Galera Therapeutics (GRTX) 10-Q 10 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 05, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Registrant Name	Galera Therapeutics, Inc.
Entity Central Index Key	0001563577
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Title of 12(b) Security	Common Stock,$0.001 par value per share
Trading Symbol	GRTX
Security Exchange Name	NASDAQ
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		26,438,767
Entity File Number	001-39114
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-1454898
Entity Address, Address Line One	2 W. Liberty Blvd #100
Entity Address, City or Town	Malvern
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19355
City Area Code	610
Local Phone Number	725-1500
Document Quarterly Report	true
Document Transition Report	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 17,632	$ 15,872
Short-term investments	71,073	56,904
Prepaid expenses and other current assets	3,983	5,153
Total current assets	92,688	77,929
Property and equipment, net	938	1,023
Acquired intangible asset	2,258	2,258
Goodwill	881	881
Right-of-use lease assets	374	530
Other assets	1,626	1,477
Total assets	98,765	84,098
Current liabilities:
Accounts payable	7,181	5,146
Accrued expenses	8,272	8,584
Lease liabilities	271	238
Total current liabilities	15,724	13,968
Royalty purchase liability	125,751	63,369
Lease liabilities, net of current portion	110	296
Deferred tax liability	273	273
Other liabilities	74	74
Total liabilities	141,932	77,980
Stockholders’ equity (deficit):
Preferred stock, $0.001 par value: 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.001 par value: 200,000,000 shares authorized; 26,438,767 and 24,976,142 shares issued and outstanding at September 30, 2021 and December 31, 2020	26	25
Additional paid-in capital	256,104	241,649
Accumulated other comprehensive income (loss)	(2)	12
Accumulated deficit	(299,295)	(235,568)
Total stockholders’ equity (deficit)	(43,167)	6,118
Total liabilities and stockholders’ equity (deficit)	$ 98,765	$ 84,098

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized (shares)	10,000,000	10,000,000
Preferred stock, shares issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized (shares)	200,000,000	200,000,000
Common stock, shares issued (shares)	26,438,767	24,976,142
Common stock, shares outstanding (shares)	26,438,767	24,976,142

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating expenses:
Research and development	$ 14,813	$ 12,133	$ 43,203	$ 40,225
General and administrative	5,487	3,945	15,667	11,384
Loss from operations	(20,300)	(16,078)	(58,870)	(51,609)
Other income (expenses):
Interest income	3	235	28	1,055
Interest expense	(2,327)	(1,235)	(4,882)	(3,625)
Foreign currency gain (loss)	(2)		(3)	27
Net loss	$ (22,626)	$ (17,078)	$ (63,727)	$ (54,152)
Net loss per share of common stock, basic and diluted	$ (0.86)	$ (0.69)	$ (2.49)	$ (2.18)
Weighted-average shares of common stock outstanding, basic and diluted	26,304,920	24,874,805	25,569,545	24,840,822

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net loss	$ (22,626)	$ (17,078)	$ (63,727)	$ (54,152)
Unrealized gain (loss) on short-term investments	(5)	(193)	(14)	85
Comprehensive loss	$ (22,631)	$ (17,271)	$ (63,741)	$ (54,067)

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive income (loss)	Accumulated Deficit
Balance at Dec. 31, 2019	$ 69,608	$ 25	$ 230,895	$ 38	$ (161,350)
Balance (in shares) at Dec. 31, 2019		24,811,567
Share-based compensation expense	1,210		1,210
Exercise of stock options	9		9
Exercise of stock options, shares		8,503
Unrealized gain (loss) on short-term investments	648			648
Net loss	(18,417)				(18,417)
Balance at Mar. 31, 2020	53,058	$ 25	232,114	686	(179,767)
Balance (in shares) at Mar. 31, 2020		24,820,070
Balance at Dec. 31, 2019	69,608	$ 25	230,895	38	(161,350)
Balance (in shares) at Dec. 31, 2019		24,811,567
Unrealized gain (loss) on short-term investments	85
Net loss	(54,152)
Balance at Sep. 30, 2020	24,695	$ 25	240,049	123	(215,502)
Balance (in shares) at Sep. 30, 2020		24,912,516
Balance at Mar. 31, 2020	53,058	$ 25	232,114	686	(179,767)
Balance (in shares) at Mar. 31, 2020		24,820,070
Issuance of common stock warrants	4,712		4,712
Share-based compensation expense	1,453		1,453
Exercise of stock options	41		41
Exercise of stock options, shares		25,728
Unrealized gain (loss) on short-term investments	(370)			(370)
Net loss	(18,657)				(18,657)
Balance at Jun. 30, 2020	40,237	$ 25	238,320	316	(198,424)
Balance (in shares) at Jun. 30, 2020		24,845,798
Share-based compensation expense	1,505		1,505
Exercise of stock options	224		224
Exercise of stock options, shares		66,718
Unrealized gain (loss) on short-term investments	(193)			(193)
Net loss	(17,078)				(17,078)
Balance at Sep. 30, 2020	24,695	$ 25	240,049	123	(215,502)
Balance (in shares) at Sep. 30, 2020		24,912,516
Balance at Dec. 31, 2020	$ 6,118	$ 25	241,649	12	(235,568)
Balance (in shares) at Dec. 31, 2020	24,976,142	24,976,142
Share-based compensation expense	$ 1,791		1,791
Exercise of stock options	235		235
Exercise of stock options, shares		217,015
Unrealized gain (loss) on short-term investments	(2)			(2)
Net loss	(18,715)				(18,715)
Balance at Mar. 31, 2021	(10,573)	$ 25	243,675	10	(254,283)
Balance (in shares) at Mar. 31, 2021		25,193,157
Balance at Dec. 31, 2020	$ 6,118	$ 25	241,649	12	(235,568)
Balance (in shares) at Dec. 31, 2020	24,976,142	24,976,142
Exercise of stock options, shares	571,257
Unrealized gain (loss) on short-term investments	$ (14)
Net loss	(63,727)
Balance at Sep. 30, 2021	$ (43,167)	$ 26	256,104	(2)	(299,295)
Balance (in shares) at Sep. 30, 2021	26,438,767	26,438,767
Balance at Mar. 31, 2021	$ (10,573)	$ 25	243,675	10	(254,283)
Balance (in shares) at Mar. 31, 2021		25,193,157
Share-based compensation expense	1,611		1,611
Exercise of stock options	120		120
Exercise of stock options, shares		60,975
Sale of shares under Open Market Sale Agreement, net	5,718	$ 1	5,717
Sale of shares under open market sale agreement, shares		665,279
Unrealized gain (loss) on short-term investments	(7)			(7)
Net loss	(22,386)				(22,386)
Balance at Jun. 30, 2021	(25,517)	$ 26	251,123	3	(276,669)
Balance (in shares) at Jun. 30, 2021		25,919,411
Share-based compensation expense	1,870		1,870
Exercise of stock options	890		890
Exercise of stock options, shares		293,267
Sale of shares under Open Market Sale Agreement, net	2,221		2,221
Sale of shares under open market sale agreement, shares		(226,089)
Unrealized gain (loss) on short-term investments	(5)			(5)
Net loss	(22,626)				(22,626)
Balance at Sep. 30, 2021	$ (43,167)	$ 26	$ 256,104	$ (2)	$ (299,295)
Balance (in shares) at Sep. 30, 2021	26,438,767	26,438,767

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities:
Net loss	$ (63,727)	$ (54,152)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	314	272
Noncash interest expense	4,882	3,625
Share-based compensation expense	5,272	4,168
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	1,171	2,089
Other assets	7	212
Accounts payable	2,035	68
Accrued expense and other liabilities	(466)	631
Cash used in operating activities	(50,512)	(43,087)
Investing activities:
Purchases of short-term investments	(67,183)	(53,650)
Proceeds from sales of short-term investments	53,000	73,750
Purchase of property and equipment	(230)	(411)
Cash provided by (used in) investing activities	(14,413)	19,689
Financing activities:
Proceeds from royalty purchase agreement	57,500	20,000
Proceeds from Open Market Sale Agreement, net	7,939
Proceeds from exercise of stock options	1,246	274
Cash provided by financing activities	66,685	20,274
Net increase (decrease) in cash and cash equivalents	1,760	(3,124)
Cash and cash equivalents at beginning of period	15,872	18,356
Cash and cash equivalents at end of period	17,632	15,232
Supplemental schedule of non-cash financing activities:
Issuance of warrants in conjunction with amendment to the royalty purchase agreement		$ 4,712
Purchase of property and equipment included in accounts payable and accrued expenses	$ 7

Organization and Description of

Organization and Description of Business	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Organization and description of business Galera Therapeutics, Inc. was incorporated as a Delaware corporation on November 19, 2012 (inception) and together with its subsidiaries (the Company, or Galera) is a clinical stage biopharmaceutical company focused on developing and commercializing a pipeline of novel, proprietary therapeutics that have the potential to transform radiotherapy in cancer. Galera's technology consists of selective small molecule dismutase mimetics that are in late-stage development in patients with cancer. Avasopasem manganese (GC4419, also referred to as avasopasem) is in development for radiotherapy-induced toxicities, including severe oral mucositis (SOM) in patients with locally advanced head and neck cancer (HNC) and esophagitis in patients with lung cancer. In February 2018, the U.S. Food and Drug Administration (FDA) granted Breakthrough Therapy Designation to avasopasem for the reduction of SOM induced by radiotherapy with or without systemic therapy. Galera’s second dismutase mimetic product candidate, rucosopasem manganese (GC4711, also referred to as rucosopasem), is in clinical-stage development to augment the anti-cancer efficacy of stereotactic body radiation therapy (SBRT) in patients with non-small cell lung cancer (NSCLC) and locally advanced pancreatic cancer (LAPC). In October 2021, the Company announced topline results from a Phase 3 trial (referred to as the ROMAN trial) evaluating avasopasem for radiotherapy-induced SOM in patients with locally advanced HNC. The trial demonstrated relative reductions in the incidence, duration and severity of SOM but did not achieve statistical significance in the primary endpoint of reduction in incidence of SOM. In September 2021, the Company announced final results from its Phase 1/2 pilot trial of avasopasem versus placebo in patients with unresectable or borderline resectable LAPC, who are undergoing SBRT. In this proof-of-concept trial, survival and tumor outcome benefits were observed. Avasopasem is also being studied in a Phase 2a multi-center trial in Europe assessing the safety of avasopasem in patients with head and neck cancer undergoing standard of care radiotherapy and in a Phase 2a trial for its ability to reduce the incidence of radiotherapy-induced esophagitis in patients with lung cancer. The Company is continuing to analyze the results of the ROMAN trial and is evaluating next steps for its programs focused on the reduction of radiotherapy-induced toxicity. In addition to developing avasopasem for the reduction of normal tissue toxicity from radiotherapy, the Company is developing its dismutase mimetics to increase the anti-cancer efficacy of higher daily doses of radiotherapy, including SBRT. The Company’s second dismutase mimetic product candidate, rucosopasem, is being developed to increase the anti-cancer efficacy of SBRT and has successfully completed Phase 1 trials of intravenous rucosopasem in healthy volunteers. The Company leveraged its observations from the pilot Phase 1/2 safety and anti-cancer efficacy trial of avasopasem in combination with SBRT in patients with LAPC to prepare rucosopasem clinical trials in combination with SBRT. The Company is currently evaluating rucosopasem in combination with SBRT in a Phase 1/2 safety and anti-cancer efficacy trial in NSCLC and a Phase 2b trial of rucosopasem in combination with SBRT in patients with LAPC. Liquidity The Company has incurred recurring losses and negative cash flows from operations since inception and has an accumulated deficit of $ 299.3 million as of September 30, 2021. The Company anticipates incurring additional losses until such time, if ever, that it can generate significant sales of its product candidates currently in development. The Company expects its existing cash, cash equivalents and short-term investments as of September 30, 2021 will enable the Company to fund its operating expenses and capital expenditure requirements into 2023, assuming limited future development and commercial activities for avasopasem during this period. These assumptions may change as a result of many factors currently unknown to the Company, including without limitation the results of further analyses of data from the ROMAN trial and potential next steps for the Company’s radiotherapy-induced toxicity programs. In the future, if the Company is not able to continue to raise sufficient capital to fund its operations, the Company may decide to delay or discontinue certain activities, including planned research and development activities, hiring plans, manufacturing activities and commercial preparation efforts. In December 2020, the Company filed a registration statement with the Securities and Exchange Commission (SEC) which covers the offering, issuance and sale of up to $ 200.0 million of the Company’s securities, which includes an Open Market Sale Agreement with Jefferies LLC (the Sales Agreement) covering the offering, issuance and sale of up to a maximum aggregate offering price of $ 50.0 million of the Company’s common stock, which could be utilized to raise funding for future operating expenses and capital expenditure requirements. During the nine months ended September 30, 2021 , we sold approximately 0.9 million shares of common stock and received net proceeds of approximately $ 7.9 million pursuant to the Sales Agreement. As of September 30, 2021 , there remains approximately $ 41.7 million available under the Sales Agreement. See Note 8.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	2. Basis of presentation and significant accounting policies The summary of significant accounting policies disclosed in the Company’s annual consolidated financial statements for the years ended December 31, 2020 and 2019 included in the Company’s annual report on Form 10-K filed with the SEC on March 11, 2021 have not materially changed, except as set forth below. Basis of presentation and consolidation The accompanying unaudited interim consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (U.S. GAAP) for interim financial information. Any reference in these notes to applicable guidance is meant to refer to U.S. GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (FASB). In the opinion of management, the accompanying interim consolidated financial statements include all normal and recurring adjustments (which consist primarily of accruals, estimates and assumptions that impact the financial statements) considered necessary to present fairly the Company’s financial position as of September 30, 2021 and its results of operations for the three and nine months ended September 30, 2021 and 2020, and statements of changes in stockholder’s equity (deficit) and cash flows for the nine months ended September 30, 2021 and 2020. Operating results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021, or for any future period. The interim consolidated financial statements, presented herein, do not contain the required disclosures under U.S. GAAP for annual financial statements. Therefore, these interim consolidated financial statements should be read in conjunction with the annual audited consolidated financial statements and related notes as of and for the year ended December 31, 2020 , included in the Company’s annual report on Form 10-K and filed with the SEC on March 11, 2021. Use of estimates The preparation of unaudited interim consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the unaudited interim consolidated financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Estimates and assumptions are periodically reviewed and the effects of revisions are reflected in the unaudited interim consolidated financial statements in the period they are determined to be necessary. Significant areas that require management’s estimates include share-based compensation assumptions, royalty purchase liability assumptions and accrued research and development expenses. Research and development expenses Research and development costs are expensed as incurred and consist primarily of funds paid to third parties for the provision of services for product candidate development, clinical and preclinical development and related supply and manufacturing costs, and regulatory compliance costs. The Company accrues and expenses preclinical studies and clinical trial activities performed by third parties based upon estimates of the proportion of work completed over the term of the individual trial and patient enrollment rates in accordance with agreements with clinical research organizations and clinical trial sites. The Company determines the estimates by reviewing contracts, vendor agreements and purchase orders, and through discussions with internal clinical personnel and external service providers as to the progress or stage of completion of trials or services and the agreed-upon fee to be paid for such services. However, actual costs and timing of clinical trials are highly uncertain, subject to risks and may change depending upon a number of factors, including the Company’s clinical development plan. Management makes estimates of the Company’s accrued expenses as of each balance sheet date in the Company’s consolidated financial statements based on facts and circumstances known to the Company at that time. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Nonrefundable advance payments for goods and services, including fees for process development or manufacturing and distribution of clinical supplies that will be used in future research and development activities, are deferred and recognized as expense in the period that the related goods are consumed or services are performed. In September 2020, the Company was awarded a Small Business Innovation Research grant from the National Cancer Institute of the National Institutes of Health, which will partially fund its Phase 1/2 safety and anti-cancer efficacy trial for rucosopasem in NSCLC (the Grant). Costs entitled to reimbursement under the Grant are accounted for as a reduction to research and development expenses. During the nine months ended September 30, 2021 , the Company recorded a reduction to research and development expense of $ 0.3 million for expenses for which it has been reimbursed, or is entitled to reimbursement, under the Grant. Net loss per share Basic loss per share of common stock is computed by dividing net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during each period. Diluted loss per share of common stock includes the effect, if any, from the potential exercise or conversion of securities, such as stock options and common stock warrants, which would result in the issuance of incremental shares of common stock. For diluted net loss per share, the weighted-average number of shares of common stock is the same for basic net loss per share due to the fact that when a net loss exists, dilutive securities are not included in the calculation as the impact is anti-dilutive. The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares of common stock outstanding, as they would be anti-dilutive: September 30, 2021 2020 Stock options 4,782,729 4,475,467 Common stock warrants 550,661 550,661 5,333,390 5,026,128 COVID-19 update The COVID-19 pandemic and related precautions have directly or indirectly impacted the timeline for some of the Company’s clinical trials. In April 2020, the Company delayed the initiation of the Phase 2a multi-center trial in Europe assessing the safety of avasopasem in patients with HNC undergoing standard-of-care radiotherapy, or EUSOM trial, due to concerns with patient enrollment. The first patient was dosed in this trial in June 2020, and target enrollment was decreased to approximately 35 patients due to the delay. This trial was expected to contribute to the safety database for avasopasem in patients with HNC receiving radiotherapy. As a result of the delay in initiating the trial in Europe, the target enrollment for the ROMAN trial was increased to approximately 450 patients to ensure the Company was positioned to maintain the overall planned size of the safety database in a timely manner. The Company reported topline data from the ROMAN trial in October 2021 and expects to report topline data from the EUSOM trial in the fourth quarter of 2021. In September 2020, the Company initiated a pilot Phase 2 clinical trial of avasopasem to evaluate its ability to improve 28-day mortality in hospitalized patients who are critically ill with COVID-19. The trial aimed to enroll up to 50 hospitalized adult patients critically ill with COVID-19 at several sites across the U.S. On June 16, 2021, the Company ceased enrolling subjects in this trial. Enrollment in the trial was limited at the three centers that participated. Due to the overall decline in COVID-related hospitalizations in the U.S. at the time, the Company determined that it was not feasible to complete the trial. Recent accounting pronouncements In December 2019, FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in Topic 740 related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The new guidance also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill and allocating consolidated income taxes to separate financial statements of entities not subject to income tax. This ASU is effective for fiscal years beginning after December 15, 2020, including interim periods therein. Upon adoption, the Company must apply certain aspects of this standard retrospectively for all periods presented while other aspects are applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. The Company adopted this ASU on January 1, 2021. There is no impact to the Company’s consolidated financial statements.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair value measurements The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels:  Level 1 Inputs: Unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date.  Level 2 Inputs: Other than quoted prices included in Level 1 inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability.  Level 3 Inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at measurement date. The following table presents the Company’s assets and liabilities that are measured at fair value on a recurring basis (amounts in thousands): September 30, 2021 (Level 1) (Level 2) (Level 3) Assets Money market funds and U.S. Treasury obligations $ 13,519 $ — $ — Short-term investments U.S. government agency securities $ — $ 5,447 $ — U.S. Treasury obligations 65,626 — — Total short-term investments $ 65,626 $ 5,447 $ — December 31, 2020 (Level 1) (Level 2) (Level 3) Assets Money market funds and U.S. Treasury obligations $ 14,943 $ — $ — Short-term investments U.S. government agency securities $ — $ 5,062 $ — U.S. Treasury obligations 51,842 — — Total short-term investments $ 51,842 $ 5,062 $ — There were no changes in valuation techniques during the nine months ended September 30, 2021 . Certain of the Company’s short-term investment instruments are classified using Level 1 inputs within the fair value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. The fair value of Level 2 securities is estimated based on observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term on the assets or liabilities.

Property and Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Property and Equipment	4. Property and equipment Property and equipment consist of (amounts in thousands): September 30, December 31, Laboratory equipment $ 1,332 $ 1,135 Computer hardware and software 292 260 Leasehold improvements 264 264 Furniture and fixtures 173 173 Property and equipment, gross 2,061 1,832 Less: Accumulated depreciation ( 1,123 ) ( 809 ) Property and equipment, net $ 938 $ 1,023 Depreciation expense was $ 0.3 million and $ 0.3 million for the nine months ended September 30, 2021 and 2020 , respectively.

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Accrued Expenses	5. Accrued expenses Accrued expenses consist of (amounts in thousands): September 30, December 31, Compensation and related benefits $ 1,984 $ 2,632 Research and development expenses 5,986 5,525 Professional fees and other expenses 302 427 $ 8,272 $ 8,584

Royalty Purchase Liability

Royalty Purchase Liability	9 Months Ended
	Sep. 30, 2021
Royalty Purchase Liability [Abstract]
Royalty Purchase Liability	6. Royalty purchase liability In November 2018, the Company entered into an Amended and Restated Purchase and Sale Agreement (the Royalty Agreement), with Clarus IV Galera Royalty AIV, L.P., Clarus IV-A, L.P., Clarus IV-B, L.P., Clarus IV-C, L.P. and Clarus IV-D, L.P. (collectively, Blackstone or Blackstone Life Sciences). Pursuant to the Royalty Agreement, Blackstone agreed to pay up to $ 80.0 million (the Royalty Purchase Price) in four tranches of $ 20.0 million each upon the achievement of specific Phase 3 clinical trial patient enrollment milestones. The Company received the first tranche of the Royalty Purchase Price in November 2018, the second tranche of the Royalty Purchase Price in April 2019, and the third tranche of the Royalty Purchase Price in February 2020, in each case in connection with the achievement of the first three milestones, respectively. In May 2020, the Company entered into Amendment No. 1 to the Royalty Agreement (the Amendment) with Clarus IV Galera Royalty AIV, L.P. (the Blackstone Purchaser). The Blackstone Purchaser is affiliated with Blackstone Life Sciences, the successor in interest to Clarus Ventures. The Amendment increased the Royalty Purchase Price by $ 37.5 million, to $ 117.5 million by increasing the fourth tranche from $ 20.0 million to $ 37.5 million and adding a new $ 20.0 million tranche upon the achievement of an additional clinical enrollment milestone. The Company accounted for the Amendment as a debt modification and is amortizing fees paid to the Blackstone Purchaser related to the Amendment over the estimated term of the royalty purchase liability utilizing the effective-interest method. In June 2021, the Company received the new tranche ($ 20.0 million) of the Amendment in connection with the enrollment of the first patient in a Phase 2b trial of rucosopasem in combination with SBRT in patients with locally advanced pancreatic cancer, which the Company refers to as the GRECO-2 trial. Also in June 2021, the Company completed enrollment in the ROMAN trial, thereby achieving the milestone associated with the fourth tranche ($ 37.5 million) of the Amendment, which was received in July 2021. The Company accounts for the Royalty Agreement as a debt instrument. The $ 117.5 million in proceeds received as of September 30, 2021 have been recorded as a liability on the accompanying consolidated balance sheets. Interest expense is imputed based on the estimated royalty repayment period described below, which takes into consideration the probability and timing of obtaining FDA approval and the potential future revenue from commercializing its product candidates, and which results in a corresponding increase in the liability balance. As the Company continues to evaluate the next steps for its programs focused on the reduction of radiotherapy-induced toxicity, planned or possible next steps may have a material impact on the royalty purchase liability. The Company recogni zed $ 2.3 million and $ 1.2 million in noncash interest expense during the three months ended September 30, 2021 and 2020 , respectively, and $ 4.9 million and $ 3.6 million i n noncash interest expense during the nine months ended September 30, 2021 and 2020, respectively. As of September 30, 2021, the effective interest rate was 8.3 %. Pursuant to the Royalty Agreement and the Amendment, in connection with the payment of each tranche of the Royalty Purchase Price, the Company has agreed to sell, convey, transfer and assign to Blackstone all of its right, title and interest in a high single-digit percentage of (i) worldwide net sales of avasopasem, rucosopasem, and any pharmaceutical product comprising or containing avasopasem or rucosopasem (collectively, the Products) and (ii) all amounts received by the Company or its affiliates, licensees and sublicensees with respect to Product-related damages (collectively, the Product Payments) during the Royalty Period. The Royalty Period means, on a Product-by-Product and country-by-country basis, the period of time commencing on the commercial launch of such Product in such country and ending on the latest to occur of (i) the 12th anniversary of such commercial launch, (ii) the expiration of all valid claims of the Company’s patents covering such Product in such country, and (iii) the expiration of regulatory data protection or market exclusivity or similar regulatory protection afforded by the health authorities in such country, to the extent such protection or exclusivity effectively prevents generic versions of such Product from entering the market in such country. The Royalty Agreement and the Amendment will remain in effect until the date on which the aggregate amount of the Product Payments paid to Blackstone exceeds a fixed single-digit multiple of the actual amount of the Royalty Purchase Price received by the Company, unless earlier terminated pursuant to the mutual written agreement of the Company and Blackstone. If no Products are commercialized, the Company would not have an obligation to make Product Payments to Blackstone, which is the sole mechanism for repaying the liability. Upon execution of the Amendment, the Company issued common stock warrants to the Blackstone Purchaser, each of which became exercisable upon the receipt by the Company of the applicable specified milestone payment. The issued warrants expire six years after the initial exercise dates, as follows: Shares Exercise Price Initial Exercise Date Expiration Date New Milestone Warrant 293,686 $ 13.62 6/7/2021 6/6/2027 Fourth Milestone Warrant 256,975 $ 13.62 7/19/2021 7/18/2027 The warrants are equity-classified and were valued at $ 4.7 million using the Black-Scholes valuation technique. The warrants were recorded as a discount to the royalty purchase liability. The Company will amortize the debt discount to interest expense over the estimated term of the royalty purchase liability utilizing the effective-interest method.

Leases

Leases	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Leases	7. Leases The Company has non-cancelable operating leases for office and laboratory space in Malvern, Pennsylvania and Creve Coeur, Missouri which, as of September 30, 2021 , have remaining lease terms of approximately 1.4 and 0.3 years, respectively. The discount rate used to account for the Company’s operating leases under FASB ASU No. 2018-11, Leases (Topic 842), is the Company’s estimated incremental borrowing rate of 5.3 %. Supplemental balance sheet information related to leases was as follows: September 30, December 31, 2021 2020 Operating Leases Right-of-use lease assets $ 374 $ 530 Lease liabilities, current 271 238 Lease liabilities, net of current portion 110 296 Total operating lease liabilities $ 381 $ 534 The components of lease expense were as follows: Three months ended Nine Months Ended 2021 2020 2021 2020 Operating lease costs Operating lease rental expense $ 76 $ 76 $ 225 $ 225 Interest on lease liabilities 5 8 18 27 Total operating lease expense $ 81 $ 84 $ 243 $ 252 Supplemental cash flow information related to leases was as follows: Nine Months Ended 2021 2020 Cash paid for amounts included in the measurement of lease Operating cash flows from operating leases $ 245 $ 344 Right-of-use assets obtained in exchange for lease obligation Operating leases 70 — Future minimum rental payments under the Company’s non-cancelable operating lease liabilities as of September 30, 2021 (amounts in thousands): Remainder of 2021 $ 83 2022 266 2023 44 Total 393 Less: imputed interest ( 12 ) $ 381

Equity

Equity	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Equity	8. Equity Equity offerings In December 2020, the Company entered into the Sales Agreement with Jefferies LLC (Jefferies) as sales agent, pursuant to which it may, from time to time, issue and sell common stock with an aggregate value of up to $ 50.0 million in “at-the-market” (ATM) offerings under the Company’s Registration Statement on Form S-3 (File No. 333-251061) filed with the SEC on December 1, 2020. Sales of common stock, if any, pursuant to the Sales Agreement, may be made in sales deemed to be an “at the market offering” as defined in Rule 415(a) of the Securities Act, including sales made directly through the Nasdaq Global Market or on any other existing trading market for the Company’s common stock. The Company is required to pay Jefferies a commission equal to three percent of the gross sales proceeds and has provided Jefferies with customary indemnification rights. During the three and nine months ended September 30, 2021 , 226,089 and 891,368 shares were sold under the Sales Agreement at a weighted average price per share of $ 10.23 and $ 9.27 , respectively. Net proceeds to the Company after deducting fees, commissions and other expenses related to the offering were approximately $ 2.2 million and $ 7.9 million for the three and nine months ended September 30, 2021, respectively. As of September 30, 2021 , there was approximately $ 41.7 million of available capacity under the Sales Agreement. Share-based compensation In connection with the Company’s IPO, in November 2019, the Company’s board of directors adopted and the Company’s stockholders approved the Galera Therapeutics, Inc. 2019 Incentive Award Plan (the 2019 Plan), which became effective upon the effectiveness of the registration statement on Form S-1 for the IPO. Upon effectiveness of the 2019 Plan, the Company ceased granting new awards under the Prior Plan (as defined herein). The 2019 Plan provides for the grant of incentive stock options, nonstatutory stock options, restricted stock awards, restricted stock units, stock appreciation rights and other stock-based awards. The number of shares of common stock initially available for issuance under the 2019 Plan was 1,948,970 shares of common stock plus the number of shares subject to awards outstanding under the Prior Plan that expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased by the Company on or after the effective date of the 2019 Plan. In addition, the number of shares of common stock available for issuance under the 2019 Plan is subject to an annual increase on the first day of each calendar year beginning on January 1, 2020 and ending on and including January 1, 2029 equal to the lesser of (i) 4 % of the Company’s outstanding shares of common stock on the final day of the immediately preceding calendar year, and (ii) such smaller number of shares of common stock as determined by the Company’s board of directors. Pursuant to this provision, the Company added 992,463 shares to the total shares available for issuance under the 2019 Plan effective January 1, 2020 and added an additional 999,045 shares to the total shares available for issuance under the 2019 Plan effective January 1, 2021. The maximum number of shares of common stock that may be issued under the 2019 Plan upon the exercise of incentive stock options is 14,130,029 . In November 2019, the Company’s board of directors adopted and the Company’s stockholders approved the Galera Therapeutics, Inc. 2019 Employee Stock Purchase Plan (the ESPP). The ESPP allows employees to buy Company stock through after-tax payroll deductions at a discount from market value. The number of shares of common stock initially available for issuance under the ESPP was 243,621 shares of common stock. In addition, the number of shares of common stock available for issuance under the ESPP is subject to an annual increase on the first day of each calendar year beginning on January 1, 2020 and ending on and including January 1, 2029 equal to the lesser of (i) 1 % of the Company’s outstanding shares of common stock on the final day of the immediately preceding calendar year and (ii) such smaller number of shares of common stock as determined by the Company’s board of directors, provided that not more than 3,288,886 shares of common stock may be issued under the ESPP. Pursuant to this provision, the Company added 248,115 shares to the total shares available for issuance under the ESPP effective January 1, 2020 and added an additional 249,761 shares to the total shares available for issuance under the ESPP effective January 1, 2021. In November 2012, the Company adopted the Equity Incentive Plan (the Prior Plan). The total number of shares subject to outstanding awards under the Prior Plan as of September 30, 2021 wa s 2,198,670 . No share s remain available for issuance under the Prior Plan and no further grants will be made under the Prior Plan; however, the Prior Plan continues to govern awards that are outstanding under it. The Company’s stock option awards vest based on the terms in the governing agreements and generally vest over four years and have a term of 10 years . Share-based compensation expense was as follows for the three and nine months ended September 30, 2021 and 2020 (in thousands): Three months ended Nine months ended 2021 2020 2021 2020 Research and development $ 790 $ 662 $ 2,141 $ 1,923 General and administrative 1,080 843 3,131 2,245 $ 1,870 $ 1,505 $ 5,272 $ 4,168 The following table summarizes the activity related to stock option grants for the nine months ended September 30, 2021: Shares Weighted Weighted- Outstanding at January 1, 2021 4,463,078 $ 7.40 Granted 1,318,852 11.07 Exercised ( 571,257 ) 2.18 Forfeited ( 427,944 ) 12.40 Outstanding at September 30, 2021 4,782,729 $ 8.59 7.3 Vested and exercisable at September 30, 2021 2,599,164 $ 6.36 6.0 Vested and expected to vest at September 30, 2021 4,782,729 $ 8.59 7.3 As of September 30, 2021, the unrecognized compensation cos t was $ 17.6 million and will be recognized over an estimated weighted-average amortization period of 2.7 years. The aggregate intrinsic value of options outstanding and options exercisable as of September 30, 2021 was $ 8.4 million and $ 8.1 million, respectively. Options granted during the nine months ended September 30, 2021 and 2020 had weighted-average grant-date fair values of $ 8.26 and $ 10.45 per share, respectively. The fair value of options is estimated using the Black-Scholes option pricing model, which takes into account inputs such as the exercise price, the estimated fair value of the underlying common stock at the grant date, expected term, expected stock price volatility, risk-free interest rate and dividend yield. The fair value of stock options during the nine months ended September 30, 2021 and 2020 was determined using the methods and assumptions discussed below.  The expected term of employee stock options with service-based vesting is determined using the “simplified” method, as prescribed in SEC’s Staff Accounting Bulletin (SAB) No. 107, whereby the expected life equals the arithmetic average of the vesting term and the original contractual term of the option due to the Company’s lack of sufficient historical data. The expected term of nonemployee options is equal to the contractual term.  The expected stock price volatility is based on historical volatilities of comparable public entities within the Company’s industry which were commensurate with the expected term assumption as described in SAB No. 107.  The risk-free interest rate is based on the interest rate payable on U.S. Treasury securities in effect at the time of grant for a period that is commensurate with the expected term.  The expected dividend yield is 0 % because the Company has not historically paid, and does not expect for the foreseeable future to pay, a dividend on its common stock.  The Company’s board of directors has determined the price per share value of the Company’s common stock based on the closing price as reported by the NASDAQ Global Market on the date of the grant. The grant date fair value of each option grant was estimated throughout the nine months ended September 30, 2021 and 2020 using the Black-Scholes option-pricing model with the following weighted-average assumptions: Nine months ended 2021 2020 Expected term (in years) 6.2 6.2 Expected stock price volatility 90.4 % 89.3 % Risk-free interest rate 0.69 % 1.26 % Expected dividend yield 0 % 0 %

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2021
Related Party Transactions [Abstract]
Related Party Transactions	9. Related party transactions IntellectMap provides information technology advisory services to the Company. The chief executive officer of IntellectMap is the brother of the Company’s chief executive officer. Fees incurred by the Company with respect to IntellectMap during the nine months ended September 30, 2021 and 2020 were $ 0.2 million an d $ 0.2 million, respectively.

Subsequent events

Subsequent events	9 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent events	10. Subsequent events ROMAN Phase 3 Trial Results On October 19, 2021, the Company announced topline results from the Phase 3 ROMAN trial designed to evaluate the ability of avasopasem to reduce radiotherapy-induced SOM in patients with locally advanced HNC. The trial demonstrated relative reductions in the incidence, duration and severity of SOM but did not achieve statistical significance in the primary endpoint of reduction in incidence of SOM. The Company is continuing to analyze the results and is evaluating next steps for its programs focused on the reduction of radiotherapy-induced toxicity. Possible or planned next steps may have an impact on the Company's consolidated financial statements, including amounts recorded for the royalty purchase liability, and such impact may be material.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Liquidity	Liquidity The Company has incurred recurring losses and negative cash flows from operations since inception and has an accumulated deficit of $ 299.3 million as of September 30, 2021. The Company anticipates incurring additional losses until such time, if ever, that it can generate significant sales of its product candidates currently in development. The Company expects its existing cash, cash equivalents and short-term investments as of September 30, 2021 will enable the Company to fund its operating expenses and capital expenditure requirements into 2023, assuming limited future development and commercial activities for avasopasem during this period. These assumptions may change as a result of many factors currently unknown to the Company, including without limitation the results of further analyses of data from the ROMAN trial and potential next steps for the Company’s radiotherapy-induced toxicity programs. In the future, if the Company is not able to continue to raise sufficient capital to fund its operations, the Company may decide to delay or discontinue certain activities, including planned research and development activities, hiring plans, manufacturing activities and commercial preparation efforts. In December 2020, the Company filed a registration statement with the Securities and Exchange Commission (SEC) which covers the offering, issuance and sale of up to $ 200.0 million of the Company’s securities, which includes an Open Market Sale Agreement with Jefferies LLC (the Sales Agreement) covering the offering, issuance and sale of up to a maximum aggregate offering price of $ 50.0 million of the Company’s common stock, which could be utilized to raise funding for future operating expenses and capital expenditure requirements. During the nine months ended September 30, 2021 , we sold approximately 0.9 million shares of common stock and received net proceeds of approximately $ 7.9 million pursuant to the Sales Agreement. As of September 30, 2021 , there remains approximately $ 41.7 million available under the Sales Agreement. See Note 8.
Basis of Presentation and Consolidation	Basis of presentation and consolidation The accompanying unaudited interim consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (U.S. GAAP) for interim financial information. Any reference in these notes to applicable guidance is meant to refer to U.S. GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (FASB). In the opinion of management, the accompanying interim consolidated financial statements include all normal and recurring adjustments (which consist primarily of accruals, estimates and assumptions that impact the financial statements) considered necessary to present fairly the Company’s financial position as of September 30, 2021 and its results of operations for the three and nine months ended September 30, 2021 and 2020, and statements of changes in stockholder’s equity (deficit) and cash flows for the nine months ended September 30, 2021 and 2020. Operating results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021, or for any future period. The interim consolidated financial statements, presented herein, do not contain the required disclosures under U.S. GAAP for annual financial statements. Therefore, these interim consolidated financial statements should be read in conjunction with the annual audited consolidated financial statements and related notes as of and for the year ended December 31, 2020 , included in the Company’s annual report on Form 10-K and filed with the SEC on March 11, 2021.
Use of Estimates	Use of estimates The preparation of unaudited interim consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the unaudited interim consolidated financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Estimates and assumptions are periodically reviewed and the effects of revisions are reflected in the unaudited interim consolidated financial statements in the period they are determined to be necessary. Significant areas that require management’s estimates include share-based compensation assumptions, royalty purchase liability assumptions and accrued research and development expenses.
Research and Development Expenses	Research and development expenses Research and development costs are expensed as incurred and consist primarily of funds paid to third parties for the provision of services for product candidate development, clinical and preclinical development and related supply and manufacturing costs, and regulatory compliance costs. The Company accrues and expenses preclinical studies and clinical trial activities performed by third parties based upon estimates of the proportion of work completed over the term of the individual trial and patient enrollment rates in accordance with agreements with clinical research organizations and clinical trial sites. The Company determines the estimates by reviewing contracts, vendor agreements and purchase orders, and through discussions with internal clinical personnel and external service providers as to the progress or stage of completion of trials or services and the agreed-upon fee to be paid for such services. However, actual costs and timing of clinical trials are highly uncertain, subject to risks and may change depending upon a number of factors, including the Company’s clinical development plan. Management makes estimates of the Company’s accrued expenses as of each balance sheet date in the Company’s consolidated financial statements based on facts and circumstances known to the Company at that time. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Nonrefundable advance payments for goods and services, including fees for process development or manufacturing and distribution of clinical supplies that will be used in future research and development activities, are deferred and recognized as expense in the period that the related goods are consumed or services are performed. In September 2020, the Company was awarded a Small Business Innovation Research grant from the National Cancer Institute of the National Institutes of Health, which will partially fund its Phase 1/2 safety and anti-cancer efficacy trial for rucosopasem in NSCLC (the Grant). Costs entitled to reimbursement under the Grant are accounted for as a reduction to research and development expenses. During the nine months ended September 30, 2021 , the Company recorded a reduction to research and development expense of $ 0.3 million for expenses for which it has been reimbursed, or is entitled to reimbursement, under the Grant.
Net Loss Per Share	Net loss per share Basic loss per share of common stock is computed by dividing net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during each period. Diluted loss per share of common stock includes the effect, if any, from the potential exercise or conversion of securities, such as stock options and common stock warrants, which would result in the issuance of incremental shares of common stock. For diluted net loss per share, the weighted-average number of shares of common stock is the same for basic net loss per share due to the fact that when a net loss exists, dilutive securities are not included in the calculation as the impact is anti-dilutive. The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares of common stock outstanding, as they would be anti-dilutive: September 30, 2021 2020 Stock options 4,782,729 4,475,467 Common stock warrants 550,661 550,661 5,333,390 5,026,128
COVID-19 Update	COVID-19 update The COVID-19 pandemic and related precautions have directly or indirectly impacted the timeline for some of the Company’s clinical trials. In April 2020, the Company delayed the initiation of the Phase 2a multi-center trial in Europe assessing the safety of avasopasem in patients with HNC undergoing standard-of-care radiotherapy, or EUSOM trial, due to concerns with patient enrollment. The first patient was dosed in this trial in June 2020, and target enrollment was decreased to approximately 35 patients due to the delay. This trial was expected to contribute to the safety database for avasopasem in patients with HNC receiving radiotherapy. As a result of the delay in initiating the trial in Europe, the target enrollment for the ROMAN trial was increased to approximately 450 patients to ensure the Company was positioned to maintain the overall planned size of the safety database in a timely manner. The Company reported topline data from the ROMAN trial in October 2021 and expects to report topline data from the EUSOM trial in the fourth quarter of 2021. In September 2020, the Company initiated a pilot Phase 2 clinical trial of avasopasem to evaluate its ability to improve 28-day mortality in hospitalized patients who are critically ill with COVID-19. The trial aimed to enroll up to 50 hospitalized adult patients critically ill with COVID-19 at several sites across the U.S. On June 16, 2021, the Company ceased enrolling subjects in this trial. Enrollment in the trial was limited at the three centers that participated. Due to the overall decline in COVID-related hospitalizations in the U.S. at the time, the Company determined that it was not feasible to complete the trial.
Recent Accounting Pronouncements	Recent accounting pronouncements In December 2019, FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in Topic 740 related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The new guidance also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill and allocating consolidated income taxes to separate financial statements of entities not subject to income tax. This ASU is effective for fiscal years beginning after December 15, 2020, including interim periods therein. Upon adoption, the Company must apply certain aspects of this standard retrospectively for all periods presented while other aspects are applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. The Company adopted this ASU on January 1, 2021. There is no impact to the Company’s consolidated financial statements.

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Dilutive Securities Excluded from Computation of Diluted Weighted Average Shares of Common Stock Outstanding	The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares of common stock outstanding, as they would be anti-dilutive: September 30, 2021 2020 Stock options 4,782,729 4,475,467 Common stock warrants 550,661 550,661 5,333,390 5,026,128

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table presents the Company’s assets and liabilities that are measured at fair value on a recurring basis (amounts in thousands): September 30, 2021 (Level 1) (Level 2) (Level 3) Assets Money market funds and U.S. Treasury obligations $ 13,519 $ — $ — Short-term investments U.S. government agency securities $ — $ 5,447 $ — U.S. Treasury obligations 65,626 — — Total short-term investments $ 65,626 $ 5,447 $ — December 31, 2020 (Level 1) (Level 2) (Level 3) Assets Money market funds and U.S. Treasury obligations $ 14,943 $ — $ — Short-term investments U.S. government agency securities $ — $ 5,062 $ — U.S. Treasury obligations 51,842 — — Total short-term investments $ 51,842 $ 5,062 $ —

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Schedule of Property Plant and Equipment	Property and equipment consist of (amounts in thousands): September 30, December 31, Laboratory equipment $ 1,332 $ 1,135 Computer hardware and software 292 260 Leasehold improvements 264 264 Furniture and fixtures 173 173 Property and equipment, gross 2,061 1,832 Less: Accumulated depreciation ( 1,123 ) ( 809 ) Property and equipment, net $ 938 $ 1,023

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of (amounts in thousands): September 30, December 31, Compensation and related benefits $ 1,984 $ 2,632 Research and development expenses 5,986 5,525 Professional fees and other expenses 302 427 $ 8,272 $ 8,584

Royalty purchase liability (Tab

Royalty purchase liability (Tables)	9 Months Ended
	Sep. 30, 2021
Royalty Purchase Liability [Abstract]
Schedule of Common Stock Warrants	Upon execution of the Amendment, the Company issued common stock warrants to the Blackstone Purchaser, each of which became exercisable upon the receipt by the Company of the applicable specified milestone payment. The issued warrants expire six years after the initial exercise dates, as follows: Shares Exercise Price Initial Exercise Date Expiration Date New Milestone Warrant 293,686 $ 13.62 6/7/2021 6/6/2027 Fourth Milestone Warrant 256,975 $ 13.62 7/19/2021 7/18/2027

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Summary of Supplemental Balance Sheet Information Related to Leases	Supplemental balance sheet information related to leases was as follows: September 30, December 31, 2021 2020 Operating Leases Right-of-use lease assets $ 374 $ 530 Lease liabilities, current 271 238 Lease liabilities, net of current portion 110 296 Total operating lease liabilities $ 381 $ 534
Summary of Components of Lease Expense	The components of lease expense were as follows: Three months ended Nine Months Ended 2021 2020 2021 2020 Operating lease costs Operating lease rental expense $ 76 $ 76 $ 225 $ 225 Interest on lease liabilities 5 8 18 27 Total operating lease expense $ 81 $ 84 $ 243 $ 252
Summary of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases was as follows: Nine Months Ended 2021 2020 Cash paid for amounts included in the measurement of lease Operating cash flows from operating leases $ 245 $ 344 Right-of-use assets obtained in exchange for lease obligation Operating leases 70 —
Summary of Future Minimum Rental Payments Under Non Cancelable Operating Leases	Future minimum rental payments under the Company’s non-cancelable operating lease liabilities as of September 30, 2021 (amounts in thousands): Remainder of 2021 $ 83 2022 266 2023 44 Total 393 Less: imputed interest ( 12 ) $ 381

Equity (Tables)

Equity (Tables)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Summary of Share-based Compensation Expense	Share-based compensation expense was as follows for the three and nine months ended September 30, 2021 and 2020 (in thousands): Three months ended Nine months ended 2021 2020 2021 2020 Research and development $ 790 $ 662 $ 2,141 $ 1,923 General and administrative 1,080 843 3,131 2,245 $ 1,870 $ 1,505 $ 5,272 $ 4,168
Summary of Activity Related to Stock Option Grants	The following table summarizes the activity related to stock option grants for the nine months ended September 30, 2021: Shares Weighted Weighted- Outstanding at January 1, 2021 4,463,078 $ 7.40 Granted 1,318,852 11.07 Exercised ( 571,257 ) 2.18 Forfeited ( 427,944 ) 12.40 Outstanding at September 30, 2021 4,782,729 $ 8.59 7.3 Vested and exercisable at September 30, 2021 2,599,164 $ 6.36 6.0 Vested and expected to vest at September 30, 2021 4,782,729 $ 8.59 7.3
Summary of Fair Value of Each Option Grant Estimated Throughout Year Using Black-Scholes Option-pricing Model	The grant date fair value of each option grant was estimated throughout the nine months ended September 30, 2021 and 2020 using the Black-Scholes option-pricing model with the following weighted-average assumptions: Nine months ended 2021 2020 Expected term (in years) 6.2 6.2 Expected stock price volatility 90.4 % 89.3 % Risk-free interest rate 0.69 % 1.26 % Expected dividend yield 0 % 0 %

Organization and description _2

Organization and description of business - Additional Information (Details) - USD ($) $ in Thousands, shares in Millions	1 Months Ended	9 Months Ended
	Dec. 31, 2020	Sep. 30, 2021
Organization And Description Of Business [Line Items]
Date of incorporation		Nov. 19, 2012
Accumulated deficit	$ (235,568)	$ (299,295)
Open Market Sale Agreement
Organization And Description Of Business [Line Items]
Number of shares sold		0.9
Net proceeds from common stock		$ 7,900
Proceeds from issuance of remaining common stock		$ 41,700
Open Market Sale Agreement | Jefferies LLC
Organization And Description Of Business [Line Items]
Maximum Offering Issuance And Sale Expense Covered In Company Securities	200,000
Maximum Aggregate Offering Price	$ 50,000

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies - Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2021USD ($)
Accounting Policies [Abstract]
Reduction to research and development expense	$ 0.3

Basis of Presentation and Sig_5

Basis of Presentation and Significant Accounting Policies - Dilutive Securities Excluded from Computation of Diluted Weighted Average Shares of Common Stock Outstanding (Details) - shares	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities excluded from computation of earnings per share	5,333,390	5,026,128
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities excluded from computation of earnings per share	4,782,729	4,475,467
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities excluded from computation of earnings per share	550,661	550,661

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Level 1 | Money Market Funds and U.S. Treasury Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, at fair value	$ 13,519	$ 14,943
Level 1 | U.S. government securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	0	0
Level 1 | U.S. government treasuries
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	65,626	51,842
Level 1 | Short- Term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	65,626	51,842
Level 2 | Money Market Funds and U.S. Treasury Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, at fair value	0	0
Level 2 | U.S. government securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	5,447	5,062
Level 2 | U.S. government treasuries
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	0	0
Level 2 | Short- Term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	5,447	5,062
Level 3 | Money Market Funds and U.S. Treasury Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, at fair value	0	0
Level 3 | U.S. government securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	0	0
Level 3 | U.S. government treasuries
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	0	0
Level 3 | Short- Term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	$ 0	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details)	9 Months Ended
	Sep. 30, 2021USD ($)
Fair Value Disclosures [Abstract]
Changes in valuation techniques	$ 0

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 2,061	$ 1,832
Less: Accumulated depreciation	(1,123)	(809)
Property and equipment, net	938	1,023
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,332	1,135
Computer Hardware and Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	292	260
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	264	264
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 173	$ 173

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Depreciation	$ 314	$ 272

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Compensation and related benefits	$ 1,984	$ 2,632
Research and development expenses	5,986	5,525
Professional fees and other expenses	302	427
Accrued expenses	$ 8,272	$ 8,584

Royalty Purchase Liability - Ad

Royalty Purchase Liability - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 30, 2018	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jul. 31, 2021	Jun. 30, 2021	Dec. 31, 2020	May 31, 2020
Royalty Purchase Liability [Line Items]
Total agreed amount of royalty purchase price		$ 125,751		$ 125,751				$ 63,369
Royalty purchase price				57,500	$ 20,000
Noncash interest expense				$ 4,882	3,625
Warrant expiration term		6 years		6 years
Fair value of equity classified warrants		$ 4,700		$ 4,700
Royalty Agreements
Royalty Purchase Liability [Line Items]
Total agreed amount of royalty purchase price	$ 80,000
Royalty purchase price				117,500
Outstanding amount of royalty agreement									$ 20,000
Noncash interest expense		$ 2,300	$ 1,200	$ 4,900	$ 3,600
Effective interest rate		8.30%		8.30%
Royalty Agreements | First Tranche
Royalty Purchase Liability [Line Items]
Royalty purchase price	$ 20,000
Royalty Agreements | Fifth Tranche
Royalty Purchase Liability [Line Items]
Outstanding amount of royalty agreement							$ 20,000
Royalty Agreements | Fourth Tranche
Royalty Purchase Liability [Line Items]
Outstanding amount of royalty agreement						$ 37,500
Amended Royalty Agreements
Royalty Purchase Liability [Line Items]
Total agreed amount of royalty purchase price									117,500
Outstanding amount of royalty agreement									37,500
Amended Royalty Agreements | Fifth Tranche
Royalty Purchase Liability [Line Items]
Outstanding amount of royalty agreement									$ 20,000

Royalty Purchase Liability - Sc

Royalty Purchase Liability - Schedule of Common Stock Warrants (Details)	9 Months Ended
	Sep. 30, 2021$ / sharesshares
New Milestone Warrant
Class of Warrant or Right [Line Items]
Class of warrant, shares issued | shares	293,686
Exercise price | $ / shares	$ 13.62
Initial Exercise Date	Jun. 7, 2021
Expiration Date	Jun. 6, 2027
Fourth Milestone Warrant
Class of Warrant or Right [Line Items]
Class of warrant, shares issued | shares	256,975
Exercise price | $ / shares	$ 13.62
Initial Exercise Date	Jul. 19, 2021
Expiration Date	Jul. 18, 2027

Leases - Additional Information

Leases - Additional Information (Details) - ASC 842	Sep. 30, 2021
Lessee Lease Description [Line Items]
Operating lease, discount rate	5.30%
Office
Lessee Lease Description [Line Items]
Non-cancelable operating lease, term	1 year 4 months 24 days
Laboratory Space
Lessee Lease Description [Line Items]
Non-cancelable operating lease, term	3 months 18 days

Leases - Summary of Balance She

Leases - Summary of Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Right-of-use lease assets	$ 374	$ 530
Lease liabilities, current	271	238
Lease liabilities, net of current portion	110	296
Total operating lease liabilities	$ 381	$ 534

Leases - Summary of Components

Leases - Summary of Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating lease rental expense	$ 76	$ 76	$ 225	$ 225
Interest on lease liabilities	5	8	18	27
Total operating lease expense	$ 81	$ 84	$ 243	$ 252

Leases - Summary of Supplementa

Leases - Summary of Supplemental Cash Flow Information Related to Lease (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating cash flows from operating leases	$ 245	$ 344
Right-of-use assets obtained in exchange for lease obligation
Operating leases	$ 70

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Rental Payments Under Non Cancelable Operating Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Remainder of 2021	$ 83
2022	266
2023	44
Total	393
Less: imputed interest	(12)
Operating lease liabilities	$ 381	$ 534

Equity - Additional Information

Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended	9 Months Ended
	Dec. 31, 2020	Nov. 30, 2019	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost			$ 17.6	$ 17.6
Estimated recognition weighted-average amortization period				2 years 8 months 12 days
Aggregate intrinsic value of options outstanding			8.4	$ 8.4
Aggregate intrinsic value of options exercisable			$ 8.1	$ 8.1
Weighted-average grant-date fair values of options granted				$ 8.26	$ 10.45
Expected dividend yield				0.00%	0.00%
2019 Incentive Award Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Sale of shares under ATM, Shares		992,463		999,045
Number of shares of common stock initially available for issuance		1,948,970
Percentage of shares of common stock outstanding		4.00%
2019 Incentive Award Plan | Common Stock | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued under the plan		14,130,029
2019 Employee Stock Purchase Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Sale of shares under ATM, Shares		248,115		249,761
Percentage of shares of common stock outstanding		1.00%
Number of shares available for issuance		243,621
2019 Employee Stock Purchase Plan | Common Stock | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued under the plan		3,288,886
2012 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance			0	0
Number of shares authorized			2,198,670	2,198,670
Vesting period				4 years
Term of award				10 years
At-the-market Offering [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate value of common stock sale under ATM offering	$ 50			$ 41.7
Commission to agent as percentage of ATM offering proceeds				3.00%
Sale of shares under ATM, Shares			226,089	891,368
Weighted average price per share			$ 10.23	$ 9.27
Net proceeds from common stock			$ 2.2	$ 7.9

Equity - Summary of Share-based

Equity - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 1,870	$ 1,505	$ 5,272	$ 4,168
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	790	662	2,141	1,923
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 1,080	$ 843	$ 3,131	$ 2,245

Equity - Summary of Activity Re

Equity - Summary of Activity Related to Stock Option Grants (Details) - $ / shares	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Shares, Outstanding beginning balance	4,463,078
Shares, Granted	1,318,852
Shares, Exercised	(571,257)
Shares, Forfeited	(427,944)
Shares, Outstanding ending balance	4,782,729
Shares, Vested and exercisable	2,599,164
Shares, Vested and expected to vest	4,782,729
Weighted average exercise price per share, Outstanding beginning balance	$ 7.40
Weighted average exercise price per share, Granted	11.07
Weighted average exercise price per share, Exercised	2.18
Weighted average exercise price per share, Forfeited	12.40
Weighted average exercise price per share, Outstanding ending balance	8.59
Weighted average exercise price per share, Vested and exercisable	6.36
Weighted average exercise price per share, Vested and expected to vest	$ 8.59
Weighted average remaining contractual life, Outstanding	7 years 3 months 18 days
Weighted average remaining contractual life, Vested and exercisable	6 years
Weighted average remaining contractual life, Vested and expected to vest	7 years 3 months 18 days

Equity - Summary of Fair Value

Equity - Summary of Fair Value of Each Option Grant Estimated Throughout Year Using Black-Scholes Option-pricing Model (Details)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)	6 years 2 months 12 days	6 years 2 months 12 days
Expected stock price volatility	90.40%	89.30%
Risk-free interest rate	0.69%	1.26%
Expected dividend yield	0.00%	0.00%

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
IntellectMap
Related Party Transaction [Line Items]
Advisory services fees	$ 0.2	$ 0.2