0001564590-21-026290 | 10-Q | XBRL Viewer

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Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2021	May 06, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Entity Registrant Name	Galera Therapeutics, Inc.
Entity Central Index Key	0001563577
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	GRTX
Security Exchange Name	NASDAQ
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		25,254,132
Entity File Number	001-39114
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-1454898
Entity Address, Address Line One	2 W. Liberty Blvd #100
Entity Address, City or Town	Malvern
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19355
City Area Code	610
Local Phone Number	725-1500
Document Quarterly Report	true
Document Transition Report	false

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 13,687	$ 15,872
Short-term investments	43,833	56,904
Prepaid expenses and other current assets	6,720	5,153
Total current assets	64,240	77,929
Property and equipment, net	1,104	1,023
Acquired intangible asset	2,258	2,258
Goodwill	881	881
Right-of-use lease assets	526	530
Other assets	1,477	1,477
Total assets	70,486	84,098
Current liabilities:
Accounts payable	9,217	5,146
Accrued expenses	6,342	8,584
Lease liabilities	296	238
Total current liabilities	15,855	13,968
Royalty purchase liability	64,622	63,369
Lease liabilities, net of current portion	235	296
Deferred tax liability	273	273
Other liabilities	74	74
Total liabilities	81,059	77,980
Stockholders’ equity (deficit):
Preferred stock, $0.001 par value: 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.001 par value: 200,000,000 shares authorized; 25,193,157 and 24,976,142 shares issued and outstanding at March 31, 2021 and December 31, 2020	25	25
Additional paid-in capital	243,675	241,649
Accumulated other comprehensive income	10	12
Accumulated deficit	(254,283)	(235,568)
Total stockholders’ equity (deficit)	(10,573)	6,118
Total liabilities and stockholders’ equity (deficit)	$ 70,486	$ 84,098

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized (shares)	10,000,000	10,000,000
Preferred stock, shares issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized (shares)	200,000,000	200,000,000
Common stock, shares issued (shares)	25,193,157	24,976,142
Common stock, shares outstanding (shares)	25,193,157	24,976,142

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating expenses:
Research and development	$ 12,423	$ 14,252
General and administrative	5,058	3,566
Loss from operations	(17,481)	(17,818)
Other income (expenses):
Interest income	19	468
Interest expense	(1,253)	(1,095)
Foreign currency gain		28
Net loss	$ (18,715)	$ (18,417)
Net loss per share of common stock, basic and diluted	$ (0.75)	$ (0.74)
Weighted-average shares of common stock outstanding, basic and diluted	24,988,198	24,815,024

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (18,715)	$ (18,417)
Unrealized gain (loss) on short-term investments	(2)	648
Comprehensive loss	$ (18,717)	$ (17,769)

- Definition

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

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+ Details

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Balance at Dec. 31, 2019	$ 69,608	$ 25	$ 230,895	$ 38	$ (161,350)
Balance (in shares) at Dec. 31, 2019		24,811,567
Share-based compensation expense	1,210		1,210
Exercise of stock options	9		9
Exercise of stock options, shares		8,503
Unrealized gain (loss) on short-term investments	648			648
Net loss	(18,417)				(18,417)
Balance at Mar. 31, 2020	53,058	$ 25	232,114	686	(179,767)
Balance (in shares) at Mar. 31, 2020		24,820,070
Balance at Dec. 31, 2020	$ 6,118	$ 25	241,649	12	(235,568)
Balance (in shares) at Dec. 31, 2020	24,976,142	24,976,142
Share-based compensation expense	$ 1,791		1,791
Exercise of stock options	$ 235		235
Exercise of stock options, shares	217,015	217,015
Unrealized gain (loss) on short-term investments	$ (2)			(2)
Net loss	(18,715)				(18,715)
Balance at Mar. 31, 2021	$ (10,573)	$ 25	$ 243,675	$ 10	$ (254,283)
Balance (in shares) at Mar. 31, 2021	25,193,157	25,193,157

- Definition

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

+ References

+ Details

- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

+ References + Details

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net loss	$ (18,715)	$ (18,417)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	106	80
Noncash interest expense	1,253	1,095
Share-based compensation expense	1,791	1,210
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(1,568)	780
Other assets	4	(31)
Accounts payable	4,071	2,695
Accrued expense and other liabilities	(2,245)	196
Cash used in operating activities	(15,303)	(12,392)
Investing activities:
Purchases of short-term investments	(6,931)	(21,107)
Proceeds from sales of short-term investments	20,000	16,750
Purchase of property and equipment	(186)	(38)
Cash provided by (used in) investing activities	12,883	(4,395)
Financing activities:
Proceeds from royalty purchase agreement		20,000
Proceeds from exercise of stock options	235	9
Cash provided by financing activities	235	20,009
Net increase (decrease) in cash and cash equivalents	(2,185)	3,222
Cash and cash equivalents at beginning of period	15,872	18,356
Cash and cash equivalents at end of period	$ 13,687	$ 21,578

Organization and Description of Business

3 Months Ended

Mar. 31, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Description of Business

1.	Organization and description of business

Galera Therapeutics, Inc. was incorporated as a Delaware corporation on November 19, 2012 (inception) and together with its subsidiaries (the Company, or Galera) is a clinical stage biopharmaceutical company focused on developing and commercializing a pipeline of novel, proprietary therapeutics that have the potential to transform radiotherapy in cancer. 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 $254.3 million as of March 31, 2021. The Company anticipates incurring additional losses until such time, if ever, that it can generate significant sales of its product candidates currently in development. The Company expects its existing cash, cash equivalents and short-term investments as of March 31, 2021, 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 requirements for at least the next twelve months from the issuance of these financial statements. 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 of the Company’s 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 6.

Basis of Presentation and Significant Accounting Policies

3 Months Ended

Mar. 31, 2021

Accounting Policies [Abstract]

Basis of Presentation and Significant Accounting Policies

2.	Basis of presentation and significant accounting policies

The summary of significant accounting policies disclosed in the Company’s annual consolidated financial statements for the years ended December 31, 2020 and 2019 included in the Company’s annual report on Form 10-K filed with the Securities and Exchange Commission (SEC) on March 11, 2021 have not materially changed, except as set forth below.

Basis of presentation and consolidation

The accompanying unaudited interim consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (U.S. GAAP) for interim financial information. Any reference in these notes to applicable

guidance is meant to refer to U.S. GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (FASB).

In the opinion of management, the accompanying interim consolidated financial statements include all normal and recurring adjustments (which consist primarily of accruals, estimates and assumptions that impact the financial statements) considered necessary to present fairly the Company’s financial position as of March 31, 2021 and its results of operations for the three months ended March 31, 2021 and 2020, and statements of changes in stockholder’s equity (deficit) and cash flows for the three months ended March 31, 2021 and 2020. Operating results for the three months ended March 31, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021, or for any future period. The interim consolidated financial statements, presented herein, do not contain the required disclosures under U.S. GAAP for annual financial statements. Therefore, these interim consolidated financial statements should be read in conjunction with the annual audited consolidated financial statements and related notes as of and for the year ended December 31, 2020, included in the Company’s annual report on Form 10-K and filed with the SEC on March 11, 2021.

Use of estimates

The preparation of unaudited interim consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the unaudited interim consolidated financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates.

Estimates and assumptions are periodically reviewed and the effects of revisions are reflected in the unaudited interim consolidated financial statements in the period they are determined to be necessary. Significant areas that require management’s estimates include share-based compensation assumptions, royalty purchase liability assumptions and accrued research and development expenses.

Research and development expenses

Research and development costs are expensed as incurred and consist primarily of funds paid to third parties for the provision of services for product candidate development, clinical and preclinical development and related supply and manufacturing costs, and regulatory compliance costs. The Company accrues and expenses preclinical studies and clinical trial activities performed by third parties based upon estimates of the proportion of work completed over the term of the individual trial and patient enrollment rates in accordance with agreements with clinical research organizations and clinical trial sites. The Company determines the estimates by reviewing contracts, vendor agreements and purchase orders, and through discussions with internal clinical personnel and external service providers as to the progress or stage of completion of trials or services and the agreed-upon fee to be paid for such services. However, actual costs and timing of clinical trials are highly uncertain, subject to risks and may change depending upon a number of factors, including the Company’s clinical development plan.

Management makes estimates of the Company’s accrued expenses as of each balance sheet date in the Company’s consolidated financial statements based on facts and circumstances known to the Company at that time. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Nonrefundable advance payments for goods and services, including fees for process development or manufacturing and distribution of clinical supplies that will be used in future research and development activities, are deferred and recognized as expense in the period that the related goods are consumed or services are performed.

In September 2020, the Company was awarded a Small Business Innovation Research grant from the National Cancer Institute of the National Institutes of Health, which will partially fund its Phase 1/2 safety and anti-cancer efficacy trial in NSCLC (the Grant). Costs entitled to reimbursement under the Grant are accounted for as a reduction to research and development expenses. During the three months ended March 31, 2021, the Company recorded a reduction to research and development expense of $0.3 million for expenses for which it has been reimbursed, or is entitled to reimbursement, under the Grant.

Net loss per share

Basic loss per share of common stock is computed by dividing net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during each period. Diluted loss per share of common stock includes the effect, if any, from the potential exercise or conversion of securities, such as stock options and common stock warrants, which would result in the issuance of incremental shares of common stock. For diluted net loss per share, the weighted-average

number of shares of common stock is the same for basic net loss per share due to the fact that when a net loss exists, dilutive securities are not included in the calculation as the impact is anti-dilutive.

The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares of common stock outstanding, as they would be anti-dilutive:

	March 31,
	2021		2020
Stock options		5,173,716		4,557,673
Common stock warrants		550,661		—
		5,724,377		4,557,673

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 the Company is 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 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 December 2019, FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in Topic 740 related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The new guidance also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill and allocating consolidated income taxes to separate financial statements of entities not subject to income tax. This ASU is effective for fiscal years beginning after December 15, 2020, including interim periods therein. Upon adoption, the Company must apply certain aspects of this standard retrospectively for all periods presented while other aspects are applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. The Company adopted this ASU on January 1, 2021. There is no impact to the Company’s consolidated financial statements.

Fair Value Measurements

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

3.	Fair value measurements

The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels:

•

Level 1 Inputs: Unadjusted quoted prices in active markets for identical assets or liabilities accessible to the reporting entity at the measurement date.

•

Level 2 Inputs: Other than quoted prices included in Level 1 inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability.

•

Level 3 Inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at measurement date.

The following table presents the Company’s assets and liabilities that are measured at fair value on a recurring basis (amounts in thousands):

	March 31, 2021
	(Level 1)		(Level 2)		(Level 3)
Assets
Money market funds and U.S. Treasury obligations (included in cash equivalents)	$	10,070	$	—	$	—

Short-term investments
U.S. government agency securities	$	—	$	5,030	$	—
U.S. Treasury obligations		38,803		—		—
Total short-term investments	$	38,803	$	5,030	$	—

	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	$	—

There were no changes in valuation techniques during the three months ended March 31, 2021. 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.

- Definition

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

+ References + Details

Property and Equipment

3 Months Ended

Mar. 31, 2021

Property Plant And Equipment [Abstract]

Property and Equipment

4.	Property and equipment

Property and equipment consist of (amounts in thousands):

	March 31, 2021			December 31, 2020
Laboratory equipment	$	1,321		$	1,135
Computer hardware and software		260			260
Leasehold improvements		264			264
Furniture and fixtures		173			173
Property and equipment, gross		2,018			1,832
Less: Accumulated depreciation		(914	)		(809	)
Property and equipment, net	$	1,104		$	1,023

Depreciation expense was $0.1 million and $0.1 million for the three months ended March 31, 2021 and 2020, respectively.

Accrued Expenses

3 Months Ended

Mar. 31, 2021

Payables And Accruals [Abstract]

Accrued Expenses

5.	Accrued expenses

Accrued expenses consist of (amounts in thousands):

	March 31, 2021		December 31, 2020
Compensation and related benefits	$	831	$	2,632
Research and development expenses		5,240		5,525
Professional fees and other expenses		271		427
	$	6,342	$	8,584

Royalty Purchase Liability

3 Months Ended

Mar. 31, 2021

Royalty Purchase Liability [Abstract]

Royalty Purchase Liability

6.	Royalty purchase liability

In November 2018, the Company entered into an Amended and Restated Purchase and Sale Agreement (the Royalty Agreement), with Clarus IV Galera Royalty AIV, L.P., Clarus IV-A, L.P., Clarus IV-B, L.P., Clarus IV-C, L.P. and Clarus IV-D, L.P. (collectively, Blackstone or Blackstone Life Sciences). Pursuant to the Royalty Agreement, Blackstone agreed to pay up to $80.0 million (the Royalty Purchase Price) in four tranches of $20.0 million each upon the achievement of specific Phase 3 clinical trial patient enrollment milestones. The Company received the first tranche of the Royalty Purchase Price in November 2018, the second tranche of the Royalty Purchase Price in April 2019, and the third tranche of the Royalty Purchase Price in February 2020, in each case in connection with the achievement of the first three milestones, respectively.

The Company accounts for the Royalty Agreement as a debt instrument. The $60.0 million 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 $1.3 million and $1.1 million in noncash interest expense during the three months ended March 31, 2021 and 2020, respectively. As of March 31, 2021, 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 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.

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

3 Months Ended

Mar. 31, 2021

Leases [Abstract]

Leases

The Company has non-cancelable operating leases for office and laboratory space in Malvern, Pennsylvania and Creve Coeur, Missouri which, as of March 31, 2021, have remaining lease terms of approximately 2.0 and 0.8 years, respectively. The discount rate used to account for the Company’s operating lease under ASC 842 is the Company’s estimated incremental borrowing rate of 5.3%.

Supplemental balance sheet information related to leases was as follows:

	March 31,		December 31,
	2021		2020
Operating Leases
Right-of-use lease assets	$	526	$	530

Lease liabilities, current		296		238
Lease liabilities, net of current portion		235		296
Total operating lease liabilities	$	531	$	534

The components of lease expense were as follows:

	Three months ended March 31,
	2021		2020
Operating lease costs
Operating lease rental expense	$	73	$	74
Interest on lease liabilities		7		10
Total operating lease expense	$	80	$	84

Supplemental cash flow information related to leases was as follows:

	Three Months Ended March 31,
	2021		2020
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$	81	$	84
Right-of-use assets obtained in exchange for lease obligation
Operating leases		70		—

Future minimum rental payments under the Company’s non-cancelable operating lease liabilities as of March 31, 2021 (amounts in thousands):

Remainder of 2021	$	245
2022		266
2023		44
Total		555
Less: imputed interest		(24	)
	$	531

Share-based Compensation

3 Months Ended

Mar. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-based Compensation

8.	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 March 31, 2021 was 2,610,863. 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.

The Company’s stock option awards vest based on the terms in the governing agreements and generally vest over four years and have a term of 10 years.

Share-based compensation expense was as follows for the three months ended March 31, 2021 and 2020 (in thousands):

	Three months ended March 31,
	2021		2020
Research and development	$	784	$	594
General and administrative		1,007		616
	$	1,791	$	1,210

The following table summarizes the activity related to stock option grants for the three months ended March 31, 2021:

	Shares			Weighted average exercise price per share		Weighted- average remaining contractual life (years)
Outstanding at January 1, 2021		4,463,078		$	7.40
Granted		968,275			11.96
Exercised		(217,015	)		1.09
Forfeited		(40,622	)		12.42
Outstanding at March 31, 2021		5,173,716		$	8.48		7.5
Vested and exercisable at March 31, 2021		2,602,125		$	5.32		5.9
Vested and expected to vest at March 31, 2021		5,173,716		$	8.48		7.5

As of March 31, 2021, the unrecognized compensation cost was $21.7 million and will be recognized over an estimated weighted-average amortization period of 3.1 years. The aggregate intrinsic value of options outstanding and options exercisable as of March 31, 2021 was $12.0 million and $11.3 million, respectively. Options granted during the three months ended March 31, 2021 and 2020 had weighted-average grant-date fair values of $9.00 and $10.72 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 three months ended March 31, 2021 and 2020 was determined using the methods and assumptions discussed below.

•

The expected term of employee stock options with service-based vesting is determined using the “simplified” method, as prescribed in SEC’s Staff Accounting Bulletin (SAB) No. 107, whereby the expected life equals the arithmetic average of the vesting term and the original contractual term of the option due to the Company’s lack of sufficient historical data. The expected term of nonemployee options is equal to the contractual term.

•

The expected stock price volatility is based on historical volatilities of comparable public entities within the Company’s industry which were commensurate with the expected term assumption as described in SAB No. 107.

•

The risk-free interest rate is based on the interest rate payable on U.S. Treasury securities in effect at the time of grant for a period that is commensurate with the expected term.

•

The expected dividend yield is 0% because the Company has not historically paid, and does not expect for the foreseeable future to pay, a dividend on its common stock.

•

The Company’s board of directors has determined the price per share value of the Company’s common stock based on the closing price as reported by the NASDAQ Global Market on the date of the grant.

The grant date fair value of each option grant was estimated throughout the quarter using the Black-Scholes option-pricing model using the following weighted-average assumptions:

	Three months ended March 31,
	2021			2020
Expected term (in years)		6.2			6.2
Expected stock price volatility		91.6	%		89.0	%
Risk-free interest rate		0.59	%		1.32	%
Expected dividend yield		0	%		0	%

Related Party Transactions

3 Months Ended

Mar. 31, 2021

Related Party Transactions

9.	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 the Company with respect to IntellectMap during the three months ended March 31, 2021 and 2020 were $49,000 and $0.1 million, respectively.

Basis of Presentation and Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2021

Accounting Policies [Abstract]

Liquidity

Basis of Presentation and Consolidation

Basis of presentation and consolidation

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).

Use of Estimates

Use of estimates

Research and Development Expenses

Research and development expenses

Net Loss Per Share

Net loss per share

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:

	March 31,
	2021		2020
Stock options		5,173,716		4,557,673
Common stock warrants		550,661		—
		5,724,377		4,557,673

Recent Accounting Pronouncements

COVID-19 Update

Recent accounting pronouncements

Basis of Presentation and Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2021

Accounting Policies [Abstract]

Dilutive Securities Excluded from Computation of Diluted Weighted Average Shares of Common Stock Outstanding

The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares of common stock outstanding, as they would be anti-dilutive:

	March 31,
	2021		2020
Stock options		5,173,716		4,557,673
Common stock warrants		550,661		—
		5,724,377		4,557,673

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis

The following table presents the Company’s assets and liabilities that are measured at fair value on a recurring basis (amounts in thousands):

	March 31, 2021
	(Level 1)		(Level 2)		(Level 3)
Assets
Money market funds and U.S. Treasury obligations (included in cash equivalents)	$	10,070	$	—	$	—

Short-term investments
U.S. government agency securities	$	—	$	5,030	$	—
U.S. Treasury obligations		38,803		—		—
Total short-term investments	$	38,803	$	5,030	$	—

	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	$	—

Property and Equipment (Tables)

3 Months Ended

Mar. 31, 2021

Property Plant And Equipment [Abstract]

Schedule of Property Plant and Equipment

Property and equipment consist of (amounts in thousands):

	March 31, 2021			December 31, 2020
Laboratory equipment	$	1,321		$	1,135
Computer hardware and software		260			260
Leasehold improvements		264			264
Furniture and fixtures		173			173
Property and equipment, gross		2,018			1,832
Less: Accumulated depreciation		(914	)		(809	)
Property and equipment, net	$	1,104		$	1,023

Accrued Expenses (Tables)

3 Months Ended

Mar. 31, 2021

Payables And Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses consist of (amounts in thousands):

	March 31, 2021		December 31, 2020
Compensation and related benefits	$	831	$	2,632
Research and development expenses		5,240		5,525
Professional fees and other expenses		271		427
	$	6,342	$	8,584

Leases (Tables)

3 Months Ended

Mar. 31, 2021

Leases [Abstract]

Summary of Supplemental Balance Sheet Information Related to Leases

Supplemental balance sheet information related to leases was as follows:

	March 31,		December 31,
	2021		2020
Operating Leases
Right-of-use lease assets	$	526	$	530

Lease liabilities, current		296		238
Lease liabilities, net of current portion		235		296
Total operating lease liabilities	$	531	$	534

Summary of Components of Lease Expense

The components of lease expense were as follows:

	Three months ended March 31,
	2021		2020
Operating lease costs
Operating lease rental expense	$	73	$	74
Interest on lease liabilities		7		10
Total operating lease expense	$	80	$	84

Summary of Supplemental Cash Flow Information Related to Leases

Supplemental cash flow information related to leases was as follows:

	Three Months Ended March 31,
	2021		2020
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$	81	$	84
Right-of-use assets obtained in exchange for lease obligation
Operating leases		70		—

Summary of Future Minimum Rental Payments Under Non Cancelable Operating Leases

Future minimum rental payments under the Company’s non-cancelable operating lease liabilities as of March 31, 2021 (amounts in thousands):

Remainder of 2021	$	245
2022		266
2023		44
Total		555
Less: imputed interest		(24	)
	$	531

Share-based Compensation (Tables)

3 Months Ended

Mar. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Share-based Compensation Expense

Share-based compensation expense was as follows for the three months ended March 31, 2021 and 2020 (in thousands):

	Three months ended March 31,
	2021		2020
Research and development	$	784	$	594
General and administrative		1,007		616
	$	1,791	$	1,210

Summary of Activity Related to Stock Option Grants

The following table summarizes the activity related to stock option grants for the three months ended March 31, 2021:

	Shares			Weighted average exercise price per share		Weighted- average remaining contractual life (years)
Outstanding at January 1, 2021		4,463,078		$	7.40
Granted		968,275			11.96
Exercised		(217,015	)		1.09
Forfeited		(40,622	)		12.42
Outstanding at March 31, 2021		5,173,716		$	8.48		7.5
Vested and exercisable at March 31, 2021		2,602,125		$	5.32		5.9
Vested and expected to vest at March 31, 2021		5,173,716		$	8.48		7.5

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 quarter using the Black-Scholes option-pricing model using the following weighted-average assumptions:

	Three months ended March 31,
	2021			2020
Expected term (in years)		6.2			6.2
Expected stock price volatility		91.6	%		89.0	%
Risk-free interest rate		0.59	%		1.32	%
Expected dividend yield		0	%		0	%

Organization and description of business - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended
	Dec. 31, 2020	Mar. 31, 2021
Organization And Description Of Business [Line Items]
Date of incorporation		Nov. 19, 2012
Accumulated deficit	$ (235,568,000)	$ (254,283,000)
Expected payments to be received from royalty purchase agreement		$ 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	200,000.0
Maximum Aggregate Offering Price	$ 50,000.0

Basis of Presentation and Significant Accounting Policies - Additional Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Accounting Policies [Abstract]
Reduction to research and development expense	$ 0.3

Basis of Presentation and Significant Accounting Policies - Dilutive Securities Excluded from Computation of Diluted Weighted Average Shares of Common Stock Outstanding (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities excluded from computation of earnings per share	5,724,377	4,557,673
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities excluded from computation of earnings per share	5,173,716	4,557,673
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

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Level 1 \| Money Market Funds and U.S. Treasury Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, at fair value	$ 10,070	$ 14,943
Level 1 \| U.S. government securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	0	0
Level 1 \| U.S. government treasuries
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	38,803	51,842
Level 1 \| Short- Term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	38,803	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	5,030	5,062
Level 2 \| U.S. government treasuries
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	0	0
Level 2 \| Short- Term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	5,030	5,062
Level 3 \| Money Market Funds and U.S. Treasury Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents, at fair value	0	0
Level 3 \| U.S. government securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	0	0
Level 3 \| U.S. government treasuries
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	0	0
Level 3 \| Short- Term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	$ 0	$ 0

Fair Value Measurements - Additional Information (Details)	3 Months Ended
	Mar. 31, 2021 USD ($)
Fair Value Disclosures [Abstract]
Changes in valuation techniques	$ 0

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 2,018	$ 1,832
Less: Accumulated depreciation	(914)	(809)
Property and equipment, net	1,104	1,023
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,321	1,135
Computer Hardware and Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	260	260
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	264	264
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 173	$ 173

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Property Plant And Equipment [Abstract]
Depreciation	$ 106	$ 80

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Compensation and related benefits	$ 831	$ 2,632
Research and development expenses	5,240	5,525
Professional fees and other expenses	271	427
Accrued expenses	$ 6,342	$ 8,584

Royalty Purchase Liability - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Nov. 30, 2018	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	May 31, 2020
Royalty Purchase Liability [Line Items]
Total agreed amount of royalty purchase price		$ 64,622		$ 63,369
Royalty purchase price			$ 20,000
Noncash interest expense		1,253	1,095
Royalty purchase liability		64,622		$ 63,369
Royalty Agreements
Royalty Purchase Liability [Line Items]
Total agreed amount of royalty purchase price	$ 80,000
Royalty purchase price		60,000
Noncash interest expense		$ 1,300	$ 1,100
Effective interest rate		8.00%
Outstanding amount of royalty agreement					$ 20,000
Royalty purchase liability	80,000
Royalty Agreements \| First Tranche
Royalty Purchase Liability [Line Items]
Royalty purchase price	$ 20,000
Amended Royalty Agreements
Royalty Purchase Liability [Line Items]
Total agreed amount of royalty purchase price					117,500
Outstanding amount of royalty agreement					37,500
Royalty purchase liability					$ 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

Leases - Additional Information (Details) - ASC 842	Mar. 31, 2021
Lessee Lease Description [Line Items]
Operating lease, discount rate	5.30%
Office
Lessee Lease Description [Line Items]
Non-cancelable operating lease, term	2 years
Laboratory Space
Lessee Lease Description [Line Items]
Non-cancelable operating lease, term	9 months 18 days

Leases - Summary of Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Right-of-use lease assets	$ 526	$ 530
Lease liabilities, current	296	238
Lease liabilities, net of current portion	235	296
Total operating lease liabilities	$ 531	$ 534

Leases - Summary of Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Leases [Abstract]
Operating lease rental expense	$ 73	$ 74
Interest on lease liabilities	7	10
Total operating lease expense	$ 80	$ 84

Leases - Summary of Supplemental Cash Flow Information Related to Lease (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Leases [Abstract]
Operating cash flows from operating leases	$ 81	$ 84
Right-of-use assets obtained in exchange for lease obligation
Operating leases	$ 70

Leases - Summary of Future Minimum Rental Payments Under Non Cancelable Operating Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Remainder of 2021	$ 245
2022	266
2023	44
Total	555
Less: imputed interest	(24)
Operating lease liabilities	$ 531	$ 534

Share-based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Nov. 30, 2019	Mar. 31, 2021	Mar. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost		$ 21.7
Estimated recognition weighted-average amortization period		3 years 1 month 6 days
Aggregate intrinsic value of options outstanding		$ 12.0
Aggregate intrinsic value of options exercisable		$ 11.3
Weighted-average grant-date fair values of options granted		$ 9.00	$ 10.72
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		2,610,863
Vesting period		4 years
Term of award		10 years

Share-based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 1,791	$ 1,210
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	784	594
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 1,007	$ 616

Share-based Compensation - Summary of Activity Related to Stock Option Grants (Details)	3 Months Ended
	Mar. 31, 2021 $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Outstanding beginning balance \| shares	4,463,078
Shares, Granted \| shares	968,275
Shares, Exercised \| shares	(217,015)
Shares, Forfeited \| shares	(40,622)
Shares, Outstanding ending balance \| shares	5,173,716
Shares, Vested and exercisable \| shares	2,602,125
Shares, Vested and expected to vest \| shares	5,173,716
Weighted average exercise price per share, Outstanding beginning balance \| $ / shares	$ 7.40
Weighted average exercise price per share, Granted \| $ / shares	11.96
Weighted average exercise price per share, Exercised \| $ / shares	1.09
Weighted average exercise price per share, Forfeited \| $ / shares	12.42
Weighted average exercise price per share, Outstanding ending balance \| $ / shares	8.48
Weighted average exercise price per share, Vested and exercisable \| $ / shares	5.32
Weighted average exercise price per share, Vested and expected to vest \| $ / shares	$ 8.48
Weighted average remaining contractual life, Outstanding	7 years 6 months
Weighted average remaining contractual life, Vested and exercisable	5 years 10 months 24 days
Weighted average remaining contractual life, Vested and expected to vest	7 years 6 months

Share-based Compensation - Summary of Fair Value of Each Option Grant Estimated Throughout Year Using Black-Scholes Option-pricing Model (Details)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions And Methodology [Abstract]
Expected term (in years)	6 years 2 months 12 days	6 years 2 months 12 days
Expected stock price volatility	91.60%	89.00%
Risk-free interest rate	0.59%	1.32%
Expected dividend yield	0.00%	0.00%

Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
IntellectMap
Related Party Transaction [Line Items]
Advisory services fees	$ 49,000.0	$ 0.1