Surface Oncology (SURF) 10-Q 4 May 23 2023 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2023	May 01, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	001-38459
Entity Registrant Name	SURFACE ONCOLOGY, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-5543980
Entity Address, Address Line One	50 Hampshire Street
Entity Address, Address Line Two	8th Floor
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02139
City Area Code	617
Local Phone Number	714-4096
Title of 12(b) Security	Common stock, $0.0001
Trading Symbol	SURF
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		60,716,873
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001718108
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 28,982	$ 50,910
Marketable securities	73,073	73,913
Prepaid expenses and other current assets	5,154	4,317
Total current assets	107,209	129,140
Property and equipment, net	4,511	4,866
Operating lease right-of-use asset	23,693	24,307
Restricted cash	1,595	1,595
Other assets	0	2
Total assets	137,008	159,910
Current liabilities:
Accounts payable	1,108	256
Accrued expenses and other current liabilities	4,612	10,214
Operating lease liability	5,811	5,790
Convertible note payable	3,219	0
Total current liabilities	14,750	16,260
Operating lease liability, non-current	23,939	24,662
Convertible note payable, non-current	22,488	25,585
Total liabilities	61,177	66,507
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.0001 par value per share; 5,000,000 shares authorized    at March 31, 2023 and December 31, 2022; no shares    issued and outstanding at March 31, 2023 and December 31, 2022	0	0
Common stock, $0.0001 par value; 150,000,000 shares    authorized at March 31, 2023 and December 31, 2022, respectively;    60,716,873 and 60,578,956 shares issued and outstanding at March 31, 2023    and December 31, 2022, respectively	6	6
Additional paid-in capital	300,464	298,741
Accumulated other comprehensive loss	(569)	(1,015)
Accumulated deficit	(224,070)	(204,329)
Total stockholders’ equity	75,831	93,403
Total liabilities and stockholders’ equity	$ 137,008	$ 159,910

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized (in shares)	5,000,000	5,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, authorized (in shares)	150,000,000	150,000,000
Common stock, issued (in shares)	60,716,873	60,578,956
Common stock, outstanding (in shares)	60,716,873	60,578,956

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
License-related revenue	$ 0	$ 30,000
Operating expenses:
Research and development	13,777	16,624
General and administrative	5,886	6,540
Total operating expenses	19,663	23,164
Income (loss) from operations	(19,663)	6,836
Interest expense	(932)	(682)
Other income, net	854	45
Net income (loss)	$ (19,741)	$ 6,199
Net income (loss) per share — basic (in dollars per share)	$ (0.33)	$ 0.13
Weighted average common shares outstanding— basic (in shares)	60,627,993	48,606,055
Net income (loss) per share — diluted (in dollars per share)	$ (0.33)	$ 0.13
Weighted average common shares outstanding— diluted (in shares)	60,627,993	49,816,784
Comprehensive income (loss):
Net income (loss)	$ (19,741)	$ 6,199
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities, net of tax of $0	446	(690)
Comprehensive income (loss)	$ (19,295)	$ 5,509

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) (Parenthetical) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Marketable securities tax	$ 0	$ 0

Condensed Consolidated Statem_3

Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2021		46,958,776
Beginning balance at Dec. 31, 2021	$ 118,900	$ 5	$ 259,859	$ (221)	$ (140,743)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		208
Issuance of common stock upon exercise    of stock options	0		0
Issuance of common stock under stock purchase plan (in shares)		51,329
Issuance of common stock under stock purchase plan	157		157
Issuance of common stock upon public offering, net of issuance costs (in shares)		7,337,251
Issuance of common stock upon public offering, net of issuance costs	20,556	$ 1	20,555
Stock-based compensation expense	1,865		1,865
Unrealized gain (loss) on marketable securities	(690)			(690)
Net income (loss)	6,199				6,199
Ending balance (in shares) at Mar. 31, 2022		54,347,564
Ending balance at Mar. 31, 2022	$ 146,987	$ 6	282,436	(911)	(134,544)
Beginning balance (in shares) at Dec. 31, 2022	60,578,956	60,578,956
Beginning balance at Dec. 31, 2022	$ 93,403	$ 6	298,741	(1,015)	(204,329)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock purchase plan (in shares)		137,917
Issuance of common stock under stock purchase plan	77		77
Stock-based compensation expense	1,646		1,646
Unrealized gain (loss) on marketable securities	446			446
Net income (loss)	$ (19,741)				(19,741)
Ending balance (in shares) at Mar. 31, 2023	60,716,873	60,716,873
Ending balance at Mar. 31, 2023	$ 75,831	$ 6	$ 300,464	$ (569)	$ (224,070)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net income (loss)	$ (19,741)	$ 6,199
Adjustments to reconcile net income (loss) to net cash provided by (used in)    operating activities:
Depreciation and amortization expense	318	345
Stock-based compensation expense	1,646	1,865
Non-cash interest expense related to note payable	122	146
Net amortization of premiums and discounts on marketable securities	(134)	178
Loss on disposal of property and equipment	3	0
Non-cash operating lease cost	614	614
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(837)	(695)
Unbilled receivable	0	(30,000)
Other assets	2	(20)
Accounts payable	852	1,074
Accrued expenses and other current liabilities	(5,582)	(2,601)
Operating lease liability	(702)	(671)
Net cash used in operating activities	(23,439)	(23,566)
Cash flows from investing activities:
Purchases of property and equipment	(17)	(35)
Proceeds from sales of property and equipment	31	0
Purchases of marketable securities	(16,930)	0
Proceeds from sales or maturities of marketable securities	18,350	12,500
Net cash provided by investing activities	1,434	12,465
Cash flows from financing activities:
Proceeds from issuance of common stock upon public offering, net	0	20,556
Proceeds from employee stock purchases	77	157
Net cash provided by financing activities	77	20,713
Net increase (decrease) in cash and cash equivalents and restricted cash	(21,928)	9,612
Cash and cash equivalents and restricted cash at beginning of period	52,505	57,640
Cash and cash equivalents and restricted cash at end of period	30,577	67,252
Supplemental disclosure of cash flow information:
Cash paid for interest	1,746	531
Supplemental disclosure of non-cash investing and financing activities:
Additional right-of-use asset and related lease liability	0	755
Purchases of property and equipment included in accounts payable and accrued expenses	$ 66	$ 43

Nature of the Business

Nature of the Business	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business	Nature of the Business Surface Oncology, Inc. (the “Company” or “Surface”) is a clinical-stage immuno-oncology company focused on using its specialized knowledge of the biological pathways critical to the immunosuppressive tumor microenvironment (“TME”) for the development of next-generation cancer therapies. Surface was incorporated in April 2014 under the laws of the State of Delaware. The Company is subject to risks common to early-stage companies in the biotechnology industry including, but not limited to, development by competitors of new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the ability to obtain additional financing to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance-reporting capabilities. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. On August 5, 2021, the Company entered into an amendment to its existing Capital on Demand™ Sales Agreement (the “Amended Sales Agreement”) with JonesTrading Institutional Services LLC (“JonesTrading”), to allow the issuance and sale of up to $80,000 in gross proceeds, from time to time during the term of the Amended Sales Agreement, through an “at-the-market” equity offering program under which JonesTrading will act as the Company’s sales agent (the “2021 ATM Facility”). The 2021 ATM Facility provides that JonesTrading will continue to be entitled to compensation for its services in an amount of up to 3.0% of the gross proceeds of any shares sold under the 2021 ATM Facility. The Company has no obligation to sell any shares under the Amended Sales Agreement and may, at any time, suspend solicitation and offers under the 2021 ATM Facility. In the three months ended March 31, 2023, the Company did not sell shares of common stock, at-the-market under the Amended Sales Agreement. In the three months ended March 31, 2022, the Company sold 7,337,251 shares of common stock at-the-market under the Amended Sales Agreement for net proceeds of $20,556. Since August 5, 2021, the Company has sold 14,611,756 shares of common stock at-the-market under the Amended Sales Agreement for net proceeds of $41,421. The Company’s financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company has primarily funded its operations with proceeds from private and public sales of its securities, proceeds from a collaboration agreement with Novartis, proceeds from a license agreement with GlaxoSmithKline Intellectual Property (No. 4) Limited (“GSK”) and issuance of a debt facility with K2 Health Ventures LLC (“K2HV”). The Company has a history of incurring losses and negative cash flows from operations. As of March 31, 2023, the Company had an accumulated deficit of $224,070. The Company expects that its operating losses and negative cash flows will continue for the foreseeable future. As of May 4, 2023, the issuance date of this Quarterly Report on Form 10-Q, the Company expects that its cash, cash equivalents and marketable securities will be sufficient to fund its operating expenses, debt service obligations and capital expenditure requirements for at least the next 12 months. The future viability of the Company beyond that date is dependent on its ability to raise additional capital to finance its operations. The Company will seek additional funding through public financings, debt financings, collaboration agreements, strategic alliances and licensing arrangements. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into collaborations or other arrangements. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to obtain funding, the Company could be required to delay, reduce, or eliminate research and development programs, product portfolio expansion, or future commercialization efforts, which could adversely affect its business prospects. Although management continues to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly owned subsidiary, Surface Securities Corporation, a Massachusetts corporation, after elimination of all intercompany accounts and transactions. The accounting policies followed in the preparation of the interim condensed consolidated financial statements are consistent in all material respects with those presented in Note 2 to the financial statements included in the Company’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission (the “SEC”) on March 9, 2023. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, revenue recognition and the accrual of research and development expenses. Estimates are periodically reviewed in light of changes in circumstances, facts, and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from the Company’s estimates. Unaudited Interim Financial Information The accompanying condensed consolidated financial statements are unaudited. The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2023 and the results of its operations and its cash flows for the three months ended March 31, 2023 and 2022. The financial data and other information disclosed in these notes related to the three months ended March 31, 2023 and 2022 are also unaudited. The condensed balance sheet at December 31, 2022, was derived from audited annual financial statements but does not contain all of the footnote disclosures from the annual financial statements. The results for the three months ended March 31, 2023 are not necessarily indicative of results to be expected for the year ending December 31, 2023, any other interim periods, or any future year period. Recently Issued Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes may result in earlier recognition of credit losses. In November 2018, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments—Credit Losses, which narrowed the scope and changed the effective date for non-public entities for ASU 2016-13. The FASB subsequently issued supplemental guidance within ASU No. 2019-05, Financial Instruments—Credit Losses (Topic 326): Targeted Transition Relief (“ASU 2019-05”). ASU 2019-05 provides an option to irrevocably elect the fair value option for certain financial assets previously measured at amortized cost basis. This standard became effective for the Company on January 1, 2023. The adoption of ASU 2016-13 did not have a material impact on the Company's financial position or results of operations. Other accounting standards that have been issued by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s financial statements upon adoption.

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	Marketable Securities As of March 31, 2023, the fair value of available-for-sale marketable debt securities by type of security was as follows: March 31, 2023 Amortized Gross Gross Fair Marketable debt securities: U.S. Treasury notes $ 35,011 $ — (367) $ 34,644 U.S. government agency bonds 16,169 — (109) 16,060 Corporate bonds $ 22,462 $ 3 $ (96) $ 22,369 $ 73,642 $ 3 $ (572) $ 73,073 The amortized cost and fair value of the Company’s available-for-sale debt securities by contractual maturity are summarized as follows: March 31, 2023 Amortized Fair Maturing in one year or less $ 71,287 $ 70,721 Maturing after one year 2,355 2,352 $ 73,642 $ 73,073 As of December 31, 2022, the fair value of available-for-sale marketable debt securities by type of security was as follows: December 31, 2022 Amortized Gross Gross Fair Marketable debt securities: U.S. Treasury notes $ 50,080 $ 1 (714) $ 49,367 U.S. government agency bonds 10,957 — (184) 10,773 Corporate bonds $ 13,891 $ — $ (118) $ 13,773 $ 74,928 $ 1 $ (1,016) $ 73,913 The amortized cost and fair value of the Company’s available-for-sale debt securities by contractual maturity are summarized as follows: December 31, 2022 Amortized Fair Maturing in one year or less $ 73,446 $ 72,453 Maturing after one year 1,482 1,460 $ 74,928 $ 73,913 The cost of securities sold is determined based on the specific identification method for purposes of recording realized gains and losses. During the three months ended March 31, 2023 and 2022, there were no realized losses on sales of marketable securities. There were no marketable securities that required adjustment for other-than-temporary declines in fair value during the three months ended March 31, 2023 and 2022.

Fair Value of Financial Assets

Fair Value of Financial Assets	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets	Fair Value of Financial Assets The following tables present information about the Company’s financial assets that are measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of March 31, 2023 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 14,255 $ — $ — $ 14,255 Marketable securities: U.S. Treasury notes — 34,644 — 34,644 U.S. government agency bonds — 16,060 — 16,060 Corporate bonds — 22,369 — 22,369 $ 14,255 $ 73,073 $ — $ 87,328 Fair Value Measurements as of December 31, 2022 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 31,189 $ — $ — $ 31,189 Marketable securities: U.S. Treasury notes — 49,367 — 49,367 U.S. Government agency bonds — 10,773 — 10,773 Corporate bonds — 13,773 — 13,773 $ 31,189 $ 73,913 $ — $ 105,102 As of March 31, 2023 and December 31, 2022, the Company’s cash equivalents were invested in money market funds and were valued based on Level 1 inputs. The Company’s investments in U.S. Treasury notes, U.S. government agency bonds and corporate bonds were valued based on Level 2 inputs. Money market funds were valued by the Company based on quoted market prices, which represent a Level 1 measurement within the fair value hierarchy. U.S. treasury notes, U.S. government agency bonds and corporate bonds were valued by obtaining third-party pricing sources, which use quoted prices in active markets for similar securities or other inputs that are observable or can be corroborated by observable market data. These represent a Level 2 measurement within the fair value hierarchy. During the three months ended March 31, 2023 and 2022, there were no transfers between Level 1, Level 2 and Level 3.

Collaboration and License Agree

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration and License Agreements	Collaboration and License Agreements Novartis Agreement In January 2016, the Company entered into a collaboration agreement with Novartis, which was subsequently amended in May 2016, July 2017, September 2017, and October 2018 (as amended, the “Novartis Agreement”). Pursuant to the Novartis Agreement, the Company granted Novartis a worldwide exclusive license to research, develop, manufacture and commercialize antibodies that target cluster of differentiation 73 (“CD73”). In addition, the Company initially granted Novartis the right to purchase exclusive option rights (each an “Option”) for up to four specified targets (each an “Option Target”) including certain development, manufacturing, and commercialization rights, pursuant to which, Novartis initially had the right to exercise up to three purchased Options. Accordingly, Novartis had the ability to exclusively license the development, manufacturing and commercial rights for up to four targets (inclusive of CD73). As of March 31, 2023, the Company had received an aggregate of $150,000 from Novartis in upfront payments, milestone payments, and option purchase payments. As of January 2020, there were no Options remaining for purchase and exercise, and accordingly the Company’s performance obligations under the Novartis Agreement ended. Under the Novartis Agreement, the Company is currently entitled to potential development milestones of $325,000 and sales milestones of $200,000, as well as tiered royalties on annual net sales by Novartis ranging from high single-digit to mid-teens percentages upon the successful commercialization of NZV930 (formerly SRF373). Due to the uncertainty of pharmaceutical development and the historical failure rates generally associated with drug development, the Company may not receive any milestone payments or any royalty payments under the Novartis Agreement. Termination Unless terminated earlier, the Novartis Agreement will continue in effect until neither the Company nor Novartis is researching, developing, manufacturing or commercializing NZV930. Novartis may terminate the Novartis Agreement for any or no reason upon prior notice to the Company within a specified time period. Either party may terminate the Novartis Agreement in full if an undisputed material breach is not cured within a certain period of time or upon notice of insolvency of the other party. To the extent Novartis terminates for convenience, or the Company terminates for Novartis’ uncured material breach, Novartis will grant the Company, on mutually agreeable financial terms, an exclusive, worldwide, irrevocable, perpetual and royalty-bearing license with respect to intellectual property controlled by Novartis that is reasonably necessary to research, develop, manufacture or commercialize NZV930. Revenue Recognition – Collaboration Revenue – Related Party In determining the appropriate amount of revenue to be recognized under ASC 606, the Company performed the following steps: (i) identified the promised goods or services in the contract; (ii) determined whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. Under ASC 606, the Company recognized revenue using the cost-to-cost method, which it believes best depicts the transfer of control to the customer. Under the cost-to-cost method, the extent of progress towards completion is measured based on the ratio of actual costs incurred to the total estimated costs expected upon satisfying the identified performance obligation. Under this method, revenue will be recorded as a percentage of the estimated transaction price based on the extent of progress towards completion. Under ASC 606, the estimated transaction price will include variable consideration. The Company does not include variable consideration to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will occur when any uncertainty associated with the variable consideration is resolved. The estimate of the Company’s measure of progress and estimate of variable consideration to be included in the transaction price will be updated at each reporting date as a change in estimate. The amount related to the unsatisfied portion will be recognized as that portion is satisfied over time. Under ASC 606 the Company accounted for (i) the license it conveyed with respect to CD73; and (ii) its obligations to perform research on CD73 and other specified targets as a single performance obligation under the Novartis Agreement. Novartis’ right to purchase exclusive options to obtain certain development, manufacturing and commercialization rights would have been accounted for separately as they did not represent material rights, based on the criteria of ASC 606. Upon the exercise of any purchased option by Novartis, the contract promises associated with an Option Target would have used a separate cost-to-cost model for purposes of revenue recognition under ASC 606. The Company did not recognize any revenue relating to the Novartis Agreement during the three months ended March 31, 2023 and 2022 as it does not have any remaining performance obligations under the agreement. GSK Agreement In December 2020, the Company entered into a license agreement with GSK, which was subsequently amended in August 2021 (as amended, the “GSK Agreement”). Pursuant to the GSK Agreement, the Company granted GSK a worldwide exclusive, sublicensable license to develop, manufacture and commercialize antibodies that target the antibody GSK4381562 (formerly SRF813), targeting CD112R, also known as PVRIG (the “Licensed Antibodies”). GSK is responsible for the development, manufacturing and commercialization of the Licensed Antibodies and a joint development committee was formed to facilitate information sharing between the Company and GSK. GSK is responsible for all costs and expenses of such development, manufacturing and commercialization and is obligated to provide the Company with updates on its development, manufacturing and commercialization activities through the joint development committee. Under the terms of the GSK Agreement, GSK made a one-time upfront payment of $85,000 and was required to make additional payments to the Company for supply services and transition services initially estimated to be $4,314 and $950, respectively. In November 2021, GSK notified the Company it received clearance from the FDA for GSK4381562 to proceed into a first-in-human clinical trial, and as a result, the Company’s performance obligations under the GSK Agreement ended. In March 2022, the Company earned a $30,000 milestone payment from GSK upon the dosing of the first patient in the Phase 1 trial of GSK4381562. The Company is eligible to receive up to $60,000 in additional clinical milestones and $155,000 in regulatory milestones. In addition, the Company may receive up to $485,000 in sales milestone payments. The Company is also eligible to receive royalties on global net sales of any approved products based on the licensed antibodies, ranging in percentages from high single digits to mid-teens. Due to the uncertainty of pharmaceutical development and the historical failure rates generally associated with drug development, the Company may not receive any milestone payments or any royalty payments under the GSK Agreement. Termination Unless terminated earlier, the GSK Agreement expires on a licensed product-by-licensed product and country-by-country basis on the later of ten years from the date of first commercial sale or when there is no longer a valid patent claim or regulatory exclusivity covering such licensed product in such country. Either party may terminate the GSK Agreement for an uncured material breach by the other party or upon the bankruptcy or insolvency of the other party. GSK may terminate the GSK Agreement for its convenience. The Company may terminate the GSK Agreement if GSK institutes certain actions related to the licensed patents or if GSK ceases development activities, other than for certain specified technical or safety reasons. In the event of termination, the Company would regain worldwide rights to the terminated program. Revenue Recognition – License-Related Revenue In determining the appropriate amount of revenue to be recognized under ASC 606, the Company performed the following steps: (i) identified the promised goods or services in the contract; (ii) determined whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company assessed the GSK Agreement in accordance with ASC 606 and concluded that GSK is a customer. The Company identified the following promises under the contract: (i) a worldwide exclusive, sublicensable license to develop, manufacture and commercialize the Licensed Antibodies; (ii) supplying Licensed Antibodies until an investigational new drug (“IND”) application is accepted by a regulatory authority (iii) transition services until an IND application is accepted by a regulatory authority; and (iv) participation on the joint development and joint patent committees. The Company assessed the above promises and determined that the worldwide exclusive, sublicensable license to develop, manufacture and commercialize the Licensed Antibodies is considered functional intellectual property and distinct from other promises under the contract. This functional license is distinct in the context of the GSK Agreement as GSK can benefit from the license on its own or together with other readily available resources. In addition, the supply and transition services are not complex or specialized, could be performed by another qualified third party, are not expected to significantly modify or customize the license to GSK4381562 and are expected to be performed only for a short period of time. The Company determined that the impact of participation on the joint development and joint patent committees was insignificant and had an immaterial impact on the accounting model. Based on these assessments, the Company identified three distinct performance obligations at the outset of the GSK Agreement. The Company determined the transaction price of the GSK Agreement, under ASC 606, to be $90,286, consisting of the upfront payment of $85,000 plus $4,524 for supply of the Licensed Antibodies and $762 for the transition services. The Company evaluated how much variable consideration related to clinical and regulatory milestones to include in the transaction price using the most likely amount approach and concluded that no amount should be included in the transaction price due to the high degree of uncertainty and risk associated with these potential payments. The Company also determined that royalties and sales milestones relate solely to the licenses of intellectual property and are therefore excluded from the transaction price under the sales- or usage-based royalty exception of ASC 606. Revenue related to these royalties and sales milestones will only be recognized when the associated sales occur, and relevant thresholds are met. As noted above, the Company identified three performance obligations in the GSK Agreement: (i) the delivery of the worldwide exclusive, sublicensable license to develop, manufacture and commercialize the Licensed Antibodies; (ii) supply of Licensed Antibodies until an IND application is accepted by a regulatory authority; and (iii) transition services until an IND application is accepted by a regulatory authority. The selling price of each performance obligation in the GSK Agreement was determined based on the Company’s standalone selling price with the objective of determining the price at which it would sell such an item if it were to be sold regularly on a standalone basis. The Company recognized revenue for the license performance obligation upon transfer of the license to GSK. As control of the license was transferred on the effective date of December 16, 2020, and GSK could begin to use and benefit from the license, the Company recognized $85,000 of license-related revenue during the year ended December 31, 2020. The Company recognized the costs allocated to supply services and transition services over time as the Company transferred control of these services and GSK received and consumed the benefit as the Company performed the services. The Company re-evaluated the transaction price at the end of each reporting period and as uncertain events were resolved, or other changes in circumstances occurred; adjusted its estimate of the transaction price as necessary. In November 2021, GSK notified the Company it received clearance from the FDA for GSK4381562 to proceed into a first-in-human clinical trial and as a result the Company’s performance obligations under the GSK Agreement ended. The transition and supply services were completed in November 2021. In March 2022, GSK notified the Company it had dosed the first patient in its Phase 1 study of GSK4381562 in patients with solid tumors. As a result of this Phase 1 study initiation, the first clinical milestone under the GSK Agreement was achieved. The Company concluded the variable consideration associated with this milestone was no longer constrained and recognized $30,000 in license-related revenue for the three months ended March 31, 2022, as it had no further performance obligations associated with the milestone. The Company did not recognize license-related revenue under the GSK Agreement during the three months ended March 31, 2023. For the three months ended March 31, 2023 and 2022 , the Company recognized the following totals of license-related revenue: Three months ended March 31, 2023 2022 License-related revenue $ — $ 30,000

Stockholders_ Equity

Stockholders’ Equity	3 Months Ended
	Mar. 31, 2023
Equity [Abstract]
Stockholders’ Equity	Stockholders’ Equity Common Stock As of March 31, 2023 and December 31, 2022, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue 150,000,000 shares of $0.0001 par value common stock. 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, as may be declared by the board of directors, if any, subject to the preferential dividend rights of any outstanding preferred stock. No dividends have been declared or paid by the Company through March 31, 2023.

Stock-Based Awards

Stock-Based Awards	3 Months Ended
	Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Awards	Stock-Based Awards 2014 Stock Incentive Plan The Company’s 2014 Stock Incentive Plan (the “2014 Plan”) provided for the Company to grant incentive stock options or nonqualified stock options, restricted stock awards, unrestricted stock awards or restricted stock units to employees, directors and consultants of the Company. The 2014 Plan is administered by the board of directors, or at the discretion of the board of directors, by a committee of the board of directors. The exercise prices, vesting and other restrictions were determined at the discretion of the board of directors, or their committee if so delegated, except that the exercise price per share of the stock options could not be less than 100% of the fair market value of a share of the Company’s common stock on the date of grant and the term of the stock options could not be greater than ten years. As of December 31, 2018, all remaining shares available under the 2014 Plan were transferred to the Company’s 2018 Stock Option and Incentive Plan (the “2018 Plan”). 2018 Stock Option and Incentive Plan In April 2018, the Company’s 2018 Plan was approved by its stockholders and became effective. The 2018 Plan provides for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock units, restricted stock awards, unrestricted stock awards, cash-based awards and dividend equivalent rights to the Company’s officers, employees, non-employee directors and other key persons (including consultants). The number of shares initially reserved for issuance under the 2018 Plan was 1,545,454, plus the shares of common stock remaining available for issuance under the 2014 Plan, the reserved shares shall be cumulatively increased each January 1 by 4% of the number of shares of the Company’s common stock outstanding on the immediately preceding December 31 or such lesser number of shares determined by the Company’s board of directors or compensation committee of the board of directors. The shares of common stock underlying any awards that are forfeited, cancelled, held back upon exercise or settlement of an award to satisfy the exercise price or tax withholding, reacquired by the Company prior to vesting, satisfied without the issuance of stock, expire or are otherwise terminated (other than by exercise) under the 2018 Plan and the 2014 Plan will be added back to the shares of common stock available for issuance under the 2018 Plan. As of March 31, 2023, 271,786 shares were available for future issuance under the 2018 Plan. Stock options granted under the 2014 Plan and 2018 Plan to employees generally vest over three years and expire after ten years. Stock Options The following table summarizes the Company’s stock option activity since December 31, 2022: Number of Weighted Weighted Aggregate (in years) Outstanding as of December 31, 2022 8,233,330 $ 5.74 6.68 $ 159 Granted 3,058,400 0.69 Exercised — — Forfeited (100,599) 4.76 Outstanding as of March 31, 2023 11,191,131 $ 4.37 7.40 $ 145 Options exercisable at March 31, 2023 5,926,959 $ 5.90 5.74 $ 118 Vested and expected to vest at March 31, 2023 11,191,131 $ 4.37 7.40 $ 145 The weighted average grant-date fair value per share of stock options granted during the three months ended March 31, 2023 and year ended December 31, 2022 was $0.50 and $2.28, respectively. As of March 31, 2023 and December 31, 2022, there were outstanding stock options held by non-employees for the purchase of 260,570 shares of common stock with service-based vesting conditions. 2018 Employee Stock Purchase Plan In April 2018, the Company’s 2018 Employee Stock Purchase Plan (the “ESPP”) was approved by its stockholders and became effective. A total of 256,818 shares of common stock were initially reserved for issuance under this plan. In addition, the number of shares of common stock that may be issued under the ESPP automatically increased on January 1, 2019, and shall increase each January 1 thereafter through January 1, 2028, by the lesser of (i) 1% of the number of shares of the Company’s common stock outstanding on the immediately preceding December 31 and (ii) such lesser number of shares as determined by the administrator of the Company’s ESPP. As of March 31, 2023, a total of 1,873,627 shares of common stock were reserved for issuance under this plan. For the three months ended March 31, 2023, the Company issued 137,917 shares of common stock under the ESPP. For the three months ended March 31, 2022, the Company issued 51,329 shares of common stock under the ESPP. 2021 Inducement Plan In December 2021, the Company adopted the Company’s 2021 Inducement Plan (the “Inducement Plan”) pursuant to which the Company reserved 600,000 shares of common stock to be used exclusively for grants of equity-based awards to individuals who were not previously employees or directors of the Company, as an inducement material to the individual’s entry into employment with the Company within the meaning of Rule 5635(c)(4) of the Marketplace Rules of the Nasdaq Stock Market, Inc. The Inducement Plan provides for the grant of equity-based awards in the form of nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, unrestricted stock awards, and dividend equivalent rights. The Inducement Plan was adopted by the Company without stockholder approval pursuant to Rule 5635(c)(4) of the Marketplace Rules of the Nasdaq Stock Market, Inc. The following table summarizes the Company’s stock option under the Inducement Plan activity since December 31, 2022: Number of Weighted Weighted Aggregate (in years) Outstanding as of December 31, 2022 210,400 $ 2.61 9.36 $ — Granted — — Exercised — — Forfeited — — Outstanding as of March 31, 2023 210,400 $ 2.61 9.11 $ — Options exercisable at March 31, 2023 26,541 $ 3.64 8.92 $ — Vested and expected to vest at March 31, 2023 210,400 $ 2.61 9.11 $ — The Company did not grant stock options under the Inducement Plan during the three months ended March 31, 2023. The weighted average grant-date fair value per share of stock options granted during the three months ended March 31, 2022 was $2.41. As of March 31, 2023, 389,600 shares were available for future issuance under the Inducement Plan. Restricted Stock Units The Company has granted restricted stock units (“RSUs”) with service-based vesting conditions. RSUs represent the right to receive shares of common stock upon meeting specified vesting requirements. Unvested shares of restricted common stock units may not be sold or transferred by the holder. These restrictions lapse according to the service-based vesting conditions of each award. In 2022, the Company granted 732,000 RSUs, of which 40% vested in August 2022 and 60% will vest in August 2023, as long as the applicable individual remains an employee of the Company at such time. The table below summarizes the Company’s RSU activity since December 31, 2022: Number of Weighted Unvested restricted stock units as of December 31, 2022 385,980 $ 3.64 Granted — — Vested — — Forfeited — — Unvested restricted stock units as of March 31, 2023 385,980 $ 3.64 The expense related to RSUs granted to employees was $346 and $209 for the three months ended March 31, 2023 and 2022, respectively. Stock-Based Compensation The Company recorded stock-based compensation expense related to stock options, ESPP and restricted stock unit awards in the following expense categories of its condensed consolidated statements of operations and comprehensive income (loss): Three months ended March 31, 2023 2022 Research and development expenses $ 646 $ 584 General and administrative expenses 1,000 1,281 $ 1,646 $ 1,865

Debt

Debt	3 Months Ended
	Mar. 31, 2023
Debt Disclosure [Abstract]
Debt	Debt On November 22, 2019, the Company entered into a loan and security agreement (the “Loan Agreement”) with K2HV (the “Lender”). The Lender agreed to make available to the Company term loans in an aggregate principal amount of up to $25,000 under the Loan Agreement. On October 1, 2021, the Company entered into a first amendment to the Loan Agreement with the Lender (as amended, the “First Loan Amendment”). On September 21, 2022, the Company entered into a second amendment to the Loan Agreement with the Lender (as further amended, the “Second Loan Amendment”). The Company plans to use the proceeds of the term loans to support clinical development as well as for working capital and general corporate purposes. The Loan Agreement provided for a term loan commitment of $25,000 in three potential tranches: (i) a $7,500 term loan facility funded on November 22, 2019 (the “First Tranche Term Loan”), (ii) a $10,000 term loan facility funded on June 5, 2020 (the “Second Tranche Term Loan”), and (iii) a $7,500 term loan facility (the “Third Tranche Term Loan”). All three of these term loans had a maturity date of December 1, 2023. The Company was obligated to pay a final fee equal to 4.45% of the aggregate amount of the term loans funded, such payment to occur upon the earliest of (i) the maturity date, (ii) the acceleration of the term loans, and (iii) the prepayment of the term loans. The Lender was able to, at its option, elect to convert any portion of no more than $4,000 of the then outstanding term loan amount and all accrued and unpaid interest thereon into shares of the Company’s common stock at a conversion price of $1.56 per share. The Company determined that the embedded conversion option was not required to be separated from the term loan. The embedded conversion option meets the derivative accounting scope exception since the embedded conversion option is indexed to the Company’s own common stock and qualifies for classification within stockholders’ equity. The Company recognized a beneficial conversion feature of $2,101, which represented the difference between the commitment date stock price of $2.33 per share and the conversion price of $1.56 per share. The beneficial conversion feature was recorded as a discount on the term loan and is accreted to interest expense using the effective interest method over the term of the loan. In August 2020, the Lender elected to convert $2,000 of the outstanding term loan amount into 1,282,050 shares of the Company’s common stock, in accordance with the Loan Agreement. In February 2021, the Lender elected to convert $1,500 of the outstanding term loan amount into 961,538 shares of the Company’s common stock, in accordance with the Loan Agreement. After the conversions, the outstanding principal balance was $14,000. In October 2021, the Loan Agreement was amended. Under the First Loan Amendment, the Lender made available to the Company term loans in an aggregate principal amount of up to $50,000, in three potential tranches: (i) a $25,000 term loan facility (including refinancing of the Company’s outstanding amounts under the Loan Agreement) funded on October 1, 2021 (the “First Tranche Refinancing Term Loan”), (ii) up to a $15,000 term loan facility (the “Second Tranche Refinancing Term Loan”), and (iii) an up to $10,000 term loan facility (the “Third Tranche Refinancing Term Loan”) (together the "Refinancing Term Loans"). All three of these tranches have a maturity date of October 1, 2025. Borrowings under all three tranches of the term loan facility bear interest at a floating per annum rate equal to the greater of (i) 8.50% and (ii) the sum of (A) the greater of (x) the prime rate last quoted in The Wall Street Journal (or a comparable replacement rate if The Wall Street Journal ceases to quote such rate) or (y) 3.25%, plus (B) 5.25%. As of March 31, 2023, the interest rate was increased to 13.25%. Under the First Loan Amendment, the Company is permitted to make interest-only payments on the outstanding principal balance of the term loan for approximately eighteen months following the funding date. The interest-only period could have been extended by an additional nine months, subject to the Company raising net cash proceeds from financing activities (including without limitation sales of the Company’s securities and up-front or milestone payments pursuant to existing or new strategic partnerships), in an aggregate amount of at least $100,000. The term of the loan facility is 48 months, with repayment in monthly installments commencing at the end of the resulting interest-only period as outlined above through the end of the 48-month term. The Company is obligated to pay a final fee equal to (i) 4.25% of the aggregate amount of the term loans funded, such payment to occur upon the earliest of (i) the maturity date, (ii) the acceleration of the term loans, and (iii) the prepayment of the term loans and (ii) $779 on the earlier of December 1, 2023 or the prepayment of the term loans. The Company has the option to prepay all, but not less than all, of the outstanding principal balance of the term loans under the First Loan Amendment. If the Company prepays all of the term loans prior to the maturity date, it will pay the Lender a prepayment penalty fee based on a percentage of the outstanding principal balance, equal to 5% if the payment occurs on or before 24 months after the initial funding date, 3% if the prepayment occurs more than 24 months after, but on or before 36 months after the initial funding date, or 1% if the prepayment occurs more than 36 months after the initial funding date. The Lender was able to, at its option, elect to convert any portion of no more than $4,500 of the then outstanding term loan amount and all accrued and unpaid interest thereon into shares of the Company’s common stock at a conversion price of (i) with respect to the first $500 converted, $1.56 per share and (ii) with respect to any additional amounts converted in excess of $500, $7.81 per share. The Company’s obligations under the First Loan Amendment are secured by a first priority security interest in substantially all of its assets. The First Loan Amendment contains customary representations, warranties and also includes customary events of default, including payment defaults, breaches of covenants, change of control and a material adverse effect clause. Upon the occurrence of an event of default, a default interest rate of an additional 5.00% per annum may be applied to the outstanding loan balances, and the Lender may declare all outstanding obligations immediately due and payable and exercise all of its rights and remedies as set forth in the First Loan Amendment and under applicable law. The First Loan Amendment was accounted for as a debt modification; as such, the financing costs of $313 were reflected as additional debt discount and is amortized as an adjustment to interest expense over the term of the First Loan Amendment. In September 2022, the Company entered into the Second Loan Amendment. Under the Second Loan Amendment, the loan facility continues to carry a 48-month term with interest only payments extended for ten months, ending on February 1, 2024. In addition, the Lender may, at its option, elect to convert any portion of no more than $4,500 of the then outstanding term loan amount and all accrued and unpaid interest thereon into shares of the Company’s common stock at a conversion price of (i) with respect to the first $500 converted, $1.56 per share and (ii) with respect to any additional amounts converted in excess of $500, $1.83 per share. The effective interest rate of the term loan as of March 31, 2023 is 15.99%. The Second Loan Amendment was accounted for as a debt modification. The financing costs were immaterial. The Company recorded interest expense related to the loan facility of $932 and $682 for the three months ended March 31, 2023 and 2022, respectively. The fair value of the loan at March 31, 2023 approximates its face amount. Future principal debt payments on the loan payable are as follows: March 31, 2023 2023 — 2024 12,339 2025 12,661 Total principal payments 25,000 Fee due in 2023 1,063 Final fee due at maturity in 2025 779 Total principal payments and final fee 26,842 Unamortized debt discount and final fee (1,135) Note payable $ 25,707

Net Income (Loss) per Share

Net Income (Loss) per Share	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Net Income (Loss) per Share	Net Income (Loss) per Share Basic and diluted net income (loss) per share attributable to common stockholders was calculated as follows: Three months ended March 31, 2023 2022 Basic net income (loss) per share: Numerator: Net income (loss) $ (19,741) $ 6,199 Denominator: Weighted average commons shares outstanding — basic 60,627,993 48,606,055 Net income (loss) per share — basic $ (0.33) $ 0.13 Diluted net income (loss) per share: Numerator: Net income (loss) - basic $ (19,741) $ 6,199 Interest expense on convertible note payable — 122 Net income (loss) - diluted $ (19,741) $ 6,321 Denominator: Weighted average commons shares outstanding — basic 60,627,993 48,606,055 Shares issuable upon conversion of convertible notes, as if converted — 832,677 Dilutive effect of restricted stock units — 230 Dilutive effect of common stock equivalents — 377,822 Weighted average common shares outstanding - diluted 60,627,993 49,816,784 Net income (loss) per share — diluted $ (0.33) $ 0.13 The Company’s potential dilutive securities have been excluded from the computation of diluted net loss per share for the three months ended March 31, 2023, as the effect would be to reduce the net loss per share. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated above because including them would have had an anti-dilutive effect: March 31, 2023 Stock options to purchase common stock 11,401,531 Shares to be issued under the 2018 ESPP 1,873,627 RSU’s issued and expected to vest 385,980 Shares available from conversion of note payable 2,506,306 16,167,444

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company did not provide for any income taxes for the three months ended March 31, 2023 or 2022. The Company has evaluated the positive and negative evidence bearing upon its ability to realize the deferred tax assets. Management has considered the Company’s history of cumulative net losses incurred since inception and its lack of commercialization of any products or generation of any revenue from product sales since inception and has concluded that it is more likely than not that the Company will not realize the benefits of the deferred tax assets. Accordingly, a full valuation allowance has been established against the deferred tax assets as of March 31, 2023 and December 31, 2022. Management reevaluates the positive and negative evidence at each reporting period. As of March 31, 2023 and December 31, 2022, the Company had no accrued interest or tax penalties recorded. The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal and state jurisdictions, where applicable. The Company’s tax years are still open under statute from 2019 to present. All years may be examined to the extent the tax credit or net operating loss carryforwards are used in future periods. There are currently no federal or state audits.

Leases

Leases	3 Months Ended
	Mar. 31, 2023
Leases [Abstract]
Leases	Leases Sublease Agreement with EQRx, Inc. In May 2022, the Company entered into the second amendment to the Sublease Agreement (as amended, the “Sublease Amendment ” ). The Sublease Amendment extended the term of the sublease for a period of 18 months, with an option to extend the sublease for a further six months upon the expiration of the Sublease Amendment. The Sublease Amendment has been accounted for as a single-modified contract. The Company determined the Sublease Amendment would continue to be accounted for as an operating lease. Consistent with the Company’s policy election for lessor operating leases, each lease component and its associated non-lease components is accounted for as a single lease component. In the three months ended March 31, 2023 and 2022, the Company recognized sublease income of $643 and $656, respectively. As of March 31, 2023, future undiscounted cash inflows under the sublease are as follows: Year Ending December 31, 2023 $ 1,907 2024 1,494 $ 3,401

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings The Company is not currently party to any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to its legal proceedings.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2023
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Novartis Institutes for BioMedical Research, Inc. Novartis is a related party because it is a greater than 5% stockholder of the Company. In January 2016, the Company entered into the Novartis Agreement and sold 2,000,000 shares of its Series A-1 Preferred Stock to Novartis for gross proceeds of $13,500. In addition, concurrent with the Company’s initial public offering of common stock, the Company issued Novartis 766,666 shares of its common stock at $15.00 per share, for proceeds of $11,500 in a private placement. During the three months ended March 31, 2023 and 2022, the Company made no cash payments to Novartis related to the Novartis Agreement. As of March 31, 2023 and 2022, no amounts were due from Novartis. The Company did not recognize any collaboration revenue - related party under the Novartis Agreement in the three months ended March 31, 2023 or 2022.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly owned subsidiary, Surface Securities Corporation, a Massachusetts corporation, after elimination of all intercompany accounts and transactions. The accounting policies followed in the preparation of the interim condensed consolidated financial statements are consistent in all material respects with those presented in Note 2 to the financial statements included in the Company’s Annual Report on Form 10-K, filed with the Securities and Exchange Commission (the “SEC”) on March 9, 2023.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, revenue recognition and the accrual of research and development expenses. Estimates are periodically reviewed in light of changes in circumstances, facts, and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from the Company’s estimates.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying condensed consolidated financial statements are unaudited. The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2023 and the results of its operations and its cash flows for the three months ended March 31, 2023 and 2022. The financial data and other information disclosed in these notes related to the three months ended March 31, 2023 and 2022 are also unaudited. The condensed balance sheet at December 31, 2022, was derived from audited annual financial statements but does not contain all of the footnote disclosures from the annual financial statements. The results for the three months ended March 31, 2023 are not necessarily indicative of results to be expected for the year ending December 31, 2023, any other interim periods, or any future year period.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes may result in earlier recognition of credit losses. In November 2018, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments—Credit Losses, which narrowed the scope and changed the effective date for non-public entities for ASU 2016-13. The FASB subsequently issued supplemental guidance within ASU No. 2019-05, Financial Instruments—Credit Losses (Topic 326): Targeted Transition Relief (“ASU 2019-05”). ASU 2019-05 provides an option to irrevocably elect the fair value option for certain financial assets previously measured at amortized cost basis. This standard became effective for the Company on January 1, 2023. The adoption of ASU 2016-13 did not have a material impact on the Company's financial position or results of operations. Other accounting standards that have been issued by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s financial statements upon adoption.

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Summary of Fair Value of Available-for-sale Marketable Debt Securities by Type of Security	As of March 31, 2023, the fair value of available-for-sale marketable debt securities by type of security was as follows: March 31, 2023 Amortized Gross Gross Fair Marketable debt securities: U.S. Treasury notes $ 35,011 $ — (367) $ 34,644 U.S. government agency bonds 16,169 — (109) 16,060 Corporate bonds $ 22,462 $ 3 $ (96) $ 22,369 $ 73,642 $ 3 $ (572) $ 73,073 As of December 31, 2022, the fair value of available-for-sale marketable debt securities by type of security was as follows: December 31, 2022 Amortized Gross Gross Fair Marketable debt securities: U.S. Treasury notes $ 50,080 $ 1 (714) $ 49,367 U.S. government agency bonds 10,957 — (184) 10,773 Corporate bonds $ 13,891 $ — $ (118) $ 13,773 $ 74,928 $ 1 $ (1,016) $ 73,913
Summary of Available-for-sale Debt Securities by Contractual Maturity	The amortized cost and fair value of the Company’s available-for-sale debt securities by contractual maturity are summarized as follows: March 31, 2023 Amortized Fair Maturing in one year or less $ 71,287 $ 70,721 Maturing after one year 2,355 2,352 $ 73,642 $ 73,073 The amortized cost and fair value of the Company’s available-for-sale debt securities by contractual maturity are summarized as follows: December 31, 2022 Amortized Fair Maturing in one year or less $ 73,446 $ 72,453 Maturing after one year 1,482 1,460 $ 74,928 $ 73,913

Fair Value of Financial Assets

Fair Value of Financial Assets (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Summary of Financial Assets Measured at Fair Value on Recurring Basis	The following tables present information about the Company’s financial assets that are measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of March 31, 2023 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 14,255 $ — $ — $ 14,255 Marketable securities: U.S. Treasury notes — 34,644 — 34,644 U.S. government agency bonds — 16,060 — 16,060 Corporate bonds — 22,369 — 22,369 $ 14,255 $ 73,073 $ — $ 87,328 Fair Value Measurements as of December 31, 2022 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 31,189 $ — $ — $ 31,189 Marketable securities: U.S. Treasury notes — 49,367 — 49,367 U.S. Government agency bonds — 10,773 — 10,773 Corporate bonds — 13,773 — 13,773 $ 31,189 $ 73,913 $ — $ 105,102

Collaboration and License Agr_2

Collaboration and License Agreements (Tables)	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Collaboration Revenue	For the three months ended March 31, 2023 and 2022 , the Company recognized the following totals of license-related revenue: Three months ended March 31, 2023 2022 License-related revenue $ — $ 30,000

Stock-Based Awards (Tables)

Stock-Based Awards (Tables)	3 Months Ended
	Mar. 31, 2023
Share-Based Payment Arrangement [Abstract]
Summary of Stock Option Activity	The following table summarizes the Company’s stock option activity since December 31, 2022: Number of Weighted Weighted Aggregate (in years) Outstanding as of December 31, 2022 8,233,330 $ 5.74 6.68 $ 159 Granted 3,058,400 0.69 Exercised — — Forfeited (100,599) 4.76 Outstanding as of March 31, 2023 11,191,131 $ 4.37 7.40 $ 145 Options exercisable at March 31, 2023 5,926,959 $ 5.90 5.74 $ 118 Vested and expected to vest at March 31, 2023 11,191,131 $ 4.37 7.40 $ 145 The following table summarizes the Company’s stock option under the Inducement Plan activity since December 31, 2022: Number of Weighted Weighted Aggregate (in years) Outstanding as of December 31, 2022 210,400 $ 2.61 9.36 $ — Granted — — Exercised — — Forfeited — — Outstanding as of March 31, 2023 210,400 $ 2.61 9.11 $ — Options exercisable at March 31, 2023 26,541 $ 3.64 8.92 $ — Vested and expected to vest at March 31, 2023 210,400 $ 2.61 9.11 $ —
Summary of Restricted Stock Unit Activity	The table below summarizes the Company’s RSU activity since December 31, 2022: Number of Weighted Unvested restricted stock units as of December 31, 2022 385,980 $ 3.64 Granted — — Vested — — Forfeited — — Unvested restricted stock units as of March 31, 2023 385,980 $ 3.64
Summary of Stock-Based Compensation Expense Related to Stock Options and Restricted Stock Awards	The Company recorded stock-based compensation expense related to stock options, ESPP and restricted stock unit awards in the following expense categories of its condensed consolidated statements of operations and comprehensive income (loss): Three months ended March 31, 2023 2022 Research and development expenses $ 646 $ 584 General and administrative expenses 1,000 1,281 $ 1,646 $ 1,865

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2023
Debt Disclosure [Abstract]
Schedule of Future Principal Debt Payments on the Loan Payable	Future principal debt payments on the loan payable are as follows: March 31, 2023 2023 — 2024 12,339 2025 12,661 Total principal payments 25,000 Fee due in 2023 1,063 Final fee due at maturity in 2025 779 Total principal payments and final fee 26,842 Unamortized debt discount and final fee (1,135) Note payable $ 25,707

Net Income (Loss) per Share (Ta

Net Income (Loss) per Share (Tables)	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders	Basic and diluted net income (loss) per share attributable to common stockholders was calculated as follows: Three months ended March 31, 2023 2022 Basic net income (loss) per share: Numerator: Net income (loss) $ (19,741) $ 6,199 Denominator: Weighted average commons shares outstanding — basic 60,627,993 48,606,055 Net income (loss) per share — basic $ (0.33) $ 0.13 Diluted net income (loss) per share: Numerator: Net income (loss) - basic $ (19,741) $ 6,199 Interest expense on convertible note payable — 122 Net income (loss) - diluted $ (19,741) $ 6,321 Denominator: Weighted average commons shares outstanding — basic 60,627,993 48,606,055 Shares issuable upon conversion of convertible notes, as if converted — 832,677 Dilutive effect of restricted stock units — 230 Dilutive effect of common stock equivalents — 377,822 Weighted average common shares outstanding - diluted 60,627,993 49,816,784 Net income (loss) per share — diluted $ (0.33) $ 0.13
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated above because including them would have had an anti-dilutive effect: March 31, 2023 Stock options to purchase common stock 11,401,531 Shares to be issued under the 2018 ESPP 1,873,627 RSU’s issued and expected to vest 385,980 Shares available from conversion of note payable 2,506,306 16,167,444

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2023
Leases [Abstract]
Schedule of Future Undiscounted Cash Inflows Under Sublease	As of March 31, 2023, future undiscounted cash inflows under the sublease are as follows: Year Ending December 31, 2023 $ 1,907 2024 1,494 $ 3,401

Nature of the Business - Additi

Nature of the Business - Additional Information (Details) - USD ($)		3 Months Ended		20 Months Ended
	Aug. 05, 2021	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Accumulated deficit		$ 224,070,000		$ 224,070,000	$ 204,329,000
Operating expenses and capital expenditure requirements (in months)		12 months
2021 ATM Facility
Class of Stock [Line Items]
Number of shares issued (in shares)		0	7,337,251	14,611,756
Net proceeds from issuance of common stock			$ 20,556,000	$ 41,421,000
2021 ATM Facility | Maximum
Class of Stock [Line Items]
Gross proceeds from issuance of common stock	$ 80,000,000
Percentage of gross proceeds of shares sold for compensation (as a percent)	3%

Marketable Securities - Summary

Marketable Securities - Summary of Fair Value of Available-for-sale Marketable Debt Securities by Type of Security (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 73,642	$ 74,928
Gross Unrealized Gains	3	1
Gross Unrealized Losses	(572)	(1,016)
Fair Value	73,073	73,913
U.S. Treasury notes
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	35,011	50,080
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(367)	(714)
Fair Value	34,644	49,367
U.S. government agency bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	16,169	10,957
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(109)	(184)
Fair Value	16,060	10,773
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	22,462	13,891
Gross Unrealized Gains	3	0
Gross Unrealized Losses	(96)	(118)
Fair Value	$ 22,369	$ 13,773

Marketable Securities - Summa_2

Marketable Securities - Summary of Fair Value of Available-for-sale Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Amortized Cost
Maturing in one year or less	$ 71,287	$ 73,446
Maturing after one year	2,355	1,482
Amortized Cost	73,642	74,928
Fair Value
Maturing in one year or less	70,721	72,453
Maturing after one year	2,352	1,460
Fair Value	$ 73,073	$ 73,913

Marketable Securities - Additio

Marketable Securities - Additional Information (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2023 USD ($) securities	Dec. 31, 2022 USD ($) securities
Investments, Debt and Equity Securities [Abstract]
Number of positions, less then 12 months | securities	22	20
Aggregate fair value, securities, less than 12 months	$ 38,342,000	$ 34,079,000
Number of positions, 12 months or longer | securities	13	18
Aggregate fair value, securities, 12 months or longer	$ 29,659,000	$ 36,857,000
Investments in other-than-temporary decline in fair value	$ 0	$ 0

Fair Value of Financial Asset_2

Fair Value of Financial Assets - Summary of Financial Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 73,073	$ 73,913
U.S. Treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	34,644	49,367
U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	16,060	10,773
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	22,369	13,773
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured on recurring basis	87,328	105,102
Fair Value, Measurements, Recurring | U.S. Treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	34,644	49,367
Fair Value, Measurements, Recurring | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	16,060	10,773
Fair Value, Measurements, Recurring | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	22,369	13,773
Fair Value, Measurements, Recurring | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	14,255	31,189
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured on recurring basis	14,255	31,189
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Fair Value, Measurements, Recurring | Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	14,255	31,189
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured on recurring basis	73,073	73,913
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	34,644	49,367
Fair Value, Measurements, Recurring | Level 2 | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	16,060	10,773
Fair Value, Measurements, Recurring | Level 2 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	22,369	13,773
Fair Value, Measurements, Recurring | Level 2 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured on recurring basis	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Fair Value, Measurements, Recurring | Level 3 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 0	$ 0

Collaboration and License Agr_3

Collaboration and License Agreements - Additional Information (Details)	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2016 target	Mar. 31, 2023 USD ($) obligation	Mar. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)	Aug. 31, 2021 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License related revenue		$ 0	$ 30,000,000
GSK Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract with customer, expiration period		10 years
Number of performance obligations | obligation		3
Transaction price		$ 90,286,000
GSK Agreement | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License related revenue		0	30,000,000
GSK Agreement | License | Transferred at Point in Time
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment					$ 85,000,000
License related revenue				$ 85,000,000
GSK Agreement | License | Transferred over Time
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Additional payments to be received		4,524,000			4,314,000
GSK Agreement | Transition Services | Transferred over Time
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Additional payments to be received		762,000			$ 950,000
GSK Agreement | Clinical Milestone Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestones payment		60,000,000
GSK Agreement | Regulatory Milestone Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestones payment		155,000,000
GSK Agreement | Sales Milestone Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestones payment		485,000,000
Novartis Collaboration
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of option targets | target	4
Number of option targets purchased | target	3
Upfront, milestone, and option purchase payments, aggregate amount		150,000,000
Novartis Collaboration | Novartis Institutes for Biomedical Research, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue		0	$ 0
Novartis Collaboration | Novartis Institutes for Biomedical Research, Inc. | Development Milestone
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestones payment		325,000,000
Novartis Collaboration | Novartis Institutes for Biomedical Research, Inc. | Sales Milestone
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestones payment		$ 200,000,000

Collaboration and License Agr_4

Collaboration and License Agreements - Schedule of Collaboration Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License-related revenue	$ 0	$ 30,000
GSK Agreement | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License-related revenue	$ 0	$ 30,000

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details)		3 Months Ended		20 Months Ended
	Aug. 05, 2021 USD ($)	Mar. 31, 2023 USD ($) vote $ / shares shares	Mar. 31, 2022 USD ($) shares	Mar. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 $ / shares shares
Subsidiary, Sale of Stock [Line Items]
Common stock, authorized (in shares)		150,000,000		150,000,000	150,000,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.0001		$ 0.0001	$ 0.0001
Number of votes entitled by each share of common stock holder | vote		1
Dividends, declared or paid | $		$ 0
Capital common shares reserved for future issuance (in shares)		26,827,193		26,827,193	23,936,163
Common stock, issued (in shares)		60,716,873		60,716,873	60,578,956
2021 ATM Facility
Subsidiary, Sale of Stock [Line Items]
Common stock, issued (in shares)		0	7,337,251	14,611,756
Net proceeds from issuance of common stock | $			$ 20,556,000	$ 41,421,000
Maximum | 2021 ATM Facility
Subsidiary, Sale of Stock [Line Items]
Gross proceeds from issuance of common stock | $	$ 80,000,000

Stock-Based Awards - Additional

Stock-Based Awards - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2018	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 1,646	$ 1,865
General and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		1,000	1,281
2018 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation cost		$ 10,059
Unrecognized stock-based compensation cost, weighted-average period (in years)		1 year 4 months 6 days
Stock options to purchase common stock | Non-Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock converted under option plan (in shares)		260,570		260,570
RSU’s issued and expected to vest
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted stock units, Granted (in shares)		0		732,000
RSU’s issued and expected to vest | Vesting August 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period percentage				40%
RSU’s issued and expected to vest | Vesting August 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period percentage				60%
RSU’s issued and expected to vest | Granted to Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 346	$ 209
2014 Plan | Stock options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of exercise price per share of stock options to fair market value of share of common stock (as a percent)		100%
Stock options granted expiry period (in years)		10 years
Weighted average grant-date fair value per share of stock options granted (in dollars per share)		$ 0.50		$ 2.28
2018 Stock Option and Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock to be issued (in shares)	1,545,454
Percentage of authorized number of shares of common stock outstanding (as a percent)	4%
Number of shares of common stock converted under option plan (in shares)		11,191,131		8,233,330
2018 Employee Stock Option and Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future issuance (in shares)		271,786
2018 Employee Stock Option and Incentive Plan | 2018 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock to be issued (in shares)	256,818	1,873,627
Percentage of authorized number of shares of common stock outstanding (as a percent)	1%
Number of shares of common stock issued (in shares)		137,917	51,329
2014 Plan and 2018 Plan | Stock options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted expiry period (in years)		10 years
Stock options granted vesting period (in years)		3 years
Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock to be issued (in shares)				600,000
Weighted average grant-date fair value per share of stock options granted (in dollars per share)			$ 2.41
Number of shares of common stock converted under option plan (in shares)		210,400		210,400
Inducement Plan | Stock options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future issuance (in shares)		389,600

Stock-Based Awards - Summary of

Stock-Based Awards - Summary of Stock Option Activity (Details) - 2018 Stock Option and Incentive Plan - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Number of Shares
Number of Shares, outstanding beginning balance (in shares)	8,233,330
Number of Shares, granted (in shares)	3,058,400
Number of Shares, exercised (in shares)	0
Number of Shares, forfeited (in shares)	(100,599)
Number of Shares, outstanding ending balance (in shares)	11,191,131	8,233,330
Number of Shares, options exercisable at June 30, 2022 (in shares)	5,926,959
Number of Shares, vested and expected to vest at June 30, 2022 (in shares)	11,191,131
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding beginning balance (in dollars per share)	$ 5.74
Weighted Average Exercise Price, Granted (in dollars per share)	0.69
Weighted Average Exercise Price, Exercised (in dollars per share)	0
Weighted Average Exercise Price, Forfeited (in dollars per share)	4.76
Weighted Average Exercise Price, Outstanding ending balance (in dollars per share)	4.37	$ 5.74
Weighted Average Exercise Price, Exercisable at June 30, 2022 (in dollars per share)	5.90
Weighted Average Exercise Price, Vested and expected to vest at June 30, 2022 (in dollars per share)	$ 4.37
Stock Option Activity, Additional Disclosures
Weighted Average Remaining Contractual Term (in years), Outstanding	7 years 4 months 24 days	6 years 8 months 4 days
Weighted Average Remaining Contractual Term (in years), Options exercisable	5 years 8 months 26 days
Weighted Average Remaining Contractual Term (in years), Vested and expected to vest	7 years 4 months 24 days
Aggregate Intrinsic Value (in dollars per share)	$ 145	$ 159
Aggregate Intrinsic Value, Options exercisable at June 30, 2022 (in dollars per share)	118
Aggregate Intrinsic Value, Vested and expected to vest at June 30, 2022 (In dollars per share)	$ 145

Stock-Based Awards - Summary _2

Stock-Based Awards - Summary of Stock Option Activity - Inducement Plan (Details) - Inducement Plan - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Number of Shares
Number of Shares, outstanding beginning balance (in shares)	210,400
Number of Shares, granted (in shares)	0
Number of Shares, exercised (in shares)	0
Number of Shares, forfeited (in shares)	0
Number of Shares, outstanding ending balance (in shares)	210,400	210,400
Number of Shares, options exercisable at June 30, 2022 (in shares)	26,541
Number of Shares, vested and expected to vest at June 30, 2022 (in shares)	210,400
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding beginning balance (in dollars per share)	$ 2.61
Weighted Average Exercise Price, Granted (in dollars per share)	0
Weighted Average Exercise Price, Exercised (in dollars per share)	0
Weighted Average Exercise Price, Forfeited (in dollars per share)	0
Weighted Average Exercise Price, Outstanding ending balance (in dollars per share)	2.61	$ 2.61
Weighted Average Exercise Price, Exercisable at June 30, 2022 (in dollars per share)	3.64
Weighted Average Exercise Price, Vested and expected to vest at June 30, 2022 (in dollars per share)	$ 2.61
Stock Option Activity, Additional Disclosures
Weighted Average Remaining Contractual Term (in years), Outstanding	9 years 1 month 9 days	9 years 4 months 9 days
Weighted Average Remaining Contractual Term (in years), Options exercisable	8 years 11 months 1 day
Weighted Average Remaining Contractual Term (in years), Vested and expected to vest	9 years 1 month 9 days
Aggregate Intrinsic Value (in dollars per share)	$ 0	$ 0
Aggregate Intrinsic Value, Options exercisable at June 30, 2022 (in dollars per share)	0
Aggregate Intrinsic Value, Vested and expected to vest at June 30, 2022 (In dollars per share)	$ 0

Stock-Based Awards - Summary _3

Stock-Based Awards - Summary of Restricted Stock Unit Activity (Details) - RSU’s issued and expected to vest - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Number of Shares
Unvested restricted stock units, beginning balance (in shares)	385,980
Unvested restricted stock units, Granted (in shares)	0	732,000
Unvested restricted stock units, Vested (in shares)	0
Unvested restricted stock units, Forfeited (in shares)	0
Unvested restricted stock units, ending balance (in shares)	385,980	385,980
Weighted Average Grant-Date Fair Value
Weighted Average Grant-Date Fair Value, beginning balance (in dollars per share)	$ 3.64
Weighted Average Grant-Date Fair Value, Granted (in dollars per share)	0
Weighted Average Grant-Date Fair Value, Vested (in dollars per share)	0
Weighted Average Grant-Date Fair Value, Forfeited (in dollars per share)	0
Weighted Average Grant-Date Fair Value, ending balance (in dollars per share)	$ 3.64	$ 3.64

Stock-Based Awards - Summary _4

Stock-Based Awards - Summary of Stock-Based Compensation Expense Related to Stock Options and Restricted Stock Awards (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,646	$ 1,865
Research and development expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	646	584
General and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,000	$ 1,281

Debt - Additional Information (

Debt - Additional Information (Details)			1 Months Ended			3 Months Ended
	Oct. 01, 2021 USD ($) $ / shares	Nov. 22, 2019 USD ($) tranche $ / shares	Sep. 30, 2022 USD ($) $ / shares	Feb. 28, 2021 USD ($) shares	Aug. 31, 2020 USD ($) shares	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)
Loan Amendment
Debt Instrument [Line Items]
Financing costs						$ 313,000
K2 Health Ventures LLC | Loan and Security Agreement
Debt Instrument [Line Items]
Commitment date stock price (in dollars per share) | $ / shares		$ 2.33
Effective interest rate (as a percent)						15.99%
K2 Health Ventures LLC | Term Loans | Loan and Security Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 25,000,000
Number of potential tranches | tranche		3
Final fee percentage (as a percent)		4.45%
Portion of outstanding term loan amount converted				$ 1,500,000	$ 2,000,000
Conversion price per share (USD per share) | $ / shares		$ 1.56
Beneficial conversion feature		$ 2,101,000
Number of shares issued upon conversion of term loan (in shares) | shares				961,538	1,282,050
Outstanding term loan principal balance						$ 14,000,000
Debt instrument interest rate, floating (as a percent)						13.25%
Interest expense						$ 932,000	$ 682,000
K2 Health Ventures LLC | Term Loans | Loan Amendment
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 50,000,000
Final fee percentage (as a percent)	4.25%
Debt instrument interest rate, floating (as a percent)	8.50%
Interest rate percentage	3.25%
Debt instrument variable rate (as a percent)	5.25%
Amount of cash from financing activities needed to extend interest-only period	$ 100,000,000
Term of the combined facility (months)	48 months		48 months
Debt instrument, term, prepayment amount	$ 779,000
K2 Health Ventures LLC | Term Loans | Loan Amendment | First $500 Converted at $1.56 per share
Debt Instrument [Line Items]
Portion of outstanding term loan amount converted	$ 500,000		$ 500,000
Conversion price per share (USD per share) | $ / shares	$ 1.56		$ 1.56
K2 Health Ventures LLC | Term Loans | Loan Amendment | Additional Amounts Converted in Excess of $500 at $7.81 per share
Debt Instrument [Line Items]
Portion of outstanding term loan amount converted	$ 500,000		$ 500,000
Conversion price per share (USD per share) | $ / shares	$ 7.81		$ 1.83
K2 Health Ventures LLC | Term Loans | Maximum | Loan and Security Agreement
Debt Instrument [Line Items]
Portion of outstanding term loan amount converted		4,000,000
K2 Health Ventures LLC | Term Loans | Maximum | Loan Amendment
Debt Instrument [Line Items]
Portion of outstanding term loan amount converted	$ 4,500,000		$ 4,500,000
K2 Health Ventures LLC | Term Loans | Payment Occurs on or before Twenty Four Months after Initial Funding Date | Loan Amendment
Debt Instrument [Line Items]
Prepayment penalty fee percentage (as a percent)	5%
Default interest rate (as a percent)	5%
K2 Health Ventures LLC | Term Loans | Prepayment Occurs More than Twenty Four Months after, but on or before Thirty Six Months after Initial Funding Date | Loan Amendment
Debt Instrument [Line Items]
Prepayment penalty fee percentage (as a percent)	3%
K2 Health Ventures LLC | Term Loans | Prepayment Occurs More than Thirty Six Months after Initial Funding Date | Loan Amendment
Debt Instrument [Line Items]
Prepayment penalty fee percentage (as a percent)	1%
K2 Health Ventures LLC | First Tranche Term Loan | Loan and Security Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		7,500,000
K2 Health Ventures LLC | First Tranche Term Loan | Loan Amendment
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 25,000,000
K2 Health Ventures LLC | Second Tranche Term Loan | Loan and Security Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		10,000,000
K2 Health Ventures LLC | Second Tranche Term Loan | Loan Amendment
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	15,000,000
K2 Health Ventures LLC | Third Tranche Term Loan | Loan and Security Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 7,500,000
K2 Health Ventures LLC | Third Tranche Term Loan | Loan Amendment
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 10,000,000

Debt - Schedule of Future Princ

Debt - Schedule of Future Principal Debt Payments on the Loan Payable (Details) - Notes Payable $ in Thousands	Mar. 31, 2023 USD ($)
Debt Instrument [Line Items]
2023	$ 0
2024	12,339
2025	12,661
Total principal payments	25,000
Fee due in 2023	1,063
Final fee due at maturity in 2025	779
Total principal payments and final fee	26,842
Unamortized debt discount and final fee	(1,135)
Note payable	$ 25,707

Net Income (Loss) per Share - S

Net Income (Loss) per Share - Schedule of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net Income (Loss) Attributable to Parent	$ (19,741)	$ 6,199
Denominator:
Weighted average commons shares outstanding—basic (shares)	60,627,993	48,606,055
Net income (loss) per share — basic (in dollars per share)	$ (0.33)	$ 0.13
Numerator:
Net income (loss) - basic	$ (19,741)	$ 6,199
Interest expense on convertible note payable	0	122
Net income (loss) - diluted (in dollars per share)	$ (19,741)	$ 6,321
Denominator:
Weighted average commons shares outstanding—basic (shares)	60,627,993	48,606,055
Shares issuable upon conversion of convertible notes, as if converted (in shares)	0	832,677
Dilutive effect of restricted stock units (in shares)	0	230
Dilutive effect of common stock equivalents (shares)	0	377,822
Weighted average common shares outstanding—diluted (shares)	60,627,993	49,816,784
Net income (loss) per share — diluted (in dollars per share)	$ (0.33)	$ 0.13

Net Income (Loss) per Share- Se

Net Income (Loss) per Share- Securities Excluded from Computation of Diluted Net Loss Per Share (Details)	3 Months Ended
	Mar. 31, 2023 shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average shares excluded from computation of diluted net income per share attributable to common stockholders (in shares)	16,167,444
Stock options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average shares excluded from computation of diluted net income per share attributable to common stockholders (in shares)	11,401,531
Shares to be issued under the 2018 ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average shares excluded from computation of diluted net income per share attributable to common stockholders (in shares)	1,873,627
RSU’s issued and expected to vest
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average shares excluded from computation of diluted net income per share attributable to common stockholders (in shares)	385,980
Shares available from conversion of note payable
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average shares excluded from computation of diluted net income per share attributable to common stockholders (in shares)	2,506,306

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income tax provision or benefit	$ 0	$ 0
Interest and penalties accrued	$ 0		$ 0

Leases - Narrative (Details)

Leases - Narrative (Details)	May 31, 2022
Leases [Abstract]
Sublease term	18 months
Sublease extension term	6 months

Leases - Schedule of Future Und

Leases - Schedule of Future Undiscounted Cash Inflows Under Sublease (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Lease Agreements [Line Items]
2024	$ 1,494
Sublease Agreement with EQRx
Lease Agreements [Line Items]
Sublease income	643	$ 656
2023	1,907
Total future sublease payments	$ 3,401

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended
	Jan. 31, 2016	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Related Party Transaction [Line Items]
Preferred stock shares issued to related party (in shares)		0		0
Amounts due from related party			$ 0
Novartis Institutes for Biomedical Research, Inc. | Novartis Collaboration
Related Party Transaction [Line Items]
Payment for reimbursement of manufacturing costs incurred		$ 0	0
Amounts due from related party		0
Revenue		$ 0	$ 0
Novartis Institutes for Biomedical Research, Inc. | Novartis Collaboration | Minimum
Related Party Transaction [Line Items]
Percentage of share holding (as a percent)	5%
Novartis Institutes for Biomedical Research, Inc. | Novartis Collaboration | Series A One Redeemable Convertible Preferred Stock
Related Party Transaction [Line Items]
Preferred stock shares issued to related party (in shares)	2,000,000
Gross proceeds from issuance of preference stock	$ 13,500,000
Novartis Institutes for Biomedical Research, Inc. | Novartis Collaboration | Private Placement
Related Party Transaction [Line Items]
Common stock, issued (in shares)	766,666
Share price (in dollars per share)	$ 15
Proceeds from issuance of private placement	$ 11,500,000