0000950170-24-090925 | 10-Q | XBRL Viewer | Terns Pharmaceuticals INC

Nature of the Business, Basis of Presentation and Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2024

Nature of the Business, Basis of Presentation and Summary of Significant Accounting Policies

1. Nature of the Business, Basis of Presentation and Summary of Significant Accounting Policies

Nature of the Business

Terns Pharmaceuticals, Inc. (Terns or the Company) is a clinical-stage biopharmaceutical company developing a portfolio of small-molecule product candidates to address serious diseases including oncology and obesity.

Terns was incorporated as an exempted company in the Cayman Islands in December 2016. In December 2020, the Company effected a de-registration of the Company in the Cayman Islands and a domestication in the State of Delaware, pursuant to which it became a Delaware corporation. Terns owns all of the share capital of Terns Pharmaceutical HongKong Limited (Terns Hong Kong) and Terns, Inc., a Delaware corporation (Terns U.S. Opco). Terns Hong Kong holds all of the share capital of Terns China Biotechnology Co., Ltd. (organized in Shanghai, People’s Republic of China (PRC)) (Terns China) and Terns (Suzhou) Biotechnology Co., Ltd. (organized in Suzhou, PRC) (Terns Suzhou).

The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions.

Basis of Presentation

The accompanying condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) and include the accounts of Terns and its wholly owned subsidiaries Terns U.S. Opco and Terns Hong Kong and its wholly owned subsidiaries Terns China and Terns Suzhou, for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The Company’s unaudited condensed consolidated financial statements have been prepared in conformity with U.S. GAAP. All intercompany balances and transactions have been eliminated in consolidation. The condensed consolidated balance sheet as of December 31, 2023 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements.

Operating results for the three and six months ended June 30, 2024 are not necessarily indicative of the results that may be expected for the year ending December 31, 2024 or for any other future periods.

Unaudited Interim Financial Information

These unaudited condensed consolidated financial statements include all adjustments necessary, consisting of only normal recurring adjustments, to fairly state the financial position and the results of the Company’s operations and cash flows for interim periods in accordance with U.S. GAAP. Interim period results are not necessarily indicative of results of operations or cash flows for a full year or any subsequent interim periods. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto in the Company’s Annual Report on Form 10-K (the Annual Report) for the fiscal year ended December 31, 2023, as filed with the SEC on March 14, 2024. There have been no significant changes to the Company's significant accounting policies described in Note 1, Nature of the Business, Basis of Presentation and Summary of Significant Accounting Policies, in Notes to Consolidated Financial Statements in Item 8 of Part II of the Form 10-K for the fiscal year ended December 31, 2023.

Any reference to these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASUs) of the Financial Accounting Standards Board (FASB).

At-the-Market Offering

In March 2022, the Company entered into a Sales Agreement with Cowen and Company, LLC (Cowen) as sales agent, pursuant to which the Company has the ability to offer and sell, from time to time, through Cowen, shares of its common stock having an aggregate offering price of up to $75.0 million in an at-the-market offering. The shares are offered pursuant to the Company's shelf registration statement on Form S-3 filed with the Securities and Exchange Commission (SEC), which became effective in March 2022. As of June 30, 2024, there were 9,781,673 shares of our common stock sold for aggregate net proceeds of $66.6 million after deducting commissions and offering expenses pursuant to this agreement. There were no sales of the Company's common stock pursuant to this agreement during the six months ended June 30, 2024.

In May 2023, the Company entered into a Sales Agreement with Cowen as sales agent, pursuant to which the Company has the ability to offer and sell, from time to time, through Cowen, shares of its common stock having an aggregate offering price of up to $150.0 million in an at-the-market offering. The shares are offered pursuant to the Company's shelf registration statement on Form S-3 filed with the SEC, which became effective in February 2023. There were no sales of the Company's common stock pursuant to this agreement through June 30, 2024.

Summary of Significant Accounting Policies

Use of Estimates

The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying condensed consolidated financial statements include, but are not limited to, the estimates for accruals of research and development expenses, accrual of research contract costs, unrecognized tax benefits, fair value of common stock and stock option valuations. On an ongoing basis, the Company evaluates its estimates and judgments, using historical and anticipated results and trends and on various other assumptions that management believes to be reasonable under the circumstances. Actual results could materially differ from those estimates.

Cash, Cash Equivalents and Marketable Securities

Cash and cash equivalents consist of standard checking accounts and money market funds. The Company considers all highly liquid investments with an original maturity of 90 days or less at the date of purchase to be cash equivalents.

The Company classifies as available-for-sale marketable securities with a remaining maturity when purchased of greater than three months. The Company’s marketable securities are maintained by investment managers and may consist of U.S. government and non-U.S. government securities, corporate debt securities and commercial paper. Debt securities are carried at fair value with the unrealized gains and losses included in the condensed consolidated statements of operations and comprehensive loss and as a component of stockholders’ equity until realized. Any premium arising at purchase is amortized to the earliest call date and any discount arising at purchase is accreted to maturity. Amortization and accretion of premiums and discounts are recorded in interest income and/or expense. Gains and losses on securities sold are recorded based on the specific identification method and are included in Interest income, net in the condensed consolidated statements of operations and comprehensive loss. The Company has not incurred any material realized gains or losses from sales of securities to date.

The Company assesses its available-for-sale debt securities for impairment as of each reporting date in order to determine if a portion of any decline in fair value below carrying value is the result of a credit loss. The Company records credit losses in the condensed consolidated statements of operations and comprehensive loss as credit loss expense within other expense, net, which is limited to the difference between the fair value and the amortized cost of the security. To date, the Company has not recorded any credit losses on its available-for-sale debt securities.

Interest receivable related to the Company's available-for-sale debt securities is presented as marketable securities on the Company's condensed consolidated balance sheets. The Company writes off interest receivable once it has determined that the asset is not realizable. To date, the Company has not written off any interest receivables associated with its marketable securities.

Operating Leases and Rent Expense

At the inception of a contractual arrangement, the Company determines whether the contract contains a lease by assessing whether there is an identified asset and whether the contract conveys the right to control the use of the identified asset in exchange for consideration over a period of time. If both criteria are met, upon lease commencement, the Company records a lease liability which represents the Company’s obligation to make lease payments arising from the lease, and a corresponding right-of-use (ROU) asset which represents the Company’s right to use an underlying asset during the lease term.

Operating lease ROU assets and liabilities are recognized on the balance sheet at the lease commencement date based on the present value of the future minimum lease payments over the lease term. In determining the net present value of the lease payments, the Company uses its incremental borrowing rate applicable to the underlying asset unless the implicit rate is readily determinable. Any lease incentives received are deferred and recorded as a reduction of the ROU asset and amortized over the term of the lease. The Company does not separate lease and non-lease components and instead treats them as a single component. Rent expense, comprised of amortization of the ROU asset and the implicit interest accreted on the operating lease liability, is recognized on a straight-line basis over the lease term. The Company determines the lease term as the noncancellable period of the lease and may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise such options.

The Company elected to not apply the recognition requirements of the new leasing standard to short-term leases with terms of 12 months or less. As a result, leases with a term of 12 months or less are not recognized on the balance sheet.

Research and Development Expenses

Research and development costs are expensed as incurred. Research and development expenses consist of costs incurred to discover, research and develop drug candidates, including personnel expenses, stock-based compensation expense, allocated facility-related and depreciation expenses, third-party license fees and external costs, including fees paid to consultants and contract research organizations (CROs) in connection with nonclinical studies and clinical trials and other related clinical trial fees, such as for investigator grants, patient screening, laboratory work, clinical trial database management, clinical trial material management and statistical compilation and analysis. Non-refundable prepayments for goods or services that will be used or rendered for future research and development activities are recorded as prepaid expenses. Such amounts are recognized as an expense as the goods are delivered or the related services are performed, or until it is no longer expected that the goods will be delivered, or the services rendered. Costs incurred in obtaining technology licenses are charged immediately to research and development expense if the technology licensed has not reached technological feasibility and has no alternative future uses.

The Company has from time to time entered into various research and development and other agreements with commercial firms, researchers, universities and others for provisions of goods and services. These agreements are generally cancelable, and the related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies or clinical trials, including the phase or completion of events, invoices received and contracted costs. Estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ materially from the Company’s estimates. Since inception, the Company’s historical accrual estimates have not been materially different from the actual costs.

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities included the following:


(in thousands)	June 30, 2024		December 31, 2023
Research and development costs	$	3,229	$	2,010
Compensation and benefit costs		3,108		5,683
Accrued professional fees		2,176		855
Other		320		278
Total accrued expenses and other current liabilities	$	8,833	$	8,826

Executive Leadership Transition

In August 2023, the Company and Senthil Sundaram, former chief executive officer, entered into a separation agreement. Pursuant to the separation agreement, Mr. Sundaram was entitled to receive severance in the amount of $0.6 million and 100% of his annual target discretionary bonus for 2023 in the amount of $0.3 million. During the year ended December 31, 2023, the Company recorded an accrued liability and recognized expense of $0.9 million related to the departure of the former chief executive officer. As of June 30, 2024, the ending accrued liability was $0.3 million and is presented within the Condensed Consolidated Balance Sheets under Accrued expenses and other current liabilities. The vesting of each equity award held by Mr. Sundaram was fully accelerated as of December 31, 2023. As a result of the change in service period for all outstanding unvested option grants to the Company’s former chief executive officer in August 2023, the Company recognized $10.5 million in stock-based compensation expense during the year ended December 31, 2023. The expense was recognized as operating expenses within the Condensed Consolidated Statements of Operations and Comprehensive Loss under General and administrative.

In August 2023, Bryan Yoon, chief operating officer and general counsel, and Mark Vignola, Ph.D., chief financial officer, received retention awards payable in cash in the aggregate amount of $0.5 million for Mr. Yoon and $0.7 million for Dr. Vignola. Each retention award is payable in two installments of 33% of the award on February 1, 2024 and 67% of the award on August 1, 2024, subject to the applicable officer’s continued employment with the Company through such date. Expense is recognized on a straight-line basis over the requisite service period. During the six months ended June 30, 2024, the Company recorded an accrued liability and recognized expense of $0.5 million related to the retention awards. These accruals are presented within the Condensed Consolidated Balance Sheets under Accrued expenses and other current liabilities. The expenses were recognized as operating expenses within the Condensed Consolidated Statements of Operations and Comprehensive Loss under General and administrative.

In July 2024, Dr. Vignola entered into a transition agreement with the Company. The transition agreement provides for Dr. Vignola’s continued service as chief financial officer for a transition period until the date of his separation from employment, anticipated to be February 1, 2025. Pursuant to the transition agreement, Dr. Vignola is entitled to receive severance in the amount of $0.5 million, equivalent to 12 months of his annual base salary, the remaining unpaid portion of his retention award of $0.5 million, his target annual bonus for 2024 of $0.2 million and, as applicable based on the separation date, a pro rata portion of his target annual bonus for 2025, and the time to exercise any outstanding equity award that is vested as of the separation date shall continue to the end of the 12th month following the separation date. In addition, the Company has agreed to pay Dr. Vignola an additional retention bonus in the amount of $0.5 million, provided Dr. Vignola remains employed until February 1, 2025, with such additional retention bonus being payable in a pro rata amount under certain conditions per the transition agreement.

In July 2024, Mr. Yoon entered into a separation agreement with the Company. The separation agreement provides for Mr. Yoon’s continued service as chief operating officer and special counsel for a transition period until September 3, 2024. Pursuant to the separation agreement, Mr. Yoon is entitled to receive severance in the amount of $0.5 million, equivalent to 12 months of his annual base salary, the remaining unpaid portion of his retention award of $0.3 million, a pro rata portion of his target annual bonus for 2024 of $0.1 million, and the time for Mr. Yoon to exercise any outstanding equity award that is vested as of the separation date shall continue to April 30, 2025.

In November 2023, Erin Quirk, M.D., former president and head of research & development, received a retention award payable in cash in the aggregate amount of $0.6 million and a recognition bonus in the aggregate amount of $0.1 million. The retention award is payable in two installments of 33% of the award on February 1, 2024, and 67% of the award on August 1, 2024, and the recognition bonus was payable on January 1, 2024, subject to Dr. Quirk's continued employment with the Company through such date. Expense is recognized on a straight-line basis over the requisite service period. On May 7, 2024, Dr. Quirk entered into a separation agreement with the Company. Pursuant to the separation agreement, Dr. Quirk was entitled to receive severance in the amount of $0.2 million and the remaining unpaid portion of her recognition bonus of $0.4 million. As of June 30, 2024, there was no ending accrued liability as all balances have been paid. As of June 30, 2024, the vesting of each equity award held by Dr. Quirk was accelerated with respect to the number of shares of common stock that would have become vested had Dr. Quirk remained employed at the Company through August 31, 2024, and the time for Dr. Quirk to exercise any vested stock options shall continue up to November 30, 2024. As a result of the change in terms for these option grants to Dr. Quirk, in May 2024, the Company recognized $0.4 million in stock-based compensation expense during the six months ended June 30, 2024. The expenses were recognized as operating expenses within the Condensed Consolidated Statements of Operations and Comprehensive Loss under Research and development.

Income Taxes

The provision for income taxes primarily relates to projected federal, state and foreign income taxes. To determine the quarterly provision for income taxes, the Company uses an estimated annual effective tax rate, which is generally based on expected annual income and statutory tax rates in the various jurisdictions in which the Company operates. In addition, the tax effects of certain significant or unusual items are recognized discretely in the quarter during which they occur and can be a source of variability in the effective tax rates from quarter to quarter.

Income taxes are computed using the asset and liability approach that requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the Company’s financial statements. In estimating future tax consequences, the Company considers all expected future events including the enactment of changes in tax laws or rates. A valuation allowance is recorded, if necessary, to reduce net deferred tax assets to their realizable values if management does not believe it is more likely than not that the net deferred tax assets will be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, and ongoing prudent and feasible tax planning strategies in assessing the amount of the valuation allowance. When the Company establishes or reduces the valuation allowance against its deferred tax assets, its provision for income taxes will increase or decrease, respectively, in the period such determination is made.

The Company assesses accounting for uncertainty in income taxes by modeling for the recognition, measurement and disclosure in financial statements any uncertain income tax positions that the Company has taken or expects to take on a tax return. The Company accrues interest and related penalties, if applicable, on all tax exposures for which reserves have been established consistent with jurisdictional tax laws. The Company includes interest and penalties related to unrecognized tax benefits within the provision for income taxes.

The Company recorded income tax expense for the three months ended June 30, 2024 and 2023 of less than $0.1 million. The Company recorded income tax expense for the six months ended June 30, 2024 and 2023 of $0.2 million and $0.1 million, respectively. The expenses are primarily related to foreign income tax expenses from China.

Comprehensive Loss

Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources.

Stock-Based Compensation

Stock-based compensation expense relates to stock options, restricted stock units (RSUs) with service conditions, and RSUs with market conditions issued under the Company’s equity incentive plan and rights to acquire stock granted under the Company’s employee stock purchase plan (ESPP). Grants are measured at the grant date based on the fair value of the awards and is recognized as an expense on a straight-line basis over the requisite service period, which is generally the vesting period. Forfeitures are recognized as they occur.

The Black-Scholes option pricing model estimates the fair value of stock options with time-based vesting and rights to acquire stock under the ESPP. The Company lacks sufficient company-specific historical and implied volatility information. Therefore, it estimates its expected stock volatility based on the historical volatility of a publicly traded set of peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. The Company estimates risk-free rates using the implied yield currently available on U.S. Treasury zero-coupon issues with a remaining term equal to the expected term and dividend yield using the Company’s expectations and historical data. The Company uses the simplified method to calculate the expected term of stock option grants as the Company has limited historical information from which to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior for its stock option grants. Under the simplified method, the expected term is estimated to be the mid-point between the vesting date and the contractual term of the option. The fair value is calculated based upon the Company’s common stock valuation on the date of the grant.

The fair value of RSUs with service conditions is based upon the Company’s common stock valuation on the date of the grant.

The Monte Carlo simulation model estimates the fair value of the RSUs with market conditions, using inputs for the common stock valuation on the date of the grant, volatility, the risk-free interest rate, and the dividend yield. Compensation expense is recognized on a straight-line basis over the derived service period commencing on the grant date. The derived service period is the median duration of the successful stock price paths to meet the price goal for each tranche as simulated in the Monte Carlo valuation model. If the related market condition is achieved earlier than its estimated derived service period, the stock-based compensation expense is accelerated, and a cumulative catch-up expense is recorded during the period in which the market condition is met.

Pre-funded Warrants

Pre-funded warrants are classified as a component of permanent stockholders’ equity within additional paid-in capital and are recorded at the issuance date using a relative fair value allocation method. The pre-funded warrants are equity classified because they (i) are freestanding financial instruments that are legally detachable and separately exercisable from the equity instruments, (ii) are immediately exercisable, (iii) do not embody an obligation for the Company to repurchase its shares, (iv) permit the holders to receive a fixed number of shares of common stock upon exercise, (v) are indexed to the Company’s common stock and (vi) meet the equity classification criteria. In addition, such pre-funded warrants do not provide any guarantee of value or return. The value of the pre-funded warrants is known at issuance, as their sales price approximates their fair value, and net proceeds from the sale are recorded as a component of additional paid-in capital.

Net Loss Per Share of Common Stock

Basic net income (loss) per share of common stock is computed by dividing the net income (loss) per share of common stock by the weighted average number of shares of common stock outstanding for the period. The weighted-average shares of common stock outstanding as of June 30, 2024 included pre-funded warrants, as the warrants were issued for minimal consideration and were immediately exercisable.

Diluted net income (loss) per share of common stock is computed by adjusting net income (loss) to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per share of common stock is computed by dividing the diluted net loss by the weighted average number of shares of common stock outstanding for the period, including potentially dilutive shares.

The Company reported a net loss for the three and six months ended June 30, 2024 and 2023. In periods in which the Company reported a net loss, diluted net loss per share of common stock was the same as basic net loss per share of common stock, since dilutive shares were not assumed to have been issued if their effect is anti-dilutive. The Company excluded the following potential shares of common stock, presented based on amounts outstanding at each period end, from the computation of diluted net loss attributable to common stockholders per share of common stock for the periods indicated because including them would have had an anti-dilutive effect:


	June 30,
	2024		2023
Options to purchase common stock		11,366,749		8,450,168
Unvested restricted stock units with service conditions		782,737		372,301
Unvested restricted stock units with market conditions		150,000		—
Shares issuable under employee stock purchase plan		13,589		9,193
Total		12,313,075		8,831,662

Deferred Offering Costs

The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated.

After consummation of the equity financing, these costs are recorded as a reduction to the carrying value of stockholders’ equity as a reduction of additional paid-in capital or equity generated as a result of such offering. Should an in-process equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations and comprehensive loss.

Commitments and Contingencies

From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of business. The Company accrues a liability for such matters when it is probable that future expenditures will be made, and such expenditures can be reasonably estimated. For all periods presented, the Company was not a party to any pending material litigation or other material legal proceedings.

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies. The Company is an emerging growth company as defined in the Jumpstart Our Business Startups Act of 2012, as amended (JOBS Act). Under the JOBS Act, emerging growth companies have extended transition periods available for complying with new or revised accounting standards. The Company has elected to use this exemption to delay adopting new or revised accounting standards until such time as those standards apply to private companies. Where allowable, the Company has early adopted certain standards as described below.

Recently Issued Accounting Pronouncements Not Yet Adopted

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (ASU 2023-09), which requires additional income tax disclosures in the annual consolidated financial statements. The amendments in ASU 2023-09 are intended to enhance the transparency and decision usefulness of income tax disclosures. For public entities, ASU 2023-09 is effective for annual periods beginning after December 15, 2024, with early adoption permitted. For non-public entities, ASU 2023-09 is effective for annual reporting periods beginning after December 15, 2025. Under the JOBS Act, emerging growth companies have extended transition periods available for complying with new or revised accounting standards. The Company is currently evaluating the impact of ASU 2023-09 on its financial statements and related disclosures.

In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (ASU 2023-07), which expands segment disclosures by requiring disclosure of significant segment expenses that are regularly provided to the chief operating decision maker and included within each reported measure of segment profit or loss, an amount and description of its composition for other segment items, and interim disclosures of a reportable segment’s profit or loss and assets. The disclosures required under ASU 2023-07 are also required for public entities with a single reportable segment. ASU 2023-07 is effective for the Company’s first fiscal year beginning after December 15, 2023 and for interim periods within the Company’s first fiscal year beginning after December 15, 2024, with early adoption permitted. The Company does not expect the adoption of ASU 2023-07 to have a material impact on its financial statements and related disclosures.

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2024

Fair Value Disclosures [Abstract]

Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis:


	Fair Value at June 30, 2024
(in thousands)	Level 1		Level 2		Level 3		Total
Cash and cash equivalents
Cash in bank balances	$	14,005	$	—	$	—	$	14,005
Money market funds		77,491		—		—		77,491
Total cash and cash equivalents	$	91,496	$	—	$	—	$	91,496
Marketable securities
U.S. government securities	$	—	$	133,801	$	—	$	133,801
Total marketable securities	$	—	$	133,801	$	—	$	133,801

	Fair Value at December 31, 2023
(in thousands)	Level 1		Level 2		Level 3		Total
Cash and cash equivalents
Cash in bank balances	$	46,138	$	—	$	—	$	46,138
Money market funds		33,788		—		—		33,788
Total cash and equivalents	$	79,926	$	—	$	—	$	79,926
Marketable securities
U.S. government securities	$	—	$	183,514	$	—	$	183,514
Total marketable securities	$	—	$	183,514	$	—	$	183,514

Schedule of Aggregate Fair Value of Marketable Securities

The aggregate amortized cost and fair value of marketable securities as of June 30, 2024, by contractual maturity, are as follows:


(in thousands)	Amortized Cost		Fair Value
Due in one year or less	$	109,760	$	109,593
Due after one year through two years		24,292		24,208
Total marketable securities	$	134,052	$	133,801

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 91,496	$ 79,926
Marketable securities	133,801	183,514
Prepaid expenses and other current assets	4,941	3,992
Total current assets	230,238	267,432
Property and equipment, net	370	506
Operating lease assets	217	523
Other assets	55	56
Total assets	230,880	268,517
Current liabilities:
Accounts payable	1,873	2,515
Accrued expenses and other current liabilities	8,833	8,826
Current portion of operating lease liabilities	249	603
Total current liabilities	10,955	11,944
Taxes payable, non-current	1,244	1,206
Total liabilities	12,199	13,150
Commitments and contingencies
Stockholders' equity:
Common stock, $0.0001 par value, 150,000,000 shares authorized at June 30, 2024 and December 31, 2023; 70,335,636 and 64,576,719 shares issued and outstanding at June 30 , 2024 and December 31, 2023, respectively	7	6
Additional paid-in capital	596,854	588,008
Accumulated other comprehensive loss	(443)	(19)
Accumulated deficit	(377,737)	(332,628)
Total stockholders' equity	218,681	255,367
Total liabilities and stockholders' equity	$ 230,880	$ 268,517

Common Stock and Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2024

Share-Based Payment Arrangement [Abstract]

Schedule of Common Stock Shares Reserved for Issuance

The Company had reserved shares of common stock for issuance in connection with the following:


	June 30, 2024		December 31, 2023
Options outstanding under incentive award plans		11,366,749		8,349,922
Unvested restricted stock units with service conditions		782,737		365,892
Unvested restricted stock units with market conditions		150,000		—
Shares available for future grant under incentive award plans		2,876,986		1,005,587
Shares available for future grant under employee stock purchase plans		614,588		701,671
Shares available for future grant under employment inducement award plans		957,834		3,291,000
Pre-funded warrants		4,186,500		9,751,500
Total shares reserved		20,935,394		23,465,572

Summary of Stock Option Activity

The following table summarizes the stock option activity for all stock plans during the six months ended June 30, 2024:


	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding as of December 31, 2023		8,349,922		$	9.04		6.82	$	2,225
Granted		3,824,500			6.50
Exercised		(4,000	)		3.00				15
Forfeited		(803,673	)		8.67
Outstanding as of June 30, 2024		11,366,749		$	8.21		6.79	$	4,425
Exercisable, June 30, 2024		5,738,075		$	8.96		4.39	$	1,909
Vested and expected to vest, June 30, 2024		11,366,749		$	8.21		6.79	$	4,425

Schedule of Stock Options Weighted Average Assumptions

The Company estimated the fair value of options granted and rights to acquire stock granted under the Company’s employee stock purchase plan using a Black-Scholes option pricing model with the following assumptions presented on a weighted average basis:


	Six Months Ended June 30,
	2024			2023
Stock Option Plans
Expected term (years)		6.05			6.05
Expected volatility		77.61	%		73.68	%
Risk-free interest rate		4.26	%		3.53	%
Fair value of underlying common stock	$	6.50		$	9.82
Weighted average grant-date fair value per share	$	4.56		$	6.61
Employee Stock Purchase Plans
Expected term (years)		1.22			1.26
Expected volatility		83.43	%		86.49	%
Risk-free interest rate		5.10	%		4.85	%
Fair value of underlying common stock	$	6.01		$	11.30
Weighted average grant-date fair value per share	$	3.03		$	5.82

Summary of Restricted Stock Award Activity

The following table summarizes the RSUs with service conditions activity for all stock plans during the six months ended June 30, 2024:


	Number of Shares			Weighted Average Grant-Date Fair Value
Unvested restricted stock units as of December 31, 2023		365,892		$	8.79
Granted		632,775			6.16
Vested		(102,930	)		9.33
Forfeited		(113,000	)		6.50
Unvested restricted stock units as of June 30, 2024		782,737		$	6.92

Schedule Of Estimated the Fair Value of RSUs with Market Conditions

The Company estimated the fair value of RSUs with market conditions granted using a Monte Carlo simulation model with the following assumptions:


	Six Months Ended June 30, 2024
Expected volatility		78.45	%
Risk-free interest rate		4.27	%
Fair value of underlying common stock	$	7.31
Weighted average grant-date fair value per share	$	5.39

Schedule of Stock-based Compensation Expense

Stock-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows:


	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2024		2023		2024		2023
Research and development expense	$	2,090	$	1,576	$	4,178	$	2,924
General and administrative expense		2,330		2,657		4,270		5,247
Total stock-based compensation expense	$	4,420	$	4,233	$	8,448	$	8,171

Cash Equivalents and Marketable Securities

6 Months Ended

Jun. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Cash Equivalents and Marketable Securities

2. Cash Equivalents and Marketable Securities

The amortized cost and fair value of cash equivalents and marketable securities by major security type is as follows:


	June 30, 2024
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	$	77,491	$	—	$	—		$	77,491
U.S. government securities		134,052		3		(254	)		133,801
Total	$	211,543	$	3	$	(254	)	$	211,292

Classified as:
Cash equivalents								$	77,491
Marketable securities									133,801
Total								$	211,292

	December 31, 2023
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	$	33,788	$	—	$	—		$	33,788
U.S. government securities		183,357		219		(62	)		183,514
Total	$	217,145	$	219	$	(62	)	$	217,302

Classified as:
Cash equivalents								$	33,788
Marketable securities									183,514
Total								$	217,302

The aggregate fair value of the Company’s available-for-sale marketable securities that have been in a continuous unrealized loss position for less than twelve months or twelve months or longer is as follows:


	June 30, 2024
	Less than 12 months					12 months or longer					Total
(in thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. government securities	$	115,214	$	(211	)	$	14,073	$	(43	)	$	129,287	$	(254	)
Total	$	115,214	$	(211	)	$	14,073	$	(43	)	$	129,287	$	(254	)

	December 31, 2023
	Less than 12 months					12 months or longer					Total
(in thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. government securities	$	80,461	$	(62	)	$	—	$	—		$	80,461	$	(62	)
Total	$	80,461	$	(62	)	$	—	$	—		$	80,461	$	(62	)

At June 30, 2024, the Company had 30 available-for-sale marketable securities in an unrealized loss position without an allowance for credit losses. The Company does not intend to sell these securities and the Company believes it is more likely than not that marketable securities in an unrealized loss position will be held until maturity and that the Company will not be required to sell these securities before recovery of their amortized cost basis. The Company believes that an allowance for credit losses is unnecessary as the securities are of high credit quality and the decline in fair value is due to market conditions and/or changes in interest rates.

Nature of the Business, Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Research and development costs	$ 3,229	$ 2,010
Compensation and benefit costs	3,108	5,683
Accrued professional fees	2,176	855
Other	320	278
Total accrued expenses and other current liabilities	$ 8,833	$ 8,826

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (22,736)	$ (22,373)	$ (17,896)	$ (21,528)

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org/1943274/2147483443/250-10-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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Reference 16: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/exampleRef
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Reference 18: http://www.xbrl.org/2003/role/disclosureRef
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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Reference 20: http://www.xbrl.org/2003/role/disclosureRef
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Reference 21: http://www.xbrl.org/2003/role/disclosureRef
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Reference 22: http://www.xbrl.org/2003/role/disclosureRef
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Reference 23: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 24: http://www.xbrl.org/2003/role/disclosureRef
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Reference 25: http://www.xbrl.org/2003/role/disclosureRef
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Reference 26: http://www.xbrl.org/2003/role/disclosureRef
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Reference 27: http://www.xbrl.org/2003/role/disclosureRef
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Reference 28: http://www.xbrl.org/2003/role/disclosureRef
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Reference 29: http://www.xbrl.org/2003/role/disclosureRef
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Reference 30: http://www.xbrl.org/2003/role/disclosureRef
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Reference 33: http://www.xbrl.org/2003/role/disclosureRef
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Reference 34: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 35: http://www.xbrl.org/2003/role/disclosureRef
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Reference 36: http://www.xbrl.org/2003/role/disclosureRef
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Reference 37: http://fasb.org/us-gaap/role/ref/legacyRef
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-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

+ Details

Leases

6 Months Ended

Jun. 30, 2024

Leases [Abstract]

Leases

4. Leases

In March 2019, the Company entered into a lease agreement for office space in Foster City, California which expires October 2024. Additionally, the Company leases office space in Shanghai and Suzhou, China.

Components of lease cost are as follows:


	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2024		2023		2024		2023
Operating lease cost	$	162	$	163	$	323	$	322
Short-term cost		3		5		7		8
Total lease cost	$	165	$	168	$	330	$	330

Weighted-average remaining lease term								0.34
Weighted-average discount rate								6.00	%

The Company's future minimum lease payments are as follows:


(in thousands)	Operating Leases
2024	$	252
2025 and thereafter		—
Total lease payments		252
Less: Imputed interest		(3	)
Present value of lease liabilities		249
Less: Current portion of lease liabilities		(249	)
Total lease liabilities, non-current	$	—

On July 1, 2024, the Company amended the lease agreement for the office space in Foster City, California to extend for three years commencing as of November 1, 2024, and expiring on October 31, 2027. The Company has the option to extend the amended lease agreement for an additional three years. The other terms of the amendment are substantially the same as the original lease agreement and annual lease payments will be approximately $0.5 million.

Assignment, License and Collaboration Agreements

6 Months Ended

Jun. 30, 2024

Assignment License And Collaboration Agreements [Abstract]

Assignment, License and Collaboration Agreements

6. Assignment, License and Collaboration Agreements

Assignment Agreement

In June 2019, the Company entered into an assignment agreement with Vintagence Biotechnology Ltd. (Vintagence) (Vintagence 2019 Assignment Agreement). Under the terms of the Vintagence 2019 Assignment Agreement, Vintagence assigned and agreed to assign to the Company any and all worldwide rights, title, and interest in and to the Vintagence technology and gave Terns a sublicensing right that allows the Company to grant sublicenses to any of its affiliates and/or to licensees or contractors to perform any portion of the development, manufacture, and/or commercialization of covered compounds or covered products. The Company will remain directly responsible for all amounts owed to Vintagence under this agreement, regardless of sublicenses. The Company is required to use commercially reasonable efforts to commercialize the covered product in the field in the major markets.

In June 2019, the Company paid Vintagence an upfront payment of $0.7 million. In addition, pursuant to the terms of the Vintagence 2019 Assignment Agreement, the Company agreed to pay Vintagence up to CNY 205.0 million in development milestones for the first covered product. The term of the Vintagence 2019 Assignment Agreement will continue in effect on a country-by-country basis until all milestone payments are made. The Company has the right to terminate the agreement in its entirety or on a covered product-by-covered product and country-by-country basis, in its sole discretion by giving 60 days advance written notice to Vintagence. As of June 30, 2024, the Company has paid $4.4 million to Vintagence which includes a milestone payment of $1.5 million in connection with the Company’s IND filing for TERN-501 in December 2020 and a milestone payment of $2.2 million in connection with the initiation of dosing in the Phase 2a DUET trial in July 2022. The Company has not recognized any research and development expense during the three and six months ended June 30, 2024 and 2023 related to this agreement.

Hansoh Option and License Agreement

In July 2020, the Company entered into an exclusive option and license agreement with Hansoh (Shanghai) Healthtech Co., Ltd. (Hansoh Healthtech) and Jiangsu Hansoh Pharmaceutical Group Company Ltd. (Jiangsu Hansoh) (collectively, Hansoh) (Hansoh 2020 Option and License Agreement). Under the terms of the Hansoh 2020 Option and License Agreement, the Company granted Hansoh an exclusive, non-transferable, non-sublicensable, fully-paid, royalty-free license to conduct preliminary studies on the licensed compound (TERN-701, formerly known as TRN-000632) with an option to exclusively license the same for development and commercialization of licensed products in all prophylactic, palliative, therapeutic and/or diagnostic uses in connection with all human diseases and disorders (including development and research activities on animal models thereof) in the field of oncology, including all types of cancers (Field) in mainland China, Taiwan, Hong Kong and Macau (collectively, the Territory).

In November 2021, Hansoh exercised its option and was granted an exclusive, royalty-bearing license, with the right to sublicense to exploit licensed compound and licensed products in the Field and in the Territory. In connection with Hansoh’s exercise of its option, the Company recognized $1.0 million in license fee revenue within the consolidated statements of operations and comprehensive loss during the year ended December 31, 2021. In addition, Hansoh has agreed to pay the Company up to $67.0 million in pre-specified clinical, regulatory and sales milestones. Hansoh must also pay the Company royalties in the mid-single digits based on net sales of all licensed products. The term of the Hansoh 2020 Option and License Agreement will continue until the end of the last-to-expire royalty term. As of June 30, 2024, no milestones have been met and future payments are all constrained.

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2024	Jul. 26, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Entity Registrant Name	Terns Pharmaceuticals, Inc.
Entity Central Index Key	0001831363
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Small Business	true
Entity Common Stock, Shares Outstanding		70,371,911
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-39926
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	98-1448275
Entity Address Address Line1	1065 East Hillsdale Blvd
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Foster City
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94404
City Area Code	650
Local Phone Number	525-5535
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	TERN
Security Exchange Name	NASDAQ

Condensed Consolidated Statements of Stockholders Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional paid-in capital	Accumulated Other Comprehensive Loss	Accumulated deficit
Balances at Dec. 31, 2022	$ 276,943	$ 5	$ 520,178	$ (822)	$ (242,418)
Balance at Beginning of period (in shares) at Dec. 31, 2022		53,723,171
Issuance of common stock in at-the-market offering	27,924		27,924
Issuance of common stock in at-the-market offering, Shares		2,929,922
Vesting of restricted stock units with service conditions (in shares)		16,503
Stock-based compensation expense	3,938		3,938
Unrealized gain (loss) on available-for-sale securities	418			418
Foreign exchange translation adjustment	(12)			(12)
Net Income (Loss)	(21,528)				(21,528)
Balances at Mar. 31, 2023	287,683	$ 5	552,040	(416)	(263,946)
Balance at end of period (in shares) at Mar. 31, 2023		56,669,596
Balances at Dec. 31, 2022	276,943	$ 5	520,178	(822)	(242,418)
Balance at Beginning of period (in shares) at Dec. 31, 2022		53,723,171
Foreign exchange translation adjustment	(73)
Balances at Jun. 30, 2023	274,150	$ 6	556,761	(775)	(281,842)
Balance at end of period (in shares) at Jun. 30, 2023		61,065,023
Balances at Mar. 31, 2023	287,683	$ 5	552,040	(416)	(263,946)
Balance at Beginning of period (in shares) at Mar. 31, 2023		56,669,596
Exercise of stock options	248		248
Exercise of stock options (in shares)		95,176
Issuance of common stock under employee stock purchase plan	241		241
Issuance of common stock under employee stock purchase plan (in shares)		114,739
Issuance of common stock in connection with exercise of pre-funded warrants		$ 1	(1)
Issuance of common stock in connection with exercise of pre-funded warrants, shares		4,174,960
Vesting of restricted stock units with service conditions (in shares)		10,552
Stock-based compensation expense	4,233		4,233
Unrealized gain (loss) on available-for-sale securities	(298)			(298)
Foreign exchange translation adjustment	(61)			(61)
Net Income (Loss)	(17,896)				(17,896)
Balances at Jun. 30, 2023	274,150	$ 6	556,761	(775)	(281,842)
Balance at end of period (in shares) at Jun. 30, 2023		61,065,023
Balances at Dec. 31, 2023	255,367	$ 6	588,008	(19)	(332,628)
Balance at Beginning of period (in shares) at Dec. 31, 2023		64,576,719
Vesting of restricted stock units with service conditions (in shares)		74,974
Stock-based compensation expense	4,028		4,028
Unrealized gain (loss) on available-for-sale securities	(293)			(293)
Foreign exchange translation adjustment	(9)			(9)
Net Income (Loss)	(22,373)				(22,373)
Balances at Mar. 31, 2024	236,720	$ 6	592,036	(321)	(355,001)
Balance at end of period (in shares) at Mar. 31, 2024		64,651,693
Balances at Dec. 31, 2023	255,367	$ 6	588,008	(19)	(332,628)
Balance at Beginning of period (in shares) at Dec. 31, 2023		64,576,719
Foreign exchange translation adjustment	(16)
Balances at Jun. 30, 2024	218,681	$ 7	596,854	(443)	(377,737)
Balance at end of period (in shares) at Jun. 30, 2024		70,335,636
Balances at Mar. 31, 2024	236,720	$ 6	592,036	(321)	(355,001)
Balance at Beginning of period (in shares) at Mar. 31, 2024		64,651,693
Exercise of stock options	12		12
Exercise of stock options (in shares)		4,000
Issuance of common stock under employee stock purchase plan	387		387
Issuance of common stock under employee stock purchase plan (in shares)		87,083
Issuance of common stock in connection with exercise of pre-funded warrants		$ 1	(1)
Issuance of common stock in connection with exercise of pre-funded warrants, shares		5,564,904
Vesting of restricted stock units with service conditions (in shares)		27,956
Stock-based compensation expense	4,420		4,420
Unrealized gain (loss) on available-for-sale securities	(115)			(115)
Foreign exchange translation adjustment	(7)			(7)
Net Income (Loss)	(22,736)				(22,736)
Balances at Jun. 30, 2024	$ 218,681	$ 7	$ 596,854	$ (443)	$ (377,737)
Balance at end of period (in shares) at Jun. 30, 2024		70,335,636

Cash Equivalents and Marketable Securities (Additional Information) (Details)	Jun. 30, 2024 Position
Investments, Debt and Equity Securities [Abstract]
Securities, available-for-sale, unrealized loss position, number of positions	30

Leases (Tables)

6 Months Ended

Jun. 30, 2024

Leases [Abstract]

Schedule of components of lease cost

Components of lease cost are as follows:


	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2024		2023		2024		2023
Operating lease cost	$	162	$	163	$	323	$	322
Short-term cost		3		5		7		8
Total lease cost	$	165	$	168	$	330	$	330

Weighted-average remaining lease term								0.34
Weighted-average discount rate								6.00	%

Schedule of future minimum lease payments required under operating leases

The Company's future minimum lease payments are as follows:


(in thousands)	Operating Leases
2024	$	252
2025 and thereafter		—
Total lease payments		252
Less: Imputed interest		(3	)
Present value of lease liabilities		249
Less: Current portion of lease liabilities		(249	)
Total lease liabilities, non-current	$	—

Leases (Additional Information) (Details) $ in Millions	6 Months Ended
Leases (Additional Information) (Details) $ in Millions	Jun. 30, 2024 USD ($)
Lessor, Lease, Description [Line Items]
Option to extend	On July 1, 2024, the Company amended the lease agreement for the office space in Foster City, California to extend for three years commencing as of November 1, 2024, and expiring on October 31, 2027. The Company has the option to extend the amended lease agreement for an additional three years.
Lease Agreements [Member]
Lessor, Lease, Description [Line Items]
Annual lease payments	$ 0.5

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Assets:
Marketable securities	$ 133,801
Recurring
Assets:
Total cash and cash equivalents	91,496	$ 79,926
Marketable securities	133,801	183,514
Recurring \| Cash in bank balances
Assets:
Total cash and cash equivalents	14,005	46,138
Recurring \| Money market funds
Assets:
Total cash and cash equivalents	77,491	33,788
Recurring \| U.S. government securities
Assets:
Marketable securities	133,801	183,514
Recurring \| Level 1
Assets:
Total cash and cash equivalents	91,496	79,926
Recurring \| Level 1 \| Cash in bank balances
Assets:
Total cash and cash equivalents	14,005	46,138
Recurring \| Level 1 \| Money market funds
Assets:
Total cash and cash equivalents	77,491	33,788
Recurring \| Level 2
Assets:
Marketable securities	133,801	183,514
Recurring \| Level 2 \| U.S. government securities
Assets:
Marketable securities	$ 133,801	$ 183,514

Common Stock and Stock-Based Compensation - Schedule of Stock Options Weighted Average Assumptions (Details) - $ / shares	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Employee Stock Purchase Plans
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (years)	1 year 2 months 19 days	1 year 3 months 3 days
Expected volatility	83.43%	86.49%
Risk-free interest rate	5.10%	4.85%
Fair value of underlying common stock	$ 6.01	$ 11.3
Weighted average grant-date fair value per share	$ 3.03	$ 5.82
Employee Stock Option
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (years)	6 years 18 days	6 years 18 days
Expected volatility	77.61%	73.68%
Risk-free interest rate	4.26%	3.53%
Fair value of underlying common stock	$ 6.5	$ 9.82
Weighted average grant-date fair value per share	$ 4.56	$ 6.61

- Definition

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

+ References

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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Section 35
-Paragraph 3
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-URI https://asc.fasb.org/1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Section 50
-Paragraph 2
-Subparagraph (a)(1)
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (a)(2)
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 2
-Subparagraph (a)(3)
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 2
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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Reference 18: http://www.xbrl.org/2003/role/disclosureRef
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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Reference 20: http://www.xbrl.org/2003/role/disclosureRef
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Reference 25: http://www.xbrl.org/2003/role/disclosureRef
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Reference 26: http://www.xbrl.org/2003/role/disclosureRef
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Reference 27: http://www.xbrl.org/2003/role/disclosureRef
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Reference 28: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
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-Subparagraph (f)(2)(v)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Common Stock and Stock-Based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 4,420	$ 4,233	$ 8,448	$ 8,171
Research and Development Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	2,090	1,576	4,178	2,924
General and Administrative Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 2,330	$ 2,657	$ 4,270	$ 5,247

- Definition

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

+ References

+ Details

Leases - Schedule of maturities of operating leases (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Operating Leases
2024	$ 252
2025 and thereafter	0
Total lease payments	252
Less: Imputed interest	(3)
Present value of lease liabilities	249
Less: Current portion of lease liabilities	(249)	$ (603)
Total lease liabilities, non-current	$ 0

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References + Details

Nature of the Business, Basis of Presentation and Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2024

Accounting Policies [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities included the following:


(in thousands)	June 30, 2024		December 31, 2023
Research and development costs	$	3,229	$	2,010
Compensation and benefit costs		3,108		5,683
Accrued professional fees		2,176		855
Other		320		278
Total accrued expenses and other current liabilities	$	8,833	$	8,826

Schedule of Antidilutive Securities Excluded from Computation of Net Loss per Share


	June 30,
	2024		2023
Options to purchase common stock		11,366,749		8,450,168
Unvested restricted stock units with service conditions		782,737		372,301
Unvested restricted stock units with market conditions		150,000		—
Shares issuable under employee stock purchase plan		13,589		9,193
Total		12,313,075		8,831,662

Nature of the Business, Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Net Loss per Share (Details) - shares	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	12,313,075	8,831,662
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	11,366,749	8,450,168
Unvested Restricted Stock Units With Service Conditions
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	782,737	372,301
Unvested Restricted Stock Units With Market Conditions
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	150,000	0
Shares Issuable Under Employee Stock Purchase Plan
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	13,589	9,193

Cash Equivalents and Marketable Securities - Schedule of Fair Value And Amortized Cost of Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Marketable Securities [Line Items]
Amortized Cost	$ 211,543	$ 217,145
Unrealized Gains	3	219
Unrealized Losses	(254)	(62)
Fair Value	211,292	217,302
Cash equivalents	77,491	33,788
Marketable securities	133,801	183,514
Total	211,292	217,302
Money market funds
Marketable Securities [Line Items]
Amortized Cost	77,491	33,788
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	77,491	33,788
U.S. government securities
Marketable Securities [Line Items]
Amortized Cost	134,052	183,357
Unrealized Gains	3	219
Unrealized Losses	(254)	(62)
Fair Value	$ 133,801	$ 183,514

Common Stock and Stock-Based Compensation - Summary of Restricted Stock Award Activity (Details) - Restricted Stock	6 Months Ended
	Jun. 30, 2024 $ / shares shares
Number of Shares
Number of Shares, Unvested restricted common stock, beginning balance \| shares	365,892
Number of Shares, Granted \| shares	632,775
Number of Shares, Vested \| shares	(102,930)
Number of Shares, Forfeited \| shares	(113,000)
Number of Shares, Unvested restricted common stock, ending balance \| shares	782,737
Grant-Date Fair Value
Grant-Date Fair Value, Unvested restricted common stock, beginning balance \| $ / shares	$ 8.79
Grant-Date Fair Value, Granted \| $ / shares	6.16
Grant-Date Fair Value, Vested \| $ / shares	9.33
Grant-Date Fair Value, Forfeited \| $ / shares	6.5
Grant-Date Fair Value, Unvested restricted common stock, ending balance \| $ / shares	$ 6.92

Common Stock and Stock-Based Compensation

6 Months Ended

Jun. 30, 2024

Share-Based Payment Arrangement [Abstract]

Common Stock and Stock-Based Compensation

5. Common Stock and Stock-Based Compensation

The Company is authorized to issue 150,000,000 shares of common stock and 10,000,000 shares of preferred stock. All classes of stock have a par value of $0.0001. There were no shares of preferred stock outstanding as of June 30, 2024 and December 31, 2023.

The Company had reserved shares of common stock for issuance in connection with the following:


	June 30, 2024		December 31, 2023
Options outstanding under incentive award plans		11,366,749		8,349,922
Unvested restricted stock units with service conditions		782,737		365,892
Unvested restricted stock units with market conditions		150,000		—
Shares available for future grant under incentive award plans		2,876,986		1,005,587
Shares available for future grant under employee stock purchase plans		614,588		701,671
Shares available for future grant under employment inducement award plans		957,834		3,291,000
Pre-funded warrants		4,186,500		9,751,500
Total shares reserved		20,935,394		23,465,572

Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive dividends, if any, as may be declared by the Company’s board of directors. Through June 30, 2024, no cash dividends have been declared or paid by the Company.

Stock-Based Compensation Plans

The Company has three stock-based compensation plans, the 2017 Incentive Award Plan (the 2017 Plan), the 2021 Incentive Award Plan (the 2021 Plan) and the 2022 Employment Inducement Award Plan (the 2022 Inducement Plan). Although awards made under the 2017 Plan continue to be governed by its terms, the 2017 Plan was terminated at the time of the Company’s IPO and no further awards are made under this plan. The 2021 Plan, while effective, authorizes the granting of equity awards to employees and directors of the Company, as well as non-employee consultants. The 2022 Inducement Plan authorizes the granting of equity awards to newly hired employees of the Company.

2021 Incentive Award Plan

In January 2021, the Company's board of directors approved the 2021 Plan which permits the granting of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance bonus awards, performance stock unit awards and other stock awards to employees, directors, officers and consultants. In February 2021, 2,400,007 shares were authorized for issuance under the 2021 Plan, which shall be cumulatively increased on the first day of each year beginning in 2022 and ending in 2031 equal to the lesser of (i) the amount equal to 5% of the number of shares issued and outstanding on the last day of the immediately preceding fiscal year or (ii) such lower number of shares as may be determined by the Company’s board of directors. The 2021 Plan is the successor to the 2017 Incentive Award Plan and no additional awards may be issued from the 2017 Plan. However, the 2017 Plan will continue to govern the terms and conditions of the outstanding awards granted under this plan. Shares of common stock subject to awards granted under the 2017 Plan that are forfeited or lapse unexercised and which following the effective date of the 2021 Plan are not issued under the 2017 Plan will be available for issuance under the 2021 Plan. The number of authorized shares reserved for issuance under the 2021 Plan was increased by 3,228,835 shares effective as of January 1, 2024. As of June 30, 2024, 2,876,986 shares of the Company’s common stock were available for future grants under the 2021 Plan.

2021 Employee Stock Purchase Plan

The 2021 Employee Stock Purchase Plan (the 2021 ESPP) was approved by the Company’s board of directors in January 2021. In February 2021, a total of 240,000 shares were initially reserved for issuance under this plan, which shall be cumulatively increased on the first day of each year beginning in 2022 and ending in 2031 equal to the lesser of (i) 1% of the shares outstanding (on an as converted basis) on the last day of the immediately preceding fiscal year and (ii) such number of shares as may be determined by the Company’s board of directors. The number of authorized shares reserved for issuance under the 2021 ESPP was increased by 645,767 shares effective as of January 1, 2024. As of June 30, 2024, 614,588 shares of the Company’s common stock were available for future grants under the 2021 ESPP.

Under the 2021 ESPP, eligible employees may select a rate of payroll deduction up to 15% of their eligible compensation subject to certain maximum purchase limitations. The duration for each offering period is 24 months and is divided into four purchase periods of approximately six months in length. Offerings are concurrent. The purchase price of the shares under the offering is the lesser of 85% of the fair market value of the shares on the offering date or 85% of the fair market value of the shares on the purchase date. A look-back feature in the 2021 ESPP causes the offering period to automatically reset if the fair value of the Company’s common stock on the last day of the purchase period is less than that on the original offering date. 2021 ESPP purchases by employees are settled with newly-issued common stock from the 2021 ESPP’s previously authorized and available pool of shares.

As of June 30, 2024, there was $0.7 million of unrecognized stock-based compensation expense related to unvested employee stock purchases. The unrecognized stock-based compensation expense is estimated to be recognized over a period of 1.34 years as of June 30, 2024. There were 87,083 and 114,739 shares purchased by employees under the 2021 ESPP during the six months ended June 30, 2024 and 2023, respectively.

2022 Employment Inducement Award Plan

In September 2022, the Company's compensation committee approved the 2022 Inducement Plan which authorized 1,400,000 shares of common stock to be issued and permitted the granting of nonqualified stock options, stock appreciation rights, restricted stock awards and restricted stock unit awards to newly hired employees and officers. In September 2023, the Company approved an amendment to the 2022 Inducement Plan which increased the number of authorized shares reserved for issuance by 3,113,250 shares. As of June 30, 2024, 957,834 shares of the Company's common stock were available for future grants under the 2022 Inducement Plan.

Pre-Funded Warrants

In August 2022, the Company sold pre-funded warrants to purchase 14,630,000 shares of common stock at a price of $2.4199 per pre-funded warrant. The purchase price per share of each pre-funded warrant represents the per share offering price for the common stock, minus the $0.0001 per share exercise price of such pre-funded warrant. As of June 30, 2024, 10,443,500 pre-funded warrants have been exercised.

Stock Options

Stock options granted to employees and non-employees under the plans generally vest over four years and allow the holder of the option to purchase common stock at a stated exercise price. Options granted under the plans generally expire ten years after the date of grant. The Company recognizes the stock-based compensation expense over the requisite service period of the individual grantees, which generally equals the vesting period.

The following table summarizes the stock option activity for all stock plans during the six months ended June 30, 2024:


	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding as of December 31, 2023		8,349,922		$	9.04		6.82	$	2,225
Granted		3,824,500			6.50
Exercised		(4,000	)		3.00				15
Forfeited		(803,673	)		8.67
Outstanding as of June 30, 2024		11,366,749		$	8.21		6.79	$	4,425
Exercisable, June 30, 2024		5,738,075		$	8.96		4.39	$	1,909
Vested and expected to vest, June 30, 2024		11,366,749		$	8.21		6.79	$	4,425

The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock.

As of June 30, 2024, there was $27.3 million of unrecognized stock-based compensation expense related to unvested stock options which is estimated to be recognized over a period of 2.95 years.

Restricted Stock Units with Service Conditions

RSUs with service conditions granted to employees under the plans generally vest over four years. The number of shares issued on the date the RSUs vest is net of the minimum statutory tax withholdings, which are paid in cash to the appropriate taxing authorities on behalf of the Company’s employees. The Company recognizes the stock-based compensation expense over the requisite service period of the individual grantees, which generally equals the vesting period.

The following table summarizes the RSUs with service conditions activity for all stock plans during the six months ended June 30, 2024:


	Number of Shares			Weighted Average Grant-Date Fair Value
Unvested restricted stock units as of December 31, 2023		365,892		$	8.79
Granted		632,775			6.16
Vested		(102,930	)		9.33
Forfeited		(113,000	)		6.50
Unvested restricted stock units as of June 30, 2024		782,737		$	6.92

As of June 30, 2024, there was $4.7 million of unrecognized stock-based compensation expense related to RSUs with service conditions which is estimated to be recognized over a period of 3.06 years.

Restricted Stock Units with Market Conditions

In March 2024, the Company granted 150,000 RSUs with market conditions, which are subject to the achievement of certain escalating stock price thresholds established by the Company's compensation committee of the board of directors. The RSUs with market conditions vest in equal installments upon the achievement of escalating stock price thresholds of $15.00 and $20.00, respectively, calculated based on the average price per share of the Company’s common stock for a period of 30 consecutive trading days equaling or exceeding the applicable price threshold, with vesting occurring as of the last day of the 30 consecutive trading day period. The escalating stock price thresholds can be met any time after the first anniversary of employment of the recipient but prior to the fourth anniversary of the date of grant.

The Company estimated the fair value of RSUs with market conditions granted using a Monte Carlo simulation model with the following assumptions:


	Six Months Ended June 30, 2024
Expected volatility		78.45	%
Risk-free interest rate		4.27	%
Fair value of underlying common stock	$	7.31
Weighted average grant-date fair value per share	$	5.39

As of June 30, 2024, none of the escalating stock price thresholds had been met for any of the RSUs with market conditions, resulting in no shares vested.

As of June 30, 2024, there was $0.6 million of unrecognized stock-based compensation expense related to RSUs with market conditions which is estimated to be recognized over a period of 1.30 years.

Stock-Based Compensation Expense


	Six Months Ended June 30,
	2024			2023
Stock Option Plans
Expected term (years)		6.05			6.05
Expected volatility		77.61	%		73.68	%
Risk-free interest rate		4.26	%		3.53	%
Fair value of underlying common stock	$	6.50		$	9.82
Weighted average grant-date fair value per share	$	4.56		$	6.61
Employee Stock Purchase Plans
Expected term (years)		1.22			1.26
Expected volatility		83.43	%		86.49	%
Risk-free interest rate		5.10	%		4.85	%
Fair value of underlying common stock	$	6.01		$	11.30
Weighted average grant-date fair value per share	$	3.03		$	5.82

Stock-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows:


	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2024		2023		2024		2023
Research and development expense	$	2,090	$	1,576	$	4,178	$	2,924
General and administrative expense		2,330		2,657		4,270		5,247
Total stock-based compensation expense	$	4,420	$	4,233	$	8,448	$	8,171

Common Stock and Stock-Based Compensation - Schedule of Estimated the Fair value of RSUs with Market Conditions (Details) - Restricted Stock Units with Market Conditions	6 Months Ended
	Jun. 30, 2024 $ / shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected volatility	78.45%
Risk-free interest rate	4.27%
Fair value of underlying common stock	$ 7.31
Weighted average grant-date fair value per share	$ 5.39

- Definition

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

+ References

+ Details

Common Stock and Stock-Based Compensation - Summary of Stock Option Activity (Details) - Employee Stock Option $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares
Number of Shares
Number of Shares, Outstanding beginning balance \| shares	8,349,922
Number of Shares, Granted \| shares	3,824,500
Number of Shares, Exercised \| shares	(4,000)
Number of Shares, Forfeited \| shares	(803,673)
Number of Shares, Outstanding ending balance \| shares	11,366,749	8,349,922
Number of Shares, Exercisable \| shares	5,738,075
Number of Shares, Vested and expected to vest \| shares	11,366,749
Weighted-Average Exercise Price
Weighted-Average Exercise Price, Outstanding beginning balance \| $ / shares	$ 9.04
Weighted-Average Exercise Price, Granted \| $ / shares	6.5
Weighted-Average Exercise Price, Exercised \| $ / shares	3
Weighted-Average Exercise Price, Forfeited \| $ / shares	8.67
Weighted-Average Exercise Price, Outstanding ending balance \| $ / shares	8.21	$ 9.04
Weighted-Average Exercise Price, Exercisable \| $ / shares	8.96
Weighted-Average Exercise Price, Vested and expected to vest \| $ / shares	$ 8.21
Weighted-Average Remaining Contractual Term and Aggregate Intrinsic Value
Weighted-Average Remaining Contractual Term, Outstanding	6 years 9 months 14 days	6 years 9 months 25 days
Weighted-Average Remaining Contractual Term, Exercisable	4 years 4 months 20 days
Weighted-Average Remaining Contractual Term, Vested and expected to vest	6 years 9 months 14 days
Aggregate Intrinsic Value, Outstanding, beginning balance \| $	$ 2,225
Aggregate Intrinsic Value, Exercised \| $	15
Aggregate Intrinsic Value, Outstanding, ending balance \| $	4,425	$ 2,225
Aggregate Intrinsic Value, Exercisable \| $	1,909
Aggregate Intrinsic Value, Vested and expected to vest \| $	$ 4,425

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, authorized	150,000,000	150,000,000
Common stock, shares issued	70,335,636	64,576,719
Common stock, shares outstanding	70,335,636	64,576,719

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash flows from operating activities:
Net loss	$ (45,109)	$ (39,424)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	8,448	8,171
Depreciation expense	170	148
Accretion on marketable securities	(925)	(1,781)
Change in deferred taxes and uncertain tax positions	68	64
Amortization of operating lease assets	306	291
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(949)	(641)
Accounts payable	(642)	4,171
Accrued expenses and other current liabilities	8	1,951
Operating lease liabilities	(352)	(325)
Net cash used in operating activities	(38,977)	(27,375)
Cash flows from investing activities:
Purchase of property and equipment	(42)	0
Purchase of investments	(50,594)	(206,693)
Proceeds from sales and maturities of investments	100,824	143,787
Net cash provided by (used in) investing activities	50,188	(62,906)
Cash flows from financing activities:
Net proceeds from issuance of common stock in at-the-market offering	0	27,924
Proceeds from stock option exercises	12	248
Payment of deferred offering costs	0	(344)
Proceeds from issuance of common stock under employee stock purchase plan	387	241
Net cash provided by financing activities	399	28,069
Effect of exchange rate changes on cash and cash equivalents	(40)	(104)
Net increase (decrease) in cash and cash equivalents	11,570	(62,316)
Cash and cash equivalents at beginning of period	79,926	143,235
Cash and cash equivalents at end of period	91,496	80,919
Supplemental disclosure of cash flow information:
Cash paid for amounts included in the measurement of lease liabilities	$ 366	$ 357

Fair Value Measurements

6 Months Ended

Jun. 30, 2024

Fair Value Disclosures [Abstract]

Fair Value Measurements

3. Fair Value Measurements

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The three levels of inputs that may be used to measure fair value are defined below:

•

Level 1—Quoted prices in active markets for identical assets or liabilities at the measurement date.

•

Level 2—Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, such as quoted prices for similar assets or liabilities, quoted prices 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 assets or liabilities.

•

Level 3—Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.

The carrying values of the Company’s other assets, accounts payable and accrued expenses and other current liabilities approximate their fair values due to the short-term nature of these assets and liabilities.

The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis:


	Fair Value at June 30, 2024
(in thousands)	Level 1		Level 2		Level 3		Total
Cash and cash equivalents
Cash in bank balances	$	14,005	$	—	$	—	$	14,005
Money market funds		77,491		—		—		77,491
Total cash and cash equivalents	$	91,496	$	—	$	—	$	91,496
Marketable securities
U.S. government securities	$	—	$	133,801	$	—	$	133,801
Total marketable securities	$	—	$	133,801	$	—	$	133,801

	Fair Value at December 31, 2023
(in thousands)	Level 1		Level 2		Level 3		Total
Cash and cash equivalents
Cash in bank balances	$	46,138	$	—	$	—	$	46,138
Money market funds		33,788		—		—		33,788
Total cash and equivalents	$	79,926	$	—	$	—	$	79,926
Marketable securities
U.S. government securities	$	—	$	183,514	$	—	$	183,514
Total marketable securities	$	—	$	183,514	$	—	$	183,514

The aggregate amortized cost and fair value of marketable securities as of June 30, 2024, by contractual maturity, are as follows:


(in thousands)	Amortized Cost		Fair Value
Due in one year or less	$	109,760	$	109,593
Due after one year through two years		24,292		24,208
Total marketable securities	$	134,052	$	133,801

There were no transfers between Level 1, Level 2 and Level 3 during the periods presented.

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 107
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-107

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
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-Name Accounting Standards Codification
-Section 55
-Paragraph 100
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-100

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2E
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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-Name Accounting Standards Codification
-Section 50
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478119/940-820-50-1

+ Details

Cash Equivalents and Marketable Securities - Schedule of Available-for-sale Marketable Securities for Unrealized Loss Position (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Marketable Securities [Line Items]
Less than 12 months, fair value	$ 115,214	$ 80,461
Less than 12 months, unrealized losses	(211)	(62)
12 months or longer, fair value	14,073	0
12 months or longer, unrealized losses	(43)	0
Total fair value	129,287	80,461
Total unrealized losses	(254)	(62)
U.S. government securities
Marketable Securities [Line Items]
Less than 12 months, fair value	115,214	80,461
Less than 12 months, unrealized losses	(211)	(62)
12 months or longer, fair value	14,073	0
12 months or longer, unrealized losses	(43)	0
Total fair value	129,287	80,461
Total unrealized losses	$ (254)	$ (62)

Common Stock and Stock-Based Compensation - Schedule of Common Stock Shares Reserved for Issuance (Details) - shares	Jun. 30, 2024	Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares reserved	20,935,394	23,465,572
Options Outstanding Under Incentive Award Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares reserved	11,366,749	8,349,922
Unvested Restricted Stock Units With Service Conditions
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares reserved	782,737	365,892
Unvested Restricted Stock Units With Market Conditions
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares reserved	150,000	0
Shares Available For Future Grant Under Incentive Award Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares reserved	2,876,986	1,005,587
Shares Available For Future Grant Under Employee Stock Purchase Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares reserved	614,588	701,671
Shares Available For Future Grant Under Employment Inducement Award Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares reserved	957,834	3,291,000
Pre-Funded Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares reserved	4,186,500	9,751,500

- Definition

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

+ References

+ Details

Nature of the Business, Basis of Presentation and Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2024

Accounting Policies [Abstract]

Basis of Presentation

Unaudited Interim Financial Information

At-the-Market Offering

Use of Estimates

Cash, Cash Equivalents and Marketable Securities

Operating Leases and Rent Expense

Research and Development Expenses

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities included the following:


(in thousands)	June 30, 2024		December 31, 2023
Research and development costs	$	3,229	$	2,010
Compensation and benefit costs		3,108		5,683
Accrued professional fees		2,176		855
Other		320		278
Total accrued expenses and other current liabilities	$	8,833	$	8,826

Executive Leadership Transition

Income Taxes

Comprehensive Loss

Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources.

Stock-Based Compensation

The fair value of RSUs with service conditions is based upon the Company’s common stock valuation on the date of the grant.

Pre-funded Warrants

Net Loss Per Share of Common Stock


	June 30,
	2024		2023
Options to purchase common stock		11,366,749		8,450,168
Unvested restricted stock units with service conditions		782,737		372,301
Unvested restricted stock units with market conditions		150,000		—
Shares issuable under employee stock purchase plan		13,589		9,193
Total		12,313,075		8,831,662

Deferred Offering Costs

Commitments and Contingencies

Recent Accounting Pronouncements

Recently Issued Accounting Pronouncements Not Yet Adopted

Nature of the Business, Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands		1 Months Ended		3 Months Ended			6 Months Ended		12 Months Ended
	May 07, 2024	Jul. 31, 2024	Aug. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Mar. 31, 2022	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023	Nov. 30, 2023
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Other Accrued Liabilities, Current				$ 320			$ 320		$ 278
Income tax expense				61	$ 72		158	$ 132
Foreign Country [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Income tax expense				100	$ 100		200	$ 100
Mr. Sundaram
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Severance Costs			$ 600
Other Accrued Liabilities, Current				300			300		900
Stock-Based Compensation Expense									$ 10,500
Discretionary Bonus			100.00%
Discretionary Bonus Amount			$ 300
Mr. Yoon
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Severance Costs		$ 500
Retention awards payable			500
Amount Equivalent to Annual Basic Salary		12 months
Unpaid Retention Award		$ 300
Target Annual Bonus		100
Dr. Vignola
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Severance Costs		$ 500
Retention awards payable			$ 700
Amount Equivalent to Annual Basic Salary		12 months
Unpaid Retention Award		$ 500
Target Annual Bonus		200
Additional Retention Bonus		$ 500
Mr. Yoon and Dr. Vignola
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Other Accrued Liabilities, Current				$ 500			500
Erin Quirk [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Severance Costs	$ 200
Retention awards payable										$ 600
Recognition bonus aggregate amount										$ 100
Unpaid Recognition Bonus portion	$ 400
Stock-based compensation expense							$ 400
At-the-Market Offering [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Offer price						$ 75,000
At-the-Market Offering [Member] \| Common Stock
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of shares issued							9,781,673
Net proceeds from issuance of common stock							$ 66,600
Sales Agreement With Cowen
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Offer price							$ 150,000

Leases - Schedule of Components of lease cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Leases [Abstract]
Operating lease cost	$ 162	$ 163	$ 323	$ 322
Short-term cost	3	5	7	8
Total lease cost	$ 165	$ 168	$ 330	$ 330
Weighted-average remaining lease term		4 months 2 days		4 months 2 days
Weighted-average discount rate		6.00%		6.00%

Fair Value Measurements - Additional Information (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($)
Fair Value Disclosures [Abstract]
Liabilities, Transfers into Level 3	$ 0
Liabilities, Transfers out of Level 3	0
Assets, Transfers into Level 3	0
Assets, Transfers out of Level 3	$ 0

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Jun. 30, 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
Rule 10b5-1 Arrangement Modified	false
Non-Rule 10b5-1 Arrangement Modified	false

Common Stock and Stock-Based Compensation - Additional Information (Details)		1 Months Ended		3 Months Ended	6 Months Ended
	Jan. 01, 2023 shares	Sep. 30, 2023 shares	Feb. 28, 2021 shares	Mar. 31, 2024 USD ($) shares	Jun. 30, 2024 USD ($) Plan Vote $ / shares shares	Jun. 30, 2023 shares	Dec. 31, 2023 $ / shares shares	Sep. 30, 2022 shares	Aug. 31, 2022 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, voting rights					Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive dividends
Number of voting rights per share \| Vote					1
Cash dividends declared or paid \| $					$ 0
Number of stock-based compensation plans \| Plan					3
Number of shares authorized					150,000,000		150,000,000
Preferred stock, shares authorized					10,000,000
Preferred stock, par or stated value per share \| $ / shares					$ 0.0001
Common stock, par value \| $ / shares					$ 0.0001		$ 0.0001
Preferred Stock, Shares Outstanding					0		0
Total shares reserved					20,935,394		23,465,572
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for future grants					3,824,500
Unrecognized stock-based compensation expense related to unvested stock options \| $					$ 27,300,000
Unrecognized stock-based compensation expense recognized period					2 years 11 months 12 days
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense related to unvested stock options \| $					$ 4,700,000
Unrecognized stock-based compensation expense recognized period					3 years 21 days
Number of Shares, Granted					632,775
Restricted Stock Units with Market Conditions
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense related to unvested stock options \| $					$ 600,000
Unrecognized stock-based compensation expense recognized period					1 year 3 months 18 days
Number of Shares, Granted				150,000
Stock Price Thresholds , Minimum \| $				$ 15
Stock Price Thresholds , Maximum \| $				$ 20
2021 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award, number of shares authorized			2,400,007
Increase of number of authorized shares reserved for issuance under the 2021 Plan	3,228,835
Share-based payment award, shares available for future grants					2,876,986
Increase of authorized shares, percent of common stock outstanding			5.00%
2017 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase of number of authorized shares reserved for issuance under the 2021 Plan			0
2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase of number of authorized shares reserved for issuance under the 2021 Plan	645,767
Share-based payment award, shares available for future grants					614,588
Total shares reserved			240,000
Shares purchased by employees under the ESPP					87,083	114,739
Increase of authorized shares, percent of common stock outstanding			1.00%
Unrecognized stock-based compensation expense recognized period					1 year 4 months 2 days
Percentage of fair market value of the shares on the offering date					85.00%
Percentage of fair market value of the shares on the purchase date					85.00%
Unrecognized stock-based compensation expense related to unvested employee stock purchases \| $					$ 700,000
2021 Employee Stock Purchase Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share Based Compensation Rate of Payroll Deduction					15.00%
2022 Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized								1,400,000
Increase of number of authorized shares reserved for issuance under the 2021 Plan		3,113,250
Shares available for future grants					957,834
Pre-Funded Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Pre Funded warrants exercised					10,443,500
Common stock, par value \| $ / shares									$ 0.0001
Pre-funded warrants to purchase									14,630,000
Pre-funded warrant price \| $ / shares									$ 2.4199

Cash Equivalents and Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Schedule of Fair Value And Amortized Cost of Marketable Securities

The amortized cost and fair value of cash equivalents and marketable securities by major security type is as follows:


	June 30, 2024
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	$	77,491	$	—	$	—		$	77,491
U.S. government securities		134,052		3		(254	)		133,801
Total	$	211,543	$	3	$	(254	)	$	211,292

Classified as:
Cash equivalents								$	77,491
Marketable securities									133,801
Total								$	211,292

	December 31, 2023
(in thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	$	33,788	$	—	$	—		$	33,788
U.S. government securities		183,357		219		(62	)		183,514
Total	$	217,145	$	219	$	(62	)	$	217,302

Classified as:
Cash equivalents								$	33,788
Marketable securities									183,514
Total								$	217,302

Schedule of Available-for-sale Marketable Securities for Unrealized Loss Position


	June 30, 2024
	Less than 12 months					12 months or longer					Total
(in thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. government securities	$	115,214	$	(211	)	$	14,073	$	(43	)	$	129,287	$	(254	)
Total	$	115,214	$	(211	)	$	14,073	$	(43	)	$	129,287	$	(254	)

	December 31, 2023
	Less than 12 months					12 months or longer					Total
(in thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. government securities	$	80,461	$	(62	)	$	—	$	—		$	80,461	$	(62	)
Total	$	80,461	$	(62	)	$	—	$	—		$	80,461	$	(62	)

Assignment, License and Collaboration Agreements - Additional Information (Details) $ in Thousands, ¥ in Millions	1 Months Ended				3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2019 CNY (¥)	Jun. 30, 2019 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2021 USD ($)
License Fee [Member]
Assignment License And Collaboration Agreements [Line Items]
License revenue									$ 1,000
Assignment Agreement
Assignment License And Collaboration Agreements [Line Items]
Aggregate pre-specified development milestones for the first covered product \| ¥			¥ 205.0
Research and development expense					$ 0	$ 0	$ 0	$ 0
Amount paid under the agreement							$ 4,400
Number of days advance written notice							60 days
Milestone payment		$ 1,500
Assignment Agreement \| Research and Development Expense
Assignment License And Collaboration Agreements [Line Items]
Upfront payment				$ 700
Hansoh Option and License Agreement \| Maximum
Assignment License And Collaboration Agreements [Line Items]
Amount agree to pay in pre-specified clinical, regulatory and sales milestones							$ 67,000
Phase 2a DUET
Assignment License And Collaboration Agreements [Line Items]
Milestone payment	$ 2,200

Fair Value Measurements - Schedule of Aggregate Amortized Cost and Fair Value of Marketable Securities (Details) $ in Thousands	Jun. 30, 2024 USD ($)
Fair Value Disclosures [Abstract]
Due in one year or less	$ 109,760
Due after one year through two years	24,292
Total marketable securities	134,052
Due in one year or less	109,593
Due after one year through two years	24,208
Total marketable securities	$ 133,801

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Operating expenses:
Research and development	$ 18,352	$ 14,151	$ 36,939	$ 31,207
General and administrative	7,185	7,008	14,044	14,109
Total operating expenses	25,537	21,159	50,983	45,316
Loss from operations	(25,537)	(21,159)	(50,983)	(45,316)
Other income:
Interest income	2,876	3,395	6,058	6,088
Other expense, net	(14)	(60)	(26)	(64)
Total other income, net	2,862	3,335	6,032	6,024
Loss before income taxes	(22,675)	(17,824)	(44,951)	(39,292)
Income tax expense	(61)	(72)	(158)	(132)
Net loss	$ (22,736)	$ (17,896)	$ (45,109)	$ (39,424)
Net loss per share, basic	$ (0.31)	$ (0.25)	$ (0.61)	$ (0.56)
Net loss per share, diluted	$ (0.31)	$ (0.25)	$ (0.61)	$ (0.56)
Weighted average common stock outstanding, basic	74,459,774	71,364,110	74,429,576	70,575,645
Weighted average common stock outstanding, diluted	74,459,774	71,364,110	74,429,576	70,575,645
Other comprehensive loss:
Net loss	$ (22,736)	$ (17,896)	$ (45,109)	$ (39,424)
Unrealized (loss) gain on available-for-sale securities, net of tax	(115)	(298)	(408)	120
Foreign exchange translation adjustment, net of tax	(7)	(61)	(16)	(73)
Comprehensive loss	$ (22,858)	$ (18,255)	$ (45,533)	$ (39,377)