Galera Therapeutics (GRTX) 10-K 11 Mar 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Mar. 05, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
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
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		24,976,142
Entity File Number	001-39114
Entity Incorporation State 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 Annual Report	true
Document Transition Report	false
Entity Voluntary Filers	No
Document Fiscal Period Focus	FY
Entity Ex Transition Period	true
ICFR Auditor Attestation Flag	false
Entity Public Float			$ 111.6
Entity Well-known Seasoned Issuer	No
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement, relating to its 2021 Annual Meeting of Stockholders to be filed with the Securities and Exchange Commission are incorporated by reference into Part III of this Annual Report on Form 10-K.

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 15,872	$ 18,356
Short-term investments	56,904	93,934
Prepaid expenses and other current assets	5,153	5,280
Total current assets	77,929	117,570
Property and equipment, net	1,023	934
Acquired intangible asset	2,258	2,258
Goodwill	881	881
Right-of-use lease assets	530	815
Other assets	1,477	918
Total assets	84,098	123,376
Current liabilities:
Accounts payable	5,146	3,945
Accrued expenses	8,584	5,452
Lease liabilities	238	297
Total current liabilities	13,968	9,694
Royalty purchase liability	63,369	43,251
Lease liabilities, net of current portion	296	534
Deferred tax liability	273	289
Other liabilities	74
Total liabilities	77,980	53,768
Commitments (Note 8)
Stockholders’ equity:
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; 24,976,142 and 24,811,567 shares issued and outstanding at December 31, 2020 and 2019, respectively.	25	25
Additional paid-in capital	241,649	230,895
Accumulated other comprehensive income	12	38
Accumulated deficit	(235,568)	(161,350)
Total stockholders’ equity	6,118	69,608
Total liabilities and stockholders’ equity	$ 84,098	$ 123,376

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
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)	24,976,142	24,976,142
Common stock, shares outstanding (shares)	24,811,567	24,811,567

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating expenses:
Research and development	$ 54,845	$ 42,333
General and administrative	15,708	8,358
Loss from operations	(70,553)	(50,691)
Other income (expenses):
Interest income	1,174	1,823
Interest expense	(4,880)	(3,031)
Foreign currency gain (loss)	25	(40)
Loss before income tax benefit	(74,234)	(51,939)
Income tax benefit	16	9
Net loss	(74,218)	(51,930)
Accretion of redeemable convertible preferred stock to redemption value		(7,176)
Net loss attributable to common stockholders	$ (74,218)	$ (59,106)
Net loss per share of common stock, basic and diluted	$ (2.98)	$ (16.31)
Weighted-average shares of common stock outstanding, basic and diluted	24,869,770	3,625,005

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (74,218)	$ (51,930)
Unrealized gain (loss) on short-term investments	(26)	35
Comprehensive loss	$ (74,244)	$ (51,895)

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (loss)	Accumulated Deficit
Balance at Dec. 31, 2018	$ (104,820)				$ 3	$ (104,823)
Balance (in shares) at Dec. 31, 2018		96,385,795
Balance at Dec. 31, 2018		$ 165,902
Balance (in shares) at Dec. 31, 2018			300,597
Share-based compensation expense	2,390			$ 2,390
Accretion of redeemable convertible preferred stock to redemption value	(7,178)	7,178		(2,581)		(4,597)
Conversion of redeemable convertible preferred stock into common stock	173,080	$ (173,080)	$ 19	173,061
Conversion of redeemable convertible preferred stock into common stock, shares		(96,385,795)	19,061,502
Sale of common stock in initial public offering, net of issuance costs of $7.3 million	58,021		$ 6	58,015
Sale of common stock in initial public offering, net of issuance costs, shares			5,445,690
Exercise of stock options	$ 10			10
Exercise of stock options, shares	3,778		3,778
Unrealized gain (loss) on short-term investments	$ 35				35
Net loss	(51,930)					(51,930)
Balance at Dec. 31, 2019	$ 69,608		$ 25	230,895	38	(161,350)
Balance (in shares) at Dec. 31, 2019	24,811,567		24,811,567
Issuance of common stock warrants	$ 4,712			4,712
Share-based compensation expense	5,536			5,536
Exercise of stock options	$ 506			506
Exercise of stock options, shares	164,575		164,575
Unrealized gain (loss) on short-term investments	$ (26)				(26)
Net loss	(74,218)					(74,218)
Balance at Dec. 31, 2020	$ 6,118		$ 25	$ 241,649	$ 12	$ (235,568)
Balance (in shares) at Dec. 31, 2020	24,811,567		24,976,142

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Statement Of Stockholders Equity [Abstract]
Sale of common stock in initial public offering, issuance costs	$ 7.3

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating activities:
Net loss	$ (74,218)	$ (51,930)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	368	267
Noncash interest expense	4,880	3,031
Share-based compensation expense	5,536	2,390
Reserve for tax incentive receivable		241
Deferred tax liability	(16)	(9)
Deferred rent		4
Changes in operating assets and liabilities:
Tax incentive receivable		629
Prepaid expenses and other current assets	127	(3,815)
Other assets	(274)	(421)
Accounts payable	1,201	77
Accrued expense	2,859	2,875
Cash used in operating activities	(59,537)	(46,661)
Investing activities:
Purchases of short-term investments	(67,746)	(123,192)
Proceeds from sales of short-term investments	104,750	96,000
Purchase of property and equipment	(457)	(633)
Cash provided by (used in) investing activities	36,547	(27,825)
Financing activities:
Proceeds from royalty purchase agreement	20,000	20,000
Proceeds from the sale of common stock in an initial public offering, net of issuance costs		58,021
Proceeds from exercise of stock options	506	10
Cash provided by financing activities	20,506	78,031
Net (decrease) increase in cash and cash equivalents	(2,484)	3,545
Cash and cash equivalents at beginning of year	18,356	14,811
Cash and cash equivalents at end of year	15,872	18,356
Supplemental schedule of non-cash financing activities:
Accretion of redeemable convertible preferred stock to redemption value		7,178
Issuance of warrants in conjunction with amendment to the Royalty Purchase Agreement	4,712
Deferred offering costs included in accounts payable and accrued expenses	$ 240
Conversion of redeemable convertible preferred stock into common stock		173,080
Initial recognition of operating lease right-of-use asset and operating lease liability		$ 1,084

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2020
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. The Company’s lead product candidate, avasopasem manganese (GC4419, also referred to as avasopasem), is a potent and highly selective small molecule dismutase mimetic being developed for the reduction of severe oral mucositis (SOM). 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. The Company is currently evaluating avasopasem in a Phase 3 registrational trial (referred to as the ROMAN trial) for its ability to reduce the incidence and severity of SOM induced by radiotherapy in patients with locally advanced head and neck cancer (HNC), its lead indication. It 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 esophagitis induced by radiotherapy in patients with lung cancer. 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 stereotactic body radiation therapy (SBRT). The Company’s second dismutase mimetic product candidate, GC4711, is being developed to increase the anti-cancer efficacy of SBRT and has successfully completed Phase 1 trials of intravenous GC4711 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 locally advanced pancreatic cancer to prepare GC4711 clinical trials in combination with SBRT. The Company is currently evaluating GC4711 in combination with SBRT in a Phase 1/2 safety and anti-cancer efficacy trial in non-small cell lung cancer and plans to initiate a Phase 2b trial of GC4711 in combination with SBRT in patients with locally advanced pancreatic cancer. Liquidity The Company has incurred recurring losses and negative cash flows from operations since inception and has an accumulated deficit of $235.6 million as of December 31, 2020. 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 December 31, 2020, together with the expected payments from Blackstone Life Sciences (formerly known as Clarus Ventures) in the amount of $57.5 million upon the achievement of certain clinical enrollment milestones in the ROMAN trial and the anti-cancer program in combination with SBRT under the Royalty Agreement and the Amendment (each as defined below), will enable the Company to fund its operating expenses and capital expenditure requirements into the second half of 2022. If the Company is not able to meet the clinical enrollment milestones in the near term, and expected payments from Blackstone Life Sciences are delayed, the Company would delay certain expenditures. This may include delaying planned programs, delaying hiring plans, delaying manufacturing activities, and delaying commercial preparation efforts, which will enable the Company to fund its operating expenses and capital expenditure requirement into the second quarter of 2022. In December 2020, the Company filed a registration statement with the SEC which covers the offering, issuance and sale of up to $200.0 million in Company securities, which includes an Open Market Sale Agreement with Jefferies LLC 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. See Note 2 and Note 6.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	2. Basis of presentation and significant accounting policies Basis of presentation and consolidation The accompanying consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (U.S. GAAP). 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). The consolidated financial statements include the accounts of Galera Therapeutics, Inc. and its wholly owned subsidiaries, Galera Therapeutics Australia Pty Ltd (Galera Australia) and Galera Labs, LLC. All intercompany accounts and transactions have been eliminated in consolidation. The Company has determined the functional currency of Galera Australia to be the U.S. dollar. The Company records remeasurement gains and losses on monetary assets and liabilities, such as accounts payable, which are not denominated in U.S. dollars in the statements of operations. The Company manages its operations as a single reportable segment for the purposes of assessing performance and making operating decisions. Use of estimates The preparation of 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 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 consolidated financial statements in the period they are determined to be necessary. Significant areas that require management’s estimates include the fair value of common stock prior to the IPO, share-based compensation assumptions, royalty purchase liability assumptions and accrued clinical trial expense. Fair value of financial instruments Management believes that the carrying amounts of the Company’s financial instruments, including accounts payable and accrued expenses, approximate fair value due to the short-term nature of those instruments. Short-term investments are recorded at their estimated fair value. The royalty purchase liability is accounted for as debt and interest is accreted over the expected repayment period which approximates fair value. Concentration of credit risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents and short-term investments. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash and cash equivalents. Cash and cash equivalents The Company considers all highly liquid investments that have maturities of three months or less when acquired to be cash equivalents. Cash and cash equivalents as of December 31, 2020 and 2019 consisted of bank deposits, U.S. Treasury obligations and a money market mutual fund invested in U.S. Treasury obligations. Short-term investments Short-term investments consist of debt securities with a maturity of greater than three months when acquired. The Company classifies its short-term investments at the time of purchase as available-for-sale securities, net of unrealized losses of $26,000 and unrealized gains of $35,000 during the years ended December 31, 2020 and 2019, respectively. Available-for-sale securities are carried at fair value. Unrealized gains and losses on available-for-sale securities are reported in accumulated other comprehensive income (loss), a component of stockholders’ equity, until realized. Property and equipment Property and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives ranging from three to five years. Leasehold improvements are amortized over the shorter of their economic lives or the remaining lease term. The costs of maintenance and repairs are expensed as incurred. Improvements and betterments that add new functionality or extend the useful life of the asset are capitalized. Impairment of long-lived assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated undiscounted future cash flows, then an impairment charge is recognized for the amount by which the carrying value of the asset exceeds the estimated fair value of the asset. As of December 31, 2020, the Company believes that no revision of the remaining useful lives or write-down of long-lived assets is required. Goodwill and acquired intangible asset In November 2012, the Company completed a Series A redeemable convertible preferred stock (Series A) financing with venture capital investors and simultaneously acquired Galera Therapeutics, LLC (LLC), a limited liability company incorporated in Missouri in 2009. LLC was renamed Galera Labs, LLC in January 2013 and operates as a wholly-owned subsidiary of the Company. The Company applied the purchase method of accounting under which the consideration given to the LLC members and noteholders was allocated to the fair value of the net assets assumed from the LLC at the date of the acquisition. The sole intangible asset acquired represented the fair value of in-process research and development (IPR&D) which has been recorded on the accompanying consolidated balance sheet as an indefinite life intangible asset. A deferred tax liability was recorded for the difference between the fair value of the acquired IPR&D and its tax basis of zero which was recognized as goodwill in applying the purchase method of accounting. Intangible assets related to IPR&D are considered indefinite-lived intangible assets and, along with goodwill, are not amortized, but are assessed for impairment annually or more frequently if impairment indicators exist. For those compounds that reach commercialization, the IPR&D assets will be amortized over their estimated useful lives. If the associated research and development effort related to IPR&D is abandoned, the related assets will be written-off and the Company will record a noncash impairment loss on its consolidated statements of operations. For the years ended December 31 , 20 20 and 201 9 , the Company determined that there was no impairment to goodwill or IPR&D. 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. The proceeds received have been recorded as long-term debt obligations. Interest expense on such obligation is imputed by estimating risk adjusted future royalty payments over the term of the Royalty Agreement which takes into consideration the probability of obtaining FDA approval. Other significant assumptions include adjustments to estimated gross revenues to arrive at net product sales from which a royalty payment can be estimated. The non-cash interest expense recorded increases the balance of the royalty obligation. The royalty obligation will be reduced when royalty payments are made, if any. 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. Actual royalty payments are highly uncertain and may change depending on a number of factors, including the Company’s ability to obtain FDA approval, successfully commercialize the Company’s product candidates and the timing of future royalty payments. The Company imputes interest expense on the royalty purchase obligations based on such factors at each reporting period. As these factors change, the Company will adjust its estimate of the imputed interest expense accordingly. Leases At lease commencement, the Company records a lease liability based on the present value of lease payments over the expected lease term including any options to extend the lease that the Company is reasonably certain to exercise. The Company calculates the present value of lease payments using an incremental borrowing rate as the Company’s leases do not provide an implicit interest rate. The Company’s incremental borrowing rate for a lease is the rate of interest it would have to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. At the lease commencement date, the Company records a corresponding right-of-use lease asset based on the lease liability, adjusted for any lease incentives received and any initial direct costs paid to the lessor prior to the lease commencement date. The Company may enter into leases with an initial term of 12 months or less (Short-Term Leases). For Short-Term Leases, the Company records the rent expense on a straight-line basis and does not record the leases on the balance sheet. The Company had no Short-Term Leases as of December 31, 2020 and 2019. After lease commencement, the Company measures its leases as follows: (i) the lease liability based on the present value of the remaining lease payments using the discount rate determined at lease commencement, and (ii) the right-of-use lease asset based on the remeasured lease liability, adjusted for any unamortized lease incentives received, any unamortized initial direct costs and the cumulative difference between rent expense and amounts paid under the lease agreement. Any lease incentives received and any initial direct costs are amortized on a straight-line basis over the expected lease term. Rent expense is recorded on a straight-line basis over the expected lease term. 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 in NSCLC (the Grant). Costs entitled to reimbursement under the Grant are accounted for as a reduction to research and development expenses. During the year ended December 31, 2020, the Company recorded a reduction to research and development expense of $0.7 million for expenses for which it has been reimbursed, or is entitled to reimbursement, under the Grant. Share-based compensation The Company measures share-based awards at their grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the awards. Estimating the fair value of share-based awards requires the input of subjective assumptions, including the estimated fair value of the Company’s common stock prior to the IPO, and, for stock options, the expected life of the options and stock price volatility. The Company accounts for forfeitures of stock option awards as they occur. The Company uses the Black-Scholes option pricing model to value its stock option awards. The assumptions used in estimating the fair value of share-based awards represent management’s estimate and involve inherent uncertainties and the application of management’s judgment. As a result, if factors change and management uses different assumptions, share-based compensation expense could be materially different for future awards. The expected life of the stock options is estimated using the “simplified method,” as the Company has limited historical information from which to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior for its stock option grants. The simplified method is the midpoint between the vesting period and the contractual term of the option. For stock price volatility, the Company uses comparable public companies as a basis for its expected volatility to calculate the fair value of option grants. The risk-free rate is based on the U.S. Treasury yield curve commensurate with the expected life of the option. Employee Benefit Plan The Company sponsors a 401(k) defined contribution plan for its employees. Employee contributions are voluntary. The Company matches employee contributions in an amount equal to 100% of the first 4% of eligible compensation, and such employer contributions are immediately vested. During the year ended December 31, 2020, the Company provided matching contributions of $0.2 million. Income taxes The Company uses the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, and operating loss and credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. The Company recognizes the benefit of an uncertain tax position that it has taken or expects to take on its income tax return if such a position is more likely than not to be sustained. 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 redeemable convertible preferred stock and stock options, 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: December 31, 2020 2019 Stock options 4,463,078 3,537,946 Common stock warrants 550,661 — 5,013,739 3,537,946 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 in order to ensure we are positioned to maintain the overall planned size of the safety database in a timely manner. The Company has since completed enrollment in the EUSOM trial and will continue to monitor the COVID-19 pandemic in Europe regarding the data readout of this trial, which is expected in the second half of 2021. Completion of enrollment for the ROMAN trial is expected in the first half of 2021 and topline data is expected in the second half of 2021, subject to the continuing impact of the COVID-19 pandemic on the Company’s business. With this change in the ROMAN trial, the assumptions underlying the Company’s calculation of interest expense on its royalty purchase liability have changed. The Company imputes interest expense on its royalty purchase obligations by estimating risk adjusted future royalty payments over the term of the Royalty Agreement, which takes into consideration the probability and timing of obtaining FDA approval and the potential future revenue from commercializing its product candidates. 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 will enroll up to 50 hospitalized adult patients critically ill with COVID-19 at several sites across the U.S. The Company expects to report topline data from this trial in the first half of 2021. Recent accounting pronouncements In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement beginning after December 15, 2019, including interim periods therein. Early adoption is permitted for any eliminated or modified disclosures upon issuance of this ASU. The Company adopt ed this ASU on January 1, 2020 and it did not have a n impact on the Company’s consolidated financial statements . In August 2018, the FASB issued ASU No. 2018-15, Intangibles – Goodwill and Other- Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Service Arrangement that is a Service Contract,

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
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): December 31, 2020 (Level 1) (Level 2) (Level 3) Assets Money market funds and U.S. Treasury obligations (included in cash equivalents) $ 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 $ — December 31, 2019 (Level 1) (Level 2) (Level 3) Assets Money market funds and U.S. Treasury obligations (included in cash equivalents) $ 17,447 $ — $ — Short-term investments U.S. Treasury obligations $ 93,934 $ — $ — There were no changes in valuation techniques during the years ended December 31, 2020 and 2019. 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	12 Months Ended
	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Property and Equipment	4. Property and equipment Property and equipment consist of (amounts in thousands): December 31, 2020 2019 Laboratory equipment $ 1,135 $ 748 Computer hardware and software 260 218 Leasehold improvements 264 262 Furniture and fixtures 173 147 Property and equipment, gross 1,832 1,375 Less: Accumulated depreciation (809 ) (441 ) Property and equipment, net $ 1,023 $ 934 Depreciation expense was $0.4 million and $0.3 million for the years ended December 31, 2020 and 2019, respectively.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2020
Payables And Accruals [Abstract]
Accrued Expenses	5. Accrued expenses Accrued expenses consist of (amounts in thousands): December 31, 2020 2019 Compensation and related benefits $ 2,632 $ 1,160 Research and development expenses 5,525 3,882 Professional fees and other expenses 427 410 $ 8,584 $ 5,452

Royalty Purchase Liability

Royalty Purchase Liability	12 Months Ended
	Dec. 31, 2020
Royalty Purchase Liability [Abstract]
Royalty Purchase Liability	6. Royalty purchase liability 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. In April 2019, the Company received a $20.0 million payment in connection with the achievement of the second milestone under the Royalty Agreement. In February 2020, the Company received a $20.0 million payment in connection with the achievement of the third milestone under the Royalty Agreement. The Company accounts for the Royalty Agreement as a debt instrument. The $60.0 million of proceeds from the first three tranches under the Royalty Agreement 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 results in a corresponding increase in the liability balance. The Company recognized $4.9 million and $3.0 million in noncash interest expense during the years ended December 31, 2020 and 2019, respectively. As of December 31, 2020, the effective interest rate was 8.0%. 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 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. Pursuant to the amended Royalty Agreement, 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 and GC4711 (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 amended Royalty Agreement 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. Upon execution of the Amendment, the Company issued common stock warrants to the Blackstone Purchaser to purchase an aggregate of 550,661 shares of the Company’s common stock with an exercise price of $13.62 per share, each of which will become exercisable upon the receipt by Galera of the applicable specified milestone payment. The issued warrants expire six years after the initial exercise dates. 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	12 Months Ended
	Dec. 31, 2020
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 December 31, 2020, have remaining lease terms of approximately 2.2 and 0.1 years, respectively. The Company adopted FASB ASU No. 2018-11, Leases (Topic 842) Supplemental balance sheet information related to leases was as follows: December 31, 2020 2019 Operating Leases Right-of-use lease assets $ 530 $ 815 Lease liabilities, current 238 297 Lease liabilities, net of current portion 296 534 Total operating lease liabilities $ 534 $ 831 The components of lease expense were as follows: Year ended December 31, 2020 2019 Operating lease costs Operating lease rental expense $ 262 $ 265 Interest on lease liabilities 35 50 Total operating lease expense $ 297 $ 315 Supplemental cash flow information related to leases was as follows: Year ended December 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 445 $ 437 Right-of-use assets obtained in exchange for lease obligation Operating leases — 1,084 Our operating lease liabilities as of December 31, 2020 will mature, as follows (amounts in thousands): 2021 $ 259 2022 260 2023 44 Total 563 Less: imputed interest (29 ) $ 534

Commitments

Commitments	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments	8. Executive employment agreements The Company has entered into employment agreements with certain key executives, providing for compensation and severance in certain circumstances, as described in the respective agreements. Legal matters The Company is subject from time to time to various claims and legal actions arising during the ordinary course of its business. Management believes that there are currently no claims or legal actions that would reasonably be expected to have a material adverse effect on the Company’s results of operations, financial condition or cash flows.

Share-based Compensation

Share-based Compensation	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-based Compensation	9 . 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 December 31, 2020 was 2,840,312. No shares 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. Share-based compensation expense was as follows for the years ended December 31, 2020 and 2019 (in thousands): Year ended December 31, 2020 2019 Research and development $ 2,450 $ 1,163 General and administrative 3,086 1,227 $ 5,536 $ 2,390 The following table summarizes the activity related to stock option grants for the years ended December 31, 2020 and 2019: Shares Weighted average exercise price per share Weighted- average remaining contractual life (years) Outstanding at January 1, 2019 2,071,616 $ 2.17 Granted 1,646,054 8.88 Exercised (3,778 ) 2.60 Forfeited (175,946 ) 4.50 Outstanding at December 31, 2019 3,537,946 5.17 Granted 1,238,573 13.68 Exercised (164,575 ) 3.07 Forfeited (148,866 ) 11.59 Outstanding at December 31, 2020 4,463,078 $ 7.40 7.0 Vested and exercisable at December 31, 2020 2,599,488 $ 4.49 5.8 Vested and expected to vest at December 31, 2020 4,463,078 $ 7.40 7.0 As of December 31, 2020, the unrecognized compensation cost was $15.1 million and will be recognized over an estimated weighted-average remaining amortization period of 2.9 years. The aggregate intrinsic value of options outstanding and options exercisable as of December 31, 2020 was $17.8 million and $16.0 million, respectively. Options granted during the years ended December 31, 2020 and 2019 had weighted-average grant-date fair values of $10.19 and $6.66 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 years ended December 31, 2020 and 2019 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. • Prior to the Company’s IPO, its board of directors had periodically estimated the fair value of the Company’s common stock considering, among other things, contemporaneous valuations of its common stock prepared by an unrelated third-party valuation firm in accordance with the guidance provided by the American Institute of Certified Public Accountants 2013 Practice Aid, Valuation of Privately-Held-Company Equity Securities Issued as Compensation. Since the closing of the IPO, the Company’s board of directors has determined the 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 year using the Black-Scholes option-pricing model using the following weighted-average assumptions: Year ended December 31, 2020 2019 Expected term (in years) 6.2 6.2 Expected stock price volatility 89.5 % 89.7 % Risk-free interest rate 1.17 % 2.26 % Expected dividend yield 0 % 0 %

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes The Company’s loss before income taxes for the years ended December 31, 2020 and 2019 is as follows (in thousands): Year ended December 31, 2020 2019 Domestic $ (73,007 ) $ (49,918 ) Foreign (1,227 ) (2,021 ) $ (74,234 ) $ (51,939 ) The Company’s tax provision (benefit) for the years ended December 31, 2020 and 2019 is summarized as follows (in thousands): Year ended December 31, 2020 2019 Current Federal $ — $ — State — — Foreign — — — — Deferred: Federal — 194 State (16 ) (203 ) Foreign — — (16 ) (9 ) Total income tax benefit $ (16 ) $ (9 ) A reconciliation of the federal income tax rate to the Company’s effective tax rate is as follows: Year ended December 31, 2020 2019 Rate reconciliation: Federal tax benefit at statutory rate 21.0 % 21.0 % State tax, net of federal benefit 5.0 4.3 Net operating loss carryforwards — (0.2 ) Change in tax rate 0.1 (0.6 ) Sale of royalty interest (7.0 ) (8.1 ) Difference in foreign rate 0.2 0.4 Research & development 2.8 4.3 Change in valuation allowance (21.9 ) (19.5 ) Share-based compensation (0.2 ) (0.4 ) Other — (1.2 ) Total provision — % — % The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities were as follows (in thousands): December 31, 2020 2019 Deferred tax assets Net operating loss carryforwards $ 40,324 $ 27,470 Share-based compensation 1,593 511 Research & development credits 7,477 5,073 Accrued expenses and other 98 — Gross deferred tax assets 49,492 33,054 Valuation allowance (48,309 ) (32,062 ) Net deferred tax asset 1,183 992 Deferred tax liabilities Accrued expenses and other (803 ) (613 ) Acquired in-process research and development (653 ) (668 ) Net deferred tax liabilities $ (273 ) $ (289 ) In assessing the need for a valuation allowance, the Company may utilize indefinite-lived deferred tax liabilities from an intangible asset as a future source of income. The Company’s acquired IPR&D intangible asset can be utilized as a source of income arising from the future reversal of temporary differences that can be offset against post 2017 indefinite-lived net operating losses (NOLs). Therefore, the Company is permitted to offset the indefinite-lived deferred tax liability up to the 80 percent limitation for NOLs generated subsequent to January 1, 2018. The following table summarizes carryforwards of federal, state and foreign NOLs as of December 31, 2020 and 2019, respectively (in thousands): December 31, 2020 2019 Combined NOL Carryforwards: Federal $ 135,580 $ 91,472 State 157,506 113,587 Foreign 1,565 1,175 The NOL carryforwards begin expiring in 2032 for federal income tax purposes, and in 2032 for state purposes. Utilization of the NOLs and general business tax credits carryforwards may be subject to a substantial limitation under Sections 382 and 383 of the Internal Revenue Code of 1986 as amended, if certain levels of changes in ownership of the Company have occurred previously or occur in the future. As of December 31, 2020, the Company also has federal and state research and development tax credit carryforwards of $6.2 million that will begin to expire in 2032, unless previously utilized, and foreign research and development tax credit carryforwards of $1.3 million which do not have an expiration date. The NOL and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service and state tax authorities. NOL and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a three-year The Company will recognize interest and penalties related to uncertain tax positions as income tax expense. As of December 31, 2020, the Company had no accrued interest and penalties related to uncertain tax positions and no amounts have been recognized in the Company’s statements of operations. Due to NOL and tax credit carryforwards that remain unutilized, income tax returns from 2017 through 2019 remain subject to examination by the taxing jurisdictions. The NOLs remain subject to review until utilized.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	1 1 . Related party transactions IntellectMap provides IT-advisory services to the Company. The chief executive officer of IntellectMap is the brother of the Company’s chief executive officer. Fees incurred by us with respect to IntellectMap during the years ended December 31, 2020 and 2019 were $0.3 million and $0.3 million, respectively.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
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 $235.6 million as of December 31, 2020. 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 December 31, 2020, together with the expected payments from Blackstone Life Sciences (formerly known as Clarus Ventures) in the amount of $57.5 million upon the achievement of certain clinical enrollment milestones in the ROMAN trial and the anti-cancer program in combination with SBRT under the Royalty Agreement and the Amendment (each as defined below), will enable the Company to fund its operating expenses and capital expenditure requirements into the second half of 2022. If the Company is not able to meet the clinical enrollment milestones in the near term, and expected payments from Blackstone Life Sciences are delayed, the Company would delay certain expenditures. This may include delaying planned programs, delaying hiring plans, delaying manufacturing activities, and delaying commercial preparation efforts, which will enable the Company to fund its operating expenses and capital expenditure requirement into the second quarter of 2022. In December 2020, the Company filed a registration statement with the SEC which covers the offering, issuance and sale of up to $200.0 million in Company securities, which includes an Open Market Sale Agreement with Jefferies LLC 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. See Note 2 and Note 6.
Basis of Presentation and Consolidation	Basis of presentation and consolidation The accompanying consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (U.S. GAAP). 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). The consolidated financial statements include the accounts of Galera Therapeutics, Inc. and its wholly owned subsidiaries, Galera Therapeutics Australia Pty Ltd (Galera Australia) and Galera Labs, LLC. All intercompany accounts and transactions have been eliminated in consolidation. The Company has determined the functional currency of Galera Australia to be the U.S. dollar. The Company records remeasurement gains and losses on monetary assets and liabilities, such as accounts payable, which are not denominated in U.S. dollars in the statements of operations. The Company manages its operations as a single reportable segment for the purposes of assessing performance and making operating decisions.
Use of Estimates	Use of estimates The preparation of 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 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 consolidated financial statements in the period they are determined to be necessary. Significant areas that require management’s estimates include the fair value of common stock prior to the IPO, share-based compensation assumptions, royalty purchase liability assumptions and accrued clinical trial expense.
Fair Value of Financial Instruments	Fair value of financial instruments Management believes that the carrying amounts of the Company’s financial instruments, including accounts payable and accrued expenses, approximate fair value due to the short-term nature of those instruments. Short-term investments are recorded at their estimated fair value. The royalty purchase liability is accounted for as debt and interest is accreted over the expected repayment period which approximates fair value.
Concentration of Credit Risk	Concentration of credit risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents and short-term investments. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash and cash equivalents.
Cash and Cash Equivalents	Cash and cash equivalents The Company considers all highly liquid investments that have maturities of three months or less when acquired to be cash equivalents. Cash and cash equivalents as of December 31, 2020 and 2019 consisted of bank deposits, U.S. Treasury obligations and a money market mutual fund invested in U.S. Treasury obligations.
Short-Term Investments	Short-term investments Short-term investments consist of debt securities with a maturity of greater than three months when acquired. The Company classifies its short-term investments at the time of purchase as available-for-sale securities, net of unrealized losses of $26,000 and unrealized gains of $35,000 during the years ended December 31, 2020 and 2019, respectively. Available-for-sale securities are carried at fair value. Unrealized gains and losses on available-for-sale securities are reported in accumulated other comprehensive income (loss), a component of stockholders’ equity, until realized.
Property and Equipment	Property and equipment Property and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives ranging from three to five years. Leasehold improvements are amortized over the shorter of their economic lives or the remaining lease term. The costs of maintenance and repairs are expensed as incurred. Improvements and betterments that add new functionality or extend the useful life of the asset are capitalized.
Impairment of Long-Lived Assets	Impairment of long-lived assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated undiscounted future cash flows, then an impairment charge is recognized for the amount by which the carrying value of the asset exceeds the estimated fair value of the asset. As of December 31, 2020, the Company believes that no revision of the remaining useful lives or write-down of long-lived assets is required.
Goodwill and Acquired Intangible Asset	Goodwill and acquired intangible asset In November 2012, the Company completed a Series A redeemable convertible preferred stock (Series A) financing with venture capital investors and simultaneously acquired Galera Therapeutics, LLC (LLC), a limited liability company incorporated in Missouri in 2009. LLC was renamed Galera Labs, LLC in January 2013 and operates as a wholly-owned subsidiary of the Company. The Company applied the purchase method of accounting under which the consideration given to the LLC members and noteholders was allocated to the fair value of the net assets assumed from the LLC at the date of the acquisition. The sole intangible asset acquired represented the fair value of in-process research and development (IPR&D) which has been recorded on the accompanying consolidated balance sheet as an indefinite life intangible asset. A deferred tax liability was recorded for the difference between the fair value of the acquired IPR&D and its tax basis of zero which was recognized as goodwill in applying the purchase method of accounting. Intangible assets related to IPR&D are considered indefinite-lived intangible assets and, along with goodwill, are not amortized, but are assessed for impairment annually or more frequently if impairment indicators exist. For those compounds that reach commercialization, the IPR&D assets will be amortized over their estimated useful lives. If the associated research and development effort related to IPR&D is abandoned, the related assets will be written-off and the Company will record a noncash impairment loss on its consolidated statements of operations. For the years ended December 31 , 20 20 and 201 9 , the Company determined that there was no impairment to goodwill or IPR&D.
Royalty Purchase Liability	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. The proceeds received have been recorded as long-term debt obligations. Interest expense on such obligation is imputed by estimating risk adjusted future royalty payments over the term of the Royalty Agreement which takes into consideration the probability of obtaining FDA approval. Other significant assumptions include adjustments to estimated gross revenues to arrive at net product sales from which a royalty payment can be estimated. The non-cash interest expense recorded increases the balance of the royalty obligation. The royalty obligation will be reduced when royalty payments are made, if any. 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. Actual royalty payments are highly uncertain and may change depending on a number of factors, including the Company’s ability to obtain FDA approval, successfully commercialize the Company’s product candidates and the timing of future royalty payments. The Company imputes interest expense on the royalty purchase obligations based on such factors at each reporting period. As these factors change, the Company will adjust its estimate of the imputed interest expense accordingly.
Leases	Leases At lease commencement, the Company records a lease liability based on the present value of lease payments over the expected lease term including any options to extend the lease that the Company is reasonably certain to exercise. The Company calculates the present value of lease payments using an incremental borrowing rate as the Company’s leases do not provide an implicit interest rate. The Company’s incremental borrowing rate for a lease is the rate of interest it would have to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. At the lease commencement date, the Company records a corresponding right-of-use lease asset based on the lease liability, adjusted for any lease incentives received and any initial direct costs paid to the lessor prior to the lease commencement date. The Company may enter into leases with an initial term of 12 months or less (Short-Term Leases). For Short-Term Leases, the Company records the rent expense on a straight-line basis and does not record the leases on the balance sheet. The Company had no Short-Term Leases as of December 31, 2020 and 2019. After lease commencement, the Company measures its leases as follows: (i) the lease liability based on the present value of the remaining lease payments using the discount rate determined at lease commencement, and (ii) the right-of-use lease asset based on the remeasured lease liability, adjusted for any unamortized lease incentives received, any unamortized initial direct costs and the cumulative difference between rent expense and amounts paid under the lease agreement. Any lease incentives received and any initial direct costs are amortized on a straight-line basis over the expected lease term. Rent expense is recorded on a straight-line basis over the expected lease term.
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 in NSCLC (the Grant). Costs entitled to reimbursement under the Grant are accounted for as a reduction to research and development expenses. During the year ended December 31, 2020, the Company recorded a reduction to research and development expense of $0.7 million for expenses for which it has been reimbursed, or is entitled to reimbursement, under the Grant.
Share-Based Compensation	Share-based compensation The Company measures share-based awards at their grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the awards. Estimating the fair value of share-based awards requires the input of subjective assumptions, including the estimated fair value of the Company’s common stock prior to the IPO, and, for stock options, the expected life of the options and stock price volatility. The Company accounts for forfeitures of stock option awards as they occur. The Company uses the Black-Scholes option pricing model to value its stock option awards. The assumptions used in estimating the fair value of share-based awards represent management’s estimate and involve inherent uncertainties and the application of management’s judgment. As a result, if factors change and management uses different assumptions, share-based compensation expense could be materially different for future awards. The expected life of the stock options is estimated using the “simplified method,” as the Company has limited historical information from which to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior for its stock option grants. The simplified method is the midpoint between the vesting period and the contractual term of the option. For stock price volatility, the Company uses comparable public companies as a basis for its expected volatility to calculate the fair value of option grants. The risk-free rate is based on the U.S. Treasury yield curve commensurate with the expected life of the option.
Employee Benefit Plan	Employee Benefit Plan The Company sponsors a 401(k) defined contribution plan for its employees. Employee contributions are voluntary. The Company matches employee contributions in an amount equal to 100% of the first 4% of eligible compensation, and such employer contributions are immediately vested. During the year ended December 31, 2020, the Company provided matching contributions of $0.2 million.
Income Taxes	Income taxes The Company uses the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, and operating loss and credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. The Company recognizes the benefit of an uncertain tax position that it has taken or expects to take on its income tax return if such a position is more likely than not to be sustained.
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 redeemable convertible preferred stock and stock options, 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: December 31, 2020 2019 Stock options 4,463,078 3,537,946 Common stock warrants 550,661 — 5,013,739 3,537,946
Recent Accounting Pronouncements	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 in order to ensure we are positioned to maintain the overall planned size of the safety database in a timely manner. The Company has since completed enrollment in the EUSOM trial and will continue to monitor the COVID-19 pandemic in Europe regarding the data readout of this trial, which is expected in the second half of 2021. Completion of enrollment for the ROMAN trial is expected in the first half of 2021 and topline data is expected in the second half of 2021, subject to the continuing impact of the COVID-19 pandemic on the Company’s business. With this change in the ROMAN trial, the assumptions underlying the Company’s calculation of interest expense on its royalty purchase liability have changed. The Company imputes interest expense on its royalty purchase obligations by estimating risk adjusted future royalty payments over the term of the Royalty Agreement, which takes into consideration the probability and timing of obtaining FDA approval and the potential future revenue from commercializing its product candidates. 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 will enroll up to 50 hospitalized adult patients critically ill with COVID-19 at several sites across the U.S. The Company expects to report topline data from this trial in the first half of 2021. Recent accounting pronouncements In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement beginning after December 15, 2019, including interim periods therein. Early adoption is permitted for any eliminated or modified disclosures upon issuance of this ASU. The Company adopt ed this ASU on January 1, 2020 and it did not have a n impact on the Company’s consolidated financial statements . In August 2018, the FASB issued ASU No. 2018-15, Intangibles – Goodwill and Other- Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Service Arrangement that is a Service Contract,

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
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: December 31, 2020 2019 Stock options 4,463,078 3,537,946 Common stock warrants 550,661 — 5,013,739 3,537,946

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
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): December 31, 2020 (Level 1) (Level 2) (Level 3) Assets Money market funds and U.S. Treasury obligations (included in cash equivalents) $ 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 $ — December 31, 2019 (Level 1) (Level 2) (Level 3) Assets Money market funds and U.S. Treasury obligations (included in cash equivalents) $ 17,447 $ — $ — Short-term investments U.S. Treasury obligations $ 93,934 $ — $ —

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Schedule of Property Plant and Equipment	Property and equipment consist of (amounts in thousands): December 31, 2020 2019 Laboratory equipment $ 1,135 $ 748 Computer hardware and software 260 218 Leasehold improvements 264 262 Furniture and fixtures 173 147 Property and equipment, gross 1,832 1,375 Less: Accumulated depreciation (809 ) (441 ) Property and equipment, net $ 1,023 $ 934

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2020
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of (amounts in thousands): December 31, 2020 2019 Compensation and related benefits $ 2,632 $ 1,160 Research and development expenses 5,525 3,882 Professional fees and other expenses 427 410 $ 8,584 $ 5,452

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Summary of Supplemental Balance Sheet Information Related to Leases	Supplemental balance sheet information related to leases was as follows: December 31, 2020 2019 Operating Leases Right-of-use lease assets $ 530 $ 815 Lease liabilities, current 238 297 Lease liabilities, net of current portion 296 534 Total operating lease liabilities $ 534 $ 831
Summary of Components of Lease Expense	The components of lease expense were as follows: Year ended December 31, 2020 2019 Operating lease costs Operating lease rental expense $ 262 $ 265 Interest on lease liabilities 35 50 Total operating lease expense $ 297 $ 315
Summary of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases was as follows: Year ended December 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 445 $ 437 Right-of-use assets obtained in exchange for lease obligation Operating leases — 1,084
Summary of Operating Leases Liabilities Maturities	Our operating lease liabilities as of December 31, 2020 will mature, as follows (amounts in thousands): 2021 $ 259 2022 260 2023 44 Total 563 Less: imputed interest (29 ) $ 534

Share-based Compensation (Table

Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Share-based Compensation Expense	Share-based compensation expense was as follows for the years ended December 31, 2020 and 2019 (in thousands): Year ended December 31, 2020 2019 Research and development $ 2,450 $ 1,163 General and administrative 3,086 1,227 $ 5,536 $ 2,390
Summary of Activity Related to Stock Option Grants	The following table summarizes the activity related to stock option grants for the years ended December 31, 2020 and 2019: Shares Weighted average exercise price per share Weighted- average remaining contractual life (years) Outstanding at January 1, 2019 2,071,616 $ 2.17 Granted 1,646,054 8.88 Exercised (3,778 ) 2.60 Forfeited (175,946 ) 4.50 Outstanding at December 31, 2019 3,537,946 5.17 Granted 1,238,573 13.68 Exercised (164,575 ) 3.07 Forfeited (148,866 ) 11.59 Outstanding at December 31, 2020 4,463,078 $ 7.40 7.0 Vested and exercisable at December 31, 2020 2,599,488 $ 4.49 5.8 Vested and expected to vest at December 31, 2020 4,463,078 $ 7.40 7.0
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 year using the Black-Scholes option-pricing model using the following weighted-average assumptions: Year ended December 31, 2020 2019 Expected term (in years) 6.2 6.2 Expected stock price volatility 89.5 % 89.7 % Risk-free interest rate 1.17 % 2.26 % Expected dividend yield 0 % 0 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Summary of Company's Loss Before Income Taxes	The Company’s loss before income taxes for the years ended December 31, 2020 and 2019 is as follows (in thousands): Year ended December 31, 2020 2019 Domestic $ (73,007 ) $ (49,918 ) Foreign (1,227 ) (2,021 ) $ (74,234 ) $ (51,939 )
Summary of Company's Tax Provision (Benefit)	The Company’s tax provision (benefit) for the years ended December 31, 2020 and 2019 is summarized as follows (in thousands): Year ended December 31, 2020 2019 Current Federal $ — $ — State — — Foreign — — — — Deferred: Federal — 194 State (16 ) (203 ) Foreign — — (16 ) (9 ) Total income tax benefit $ (16 ) $ (9 )
Summary of Effective Tax Rate of Reconciliation of Federal Income Tax Rate	A reconciliation of the federal income tax rate to the Company’s effective tax rate is as follows: Year ended December 31, 2020 2019 Rate reconciliation: Federal tax benefit at statutory rate 21.0 % 21.0 % State tax, net of federal benefit 5.0 4.3 Net operating loss carryforwards — (0.2 ) Change in tax rate 0.1 (0.6 ) Sale of royalty interest (7.0 ) (8.1 ) Difference in foreign rate 0.2 0.4 Research & development 2.8 4.3 Change in valuation allowance (21.9 ) (19.5 ) Share-based compensation (0.2 ) (0.4 ) Other — (1.2 ) Total provision — % — %
Schedule of Significant Portions of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities were as follows (in thousands): December 31, 2020 2019 Deferred tax assets Net operating loss carryforwards $ 40,324 $ 27,470 Share-based compensation 1,593 511 Research & development credits 7,477 5,073 Accrued expenses and other 98 — Gross deferred tax assets 49,492 33,054 Valuation allowance (48,309 ) (32,062 ) Net deferred tax asset 1,183 992 Deferred tax liabilities Accrued expenses and other (803 ) (613 ) Acquired in-process research and development (653 ) (668 ) Net deferred tax liabilities $ (273 ) $ (289 )
Summary of Carryforwards of Federal, State and Foreign NOLs and Tax Credits	The following table summarizes carryforwards of federal, state and foreign NOLs as of December 31, 2020 and 2019, respectively (in thousands): December 31, 2020 2019 Combined NOL Carryforwards: Federal $ 135,580 $ 91,472 State 157,506 113,587 Foreign 1,565 1,175

Organization and description _2

Organization and description of business - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Organization And Description Of Business [Line Items]
Date of incorporation		Nov. 19, 2012
Accumulated deficit	$ (235,568,000)	$ (235,568,000)	$ (161,350,000)
Expected payments to be received from royalty purchase agreement	57,500,000	57,500,000
Open Market Sale Agreement | Jefferies LLC
Organization And Description Of Business [Line Items]
Maximum offering, issuance and sale expense covered in company securities	200,000,000
Maximum aggregate offering price	$ 50,000,000	$ 50,000,000

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Line Items]
Property, plant and equipment, depreciation methods	straight-line method
Impairment to goodwill	$ 0	$ 0
Reduction to research and development expense	$ 700,000
Defined Contribution Plan, Employer Matching Contribution, Percent	100.00%
Percentage of Employee Eligible for Compensation and Employer Contribution	4.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 200,000
Minimum
Accounting Policies [Line Items]
Property, plant and equipment, estimated useful lives	3 years
Maximum
Accounting Policies [Line Items]
Property, plant and equipment, estimated useful lives	5 years
US Treasury Securities
Accounting Policies [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss	$ 26,000
Unrealized gain on short-term investments		$ 35,000

Royalty Purchase Liability - Ad

Royalty Purchase Liability - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			12 Months Ended
	Feb. 29, 2020	Apr. 30, 2019	Nov. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	May 31, 2020
Royalty Purchase Liability [Line Items]
Royalty purchase liability				$ 63,369	$ 43,251
Proceeds from royalty purchase agreement				20,000	20,000
Total agreed amount of royalty purchase price				63,369	43,251
Royalty purchase price				20,000	20,000
Noncash interest expense				4,880	3,031
Royalty Agreements
Royalty Purchase Liability [Line Items]
Royalty purchase liability			$ 80,000
Proceeds from royalty purchase agreement				60,000
Outstanding amount of royalty agreement						$ 20,000
Total agreed amount of royalty purchase price			80,000
Royalty purchase price				60,000
Noncash interest expense				$ 4,900	$ 3,000
Effective interest rate				8.00%
Royalty Agreements | First Tranche
Royalty Purchase Liability [Line Items]
Proceeds from royalty purchase agreement			20,000
Royalty purchase price			$ 20,000
Royalty Agreements | Second Tranche
Royalty Purchase Liability [Line Items]
Proceeds from royalty purchase agreement		$ 20,000
Royalty purchase price		$ 20,000
Royalty Agreements | Third Tranche
Royalty Purchase Liability [Line Items]
Proceeds from royalty purchase agreement	$ 20,000
Royalty purchase price	$ 20,000
Amended Royalty Agreements
Royalty Purchase Liability [Line Items]
Royalty purchase liability						117,500
Outstanding amount of royalty agreement						37,500
Total agreed amount of royalty purchase price						$ 117,500
Class of warrant, shares issued						550,661
Common stock, exercise price per share						$ 13.62
Fair value of equity classified warrants						$ 4,700
Amended Royalty Agreements | Fifth Tranche
Royalty Purchase Liability [Line Items]
Outstanding amount of royalty agreement						$ 20,000

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	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities excluded from computation of earnings per share	5,013,739	3,537,946
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
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities excluded from computation of earnings per share	4,463,078	3,537,946

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
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	$ 14,943	$ 17,447
Level 1 | U.S. government securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	0
Level 1 | US Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	51,842	93,934
Level 1 | Short- Term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	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	5,062
Level 2 | US Treasury Securities
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	5,062
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
Level 3 | US Treasury Securities
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

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Changes in valuation techniques	$ 0	$ 0

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,832	$ 1,375
Less: Accumulated depreciation	(809)	(441)
Property and equipment, net	1,023	934
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,135	748
Computer Hardware and Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	260	218
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	264	262
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 173	$ 147

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Abstract]
Depreciation	$ 368	$ 267

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Compensation and related benefits	$ 2,632	$ 1,160
Research and development expenses	5,525	3,882
Professional fees and other expenses	427	410
Accrued expenses	$ 8,584	$ 5,452

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Lessee Lease Description [Line Items]
Operating lease liability, non current	$ 296	$ 534
Operating lease, right-of-use asset	$ 530	$ 815
ASC 842
Lessee Lease Description [Line Items]
Operating lease liability, current			$ 300
Operating lease liability, non current			800
Operating lease, right-of-use asset			$ 1,100
Operating lease, discount rate	5.30%
ASC 842 | Office
Lessee Lease Description [Line Items]
Non-cancelable operating lease, term	2 years 2 months 12 days
ASC 842 | Laboratory Space
Lessee Lease Description [Line Items]
Non-cancelable operating lease, term	1 month 6 days

Leases - Summary of Balance She

Leases - Summary of Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Right-of-use lease assets	$ 530	$ 815
Lease liabilities, current	238	297
Lease liabilities, net of current portion	296	534
Total operating lease liabilities	$ 534	$ 831

Leases - Summary of Components

Leases - Summary of Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease rental expense	$ 262	$ 265
Interest on lease liabilities	35	50
Total operating lease expense	$ 297	$ 315

Leases - Summary of Supplementa

Leases - Summary of Supplemental Cash Flow Information Related to Lease (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating cash flows from operating leases	$ 445	$ 437
Right-of-use assets obtained in exchange for lease obligation
Operating leases		$ 1,084

Leases - Summary of Operating L

Leases - Summary of Operating Leases Liabilities Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
2021	$ 259
2022	260
2023	44
Total	563
Less: imputed interest	(29)
Operating lease liabilities	$ 534	$ 831

Commitments - Additional Inform

Commitments - Additional Information (Details)	Dec. 31, 2020Claim
Commitments And Contingencies Disclosure [Abstract]
Number of pending claims or legal actions	0

Share-based Compensation - Addi

Share-based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Nov. 30, 2019	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost		$ 15.1
Estimated recognition weighted-average remaining amortization period		2 years 10 months 24 days
Aggregate intrinsic value of options outstanding		$ 17.8
Aggregate intrinsic value of options exercisable		$ 16
Weighted-average grant-date fair values of options granted		$ 10.19	$ 6.66
Expected dividend yield		0.00%	0.00%
2019 Incentive Award Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock initially available for issuance	1,948,970
Percentage of shares of common stock outstanding	4.00%
Number of additional shares available for issuance	992,463	999,045
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]
Percentage of shares of common stock outstanding	1.00%
Number of additional shares available for issuance	248,115	249,761
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
Number of shares authorized		2,840,312

Share-based Compensation - Summ

Share-based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 5,536	$ 2,390
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	2,450	1,163
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 3,086	$ 1,227

Share-based Compensation - Su_2

Share-based Compensation - Summary of Activity Related to Stock Option Grants (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Outstanding beginning balance	3,537,946	2,071,616
Shares, Granted	1,238,573	1,646,054
Shares, Exercised	(164,575)	(3,778)
Shares, Forfeited	(148,866)	(175,946)
Shares, Outstanding ending balance	4,463,078	3,537,946
Shares, Vested and exercisable	2,599,488
Shares, Vested and expected to vest	4,463,078
Weighted average exercise price per share, Outstanding beginning balance	$ 5.17	$ 2.17
Weighted average exercise price per share, Granted	13.68	8.88
Weighted average exercise price per share, Exercised	3.07	2.60
Weighted average exercise price per share, Forfeited	11.59	4.50
Weighted average exercise price per share, Outstanding ending balance	7.40	$ 5.17
Weighted average exercise price per share, Vested and exercisable	4.49
Weighted average exercise price per share, Vested and expected to vest	$ 7.40
Weighted average remaining contractual life, Outstanding		7 years
Weighted average remaining contractual life, Vested and exercisable		5 years 9 months 18 days
Weighted average remaining contractual life, Vested and expected to vest		7 years

Share-based Compensation - Su_3

Share-based Compensation - Summary of Fair Value of Each Option Grant Estimated Throughout Year Using Black-Scholes Option-pricing Model (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
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	89.50%	89.70%
Risk-free interest rate	1.17%	2.26%
Expected dividend yield	0.00%	0.00%

Income Taxes - Summary of Compa

Income Taxes - Summary of Company's Loss Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Domestic	$ (73,007)	$ (49,918)
Foreign	(1,227)	(2,021)
Loss before income tax benefit	$ (74,234)	$ (51,939)

Income Taxes - Summary of Com_2

Income Taxes - Summary of Company's Tax Provision (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Current - Federal	$ 0	$ 0
Current - State	0	0
Current - Foreign	0	0
Current - Total	0	0
Deferred - Federal	0	194
Deferred - State	(16)	(203)
Deferred - Foreign	0	0
Deferred - Total	(16)	(9)
Total income tax benefit	$ (16)	$ (9)

Income Taxes - Summary of Effec

Income Taxes - Summary of Effective Tax Rate of Reconciliation of Federal Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Federal tax benefit at statutory rate	21.00%	21.00%
State tax, net of federal benefit	5.00%	4.30%
Net operating loss carryforwards		(0.20%)
Change in tax rate	0.10%	(0.60%)
Sale of royalty interest	(7.00%)	(8.10%)
Difference in foreign rate	0.20%	0.40%
Research & development	2.80%	4.30%
Change in valuation allowance	(21.90%)	(19.50%)
Share-based compensation	(0.20%)	(0.40%)
Other		(1.20%)

Income Taxes - Schedule of Sign

Income Taxes - Schedule of Significant Portions of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets
Net operating loss carryforwards	$ 40,324	$ 27,470
Share-based compensation	1,593	511
Research & development credits	7,477	5,073
Accrued expenses and other	98
Gross deferred tax assets	49,492	33,054
Valuation allowance	(48,309)	(32,062)
Net deferred tax asset	1,183	992
Deferred tax liabilities
Accrued expenses and other	(803)	(613)
Acquired in-process research and development	(653)	(668)
Net deferred tax liabilities	$ (273)	$ (289)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Line Items]
Percentage of maximum offset indefinite lived deferred tax liability for net operating loss	80.00%
Income tax benefit	$ (16)	$ (9)
Income tax benefit	3 years
Tax credit carryforward, amount	50.00%
Accrued interest and penalties	$ 0
Federal
Income Tax Disclosure [Line Items]
Net operating loss carryforwards expiration date	Dec. 31, 2032
State
Income Tax Disclosure [Line Items]
Net operating loss carryforwards expiration date		Dec. 31, 2032
Research and Development | Federal
Income Tax Disclosure [Line Items]
Tax credit carryforward, amount	$ 6,200
Tax credit carryforward expire date	Dec. 31, 2032
Research and Development | State
Income Tax Disclosure [Line Items]
Tax credit carryforward, amount		$ 6,200
Tax credit carryforward expire date		Dec. 31, 2032
Research and Development | Foreign
Income Tax Disclosure [Line Items]
Tax credit carryforward, amount	$ 1,300
Valuation Allowance, Operating Loss Carryforward
Income Tax Disclosure [Line Items]
Increase in valuation allowance	$ 16,200	$ 10,200

Income Taxes - Summary of Carry

Income Taxes - Summary of Carryforwards of Federal, State and Foreign NOLs and Tax Credits (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Federal
Operating Loss Carryforwards [Line Items]
Combined NOL Carryforwards	$ 135,580	$ 91,472
State
Operating Loss Carryforwards [Line Items]
Combined NOL Carryforwards	157,506	113,587
Foreign
Operating Loss Carryforwards [Line Items]
Combined NOL Carryforwards	$ 1,565	$ 1,175

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
IntellectMap
Related Party Transaction [Line Items]
Advisory services fees	$ 0.3	$ 0.3