SELLAS Life Sciences (SLS) 10-Q 11 Aug 22 2022 Q2 Quarterly report Financial data

Cover

Cover - shares	6 Months Ended
	Jun. 30, 2022	Aug. 10, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2022
Document Transition Report	false
Entity File Number	001-33958
Entity Registrant Name	SELLAS Life Sciences Group, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-8099512
Entity Address, Address Line One	7 Times Square, Suite 2503,
Entity Address, City or Town	New York,
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10036
City Area Code	(646)
Local Phone Number	200-5278
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	SLS
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		20,551,918
Entity Central Index Key	0001390478
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 26,987	$ 21,355
Restricted cash and cash equivalents	100	100
Prepaid expenses and other current assets	1,650	1,589
Total current assets	28,737	23,044
Operating lease right-of-use assets	1,045	723
Goodwill	1,914	1,914
Deposits and other assets	514	594
Total assets	32,210	26,275
Current liabilities:
Accounts payable	3,339	2,144
Accrued expenses and other current liabilities	3,006	2,640
Operating lease liabilities	341	198
Acquired in-process research and development payable	5,500	0
Total current liabilities	12,186	4,982
Operating lease liabilities, non-current	783	610
Warrant liability	3	40
Contingent consideration	181	296
Total liabilities	13,153	5,928
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.0001 par value; 5,000,000 shares authorized; Series A convertible preferred stock, 17,500 shares designated; no shares issued and outstanding at June 30, 2022 and December 31, 2021	0	0
Common stock, $0.0001 par value; 350,000,000 shares authorized, 20,551,918 and 15,895,637 shares issued and outstanding at June 30, 2022 and December 31, 2021, respectively	2	2
Additional paid-in capital	182,816	158,948
Accumulated deficit	(163,761)	(138,603)
Total stockholders’ equity	19,057	20,347
Total liabilities and stockholders’ equity	$ 32,210	$ 26,275

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2022	Dec. 31, 2021
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	350,000,000	350,000,000
Common stock, shares issued (in shares)	20,551,918	15,895,637
Common stock, shares outstanding (in shares)	20,551,918	15,895,637
Series A Preferred Stock
Preferred stock, shares authorized (in shares)	17,500	17,500

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement [Abstract]
Licensing revenue	$ 0	$ 1,900	$ 1,000	$ 7,600
Operating expenses:
Cost of licensing revenue	0	100	100	200
Research and development	5,529	3,456	10,140	7,740
Acquired in-process research and development	0	0	10,000	0
General and administrative	3,094	2,797	6,118	6,358
Total operating expenses	8,623	6,353	26,358	14,298
Operating loss	(8,623)	(4,453)	(25,358)	(6,698)
Non-operating income (expense), net:
Change in fair value of warrant liability	48	(28)	37	(59)
Change in fair value of contingent consideration	115	(134)	115	(263)
Interest income	46	2	48	4
Total non-operating income (expense), net	209	(160)	200	(318)
Net loss	$ (8,414)	$ (4,613)	$ (25,158)	$ (7,016)
Per share information:
Net loss per common share, basic (in dollars per share)	$ (0.41)	$ (0.30)	$ (1.39)	$ (0.47)
Net loss per common share, diluted (in dollars per share)	$ (0.41)	$ (0.30)	$ (1.39)	$ (0.47)
Weighted-average common shares outstanding, basic (in shares)	20,286,624	15,270,288	18,104,176	15,074,887
Weighted-average common shares outstanding, diluted (in shares)	20,286,624	15,270,288	18,104,176	15,074,887

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2020		14,254,554
Beginning balance at Dec. 31, 2020	$ 27,961	$ 1	$ 145,864	$ (117,904)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock and common stock warrants, net of issuance costs (in shares)		786,927
Issuance of common stock and common stock warrants, net of issuance costs	9,005		9,005
Issuance of common stock upon exercise of warrants (in shares)		832,460
Issuance of common stock upon exercise of warrants	3,017	$ 1	3,016
Stock-based compensation	448		448
Net loss	(7,016)			(7,016)
Ending balance (in shares) at Jun. 30, 2021		15,873,941
Ending balance at Jun. 30, 2021	33,415	$ 2	158,333	(124,920)
Beginning balance (in shares) at Mar. 31, 2021		15,084,754
Beginning balance at Mar. 31, 2021	28,742	$ 2	149,047	(120,307)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock and common stock warrants, net of issuance costs (in shares)		786,927
Issuance of common stock and common stock warrants, net of issuance costs	9,005		9,005
Issuance of common stock upon exercise of warrants (in shares)		2,260
Issuance of common stock upon exercise of warrants	17		17
Stock-based compensation	264		264
Net loss	(4,613)			(4,613)
Ending balance (in shares) at Jun. 30, 2021		15,873,941
Ending balance at Jun. 30, 2021	33,415	$ 2	158,333	(124,920)
Beginning balance (in shares) at Dec. 31, 2021		15,895,637
Beginning balance at Dec. 31, 2021	20,347	$ 2	158,948	(138,603)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock and common stock warrants, net of issuance costs (in shares)		4,645,919
Issuance of common stock and common stock warrants, net of issuance costs	22,996		22,996
Issuance of common stock under employee stock purchase plan (in shares)		10,362
Issuance of common stock under employee stock purchase plan	47		47
Stock-based compensation	825		825
Net loss	(25,158)			(25,158)
Ending balance (in shares) at Jun. 30, 2022		20,551,918
Ending balance at Jun. 30, 2022	19,057	$ 2	182,816	(163,761)
Beginning balance (in shares) at Mar. 31, 2022		15,905,999
Beginning balance at Mar. 31, 2022	4,025	$ 2	159,370	(155,347)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock and common stock warrants, net of issuance costs (in shares)		4,645,919
Issuance of common stock and common stock warrants, net of issuance costs	22,996		22,996
Stock-based compensation	450		450
Net loss	(8,414)			(8,414)
Ending balance (in shares) at Jun. 30, 2022		20,551,918
Ending balance at Jun. 30, 2022	$ 19,057	$ 2	$ 182,816	$ (163,761)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net loss	$ (25,158)	$ (7,016)
Adjustment to reconcile net loss to net cash used in operating activities:
Acquired in-process research and development expense	10,000	0
Non-cash stock-based compensation	825	448
Change in operating lease right of use assets	127	0
Change in fair value of common stock warrants	(37)	59
Change in fair value of contingent consideration	(115)	263
Changes in operating assets and liabilities:
Contract asset	0	1,128
Prepaid expenses and other assets	19	(1,932)
Accounts payable	1,195	(2,381)
Accrued expenses and other current liabilities	366	(136)
Operating lease liabilities	(133)	0
Deferred revenue	0	(5,600)
Net cash used in operating activities	(12,911)	(15,167)
Cash flows from investing activities:
Cash paid for acquisition of in-process research and development	(4,500)	0
Net cash used in investing activities	(4,500)	0
Cash flows from financing activities:
Proceeds from issuance of common stock and common stock warrants, net of offering costs	22,996	6,765
Proceeds from employee stock purchases	47	0
Net proceeds from exercise of warrants	0	3,017
Net cash provided by financing activities	23,043	9,782
Net increase (decrease) in cash, cash equivalents, restricted cash, and restricted cash equivalents	5,632	(5,385)
Cash, cash equivalents, restricted cash, and restricted cash equivalents at the beginning of period	21,455	35,402
Cash, cash equivalents, restricted cash, and restricted cash equivalents at the end of period	27,087	30,017
Supplemental disclosure of cash flow information:
Cash received during the period for interest	48	4
Supplemental disclosure of non-cash investing and financing activities:
Payable for acquired in-process research and development	5,500	0
Stock subscription receivable	0	2,240
Increase in operating right of use asset and current and non-current lease liability	$ 449	$ 0

Description of Business

Description of Business	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Overview SELLAS Life Sciences Group, Inc. (the "Company" or "SELLAS") is a late-stage clinical biopharmaceutical company focused on novel therapeutics for a broad range of cancer indications. SELLAS’ lead product candidate, galinpepimut-S ("GPS"), is a cancer immunotherapeutic agent licensed from Memorial Sloan Kettering Cancer Center ("MSK") and targets the Wilms Tumor 1 ("WT1") protein, which is present in an array of tumor types. GPS has potential as a monotherapy or in combination with other immunotherapeutic agents to address a broad spectrum of hematologic, or blood, cancers and solid tumor indications. SELLAS' second product candidate is GFH009, a small molecule, highly selective cyclin-dependent kinase 9 ("CDK9") inhibitor, which is licensed from GenFleet Therapeutics (Shanghai), Inc., for all therapeutic and diagnostic uses in the world outside of Greater China.

Liquidity

Liquidity	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Liquidity	Liquidity On April 5, 2022, the Company closed an underwritten public offering (the "April 2022 Offering"), issuing 4,629,630 shares of common stock and accompanying common stock warrants to purchase an aggregate of 4,629,630 shares of common stock. The shares of common stock and accompanying common stock warrants were sold at a combined price of $5.40 per share and accompanying common stock warrant. Each common stock warrant sold with the shares of common stock represents the right to purchase one share of the Company’s common stock at an exercise price of $5.40 per share. The common stock warrants are exercisable immediately and will expire on April 5, 2027, five years from the date of issuance. The net proceeds to the Company from the April 2022 Offering, after deducting the underwriting discounts and commissions and other offering expenses, and excluding the exercise of any warrants, were approximately $23.0 million. On March 31, 2022, the Company entered into an exclusive license agreement with GenFleet Therapeutics (Shanghai) Inc. ("GenFleet") pursuant to which GenFleet granted to the Company a sublicensable, royalty-bearing license, under certain of its intellectual property, to develop, manufacture, and commercialize a small molecule CDK9 inhibitor for the treatment, diagnosis or prevention of disease in humans and animals in all countries and territories of the world other than mainland China, Hong Kong, Macau and Taiwan (the "GFH009 Territory"). The CDK9 inhibitor, GFH009, is currently in a Phase 1 clinical trial in the United States and China. In consideration for the exclusive license, the Company agreed to pay GenFleet (i) an upfront and technology transfer fee of $10.0 million, of which $4.5 million was paid in April 2022 and $5.5 million is due upon the first day of the 15th calendar month following the effective date of the license agreement, (ii) development and regulatory milestone payments for up to three indications totaling up to $48.0 million in the aggregate, and (iii) sales milestone payments totaling up to $92.0 million in the aggregate upon the achievement of certain net sales thresholds in a given calendar year. The Company has also agreed to pay GenFleet single-digit tiered royalties based upon a percentage of annual net sales of GFH009 in the GFH009 Territory, with the royalty rate escalating based on the level of annual net sales ranging from the low to high single digits. On March 31, 2022, the Company announced that an investigational new drug ("IND") application filed by 3D Medicines Inc. ("3DMed"), pursuant to its Exclusive License Agreement with the Company (the “3DMed License Agreement) for a small Phase 1 clinical trial investigating safety of GPS in China, was approved by China's National Medical Products Administration ("NMPA"). The IND approval by the NMPA triggered a $1.0 million milestone payment to the Company which was recognized as licensing revenue in the first quarter of 2022 and payment was received in May 2022. An additional $191.5 million in potential future development, regulatory, and sales milestones, not including future royalties, remains under the 3DMed License Agreement as of June 30, 2022, which milestones are variable in nature and not under the Company's control. The current clinical development plan provides for initiation of a Phase 2 clinical trial following receipt of satisfactory safety data from the Phase 1 clinical trial. In addition, the Company and 3DMed are planning a regulatory submission in China by the end of 2022 for the commencement of a Phase 1 or Phase 1/2 clinical trial of GPS in combination with envafolimab, 3DMed's checkpoint inhibitor which has been approved in China and is the first single-domain PD-L1 targeting antibody administered by rapid subcutaneous injection. Under the terms of the 3DMed License Agreement, the initiation of a Phase 2 clinical trial will trigger a milestone payment to the Company. On April 16, 2021, the Company entered into a Controlled Equity Offering SM Sales Agreement (the "Sales Agreement") with Cantor Fitzgerald & Co. (the "Agent"). From time to time during the term of the Sales Agreement, the Company may offer and sell shares of common stock having an aggregate offering price up to a total of $50.0 million in gross proceeds. The Agent will collect a fee equal to 3% of the gross sales price of all shares of common stock sold. Shares of common stock sold under the Sales Agreement are offered and sold pursuant to the Company's registration statement on Form S-3, which was filed with the SEC on April 16, 2021 and declared effective on April 29, 2021. During the year ended December 31, 2021, the Company sold a total of 786,927 shares of common stock pursuant to the Sales Agreement at an average price of $12.04 per share for aggregate net proceeds of approximately $9.0 million. During the six months ended June 30, 2022, the Company sold an additional 16,289 shares of common stock pursuant to the Sales Agreement at an average price of $3.16 per share for aggregate gross proceeds of approximately $0.1 million. There remains approximately $40.5 million available for future sales of shares of common stock under the Sales Agreement. Other than the Sales Agreement, the Company currently does not have any commitments to obtain additional funds. Since inception, the Company has incurred recurring losses and negative cash flows from operations and, as of June 30, 2022, has an accumulated deficit of $163.8 million. During the six months ended June 30, 2022, the Company incurred a net loss of $25.2 million, which includes a one-time $10.0 million expense for acquired in-process research and development related to the upfront license fee for GFH009, and used $12.9 million of cash in operations. The Company expects to generate losses from operations for the foreseeable future primarily due to research and development costs for its product candidates, which raises substantial doubt about the Company's ability to continue as a going concern. As of June 30, 2022, the Company had cash and cash equivalents of approximately $27.0 million and restricted cash and cash equivalents of $0.1 million. In accordance with Accounting Standards Codification ("ASC") 205-40, Presentation of Financial Statements - Going Concern , the Company evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about its ability to continue as a going concern within one year after the consolidated financial statements are issued. The Company expects its cash and cash equivalents will not be sufficient to fund its current planned operations for at least the next twelve months from the date of issuance of these financial statements. The Company has prepared its consolidated financial statements assuming that it will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation and Significant Accounting PoliciesThe Company's complete summary of significant accounting policies can be found in "Item 8. Financial Statements and Supplementary Data - Note 3. Basis of Presentation and Significant Accounting Policies" in the audited annual consolidated financial statements included in the 2021 Annual Report. The significant accounting policies summarized and included in the 2021 Annual Report have not materially changed, except as set forth below. Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”). Any reference in these notes to applicable guidance is meant to refer to U.S. GAAP as found in the ASC and Accounting Standards Updates ("ASUs") of the Financial Accounting Standards Board ("FASB"). Principles of Consolidation The consolidated financial statements include the financial statements of the Company and its wholly owned subsidiaries. All significant intercompany accounts and transactions have been eliminated upon consolidation. Unless the context otherwise indicates, reference in these notes to the "Company" refer to SELLAS Life Sciences Group, Inc., and its wholly owned subsidiaries, SELLAS Life Sciences Group, Ltd., a privately held Bermuda exempted company, SLSG Limited, LLC, Sellas Life Sciences Limited, and Apthera, Inc. Unaudited Interim Results These consolidated financial statements and accompanying notes should be read in conjunction with the Company's annual consolidated financial statements and the notes thereto included in the 2021 Annual Report. The accompanying consolidated financial statements as of June 30, 2022 and for the three and six months ended June 30, 2022 and 2021, are unaudited, but include all adjustments, consisting of normal recurring entries, that management believes to be necessary for a fair presentation of the periods presented. Interim results are not necessarily indicative of results for a full year. Balance sheet amounts as of December 31, 2021 have been derived from the audited financial statements as of that date. Impact of COVID-19 The ongoing global COVID-19 pandemic, including the surges of cases from various variants, continues to disrupt the Company’s business operations and those of its collaborators, including 3DMed and GenFleet, contractors, contract research organizations (“CROs”), suppliers, clinical sites, contract manufacturing organizations (“CMOs”), and other partners. The COVID-19 pandemic has and may continue to affect the health and availability of the Company’s workforce and that of the third-parties it relies on, such as its CROs, clinical sites, CMOs, and other contractors as well as the governmental agencies, such as the U.S. Food and Drug Administration (“FDA”) and health authorities in other countries which could delay or otherwise adversely impact the ability of such parties to fulfill their obligations. The Company is continuously monitoring the impact of the pandemic on its clinical development programs. The full extent to which the COVID-19 pandemic will continue to directly or indirectly impact the Company’s business, results of operations and financial condition will depend on future developments that are highly uncertain, subject to change and cannot be predicted with confidence, including the duration of the outbreak, the continued availability and efficacy of vaccines and booster shots, new information which may emerge concerning the severity of COVID-19, the emergence of new variants of COVID-19, the actions to contain COVID-19 or treat its impact, including continuing or new lockdowns, among others, and the direct and indirect economic effects of the pandemic, including as a result of inflation, supply chain disruptions and labor shortages. Acquired In-Process Research and Development Costs incurred in obtaining technology licenses are immediately recognized as acquired in-process research and development expense, provided the technology licensed has no alternative future use. Payments related to contingent consideration such as development milestones, commercial milestones and royalties (Note 5) will be recognized when the contingency is probable and reasonably estimable as prescribed by ASC 450, Contingencies . Net Loss Per Share Net loss per share is computed by dividing net loss applicable to common stockholders by the weighted average number of shares of common stock outstanding during each period. Diluted loss per share includes the effect, if any, from the potential exercise or conversion of securities, such as warrants, stock options and unvested restricted stock that would result in the issuance of incremental shares of common stock. In computing the basic and diluted net loss per share, the weighted average number of shares remains the same for both calculations due to the fact that, when a net loss exists, dilutive shares are not included in the calculation as the impact is anti-dilutive. The following potentially dilutive securities outstanding have been excluded from the computation of diluted weighted average shares outstanding, as they would be anti-dilutive (in thousands): Six Months Ended June 30, 2022 2021 Common stock warrants 5,148 559 Stock options 1,012 520 Restricted stock units ("RSUs") 297 210 6,457 1,289 Recent Accounting Standards Adopted In May 2021, the FASB issued ASU No. 2021-04, Issuer’s Accounting for Certain Modifications of Exchanges of Freestanding Equity-Classified Written Call Options to clarify the accounting for modifications or exchanges of freestanding equity-classified written call options, such as warrants, that remain equity classified after modification or exchange. This ASU became effective for the Company on January 1, 2022 and did not have a material impact on the Company's consolidated financial statements. Recent Accounting Standards Not Yet Adopted In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity which, among other things, simplifies the accounting models for the allocation of proceeds attributable to the issuance of a convertible debt instrument. As a result, after adopting the ASU’s guidance, entities will not separately present in equity an embedded conversion feature in such debt. Instead, they will account for a convertible debt instrument wholly as debt, and for convertible preferred stock wholly as preferred stock (i.e., as a single unit of account), unless (i) a convertible instrument contains features that require bifurcation as a derivative under ASC 815 or (ii) a convertible debt instrument was issued at a substantial premium. The standard becomes effective for the Company in the first quarter of 2024 and early adoption is permitted. The Company is currently evaluating the potential impact of the adoption of this standard on its consolidated financial statements.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The following tables present information about the Company's assets and liabilities measured at fair value on a recurring basis in the consolidated balance sheets (in thousands): Description June 30, 2022 Quoted Prices In Significant Other Unobservable Assets: Cash equivalents $ 25,984 $ 25,984 $ — $ — Restricted cash equivalents 100 100 — — Total assets measured and recorded at fair value $ 26,084 $ 26,084 $ — $ — Liabilities: Warrant liability $ 3 $ — $ — $ 3 Contingent consideration 181 — — 181 Total liabilities measured and recorded at fair value $ 184 $ — $ — $ 184 Description December 31, 2021 Quoted Prices In Significant Other Unobservable Assets: Cash equivalents $ 21,000 $ 21,000 $ — $ — Restricted cash equivalents 100 100 — — Total assets measured and recorded at fair value $ 21,100 $ 21,100 $ — $ — Liabilities: Warrant liability $ 40 $ — $ — $ 40 Contingent consideration 296 — — 296 Total liabilities measured and recorded at fair value $ 336 $ — $ — $ 336 The Company did not transfer any financial instruments into or out of Level 3 classification, during the six months ended June 30, 2022 or during the year ended December 31, 2021. See Note 9, Warrants to Acquire Shares of Common Stock, for a reconciliation of the changes in the fair value of the warrant liability for the six months ended June 30, 2022. A reconciliation of the change in the fair value of the contingent consideration liability for the six months ended June 30, 2022 is as follows (in thousands): Fair Value Measurements Contingent consideration, December 31, 2021 $ 296 Change in the estimated fair value of the contingent consideration (115) Contingent consideration, June 30, 2022 $ 181 The contingent consideration relates to the future contingent payments of up to $32.0 million based on the achievement of certain development and commercial milestones relating to the Company’s nelipepimut-S ("NPS") product candidate, of which $2.0 million has been paid to date. The remaining contingent consideration of up to $30.0 million is payable at the election of the Company in either cash or shares of common stock, provided that the Company may not issue any shares in satisfaction of any contingent consideration, unless it has first obtained approval from its stockholders in accordance with Rule 5635(a) of the Nasdaq Marketplace Rules. The fair value of the contingent consideration is measured at the end of each reporting period using Level 3 inputs. The fair value of development and regulatory milestones are estimated utilizing a probability adjusted, discounted cash flow approach and the fair value of net sales milestones is estimated utilizing an option pricing model with Monte Carlo simulation. The following significant unobservable inputs were used in the valuation of the contingent consideration liability: As of June 30, 2022 As of December 31, 2021 Potential milestone payments $0 - $30 million $0 - $30 million Discount rate 16.5 % 15.5 % Cumulative probability of success 5.3 % 5.3 % Projected years of payments 2028 - 2031 2028 - 2031

Acquired In-Process Research an

Acquired In-Process Research and Development	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Acquired In-Process Research and Development	Acquired In-Process Research and Development Exclusive License Agreement with GenFleet Therapeutics (Shanghai) Inc. On March 31, 2022, the Company entered into an exclusive license agreement with GenFleet pursuant to which GenFleet granted to the Company a sublicensable, royalty-bearing license, under certain of its intellectual property, to develop, manufacture, and commercialize GFH009 for the treatment, diagnosis or prevention of disease in humans and animals in the GFH009 Territory. GFH009 is currently in a Phase 1 clinical trial in the United States and China. In consideration for the exclusive license, the Company has agreed to pay to GenFleet (i) an upfront and technology transfer fee of $10.0 million, of which $4.5 million was paid in April 2022 and $5.5 million is due upon the first day of the 15th calendar month following the effective date of the license agreement, (ii) development and regulatory milestone payments for up to three indications totaling up to $48.0 million in the aggregate, and (iii) sales milestone payments totaling up to $92.0 million in the aggregate upon the achievement of certain net sales thresholds in a given calendar year. The Company has also agreed to pay GenFleet single-digit tiered royalties based upon a percentage of annual net sales of GFH009 in the GFH009 Territory, with the royalty rate escalating based on the level of annual net sales ranging from the low to high single digits. During the six months ended June 30, 2022, the Company expensed $10.0 million related to the acquired technology as in-process research and development based on the assessment that the technology has no alternative future use, $4.5 million of which was paid in April 2022 and the remaining $5.5 million expected to be paid by the end of the second quarter of 2023 for which the Company has recorded a current payable as of June 30, 2022.

Balance Sheet Accounts

Balance Sheet Accounts	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Accounts	Balance Sheet Accounts Prepaid expenses and other current assets consist of the following (in thousands): June 30, 2022 December 31, 2021 Insurance $ 1,206 $ 217 Clinical development 240 1,309 Professional fees 111 36 Other 93 27 Prepaid expenses and other current assets $ 1,650 $ 1,589 Accrued expenses and other current liabilities consist of the following (in thousands): June 30, 2022 December 31, 2021 Clinical trial costs $ 1,815 $ 1,325 Compensation and related benefits 869 989 Professional fees 30 165 Other 292 161 Accrued expenses and other current liabilities $ 3,006 $ 2,640

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Leases The Company has a non-cancelable operating lease for certain executive, administrative, and general business office space for its headquarters in New York, New York, which began on June 5, 2020, was amended in February 2022 to add additional space, and has a term through December 31, 2024. The Company assessed the lease amendment for the additional space and determined it should be accounted for as a separate contract. The weighted average discount rate of the Company's operating leases under FASB Topic ASC 842, Leases is approximately 13.95%. As of June 30, 2022, the leases have a remaining term of 2.50 years. Rent expense related to the Company's operating leases was approximately $0.1 million f or each of the three months ended June 30, 2022 and 2021, and $0.2 million and $0.1 million for the six months ended June 30, 2022 and 2021, respectively. The Company made cash payments related to its operating leases of approximately $0.1 million for each of the three months ended June 30, 2022 and 2021 and $0.2 million for each of the six months ended June 30, 2022 and 2021. Future minimum lease payments are as follows as of June 30, 2022 (in thousands): Future minimum lease payments: 2022 (remaining) $ 253 2023 518 2024 533 Total future minimum lease payments 1,304 Less: imputed interest (180) Current and non-current operating lease liabilities $ 1,124 Legal Proceedings From time to time, the Company is subject to various pending or threatened legal actions and proceedings, including those that arise in the ordinary course of its business, which may include employment matters, breach of contract disputes and stockholder litigation. Such actions and proceedings are subject to many uncertainties and to outcomes that are not predictable with assurance and that may not be known for extended periods of time. The Company records a liability in its consolidated financial statements for costs related to claims, including future legal costs, settlements and judgments, when the Company has assessed that a loss is probable and an amount can be reasonably estimated. If the reasonable estimate of a probable loss is a range, the Company records the most probable estimate of the loss or the minimum amount when no amount within the range is a better estimate than any other amount. The Company discloses a contingent liability even if the liability is not probable or the amount is not estimable, or both, if there is a reasonable possibility that a material loss may have been incurred. In the opinion of management, as of the date of filing of these unaudited interim consolidated financial statements as of and for the period ended June 30, 2022, the amount of liability, if any, with respect to these matters, individually or in the aggregate, will not materially affect the Company’s consolidated results of operations, financial position or cash flows. As of June 30, 2022 there was no pending or threatened litigation.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2022
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Preferred Stock The Company has authorized up to 5,000,000 shares of preferred stock, $0.0001 par value per share, for issuance. There were no preferred shares outstanding as of June 30, 2022 and December 31, 2021. Common Stock The Company has authorized up to 350,000,000 shares of common stock, $0.0001 par value per share, for issuance. As of June 30, 2022, the Company has shares of common stock reserved for future issuance as follows (in thousands): Warrants outstanding 5,148 Stock options outstanding 1,012 RSUs outstanding 297 Shares reserved for future issuance under the Company’s 2019 Equity Incentive Plan 666 Shares reserved for future issuance under the 2021 Employee Stock Purchase Plan 290 Total common stock reserved for future issuance 7,413

Warrants to Acquire Shares of C

Warrants to Acquire Shares of Common Stock	6 Months Ended
	Jun. 30, 2022
Warrants and Rights Note Disclosure [Abstract]
Warrants to Acquire Shares of Common Stock	Warrants to Acquire Shares of Common Stock Warrants Outstanding The following is a summary of the activity of the Company's warrants to acquire shares of common stock for the six months ended June 30, 2022 (in thousands): Warrant Issuance Outstanding, December 31, 2021 Granted Canceled/Expired Outstanding, June 30, 2022 Exercise Price per Share Expiration Warrants classified as equity: April 2022 Offering — 4,630 — 4,630 $ 5.40 April 2027 January 2020 Offering 309 — — 309 $ 3.93 July 2025 July 2020 PIPE Offering 25 — — 25 $ 3.30 August 2025 July 2018 Offering 132 — — 132 $ 7.50 July 2023 March 2019 Exercise Agreement 30 — — 30 $ 7.50 March 2024 Other 9 — — 9 $ 306.66 December 2022 - June 2024 505 4,630 — 5,135 Warrants classified as liability 14 — (1) 13 $ 7.50 September 2023 - November 2023 519 4,630 (1) 5,148 Warrants to acquire shares of common stock primarily consist of equity-classified warrants. In addition, warrants to acquire shares of common stock that may require the Company to settle in cash are liability-classified warrants. Warrants Classified as Equity The warrants to acquire shares of common stock issued during the April 2022 Offering were recorded as equity upon issuance. During its evaluation of equity classification of these warrants, the Company considered the conditions as prescribed within ASC 815-40, Derivatives and Hedging, Contracts in an Entity’s own Equity (“ASC 815-40”). The conditions within ASC 815-40 are not subject to a probability assessment. The warrants to acquire shares of common stock do not fall under the liability criteria within ASC 480, Distinguishing Liabilities from Equity , as they are not puttable and do not represent an instrument that has a redeemable underlying security. The warrants do meet the definition of a derivative instrument under ASC 815, but are eligible for the scope exception as they are indexed to the Company’s own stock and would be classified in permanent equity if freestanding. Warrants Classified as Liabilities Liability-classified warrants consist of warrants to acquire common stock issued in connection with certain previous equity financings. These warrants may be settled in cash and were determined not to be indexed to the Company’s common stock. The estimated fair value of outstanding warrants accounted for as liabilities is determined at each balance sheet date. Any decrease or increase in the estimated fair value of the warrant liability since the most recent balance sheet date is recorded in the consolidated statement of operations as change in fair value of warrant liability. The fair value of the warrants is estimated using a Black-Scholes pricing model with the following inputs: June 30, 2022 December 31, 2021 Risk free interest rate 2.83 % 0.65 % Volatility 90.76 % 131.04 % Expected term (years) 1.26 1.75 Expected dividend yield — % — % Strike price $ 7.50 $ 7.50 The expected volatility assumptions are based on the Company's implied volatility in combination with the implied volatilities of similar publicly traded entities. The expected life assumption is based on the remaining contractual terms of the warrants. The risk-free rate is based on the zero coupon rates in effect at the time of valuation. The dividend yield used in the pricing model is zero, because the Company has no present intention to pay cash dividends. The changes in fair value of the warrant liability for the six months ended June 30, 2022 were as follows (in thousands): Warrant liability, December 31, 2021 $ 40 Change in fair value of warrants (37) Warrant liability, June 30, 2022 $ 3

License Revenue

License Revenue	6 Months Ended
	Jun. 30, 2022
Revenue from Contract with Customer [Abstract]
License Revenue	License Revenue Exclusive License Agreement with 3D Medicines Inc. In December 2020, the Company, together with its wholly-owned subsidiary, SLSG Limited, LLC, entered into an Exclusive License Agreement (the “3DMed License Agreement”) with 3D Medicines Inc. ("3DMed"), pursuant to which the Company granted 3DMed a sublicensable, royalty-bearing license, under certain intellectual property owned or controlled by the Company, to develop, manufacture and have manufactured, and commercialize GPS and heptavalent GPS (referred to as GPS Plus) product candidates ("GPS Licensed Products") for all therapeutic and other diagnostic uses in mainland China, Hong Kong, Macau and Taiwan ("3DMed Territory"). The license is exclusive, except with respect to certain know-how that has been non-exclusively licensed to the Company and is sublicensed to 3DMed on a non-exclusive basis. The Company has retained development, manufacturing and commercialization rights with respect to the GPS Licensed Products in the rest of the world. In partial consideration for the rights granted by the Company, 3DMed agreed to pay the Company (i) a one-time upfront cash payment of $7.5 million, and (ii) milestone payments totaling up to $194.5 million in the aggregate upon the achievement of certain technology transfer, development and regulatory milestones, as well as sales milestones based on certain net sales thresholds of GPS Licensed Products in the 3DMed Territory in a given calendar year. 3DMed also agreed to pay tiered royalties based upon a percentage of annual net sales of GPS Licensed Products in the 3DMed Territory ranging from the high single digits to the low double digits. The Company determined the initial transaction price of the single performance obligation to be $9.5 million, which included the $7.5 million upfront fee as well as $2.0 million in development milestones that were assessed as probable of being achieved at the inception of the 3DMed License Agreement and therefore were not constrained. As of December 31, 2021, the full $9.5 million initial transaction price was fully recognized as licensing revenue. The Company determined that the remaining $192.5 million in certain future development, regulatory, and sales milestones is variable consideration subject to constraint at inception. At the end of each reporting period, the Company reevaluates the probability of achievement of the future development, regulatory, and sales milestones subject to constraint and, if necessary, will adjust its estimate of the overall transaction price. Any such adjustments will be recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. On March 31, 2022, the Company announced that an IND application filed by 3DMed, pursuant to its 3DMed License Agreement for GPS, for a small Phase 1 clinical trial investigating safety of GPS in China was approved by China's NMPA. The IND approval by the NMPA triggered a $1.0 million milestone payment to the Company which was recognized as licensing revenue in the first quarter of 2022 and payment was received in May 2022. An additional $191.5 million in potential future development, regulatory, and sales milestones, not including future royalties, remains under the 3DMed License Agreement as of June 30, 2022, which milestones are variable in nature and not under the Company's control. The current clinical development plan provides for initiation of a Phase 2 clinical trial following receipt of satisfactory safety data from the Phase 1 clinical trial as well as a Phase 1 or Phase 1/2 clinical trial of GPS in combination with envafolimab, 3DMed’s checkpoint inhibitor which has been approved in China. Under the 3DMed License Agreement, the initiation of a Phase 2 clinical trial will trigger a milestone payment to the Company. For the sales-based royalties, the Company will recognize revenue when the related sales occur. To date, the Company has not recognized any royalty revenue resulting from any of its licensing arrangements. There was no license revenue recognized during the three months ended June 30, 2022, and $1.9 million in license revenue recognized during the three months ended June 30, 2021. There was $1.0 million and $7.6 million in license revenue recognized during the six months ended June 30, 2022 and 2021, respectively.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation 2017 Equity Incentive Plan On December 29, 2017, the 2017 Equity Incentive Plan was approved by the stockholders of the Company, which currently allows for issuance of up to approximately 22,000 shares of common stock underlying stock options granted prior to September 10, 2019. The 2017 Equity Incentive Plan was terminated upon the approval of the 2019 Incentive Plan subject to outstanding stock options granted under the 2017 Equity Incentive Plan that remain exercisable through maturity for the Company's employees and directors. 2019 Equity Incentive Plan On September 10, 2019, the 2019 Equity Incentive Plan was approved by the stockholders of the Company, which currently allows for issuance of up to approximately 1,964,000 shares of common stock in connection with the grant of stock-based awards, including stock options, restricted stock, restricted stock units, stock appreciation rights and other types of awards as deemed appropriate. The number of shares reserved for issuance under the 2019 Equity Incentive Plan will automatically increase on January 1 of each year, for a period of not more than four years, commencing on January 1, 2020 and ending on (and including) January 1, 2023, by an amount equal to the lesser of (i) 5% of the total number of shares of common stock outstanding at the end of the prior fiscal year; and (ii) an amount determined by the board of directors or authorized committee. As of June 30, 2022, approximately 666,000 shares of common stock were reserved for future grants under the 2019 Equity Incentive Plan. The following table summarizes the components of stock-based compensation expense in the consolidated statements of operations for the three and six months ended June 30, 2022 and 2021, respectively (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Research and development $ 70 $ 35 $ 125 $ 48 General and administrative 380 229 700 400 Total stock-based compensation $ 450 $ 264 $ 825 $ 448 Options to Purchase Shares of Common Stock The following table summarizes stock option activity of the Company for the six months ended June 30, 2022: Total Weighted Weighted Average Remaining Contractual Term (In Years) Aggregate Outstanding at December 31, 2021 534 $ 10.09 8.77 $ 681 Granted 478 5.28 Outstanding at June 30, 2022 1,012 $ 7.81 8.92 $ 67 Options exercisable at June 30, 2022 251 $ 13.49 8.07 $ 41 The aggregate intrinsic values of outstanding and exercisable stock options at June 30, 2022 were calculated based on the closing price of the Company’s common stock as reported on the Nasdaq Capital Market on June 30, 2022 of $2.23 per share. The aggregate intrinsic value equals the positive difference between the closing fair market value of the Company’s common stock and the exercise price of the underlying stock options. The Company uses the Black-Scholes option-pricing model to determine the fair value of all its stock options granted. The weighted average assumptions used during the three and six months ended June 30, 2022 and 2021, respectively, were as follows: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Risk free interest rate 2.87 % 1.12 % 1.80 % 1.04 % Volatility 144.75 % 121.47 % 130.60 % 121.23 % Expected lives (years) 6.25 6.25 6.21 6.18 Expected dividend yield — % — % — % — % The weighted-average grant date fair value of options granted during the three months ended June 30, 2022 and 2021 was $2.13 and $6.89, respectively. The weighted-average grant date fair value of options granted during the six months ended June 30, 2022 and 2021 was $4.76 and $6.97, respectively. The Company’s expected common stock price volatility assumption is based upon the Company's own implied volatility in combination with the implied volatility of a basket of comparable companies. The expected life assumptions for employee grants were based upon the simplified method, which averages the contractual term of the Company’s options of ten years with the average vesting term of four years for an average of approximately six years. The expected life assumptions for non-employees were based upon the contractual term of the option. The dividend yield assumption is zero because the Company has never paid cash dividends and presently has no intention to do so. The risk-free interest rate used for each grant was also based upon prevailing short-term interest rates. The Company accounts for forfeitures as they occur. As of June 30, 2022, there was $3.6 million of unrecognized compensation cost related to outstanding stock options that is expected to be recognized as a component of the Company’s operating expenses over a weighted-average period of 2.88 years. Time-vested RSUs and RSUs with Performance Conditions The following table summarizes RSU activity of the Company for the six months ended June 30, 2022: Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2021 200 $ 2.81 Granted 97 $ 5.34 Unvested at June 30, 2022 297 $ 3.64 As of June 30, 2022, there was $1.0 million of unrecognized compensation cost related to outstanding RSUs that is expected to be recognized as a component of the Company's operating expenses over a weighted-average period of 2.51 years. No RSUs vested during the six months ended June 30, 2022. 2021 Employee Stock Purchase Plan On April 22, 2021, the Board of Directors adopted the 2021 Employee Stock Purchase Plan ("2021 ESPP") which was approved by the Company's stockholders on June 8, 2021. The 2021 ESPP allows employees to contribute up to 20% of their cash earnings, subject to a maximum of $25,000 per year under Internal Revenue Service rules, to be used to purchase shares of the Company’s common stock on semi-annual purchase dates. The 2021 ESPP allows eligible employees to purchase shares of common stock at a price per share equal to 85% of the lower of the fair market value of the common stock at the beginning or end of each six-month offering period during the term of the 2021 ESPP. During the six months ended June 30, 2022, 10,362 shares of common stock were purchased by employees under the 2021 ESPP for proceeds of approximately $47,000. There are currently 289,638 shares of common stock reserved for issuance under the 2021 ESPP as of June 30, 2022.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2022
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsThe Company evaluated all events or transactions that occurred after June 30, 2022 up through the date these financial statements were issued. Other than as disclosed elsewhere in the notes to the consolidated financial statements, the Company did not have any material subsequent events.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”). Any reference in these notes to applicable guidance is meant to refer to U.S. GAAP as found in the ASC and Accounting Standards Updates ("ASUs") of the Financial Accounting Standards Board ("FASB").
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the financial statements of the Company and its wholly owned subsidiaries. All significant intercompany accounts and transactions have been eliminated upon consolidation. Unless the context otherwise indicates, reference in these notes to the "Company" refer to SELLAS Life Sciences Group, Inc., and its wholly owned subsidiaries, SELLAS Life Sciences Group, Ltd., a privately held Bermuda exempted company, SLSG Limited, LLC, Sellas Life Sciences Limited, and Apthera, Inc.
Acquired In-Process Research and Development	Acquired In-Process Research and Development Costs incurred in obtaining technology licenses are immediately recognized as acquired in-process research and development expense, provided the technology licensed has no alternative future use. Payments related to contingent consideration such as development milestones, commercial milestones and royalties (Note 5) will be recognized when the contingency is probable and reasonably estimable as prescribed by ASC 450, Contingencies
Net Loss Per Share	Net Loss Per Share Net loss per share is computed by dividing net loss applicable to common stockholders by the weighted average number of shares of common stock outstanding during each period. Diluted loss per share includes the effect, if any, from the potential exercise or conversion of securities, such as warrants, stock options and unvested
Recent Accounting Standards Adopted and Recent Accounting Standards Not Yet Adopted	Recent Accounting Standards Adopted In May 2021, the FASB issued ASU No. 2021-04, Issuer’s Accounting for Certain Modifications of Exchanges of Freestanding Equity-Classified Written Call Options to clarify the accounting for modifications or exchanges of freestanding equity-classified written call options, such as warrants, that remain equity classified after modification or exchange. This ASU became effective for the Company on January 1, 2022 and did not have a material impact on the Company's consolidated financial statements. Recent Accounting Standards Not Yet Adopted In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity which, among other things, simplifies the accounting models for the allocation of proceeds attributable to the issuance of a convertible debt instrument. As a result, after adopting the ASU’s guidance, entities will not separately present in equity an embedded conversion feature in such debt. Instead, they will account for a convertible debt instrument wholly as debt, and for convertible preferred stock wholly as preferred stock (i.e., as a single unit of account), unless (i) a convertible instrument contains features that require bifurcation as a derivative under ASC 815 or (ii) a convertible debt instrument was issued at a substantial premium. The standard becomes effective for the Company in the first quarter of 2024 and early adoption is permitted. The Company is currently evaluating the potential impact of the adoption of this standard on its consolidated financial statements.

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following potentially dilutive securities outstanding have been excluded from the computation of diluted weighted average shares outstanding, as they would be anti-dilutive (in thousands): Six Months Ended June 30, 2022 2021 Common stock warrants 5,148 559 Stock options 1,012 520 Restricted stock units ("RSUs") 297 210 6,457 1,289

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value	The following tables present information about the Company's assets and liabilities measured at fair value on a recurring basis in the consolidated balance sheets (in thousands): Description June 30, 2022 Quoted Prices In Significant Other Unobservable Assets: Cash equivalents $ 25,984 $ 25,984 $ — $ — Restricted cash equivalents 100 100 — — Total assets measured and recorded at fair value $ 26,084 $ 26,084 $ — $ — Liabilities: Warrant liability $ 3 $ — $ — $ 3 Contingent consideration 181 — — 181 Total liabilities measured and recorded at fair value $ 184 $ — $ — $ 184 Description December 31, 2021 Quoted Prices In Significant Other Unobservable Assets: Cash equivalents $ 21,000 $ 21,000 $ — $ — Restricted cash equivalents 100 100 — — Total assets measured and recorded at fair value $ 21,100 $ 21,100 $ — $ — Liabilities: Warrant liability $ 40 $ — $ — $ 40 Contingent consideration 296 — — 296 Total liabilities measured and recorded at fair value $ 336 $ — $ — $ 336
Schedule of Reconciliation of Level 3 Liabilities	A reconciliation of the change in the fair value of the contingent consideration liability for the six months ended June 30, 2022 is as follows (in thousands): Fair Value Measurements Contingent consideration, December 31, 2021 $ 296 Change in the estimated fair value of the contingent consideration (115) Contingent consideration, June 30, 2022 $ 181
Schedule of Fair Value Measurement Inputs and Valuation Techniques	The following significant unobservable inputs were used in the valuation of the contingent consideration liability: As of June 30, 2022 As of December 31, 2021 Potential milestone payments $0 - $30 million $0 - $30 million Discount rate 16.5 % 15.5 % Cumulative probability of success 5.3 % 5.3 % Projected years of payments 2028 - 2031 2028 - 2031

Balance Sheet Accounts (Tables)

Balance Sheet Accounts (Tables)	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consist of the following (in thousands): June 30, 2022 December 31, 2021 Insurance $ 1,206 $ 217 Clinical development 240 1,309 Professional fees 111 36 Other 93 27 Prepaid expenses and other current assets $ 1,650 $ 1,589
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): June 30, 2022 December 31, 2021 Clinical trial costs $ 1,815 $ 1,325 Compensation and related benefits 869 989 Professional fees 30 165 Other 292 161 Accrued expenses and other current liabilities $ 3,006 $ 2,640

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments	Future minimum lease payments are as follows as of June 30, 2022 (in thousands): Future minimum lease payments: 2022 (remaining) $ 253 2023 518 2024 533 Total future minimum lease payments 1,304 Less: imputed interest (180) Current and non-current operating lease liabilities $ 1,124

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2022
Equity [Abstract]
Schedule of Common Stock Reserved for Future Issuance	As of June 30, 2022, the Company has shares of common stock reserved for future issuance as follows (in thousands): Warrants outstanding 5,148 Stock options outstanding 1,012 RSUs outstanding 297 Shares reserved for future issuance under the Company’s 2019 Equity Incentive Plan 666 Shares reserved for future issuance under the 2021 Employee Stock Purchase Plan 290 Total common stock reserved for future issuance 7,413

Warrants to Acquire Shares of_2

Warrants to Acquire Shares of Common Stock (Tables)	6 Months Ended
	Jun. 30, 2022
Warrants and Rights Note Disclosure [Abstract]
Schedule of Warrant Activity	The following is a summary of the activity of the Company's warrants to acquire shares of common stock for the six months ended June 30, 2022 (in thousands): Warrant Issuance Outstanding, December 31, 2021 Granted Canceled/Expired Outstanding, June 30, 2022 Exercise Price per Share Expiration Warrants classified as equity: April 2022 Offering — 4,630 — 4,630 $ 5.40 April 2027 January 2020 Offering 309 — — 309 $ 3.93 July 2025 July 2020 PIPE Offering 25 — — 25 $ 3.30 August 2025 July 2018 Offering 132 — — 132 $ 7.50 July 2023 March 2019 Exercise Agreement 30 — — 30 $ 7.50 March 2024 Other 9 — — 9 $ 306.66 December 2022 - June 2024 505 4,630 — 5,135 Warrants classified as liability 14 — (1) 13 $ 7.50 September 2023 - November 2023 519 4,630 (1) 5,148
Schedule of Fair Value of Warrants is Estimated Using Black-Scholes Option Pricing Model	The fair value of the warrants is estimated using a Black-Scholes pricing model with the following inputs: June 30, 2022 December 31, 2021 Risk free interest rate 2.83 % 0.65 % Volatility 90.76 % 131.04 % Expected term (years) 1.26 1.75 Expected dividend yield — % — % Strike price $ 7.50 $ 7.50
Schedule of Changes in Fair Value of Warrant Liability	The changes in fair value of the warrant liability for the six months ended June 30, 2022 were as follows (in thousands): Warrant liability, December 31, 2021 $ 40 Change in fair value of warrants (37) Warrant liability, June 30, 2022 $ 3

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Schedule of Allocated Stock-based Compensation Expense	The following table summarizes the components of stock-based compensation expense in the consolidated statements of operations for the three and six months ended June 30, 2022 and 2021, respectively (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Research and development $ 70 $ 35 $ 125 $ 48 General and administrative 380 229 700 400 Total stock-based compensation $ 450 $ 264 $ 825 $ 448
Schedule of Stock Option Activity	The following table summarizes stock option activity of the Company for the six months ended June 30, 2022: Total Weighted Weighted Average Remaining Contractual Term (In Years) Aggregate Outstanding at December 31, 2021 534 $ 10.09 8.77 $ 681 Granted 478 5.28 Outstanding at June 30, 2022 1,012 $ 7.81 8.92 $ 67 Options exercisable at June 30, 2022 251 $ 13.49 8.07 $ 41
Schedule of Assumptions for Option Grants Issued	The Company uses the Black-Scholes option-pricing model to determine the fair value of all its stock options granted. The weighted average assumptions used during the three and six months ended June 30, 2022 and 2021, respectively, were as follows: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Risk free interest rate 2.87 % 1.12 % 1.80 % 1.04 % Volatility 144.75 % 121.47 % 130.60 % 121.23 % Expected lives (years) 6.25 6.25 6.21 6.18 Expected dividend yield — % — % — % — %
Schedule of RSU Activity	The following table summarizes RSU activity of the Company for the six months ended June 30, 2022: Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2021 200 $ 2.81 Granted 97 $ 5.34 Unvested at June 30, 2022 297 $ 3.64

Liquidity (Details)

Liquidity (Details) - USD ($)				1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 05, 2022	Mar. 31, 2022	Apr. 16, 2021	May 31, 2022	Apr. 30, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cash paid for acquisition of in-process research and development								$ 4,500,000	$ 0
Milestone payment received				$ 1,000,000
Potential milestone payments to be received						$ 191,500,000		$ 191,500,000		$ 192,500,000
Shares of common stock reserved for issuance (in shares)						7,413,000		7,413,000
Accumulated deficit						$ 163,761,000		$ 163,761,000		138,603,000
Net loss						8,414,000	$ 4,613,000	25,158,000	7,016,000
Acquired in-process research and development expense						0	$ 0	10,000,000	0
Net cash used in operating activities								12,911,000	$ 15,167,000
Cash and cash equivalents						26,987,000		26,987,000		21,355,000
Restricted cash and cash equivalents						100,000		100,000		$ 100,000
GenFleet Therapeutics (Shanghai) Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront fee		$ 10,000,000
Cash paid for acquisition of in-process research and development					$ 4,500,000
Acquired in-process research and development payable, non-current		5,500,000				$ 5,500,000		5,500,000
Eligible payment from collaboration for development and regulatory milestone achievement under collaborations agreement		48,000,000
Maximum amount eligible for milestones under collaborations agreement		$ 92,000,000
Acquired in-process research and development expense								$ 10,000,000
Underwriting Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of shares of stock (in shares)	4,629,630
Common stock to be called by warrants (in shares)	4,629,630
Offering (in dollars per share)	$ 5.40
Number of securities called by each warrant	1
Exercise price (in dollars per share)	$ 5.40
Warrant term	5 years
Proceeds of common stock	$ 23,000,000
Sales Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of shares of stock (in shares)								16,289		786,927
Proceeds of common stock								$ 100,000		$ 9,000,000
Sale of shares, common stock gross proceeds			$ 50,000,000
Percentage gross proceeds from the sale of shares (as a percent)			3%
Stock price per share (in dollars per share)						$ 3.16		$ 3.16		$ 12.04
Shares of common stock reserved for issuance (in shares)						40,500,000		40,500,000

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	6,457	1,289
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	5,148	559
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	1,012	520
Restricted stock units ("RSUs")
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	297	210

Fair Value Measurements - Conti

Fair Value Measurements - Contingent Purchase Price Consideration, Measured at Estimated Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Liabilities:
Warrant liability	$ 3	$ 40
Fair Value, Measurements, Recurring
Assets:
Cash equivalents	25,984	21,000
Restricted cash equivalents	100	100
Total assets measured and recorded at fair value	26,084	21,100
Liabilities:
Warrant liability	3	40
Contingent consideration	181	296
Total liabilities measured and recorded at fair value	184	336
Fair Value, Measurements, Recurring | Quoted Prices In Active Markets (Level 1)
Assets:
Cash equivalents	25,984	21,000
Restricted cash equivalents	100	100
Total assets measured and recorded at fair value	26,084	21,100
Liabilities:
Warrant liability	0	0
Contingent consideration	0	0
Total liabilities measured and recorded at fair value	0	0
Fair Value, Measurements, Recurring | Significant Other Observable  Inputs (Level 2)
Assets:
Cash equivalents	0	0
Restricted cash equivalents	0	0
Total assets measured and recorded at fair value	0	0
Liabilities:
Warrant liability	0	0
Contingent consideration	0	0
Total liabilities measured and recorded at fair value	0	0
Fair Value, Measurements, Recurring | Unobservable  Inputs (Level 3)
Assets:
Cash equivalents	0	0
Restricted cash equivalents	0	0
Total assets measured and recorded at fair value	0	0
Liabilities:
Warrant liability	3	40
Contingent consideration	181	296
Total liabilities measured and recorded at fair value	$ 184	$ 336

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation of Level 3 Liabilities (Details) - Unobservable  Inputs (Level 3) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration, beginning balance	$ 296
Change in the estimated fair value of the contingent consideration	(115)
Contingent consideration, ending balance	$ 181

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - Apthera, Inc.	6 Months Ended
	Jun. 30, 2022 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration payable, maximum amount	$ 32,000,000
Contingent consideration paid	2,000,000
Contingent consideration	$ 30,000,000

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Measurement Inputs and Valuation Techniques (Details) - Apthera	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration payable, minimum amount	$ 0	$ 0
Contingent consideration payable, maximum amount	$ 30,000,000	$ 30,000,000
Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Business combination, contingent consideration, measurement input (as a percent)	0.165	0.155
Cumulative probability of success
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Business combination, contingent consideration, measurement input (as a percent)	0.053	0.053

Acquired In-Process Research _2

Acquired In-Process Research and Development (Details) - USD ($)		1 Months Ended	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Apr. 30, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
License And Collaboration Agreements [Line Items]
Cash paid for acquisition of in-process research and development					$ 4,500,000	$ 0
Acquired in-process research and development expense			$ 0	$ 0	10,000,000	$ 0
GenFleet Therapeutics (Shanghai) Inc
License And Collaboration Agreements [Line Items]
Upfront fee	$ 10,000,000
Cash paid for acquisition of in-process research and development		$ 4,500,000
Acquired in-process research and development payable, non-current	5,500,000		$ 5,500,000		5,500,000
Eligible payment from collaboration for development and regulatory milestone achievement under collaborations agreement	48,000,000
Maximum amount eligible for milestones under collaborations agreement	$ 92,000,000
Acquired in-process research and development expense					$ 10,000,000

Balance Sheet Accounts - Prepai

Balance Sheet Accounts - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Insurance	$ 1,206	$ 217
Clinical development	240	1,309
Professional fees	111	36
Other	93	27
Prepaid expenses and other current assets	$ 1,650	$ 1,589

Balance Sheet Accounts - Accrue

Balance Sheet Accounts - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Clinical trial costs	$ 1,815	$ 1,325
Compensation and related benefits	869	989
Professional fees	30	165
Other	292	161
Accrued expenses and other current liabilities	$ 3,006	$ 2,640

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Operating lease, discount rate (as a percent)	13.95%		13.95%
Operating lease, remaining term			2 years 6 months
Rent expense	$ 0.1	$ 0.1	$ 0.2	$ 0.1
Cash payments related to operating lease	$ 0.1	$ 0.1	$ 0.2	$ 0.2

Commitments and Contingencies_2

Commitments and Contingencies - Maturities of Lease Liabilities - 842 (Details) $ in Thousands	Jun. 30, 2022 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2022 (remaining)	$ 253
2023	518
2024	533
Total future minimum lease payments	1,304
Less: imputed interest	(180)
Current and non-current operating lease liabilities	$ 1,124

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - $ / shares	Jun. 30, 2022	Dec. 31, 2021
Equity [Abstract]
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares outstanding (in shares)	0	0
Common stock, shares authorized (in shares)	350,000,000	350,000,000
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock are Reserved for Future Issuance (Details) - shares shares in Thousands	Jun. 30, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding (in shares)	5,148	519
Stock options outstanding (in shares)	1,012	534
Total common stock reserved for future issuance (in shares)	7,413
2019 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	666
2021 ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	290
Restricted stock units ("RSUs")
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs outstanding (in shares)	297	200

Warrants to Acquire Shares of_3

Warrants to Acquire Shares of Common Stock - Warrants Outstanding (Details) shares in Thousands	6 Months Ended
	Jun. 30, 2022 $ / shares shares
Class of Warrant or Right, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	519
Granted (in shares)	4,630
Canceled/Expired (in shares)	(1)
Outstanding, end of period (in shares)	5,148
Common stock warrants
Class of Warrant or Right, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	505
Granted (in shares)	4,630
Canceled/Expired (in shares)	0
Outstanding, end of period (in shares)	5,135
April 2022 Offering | Common stock warrants
Class of Warrant or Right, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	0
Granted (in shares)	4,630
Canceled/Expired (in shares)	0
Outstanding, end of period (in shares)	4,630
Exercise price (in dollars per share) | $ / shares	$ 5.40
January 2020 Offering | Common stock warrants
Class of Warrant or Right, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	309
Granted (in shares)	0
Canceled/Expired (in shares)	0
Outstanding, end of period (in shares)	309
Exercise price (in dollars per share) | $ / shares	$ 3.93
July 2020 PIPE Offering | Common stock warrants
Class of Warrant or Right, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	25
Granted (in shares)	0
Canceled/Expired (in shares)	0
Outstanding, end of period (in shares)	25
Exercise price (in dollars per share) | $ / shares	$ 3.30
July 2018 Offering | Common stock warrants
Class of Warrant or Right, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	132
Granted (in shares)	0
Canceled/Expired (in shares)	0
Outstanding, end of period (in shares)	132
Exercise price (in dollars per share) | $ / shares	$ 7.50
March 2019 Exercise Agreement | Common stock warrants
Class of Warrant or Right, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	30
Granted (in shares)	0
Canceled/Expired (in shares)	0
Outstanding, end of period (in shares)	30
Exercise price (in dollars per share) | $ / shares	$ 7.50
Other | Common stock warrants
Class of Warrant or Right, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	9
Granted (in shares)	0
Canceled/Expired (in shares)	0
Outstanding, end of period (in shares)	9
Exercise price (in dollars per share) | $ / shares	$ 306.66
Warrants classified as liability
Class of Warrant or Right, Outstanding [Roll Forward]
Outstanding, beginning of period (in shares)	14
Granted (in shares)	0
Canceled/Expired (in shares)	(1)
Outstanding, end of period (in shares)	13
Exercise price (in dollars per share) | $ / shares	$ 7.50

Warrants to Acquire Shares of_4

Warrants to Acquire Shares of Common Stock - Fair Value of Warrants is Estimated Using Black-Scholes Option Pricing Model (Details)	Jun. 30, 2022	Dec. 31, 2021
Risk free interest rate
Class of Warrant or Right [Line Items]
Warrants, measurement input	0.0283	0.0065
Volatility
Class of Warrant or Right [Line Items]
Warrants, measurement input	0.9076	1.3104
Expected term (years)
Class of Warrant or Right [Line Items]
Warrants, measurement input	1.26	1.75
Expected dividend yield
Class of Warrant or Right [Line Items]
Warrants, measurement input	0	0
Strike price
Class of Warrant or Right [Line Items]
Warrants, measurement input	7.50	7.50

Warrants to Acquire Shares of_5

Warrants to Acquire Shares of Common Stock - Narrative (Details)	Jun. 30, 2022	Dec. 31, 2021
Coupon rate
Class of Warrant or Right [Line Items]
Expected dividend yield	0
Expected dividend yield
Class of Warrant or Right [Line Items]
Expected dividend yield	0	0

Warrants to Acquire Shares of_6

Warrants to Acquire Shares of Common Stock - Changes in Fair Value of Warrant Liability (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Class of Warrant or Right, Fair Value [Roll Forward]
Warrant liability, December 31, 2021	$ 40
Change in fair value of warrants	(37)
Warrant liability, June 30, 2022	$ 3

License Revenue - Narrative (De

License Revenue - Narrative (Details) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	May 31, 2022	Dec. 31, 2020	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 13, 2020
Revenue from Contract with Customer [Abstract]
Upfront cash payment received		$ 7,500,000
Future milestone payments received		194,500,000
Performance obligation, amount								$ 9,500,000
Milestones probable of being achieved		$ 2,000,000
Deferred revenue recognized license							$ 9,500,000
Potential milestone payments to be received			$ 191,500,000		$ 191,500,000		$ 192,500,000
Milestone payment received	$ 1,000,000
Licensing revenue			0	$ 1,900,000	1,000,000	$ 7,600,000
Cost of licensing revenue			$ 0	$ 100,000	$ 100,000	$ 200,000

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		6 Months Ended
	Apr. 22, 2021	Sep. 10, 2019	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 29, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance (in shares)			7,413,000		7,413,000
Closing price of the Company's common stock (in dollars per share)			$ 2.23		$ 2.23
Weighted average exercise price, granted (in dollars per share)			$ 2.13	$ 6.89	$ 4.76	$ 6.97
Averages contractual term					10 years
Expected dividend yield (as a percent)			0%	0%	0%	0%
Unrecognized compensation cost, options			$ 3,600		$ 3,600
Operating expenses weighted average period					2 years 10 months 17 days
Proceeds from employee stock purchases					$ 47	$ 0
Restricted stock units ("RSUs")
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price, granted (in dollars per share)					$ 5.34
Operating expenses weighted average period					2 years 6 months 3 days
Unrecognized compensation cost			$ 1,000		$ 1,000
RSUs vested (in shares)					0
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Average vesting term					6 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Average vesting term					4 years
2017 Equity Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock authorized for issuance (in shares)							22,000
2019 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock authorized for issuance (in shares)		1,964,000
Option term		4 years
Increase in number of shares available for future issuance under stock based awards (as a percent)		5%
Shares of common stock reserved for issuance (in shares)			666,000		666,000
2021 ESPP | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance (in shares)			289,638		289,638
Cash earnings contributed per year	20%
Purchase price of common stock	85%
Offering period	6 months
Share-based compensation arrangement by share-based payment award, shares purchased for award					10,362
Proceeds from employee stock purchases					$ 47

Stock-Based Compensation - Allo

Stock-Based Compensation - Allocated Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share based compensation expense	$ 450	$ 264	$ 825	$ 448
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share based compensation expense	70	35	125	48
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share based compensation expense	$ 380	$ 229	$ 700	$ 400

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, beginning balance (in shares)	534
Granted (in shares)	478
Options outstanding, ending balance (in shares)	1,012	534
Options exercisable (in shares)	251
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price, beginning balance (in dollars per share)	$ 10.09
Weighted average exercise price, granted (in dollars per share)	5.28
Weighted average exercise price, ending balance (in dollars per share)	7.81	$ 10.09
Weighted average exercise price, exercisable (in dollars per share)	$ 13.49
Weighted average remaining contractual term, outstanding (in years)	8 years 11 months 1 day	8 years 9 months 7 days
Weighted average remaining contractual term, options exercisable (in years)	8 years 25 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Aggregate Intrinsic Value [Roll Forward]
Aggregate intrinsic value, beginning balance	$ 681
Aggregate intrinsic value, ending balance	67	$ 681
Aggregate intrinsic value, options exercisable	$ 41

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions for Option Grants Issued (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Share-Based Payment Arrangement [Abstract]
Risk free interest rate	2.87%	1.12%	1.80%	1.04%
Volatility	144.75%	121.47%	130.60%	121.23%
Expected lives (years)	6 years 3 months	6 years 3 months	6 years 2 months 15 days	6 years 2 months 4 days
Expected dividend yield	0%	0%	0%	0%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of RSU Activity (Details) - $ / shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Weighted Average Grant Date Fair Value
Granted (in dollars per share)	$ 2.13	$ 6.89	$ 4.76	$ 6.97
Restricted stock units ("RSUs")
Shares
Beginning balance (in shares)			200
Granted (in shares)			97
Ending balance (in shares)	297		297
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share)			$ 2.81
Granted (in dollars per share)			5.34
Ending balance (in dollars per share)	$ 3.64		$ 3.64