum tax on applicable corporations. There is no impact to the Company’s current tax provision from this legislation.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Net Loss Per Share	11. Net Loss Per Share The following table sets forth the computation of the basic and diluted net loss per share of the years ended December 31, 2024 and 2023 (in thousands, except share and per share data): Twelve Months Ended 2024 2023 Numerator: Net loss $ ( 129,865 ) $ ( 116,798 ) Denominator: Weighted-average shares used to compute net loss per share, basic and diluted 40,761,143 38,338,161 Net loss per share, basic and diluted $ ( 3.19 ) $ ( 3.05 ) For the years ended December 31, 2024 and 2023 , 83,403,425 and 4,000,000 pre-funded warrants to purchase the Company's shares of common stock, respectively, issued in private placement financings (see Note 8), were included in the basic and diluted net loss per share calculation. Potentially dilutive securities that were not included in the diluted per share calculations because they would be anti-dilutive were as follows: As of December 31, 2024 2023 Stock options issued and outstanding under the 2019 Plan and 2015 Stock Plan 5,005,320 4,099,947 Estimated shares issuable under the 2019 ESPP 62,896 21,904 RSUs subject to future vesting — 13,500 Total 5,068,216 4,135,351

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and include the accounts of the Company. The Company was an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”) until December 31, 2024.
Use of Estimates	Use of Estimates The preparation of the financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, management evaluates its critical accounting policies or estimates related to revenue recognition, clinical trial accruals, fair value of assets and liabilities and stock-based compensation. The Company bases its estimates on historical experience and market-specific or other relevant assumptions that it believes are reasonable under the circumstances. The amounts of assets and liabilities reported in the Company’s balance sheets and the amounts of expenses and revenue reported for each of the periods presented are affected by estimates and assumptions. Actual results could differ from such estimates or assumptions.
Concentration of Credit Risk and Other Risks and Uncertainties	Concentration of Credit Risk and Other Risks and Uncertainties The Company is subject to a number of risks similar to other biopharmaceutical companies in the early stage, including, but not limited to, the need to obtain adequate additional funding, possible failure of preclinical testing or clinical trials, the need to obtain marketing approval for its product candidates, competitors developing new technological innovations, the need to successfully commercialize and gain market acceptance of the Company’s products and protection of proprietary technology. If the Company does not successfully obtain regulatory approval, commercialize or partner any of its product candidates, it will be unable to generate revenue from product sales or achieve profitability. Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents and marketable securities. Substantially all the Company’s cash is held by two financial institutions. Such deposits may, at times, exceed federally insured limits. The Company invests its cash equivalents in highly rated money market funds and short-term marketable securities comprising commercial paper, corporate bonds and U.S. government agency securities.
Segments	Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the chief operating decision maker (“CODM”), in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its chief executive officer , Brian Wong, M.D., Ph.D. Based on the information used by the CODM to allocate resources, the Company has determined it operates in one segment. The CODM assesses performance for the Company’s operating segment and decides how to allocate resources based on the Company’s cash runway and net loss that also is reported on the statements of operations and comprehensive loss as net loss. Net loss is used to monitor budget versus actual results. The measure of segment assets is reported on the balance sheets as total assets. As of December 31, 2024 and 2023, all of the Company’s property and equipment was maintained in the U.S.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amount of the Company’s financial instruments, including certain prepaid and accrued expenses, approximates fair value due to their short-term maturities.
Cash Equivalents	Cash Equivalents The Company considers all highly liquid investments with original maturities of 90 days or less from the date of purchase to be cash equivalents.
Marketable Securities	Marketable Securities Marketable securities primarily consist of commercial paper, corporate debt securities and U.S. government agency securities. The Company has classified its marketable securities as available-for-sale and may sell these securities prior to their stated maturities. The Company views these marketable securities as available to support current operations and classifies marketable securities with maturities beyond 12 months as current assets. The Company’s marketable securities are carried at estimated fair value, which is derived from independent pricing sources based on quoted prices in active markets for similar securities. Unrealized gains and losses are reported as a component of accumulated other comprehensive income (loss). The cost of marketable securities is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in other income, net on the statements of operations. All of the Company's available-for-sale investments are subject to a periodic impairment review. For each available-for-sale investment whose fair value is below its amortized cost, the Company determines if the impairment is a result of a credit-related loss or other factors using both quantitative and qualitative factors, including the length of time and extent to which the market value has been less than amortized cost, the financial condition and near-term prospects of the issuer and the Company’s intent and ability to retain its investment in the issuer for a period of time sufficient to allow for any anticipated recovery in market value. If the impairment is a result of a credit-related loss, the Company recognizes an allowance for credit losses. If the impairment is not a result of a credit loss, the Company recognizes the loss in other comprehensive loss.
Property and Equipment	Property and Equipment Property and equipment consist of computer equipment, laboratory equipment, leasehold improvements and furniture and fixtures, and is recorded at cost, less accumulated depreciation and amortization. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the respective assets, generally three to five years . Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the improvements. Depreciation and amortization begin at the time the asset is placed in service. Maintenance and repairs are charged to expense as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation and amortization are removed from the balance sheet and the resulting gain or loss is reflected in the results of operations.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates its long-lived assets for impairment annually or more frequently whenever events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. Recoverability of these assets is measured by comparing the carrying amount of each asset to the future undiscounted cash flows the asset is expected to generate over its remaining life. If the asset is considered to be impaired, the amount of any impairment is measured as the difference between the carrying value and the fair value of the impaired asset. For the years ended December 31, 2024 and 2023 , the Company did no t record any impairment losses on long-lived assets.
Leases	Leases At inception of a contract, the Company determines whether an arrangement is or contains a lease. For all leases, the Company determines the classification as either operating leases or financing leases. Operating leases are included in operating lease right-of-use (“ROU”) assets and operating lease liabilities in the Company’s balance sheets. Lease recognition occurs at the commencement date and lease liability amounts are based on the present value of lease payments over the lease term. The lease term may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. The Company uses an implicit rate when readily available, or its incremental borrowing rate based on the information available at lease commencement date, in determining the present value of lease payments. ROU assets represent the Company's right to use underlying assets for the lease term and operating lease liabilities represent the Company's obligation to make lease payments under the lease. ROU assets also include any lease payments made prior to the commencement date and exclude lease incentives received. Operating lease expense is recognized on a straight-line basis over the lease term. Lease agreements with both lease and nonlease components are generally accounted for together as a single lease component .
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Research and development costs consist primarily of salaries and benefits of research and development personnel, costs related to research activities, preclinical studies, clinical trials, drug manufacturing and allocated overhead and facility-related expenses. Amounts incurred in connection with license agreements, such as upfront license and milestone fees are also included in research and development expense. The Company accounts for non-refundable advance payments for goods or services that will be used in future research and development activities as expenses when the goods have been received or when the service has been performed rather than when the payment is made. Clinical trial costs are a component of research and development expenses. The Company expenses costs for its clinical trial activities performed by third parties, including clinical research organizations (“CROs”) and other service providers, as they are incurred, based upon estimates of the work completed over the life of the individual study in accordance with associated agreements. The Company uses information it receives from internal personnel and outside service providers to estimate the clinical trial costs incurred.
Stock-Based Compensation	Stock-Based Compensation The Company determines employee, non-employee and director stock-based compensation expense for all stock-based awards based on their grant date fair value using the Black-Scholes option-pricing model. For stock-based awards with service conditions only, stock-based compensation expense is recognized over the requisite service period using the straight-line method. Forfeitures are recognized as they occur. The fair value of restricted stock awards granted is determined based on the stock price on the date of grant. The estimated fair value is amortized as compensation expense over the service period of the award.
Foreign Currency Transactions	Foreign Currency Transactions The Company is subject to foreign currency risk with respect to its clinical contracts denominated in currencies other than the U.S. dollar. Payments on contracts denominated in foreign currencies are made at the spot rate on the day of payment. The cumulative adjustment resulting from the translation of financial statements to the reporting currency is recorded in other comprehensive income (loss).
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period such tax rate changes are enacted. The Company recognizes the effect of income tax positions only if those positions are more likely than not to be sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely to be realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. Valuation allowances are established when necessary to reduce deferred tax assets to amounts more likely than not to be realized. Interest and penalties related to unrecognized tax benefits are recognized as a component of income tax expense.
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes net loss and certain changes in stockholders’ deficit that are excluded from net loss, primarily unrealized gains and losses from marketable securities and foreign currency translation adjustments.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding during the period, without consideration of potential dilutive securities. Diluted net loss per common share is computed by dividing the net loss by the sum of the weighted average number of common shares outstanding during the period plus the number of potential dilutive securities outstanding during the period calculated in accordance with the treasury stock method. Diluted net loss per share is the same as basic net loss per share since the effect of potentially dilutive securities is anti-dilutive.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies and adopted by the Company as of the specified effective date. Under the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), the Company meets the definition of an emerging growth company and has elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which provides updates to qualitative and quantitative reportable segment disclosure requirements, including enhanced disclosures about significant segment expenses and increased interim disclosure requirements, among others. ASU No. 2023-07 is effective for fiscal years beginning after December 15, 2023, and interim periods in fiscal years beginning after December 15, 2024. The amendments in this ASU should be applied retrospectively to all prior periods presented in the financial statements. The Company retrospectively adopted ASU 2023-07 on January 1, 2024 and will adopt it for its interim reporting starting with the quarter ending March 31, 2025 . The adoption of ASU 2023-07 did no t have a material impact on the Company’s financial statements. Recent Accounting Pronouncements Not Yet Adopted In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (“ASU 2024-03”). ASU 2024-03 requires disaggregated disclosures of certain categories of expenses in the notes to the financial statements that are included in expense line items on the face of the income statement in annual and interim periods. ASU 2024-03 is effective for annual periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027. The Company is currently evaluating the impact of this guidance on its financial statements and related disclosures. In December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures, which requires disclosure of disaggregated income taxes paid, prescribes standard categories for the components of the effective tax rate reconciliation, and modifies other income tax-related disclosures. ASU No. 2023-09 is effective for fiscal years beginning after December 15, 2024 and allows for adoption on a prospective basis, with a retrospective option. Early adoption is permitted. The Company is currently evaluating the impact of this standard on the income tax disclosures within the financial statements.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Cash Equivalents and Marketable Securities Classified as Available-for-Sale Securities Measured at Fair Value on Recurring Basis	Cash equivalents and marketable securities, all of which are classified as available-for-sale securities and measured at fair value on a recurring basis, consisted of the following (in thousands): As of December 31, 2024 Fair Value Amortized Unrealized Unrealized Fair Financial assets: Money market funds Level 1 $ 152,776 $ — $ — $ 152,776 Corporate debt Level 2 17,772 21 ( 3 ) 17,790 Asset-backed securities Level 2 3,820 5 — 3,825 Commercial paper Level 2 16,795 — — 16,795 U.S. government agency securities Level 2 39,743 27 — 39,770 Subtotal 230,906 53 ( 3 ) 230,956 Less: Cash equivalents ( 169,636 ) — — ( 169,636 ) Marketable securities $ 61,270 $ 53 $ ( 3 ) $ 61,320 As of December 31, 2023 Fair Value Amortized Unrealized Unrealized Fair Financial assets: Money market funds Level 1 $ 10,869 $ — $ — $ 10,869 Corporate debt Level 2 19,531 37 ( 9 ) 19,559 Asset-backed securities Level 2 5,242 7 ( 4 ) 5,245 Commercial paper Level 2 59,828 7 ( 8 ) 59,827 U.S. government agency securities Level 2 63,206 91 ( 18 ) 63,279 Subtotal 158,676 142 ( 39 ) 158,779 Less: Cash equivalents ( 47,395 ) — — ( 47,395 ) Marketable securities $ 111,281 $ 142 $ ( 39 ) $ 111,384
Schedule of Remaining Contractual Maturities of Marketable Securities	The following table presents the remaining contractual maturities of the Company’s marketable securities as of December 31, 2024 (in thousands): December 31, 2024 Maturing in one year or less $ 61,320 Maturing after one year through five years — Total $ 61,320

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following (in thousands): December 31, December 31, 2024 2023 Laboratory equipment $ 7,035 $ 7,399 Leasehold improvements 3,295 3,295 Computer equipment 706 727 Furniture and fixtures 411 394 Total property and equipment 11,448 11,815 Less accumulated depreciation and amortization ( 10,081 ) ( 9,367 ) Property and equipment, net $ 1,367 $ 2,448

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2024
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): December 31, December 31, 2024 2023 Accrued research and development expenses $ 1,239 $ 7,281 Accrued compensation 6,723 6,303 Accrued professional and consulting services 1,493 341 Other 142 178 Total accrued expenses $ 9,597 $ 14,103

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Summary of Maturities of Lease Liabilities	The following table summarizes maturities of operating lease liabilities as of December 31, 2024 (in thousands): 2025 $ 2,662 2026 2,137 Thereafter — Total future undiscounted lease payments 4,799 Less: Imputed interest ( 307 ) Total Lease Liabilities $ 4,492
Summary of Supplemental Balance Sheet Information Related Operating leases	The following table summarizes the supplemental balance sheet information related to operating leases at December 31, 2024 (in thousands): Operating leases December 31, December 31, 2024 2023 Operating lease right-of-use assets $ 3,333 $ 5,228 Operating lease liabilities, current 2,422 2,448 Operating lease liabilities, non-current 2,070 4,458 Total operating lease liabilities $ 4,492 $ 6,906

Common Stock (Tables)

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Summary of Reserved Shares of Common Stock on Converted Basis for Future Issuance	The Company had reserved the following shares of common stock, on an as-converted basis, for future issuance as follows: Year Ended December 31, 2024 2023 Options issued and outstanding under the 2019 Equity Incentive Plan and 5,005,320 4,099,947 Restricted stock units issued and outstanding under the 2019 Equity — 13,500 Shares available for future grants under the 2019 Equity Incentive Plan 3,489,005 3,032,820 Pre-funded warrants issued and outstanding 83,403,425 4,000,000 Shares reserved under the 2019 Employee Stock Purchase Plan 492,307 410,522 Total 92,390,057 11,556,789

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2024
Summary of Option Plans	Stock option activity under the 2019 Plan is set forth below for the year ended December 31, 2024: Weighted Average Average Remaining Aggregate Number of Exercise Contractual Intrinsic Shares Price Per Term Value Outstanding Share (Years) (in thousands) Balances at December 31, 2023 4,099,947 $ 21.00 7.6 $ 23,206 Stock options granted 1,648,459 21.74 Stock options exercised ( 14,374 ) 4.67 Stock options forfeited ( 728,712 ) 23.36 Balances at December 31, 2024 5,005,320 $ 20.94 7.2 $ 1 Vested and expected to vest at December 31, 2024 5,005,320 20.94 7.2 $ 1 Exercisable at December 31, 2024 3,224,884 19.65 6.5 —
Summary of RSU Activity	Restricted Stock Units (“RSU”) activity under the 2019 Plan is set forth below for the year ended December 31, 2024: Weighted Average Number of Grant Date Shares Fair Value Outstanding Per Share Balances at December 31, 2023 13,500 $ 44.66 RSUs granted — — RSUs vested and settled ( 13,500 ) 44.66 RSUs forfeited — — Balances at December 31, 2024 — $ —
Summary of Assumptions Used to Value Under Stock Option Plans	The fair value of the rights granted to employees under the 2019 ESPP was estimated using a Black-Scholes option-pricing model with the following valuation assumptions: For the Year 2024 2023 Fair value $ 0.91 - $ 5.90 $ 4.79 - $ 12.12 Expected term (in years) 0.50 - 2.00 0.50 - 2.00 Volatility 95.6 % - 165.3 % 64.3 % - 93.2 % Risk-free interest rate 4.21 % - 5.53 % 4.14 % - 5.51 % Dividend yield — —
Summary of Stock-based Compensation Expense	Total stock-based compensation expense recognized for stock options and RSUs granted to both employees and non-employees and for the employee stock purchase plan was as follows (in thousands): For the Year 2024 2023 Research and development $ 9,203 $ 7,941 General and administrative 10,732 9,150 Total stock-based compensation expense $ 19,935 $ 17,091
Employee and Non-employees
Summary of Assumptions Used to Value Under Stock Option Plans	The assumptions used to value employee and non-employee stock option awards granted under the Option Plans during the years ended December 31, 2024 and 2023, using the Black-Scholes option pricing model, were as follows: For the Year 2024 2023 Fair value $ 1.16 - $ 24.75 $ 11.25 - $ 23.70 Expected term (in years) 5.88 - 6.06 5.87 - 6.06 Volatility 99.6 % - 110.7 % 94.9 % - 97.8 % Risk-free interest rate 3.93 % - 4.64 % 3.46 % - 4.71 % Dividend yield — —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Schedule of Domestic and Foreign Components of Income (Loss) before Income Taxes	The following table presents domestic and foreign components of income (loss) before income taxes for the periods presented (in thousands): December 31, 2024 2023 United States $ ( 129,865 ) $ ( 116,798 ) Foreign — — $ ( 129,865 ) $ ( 116,798 )
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the statutory U.S. federal rate and effective rate is as follows: December 31, 2024 2023 Federal tax 21.0 % 21.0 % State tax — — Stock-based compensation ( 1.4 ) ( 0.9 ) Research and development tax credit 1.9 2.4 Foreign losses not benefited — — Global intangible low-taxed income — — Change in valuation allowance ( 21.5 ) ( 22.4 ) Other — ( 0.1 ) Income tax expense — % — %
Schedule of Components of Deferred Tax Assets and Liabilities	The components of the Company’s deferred tax assets and liabilities are as follows (in thousands): December 31, 2024 2023 Deferred tax assets: Net operating loss carryforwards $ 67,565 $ 58,248 Federal and state research and development tax credits 15,086 12,601 Accrued liabilities and reserves 1,355 1,234 Stock-based compensation 8,588 6,238 Depreciation and amortization 8,036 689 Lease liability 944 1,450 Research and development capitalized expenditures 33,708 27,290 Gross deferred tax assets 135,282 107,750 Valuation allowance ( 134,582 ) ( 106,652 ) Deferred tax liabilities: Right of use asset ( 700 ) ( 1,098 ) Other — — Gross deferred tax liabilities ( 700 ) ( 1,098 ) Net deferred taxes $ — $ —
Schedule of Reconciliation of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amounts of unrecognized tax benefits for the years ended December 31, 2024 and 2023 resulting primarily from research and development tax credits claimed for both U.S. and foreign operations on the Company’s annual tax returns were as follows (in thousands): December 31, 2024 2023 Balance at beginning of year $ 4,674 $ 3,663 Additions on tax positions related to prior years — ( 3 ) Additions on tax positions related to current year 905 1,014 Balance at end of year $ 5,579 $ 4,674

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Loss per Share	The following table sets forth the computation of the basic and diluted net loss per share of the years ended December 31, 2024 and 2023 (in thousands, except share and per share data): Twelve Months Ended 2024 2023 Numerator: Net loss $ ( 129,865 ) $ ( 116,798 ) Denominator: Weighted-average shares used to compute net loss per share, basic and diluted 40,761,143 38,338,161 Net loss per share, basic and diluted $ ( 3.19 ) $ ( 3.05 )
Potentially Dilutive Securities not Included in Diluted per Share Calculations	Potentially dilutive securities that were not included in the diluted per share calculations because they would be anti-dilutive were as follows: As of December 31, 2024 2023 Stock options issued and outstanding under the 2019 Plan and 2015 Stock Plan 5,005,320 4,099,947 Estimated shares issuable under the 2019 ESPP 62,896 21,904 RSUs subject to future vesting — 13,500 Total 5,068,216 4,135,351

Organization - Additional Infor

Organization - Additional Information (Details)	1 Months Ended	12 Months Ended
	Jul. 31, 2024 USD ($) Employees	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net loss		$ 129,865,000	$ 116,798,000
Cash used in operations		83,297,000	$ 97,048,000
Cash and cash equivalents and marketable securities		231,100,000
Working capital		186,900,000
Number of workforce reduction | Employees	47
Percentage of reduction existing headcount	40%
Restructuring charges	$ 900,000
Accrued expenses related to workforce reduction plan		$ 0

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2024 USD ($) Institution	Dec. 31, 2023 USD ($)
Significant Accounting Policies [Line Items]
Number of financial institutions | Institution	2
Impairment losses on long-lived assets | $	$ 0	$ 0
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]	srt:ChiefExecutiveOfficerMember
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description	The CODM assesses performance for the Company’s operating segment and decides how to allocate resources based on the Company’s cash runway and net loss that also is reported on the statements of operations and comprehensive loss as net loss. Net loss is used to monitor budget versus actual results. The measure of segment assets is reported on the balance sheets as total assets.
ASU No. 2023-07
Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2024
Change in accounting principle, accounting standards update, immaterial effect	true
Minimum [Member]
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	3 years
Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	5 years

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Cash Equivalents and Marketable Securities Classified as Available-for-Sale Securities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 230,906	$ 158,676
Unrealized Gains	53	142
Unrealized Losses	(3)	(39)
Fair Value	230,956	158,779
Less: Cash equivalents	(169,636)	(47,395)
Marketable securities, Amortized Cost	61,270	111,281
Marketable securities, Unrealized Gains	53	142
Marketable securities, Unrealized Losses	(3)	(39)
Marketable securities, Fair Value	61,320	111,384
Level 1 | Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	152,776	10,869
Fair Value	152,776	10,869
Level 2 | Corporate Debt
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	17,772	19,531
Unrealized Gains	21	37
Unrealized Losses	(3)	(9)
Fair Value	17,790	19,559
Level 2 | Asset-backed Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	3,820	5,242
Unrealized Gains	5	7
Unrealized Losses		(4)
Fair Value	3,825	5,245
Level 2 | Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	16,795	59,828
Unrealized Gains		7
Unrealized Losses		(8)
Fair Value	16,795	59,827
Level 2 | U.S. Government Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	39,743	63,206
Unrealized Gains	27	91
Unrealized Losses		(18)
Fair Value	$ 39,770	$ 63,279

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	Dec. 31, 2024	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Allowance for credit losses or other impairment charges related to marketable securities	$ 0	$ 0

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Remaining Contractual Maturities of Marketable Securities (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Investments, Debt and Equity Securities [Abstract]
Maturing in one year or less	$ 61,320
Maturing after one year through five years	0
Total	$ 61,320

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property Plant And Equipment [Line Items]
Total property and equipment	$ 11,448	$ 11,815
Less accumulated depreciation and amortization	(10,081)	(9,367)
Property and equipment, net	1,367	2,448
Laboratory Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	7,035	7,399
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	3,295	3,295
Computer Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	706	727
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	$ 411	$ 394

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation and amortization expenses	$ 1,203	$ 1,216

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued research and development expenses	$ 1,239	$ 7,281
Accrued compensation	6,723	6,303
Accrued professional and consulting services	1,493	341
Other	142	178
Total accrued expenses	$ 9,597	$ 14,103

Commitments - Additional Inform

Commitments - Additional Information (Details)	1 Months Ended			12 Months Ended
	Nov. 30, 2022 ft²	Apr. 30, 2018 ft²	May 31, 2015 ft²	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Lessee Lease Description [Line Items]
Contingency losses, accrued | $				$ 0	$ 0
Lease expiration period	2025-07
Additional laboratory and office facilities under lease | ft²		6,378
Increased of leased premises | ft²		36,754
Lessee operating lease extended lease term		2026-11
Lease existence of option to extend	true		true
Lessee operating lease option to extend	6 months		5 years
Lease expense | $				2,300,000	2,300,000
Rent expense | $				3,100,000	$ 2,900,000
Cash paid for operating lease liabilities | $				$ 2,900,000
Operating lease, weighted average remaining lease term				1 year 8 months 19 days
Operating lease, weighted average discount rate, percent				8.21%
South San Francisco and California
Lessee Lease Description [Line Items]
Laboratory and office facilities under lease | ft²			30,376
Additional office facilities under lease | ft²	13,232

Commitments - Summary of Maturi

Commitments - Summary of Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
2025	$ 2,662
2026	2,137
Total future undiscounted lease payments	4,799
Less: Imputed interest	(307)
Total lease liabilities	$ 4,492	$ 6,906

Commitments - Summary of Balanc

Commitments - Summary of Balance Sheet Classification of Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Operating lease right-of-use assets	$ 3,333	$ 5,228
Operating lease liabilities, current	2,422	2,448
Operating lease liabilities, non-current	2,070	4,458
Total operating lease liabilities	$ 4,492	$ 6,906

License and Collaboration Agr_2

License and Collaboration Agreements - Additional Information (Details) - License Agreement - Shanghai Jemincare Pharmaceutical Co., Ltd. $ in Millions	Dec. 31, 2024 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront license fee	$ 35
Contingent payments upon completion of manufacturing technology transfer	1.5
Accrued upfront license fee	35
Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payments	672.5
Contingent payments upon achievement of specified development and regulatory milestones	226
Contingent payments upon achievement of specified commercial milestones	$ 445

Common Stock - Additional Infor

Common Stock - Additional Information (Details)	1 Months Ended			12 Months Ended
	Dec. 31, 2024 USD ($) $ / shares shares	Aug. 31, 2023 USD ($)	May 31, 2022 USD ($) $ / shares shares	Dec. 31, 2024 USD ($) Vote $ / shares shares	Dec. 31, 2023 USD ($) shares	May 24, 2022 $ / shares
Class of Stock [Line Items]
Number of votes per share | Vote				1
Dividends declared				$ 0	$ 0
Net proceeds received after deducting underwriting discounts and commissions and other offering related costs				$ 8,957,000	$ 0
Additional common stock reserved for issuance | shares	92,390,057			92,390,057	11,556,789
ATM Sales Agreement
Class of Stock [Line Items]
Shares issued during period value				$ 8,957,000
ATM Sales Agreement | Sales Agreement
Class of Stock [Line Items]
Shares issued during period | shares				365,316
Net proceeds received after deducting underwriting discounts and commissions and other offering related costs				$ 9,000,000
Maximum | ATM Sales Agreement
Class of Stock [Line Items]
Shares issued during period value		$ 450,000,000
Maximum | ATM Sales Agreement | Sales Agreement
Class of Stock [Line Items]
Common stock available for future issuance of shares				$ 140,600,000
Pre-funded Warrants
Class of Stock [Line Items]
Warrants to purchase shares of common stock | shares	76,452,000		4,000,000	76,452,000
Exercise price per warrant share | $ / shares			$ 0.0001
Purchase price per warrant | $ / shares	$ 0.8499		$ 12.4999	$ 0.8499
Net proceeds from issuance of pre-funded warrants	$ 143,000,000		$ 49,800,000
Common Stock
Class of Stock [Line Items]
Shares issued during period | shares	100,000,000
Shares issued, price per share | $ / shares	$ 0.85			$ 0.85
Closing Price Per Share | $ / shares						$ 12.5
Common Stock | ATM Sales Agreement
Class of Stock [Line Items]
Shares issued during period | shares				365,316
Common Stock | Maximum | ATM Sales Agreement | Sales Agreement
Class of Stock [Line Items]
Shares issued during period value		$ 150,000,000
Exchange Warrants
Class of Stock [Line Items]
Exchange of common stock for pre-funded warrants | shares	2,951,425			2,951,425
Exchange Warrants | Maximum
Class of Stock [Line Items]
Warrants to purchase shares of common stock | shares	2,951,425			2,951,425

Common Stock - Summary of Reser

Common Stock - Summary of Reserved Shares of Common Stock on Converted Basis for Future Issuance (Detail) - shares	Dec. 31, 2024	Dec. 31, 2023
Class Of Stock [Line Items]
Total shares reserved	92,390,057	11,556,789
Pre-funded warrants issued and outstanding
Class Of Stock [Line Items]
Total shares reserved	83,403,425	4,000,000
2019 Equity Incentive Plan and 2015 Stock Plan | Options Issued and Outstanding
Class Of Stock [Line Items]
Total shares reserved	5,005,320	4,099,947
2019 Equity Incentive Plan | Restricted Stock Units Issued and Outstanding
Class Of Stock [Line Items]
Total shares reserved		13,500
2019 Equity Incentive Plan | Shares Available for Future Grants
Class Of Stock [Line Items]
Total shares reserved	3,489,005	3,032,820
2019 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Total shares reserved	492,307	410,522

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)		1 Months Ended	12 Months Ended
	Nov. 12, 2024	Oct. 31, 2019	Dec. 31, 2024	Dec. 31, 2023	Jan. 01, 2024
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Additional common stock reserved for issuance			92,390,057	11,556,789
Cash received from stock option exercises			$ 67,000	$ 500,000
Stock-based compensation expense			$ 19,935,000	$ 17,091,000
Weighted-average grant-date fair value per share			$ 17.48	$ 20.20
Stock options grant date fair value			$ 28,800,000	$ 24,600,000
Number of stock options, exercises intrinsic value			100,000	700,000
Stock option vested aggregate fair value			18,800,000	15,200,000
Expected dividend yield			0
Unrecognized stock-based compensation cost related to outstanding unvested stock options and RSUs that are expected to vest			$ 32,700,000
Unrecognized stock-based compensation cost, expected period to be recognized			2 years 4 months 24 days
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense			$ 10,732,000	9,150,000
2019 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of increase in shares reserved for issuance on common stock outstanding		1%
Total shares reserved		240,336			240,336
Increase in shares at the beginning of each calendar year		240,336
Maximum employee subscription rate on salary		15%
Offering period		24 months
Purchase period		6 months
Purchase price of common stock as percentage of fair market value		85%
Stock-based compensation expense			$ 1,100,000	$ 1,300,000
Share-based compensation, employee purchased shares			158,551	87,671
Share-based compensation, shares at weighted average exercise price			$ 4.91	$ 12.34
Repriced Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option repricing program, minimum exercise price	$ 8
Share price	$ 1.57
Number of shares underlying all Eligible Options	3,900,000
Incremental cost	$ 1,600,000
Repriced Stock Options | General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental cost			$ 100,000
Repriced Stock Options | Recognized Through The End Of The Retention Period
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental cost	500,000
Repriced Stock Options | Recognized After The End Of The Retention Period
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental cost	$ 1,100,000
Option Plans | Employees, Officers, Directors, Advisors, and Consultants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period			4 years
Additional common stock reserved for issuance					1,375,932
Option Plans | Maximum | Employees, Officers, Directors, Advisors, and Consultants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted, expiration period			10 years
2019 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of increase in shares reserved for issuance on common stock outstanding			4%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Option Plans (Details) - Option Plans - Share-based Payment Arrangement, Option - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares Outstanding, Beginning Balance	4,099,947
Number of Shares Outstanding, Stock options granted	1,648,459
Number of Shares Outstanding, Stock options exercised	(14,374)
Number of Shares Outstanding, Stock options forfeited	(728,712)
Number of Shares Outstanding, Ending Balance	5,005,320	4,099,947
Number of Shares Outstanding, Vested and expected to vest	5,005,320
Number of Shares Outstanding, Exercisable	3,224,884
Weighted Average Exercise Price Per Share, Beginning Balance	$ 21
Weighted Average Exercise Price Per Share, Stock options granted	21.74
Weighted Average Exercise Price Per Share, Stock options exercised	4.67
Weighted Average Exercise Price Per Share, Stock options forfeited	23.36
Weighted Average Exercise Price Per Share, Ending Balance	20.94	$ 21
Weighted Average Exercise Price Per Share, Vested and expected to vest	20.94
Weighted Average Exercise Price Per Share, Exercisable	$ 19.65
Average Remaining Contractual Term (Years), Balance	7 years 2 months 12 days	7 years 7 months 6 days
Average Remaining Contractual Term (Years), Vested and expected to vest	7 years 2 months 12 days
Average Remaining Contractual Term (Years), Exercisable	6 years 6 months
Aggregate Intrinsic Value	$ 1	$ 23,206
Aggregate Intrinsic Value, Vested and expected to vest	$ 1

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of RSU Activity (Details) - 2019 Plan - Restricted Stock Unit ("RSU")	12 Months Ended
	Dec. 31, 2024 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares Outstanding, Beginning Balance | shares	13,500
Number of Shares Outstanding, RSUs vested and settled | shares	(13,500)
Number of Shares Outstanding, Ending Balance | shares	0
Weighted Average Grant Date Fair Value Per Share, Beginning Balance | $ / shares	$ 44.66
Weighted Average Grant Date Fair Value Per Share, RSUs vested and settled | $ / shares	44.66
Weighted Average Grant Date Fair Value Per Share, Ending Balance | $ / shares	$ 0

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Assumptions Used to Value Under Stock Option Plans (Details) - Employee and Non-employees - Share-based Payment Arrangement, Option - $ / shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
2019 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility, minimum	95.60%	64.30%
Volatility, maximum	165.30%	93.20%
Risk-free interest rate, minimum	4.21%	4.14%
Risk-free interest rate, maximum	5.53%	5.51%
Option Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility, minimum	99.60%	94.90%
Volatility, maximum	110.70%	97.80%
Risk-free interest rate, minimum	3.93%	3.46%
Risk-free interest rate, maximum	4.64%	4.71%
Minimum | 2019 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value	$ 0.91	$ 4.79
Expected term (in years)	6 months	6 months
Minimum | Option Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value	$ 1.16	$ 11.25
Expected term (in years)	5 years 10 months 17 days	5 years 10 months 13 days
Maximum | 2019 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value	$ 5.9	$ 12.12
Expected term (in years)	2 years	2 years
Maximum | Option Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value	$ 24.75	$ 23.7
Expected term (in years)	6 years 21 days	6 years 21 days

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 19,935	$ 17,091
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	9,203	7,941
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 10,732	$ 9,150

Income Taxes - Schedule of Dome

Income Taxes - Schedule of Domestic and Foreign Components of Income (Loss) before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
United States	$ (129,865)	$ (116,798)
Net loss before taxes	$ (129,865)	$ (116,798)

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Federal tax	21%	21%
Stock-based compensation	(1.40%)	(0.90%)
Research and development tax credit	1.90%	2.40%
Change in valuation allowance	(21.50%)	(22.40%)
Other		(0.10%)

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Net operating loss carryforwards	$ 67,565	$ 58,248
Federal and state research and development tax credits	15,086	12,601
Accrued liabilities and reserves	1,355	1,234
Stock-based compensation	8,588	6,238
Depreciation and amortization	8,036	689
Lease liabilities	944	1,450
Research and development capitalized expenditures	33,708	27,290
Gross deferred tax assets	135,282	107,750
Valuation allowance	(134,582)	(106,652)
Deferred tax liabilities:
Right-of-use asset	(700)	(1,098)
Gross deferred tax liabilities	(700)	(1,098)
Net deferred taxes	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Line Items]
Increase in valuation allowance	$ 27,900,000	$ 26,200,000
Interest expense or penalties related to unrecognized tax benefits	0
Increase in deferred tax assets related to capitalized research expenses	6,400,000	15,500,000
Federal
Income Tax Disclosure [Line Items]
Operating loss carryforwards	$ 317,600,000	273,300,000
Operating loss carryforwards expiration beginning year	2035
Uncertain tax positions reserves	$ 3,100,000
Research and experimental expenses required to amortized term	5 years
Federal | Research and Development
Income Tax Disclosure [Line Items]
Tax credit carryforwards amount	$ 12,400,000	10,200,000
State
Income Tax Disclosure [Line Items]
Operating loss carryforwards	$ 12,100,000	12,100,000
Operating loss carryforwards expiration beginning year	2035
Uncertain tax positions reserves	$ 2,500,000
State | Research and Development
Income Tax Disclosure [Line Items]
Tax credit carryforwards amount	$ 9,900,000	$ 8,400,000
Foreign
Income Tax Disclosure [Line Items]
Research and experimental expenses required to amortized term	15 years

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 4,674	$ 3,663
Additions on tax positions related to prior years		(3)
Additions on tax positions related to current year	905	1,014
Balance at end of year	$ 5,579	$ 4,674

Net Loss Per Share - Computatio

Net Loss Per Share - Computation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Numerator:
Net loss	$ (129,865)	$ (116,798)
Denominator:
Weighted-average shares used to compute net loss per share, basic	40,761,143	38,338,161
Weighted-average shares used to compute net loss per share, diluted	40,761,143	38,338,161
Net loss per share, basic	$ (3.19)	$ (3.05)
Net loss per share, diluted	$ (3.19)	$ (3.05)

Net Loss Per Share Additional I

Net Loss Per Share Additional Information (Details) - shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Earnings Per Share [Abstract]
Pre-funded warrants to purchase common stock	83,403,425	4,000,000

Net Loss Per Share - Potentiall

Net Loss Per Share - Potentially Dilutive Securities not Included in Diluted per Share Calculations (Details) - shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	5,068,216	4,135,351
Stock Options Issued and Outstanding Under the 2019 Plan and 2015 Stock Plan
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	5,005,320	4,099,947
Estimated Shares Issuable Under the 2019 ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	62,896	21,904
RSUs Subject to Future Vesting
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	0	13,500