Galera Therapeutics (GRTX) 10-Q 12 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	May 07, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
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		24,824,623
Entity File Number	001-39114
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-1454898
Entity Address, Address Line One	2 W. Liberty Blvd #100
Entity Address, City or Town	Malvern
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19355
City Area Code	610
Local Phone Number	725-1500
Document Quarterly Report	true
Document Transition Report	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 21,578	$ 18,356
Short-term investments	98,939	93,934
Prepaid expenses and other current assets	4,501	5,280
Total current assets	125,018	117,570
Property and equipment, net	892	934
Acquired intangible asset	2,258	2,258
Goodwill	881	881
Right-of-use lease asset	745	815
Other assets	1,019	918
Total assets	130,813	123,376
Current liabilities:
Accounts payable	6,640	3,945
Accrued expenses	5,723	5,452
Lease liability	285	297
Total current liabilities	12,648	9,694
Royalty purchase liability	64,346	43,251
Lease liability, net of current portion	472	534
Deferred tax liability	289	289
Total liabilities	77,755	53,768
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; 24,820,070 and 24,811,567 shares issued and outstanding at March 31, 2020 and December 31, 2019	25	25
Additional paid-in capital	232,114	230,895
Accumulated other comprehensive income	686	38
Accumulated deficit	(179,767)	(161,350)
Total stockholders’ equity	53,058	69,608
Total liabilities and stockholders’ equity	$ 130,813	$ 123,376

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 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)	24,820,070	24,811,567
Common stock, shares outstanding (shares)	24,820,070	24,811,567

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating expenses:
Research and development	$ 14,252	$ 8,502
General and administrative	3,566	1,894
Loss from operations	(17,818)	(10,396)
Other income (expenses):
Interest income	468	457
Interest expense	(1,095)	(439)
Foreign currency loss	28	29
Net loss	(18,417)	(10,349)
Accretion of redeemable convertible preferred stock to redemption value		(2,011)
Net loss attributable to common stockholders	$ (18,417)	$ (12,360)
Net loss per share of common stock, basic and diluted	$ (0.74)	$ (41.12)
Weighted-average shares of common stock outstanding, basic and diluted	24,815,024	300,597

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (18,417)	$ (10,349)
Unrealized gain on short-term investments	648	10
Comprehensive loss	$ (17,769)	$ (10,339)

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	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	499			$ 499
Accretion of redeemable convertible preferred stock to redemption value	(2,011)	$ 2,011		(499)		(1,512)
Unrealized gain on short-term investments	10				10
Net loss	(10,349)					(10,349)
Balance at Mar. 31, 2019	(116,671)				13	(116,684)
Balance (in shares) at Mar. 31, 2019		96,385,795
Balance at Mar. 31, 2019		$ 167,913
Balance (in shares) at Mar. 31, 2019			300,597
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
Share-based compensation expense	$ 1,210			1,210
Exercise of stock options	$ 9			9
Exercise of stock options, shares	8,503		8,503
Unrealized gain 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		24,820,070

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities:
Net loss	$ (18,417,000)	$ (10,349,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	80,000	46,000
Noncash interest expense	1,095,000	439,000
Share-based compensation expense	1,210,000	499,000
Reserve for tax incentive receivable		241,000
Deferred rent		(1,000)
Changes in operating assets and liabilities:
Tax incentive receivable		629,000
Prepaid expenses and other current assets	780,000	(1,072,000)
Other assets	(31,000)	(2,000)
Accounts payable	2,695,000	261,000
Accrued expense and other liabilities	196,000	380,000
Cash used in operating activities	(12,392,000)	(8,929,000)
Investing activities:
Purchases of short-term investments	(21,107,000)	(12,160,000)
Proceeds from sales of short-term investments	16,750,000	15,059,000
Purchase of property and equipment	(38,000)	(303,000)
Cash provided by (used in) investing activities	(4,395,000)	2,596,000
Financing activities:
Proceeds from royalty purchase agreement	20,000,000
Proceeds from exercise of stock options	9,000
Cash provided by financing activities	20,009,000
Net increase (decrease) in cash and cash equivalents	3,222,000	(6,333,000)
Cash and cash equivalents at beginning of period	18,356,000	14,811,000
Cash and cash equivalents at end of period	$ 21,578,000	8,478,000
Supplemental schedule of non-cash financing activities:
Accretion of redeemable convertible preferred stock to redemption value		2,011,000
Deferred offering costs included in accounts payable and accrued expenses		1,408,000
Initial recognition of operating lease right-of-use asset and operating lease liability		$ 1,084,000

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 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, 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 plans to leverage its observations from the ongoing avasopasem SBRT pilot Phase 1b/2a trial in locally advanced pancreatic cancer (LAPC) to prepare a GC4711 SBRT combination Phase 1b/2a safety and anti-cancer efficacy trial in non-small cell lung cancer (NSCLC). Liquidity The Company has incurred recurring losses and negative cash flows from operations since inception and has an accumulated deficit of $179.8 million as of March 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, 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 (as defined below) and Amendment No. 1 to the Royalty Agreement, will enable the Company to fund its operating expenses On November 12, 2019, the Company completed an initial public offering (IPO) of its common stock, which resulted in the issuance and sale of 5,000,000 shares of its common stock at a public offering price of $12.00 per share, generating net proceeds of $53.1 million after deducting underwriting discounts and other offering costs.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	3 Months Ended
	Mar. 31, 2020
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, 2019 and 2018 included in the Company’s annual report on Form 10-K filed with the Securities and Exchange Commission (SEC) on March 10, 2020 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, 2020 and its results of operations for the three months ended March 31, 2020 and 2019, and statements of changes in redeemable convertible preferred stock and stockholder’s equity (deficit) and cash flows for the three months ended March 31, 2020 and 2019. Operating results for the three months ended March 31, 2020 are not necessarily indicative of the results that may be expected for the year ending December 31, 2020, 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, 2019, included in the Company’s annual report on Form 10-K and filed with the SEC on March 10, 2020. 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 the fair value of common stock, prior to the IPO, share-based compensation assumptions, royalty purchase liability assumptions and accrued clinical trial expense. The full extent to which the COVID-19 pandemic will directly or indirectly impact our business, results of operations and financial condition, including manufacturing, clinical trials, research and development costs and employee-related amounts, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain or treat COVID-19, as well as the economic impact on local, regional, national and international customers and markets. Management has made estimates regarding the impact of COVID-19 within the Company’s financial disclosures and there may be changes to those estimates in future periods. Actual results may differ from these estimates. 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: March 31, 2020 2019 Stock options 4,557,673 3,142,879 Redeemable convertible preferred stock — 19,061,502 4,557,673 22,204,381 Amounts in the above table reflect the common stock equivalents for the redeemable convertible preferred stock. 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

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 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): March 31, 2020 (Level 1) (Level 2) (Level 3) Assets Money market funds and U.S. Treasury obligations (included in cash equivalents) $ 19,946 $ — $ — Short-term investments $ 98,939 $ — $ — 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 $ 93,934 $ — $ — There were no changes in valuation techniques during the three months ended March 31, 2020. 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.

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2020
Property Plant And Equipment [Abstract]
Property and Equipment	4. Property and equipment Property and equipment consist of (amounts in thousands): March 31, 2020 December 31, 2019 Laboratory equipment $ 786 $ 748 Computer hardware and software 218 218 Leasehold improvements 262 262 Furniture and fixtures 147 147 Property and equipment, gross 1,413 1,375 Less: Accumulated depreciation (521 ) (441 ) Property and equipment, net $ 892 $ 934 Depreciation expense was $80,000 and $46,000 for the three months ended March 31, 2020 and 2019, respectively.

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Accrued Expenses	5. Accrued expenses Accrued expenses consist of (amounts in thousands): March 31, 2020 December 31, 2019 Compensation and related benefits $ 726 $ 1,160 Research and development expenses 4,842 3,882 Professional fees and other expenses 155 410 $ 5,723 $ 5,452

Royalty Purchase Liability

Royalty Purchase Liability	3 Months Ended
	Mar. 31, 2020
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. In April 2019, the Company received $20.0 million 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 proceeds from the first three tranches under the Royalty Agreement have been recorded as a liability on the Company’s 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 $1.1 million and $0.4 million in noncash interest expense during the three months ended March 31, 2020 and 2019, respectively. As of March 31, 2020, the effective interest rate was 8.7%. Blackstone is entitled to a mid single-digit percentage royalty based on the worldwide net sales of avasopasem and GC4711 (the Products). The royalty period will continue until the latest to occur of (i) the 12th anniversary of commercial launch of the Products, (ii) the expiration of the patents covering such Products, 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 Products from entering the market in such country. If Blackstone fails to fund the remaining $20.0 million Royalty Purchase Price within two days of the conditions to the payment of such tranche having been satisfied, the Company may terminate its obligation to accept such tranche. In such an event, the Company’s royalty obligations to Blackstone shall be reduced to a low single-digit percentage. The Royalty Agreement will remain in effect until the aggregate amount of the royalty 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. On May 11, 2020, the Company entered into Amendment No. 1 to Amended and Restated Purchase and Sale Agreement with Clarus IV Galera Royalty AIV, L.P. See Note 10.

Leases

Leases	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Leases	7. Leases The Company has non-cancelable operating leases for office and laboratory space in Malvern, Pennsylvania and St. Louis, Missouri which, as of March 31, 2020, have remaining lease terms of approximately 3.0 and 0.9 years, respectively. The Company adopted ASC 842 on January 1, 2019 resulting in the recognition of a current operating lease liability of $0.3 million and a noncurrent operating lease liability of $0.8 million with a corresponding $1.1 million right-of-use (ROU) asset, which was based on the present value of the minimum rental payments of the lease. 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, 2020 2019 Operating Leases Operating lease right-of-use assets $ 745 $ 815 Other current liabilities 285 297 Operating lease liabilities 472 534 Total operating lease liabilities $ 757 $ 831 The components of lease expense were as follows: Three months ended March 31, 2020 2019 Operating lease costs Operating lease rental expense $ 74 $ 52 Interest on lease liabilities 10 14 Total operating lease liabilities $ 84 $ 66 Supplemental cash flow information related to leases was as follows: Three months ended March 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 84 $ 66 Right-of-use assets obtained in exchange for lease obligation Operating leases — 1,084 Future minimum rental payments under the Company’s non-cancelable operating leases were as follows as of March 31, 2020 (amounts in thousands): Remainder of 2020 $ 248 2021 259 2022 260 2023 44 Total 811 Less: imputed interest (54 ) $ 757

Share-based Compensation

Share-based Compensation	3 Months Ended
	Mar. 31, 2020
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 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 is 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. 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 is 243,621 shares of common stock plus 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. In November 2012, the Company adopted the Equity Incentive Plan (the Prior Plan). The total number of shares authorized under the Prior Plan as of December 31, 2019 was 3,038,259, all of which were subject to outstanding awards. 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, 2020 and 2019 (in thousands): Three months ended March 31, 2020 2019 Research and development $ 594 $ 238 General and administrative 616 261 $ 1,210 $ 499 The following table summarizes the activity related to stock option grants for the three months ended March 31, 2020: Shares Weighted average exercise price per share Weighted- average remaining contractual life (years) Outstanding at January 1, 2020 3,537,946 $ 5.17 Granted 1,028,230 14.40 Exercised (8,503 ) 1.07 Forfeited — — Outstanding at March 31, 2020 4,557,673 $ 7.26 7.7 Vested and exercisable at March 31, 2020 2,189,443 $ 3.06 5.9 Vested and expected to vest at March 31, 2020 4,557,673 $ 7.26 7.7 As of March 31, 2020, the unrecognized compensation cost was $19.1 million and will be recognized over an estimated weighted-average amortization period of 3.5 years. The aggregate intrinsic value of options outstanding and options exercisable as of March 31, 2020 was $16.6 million and $14.3 million, respectively. Options granted during the three months ended March 31, 2020 and 2019 had weighted-average grant-date fair values of $10.72 and $5.45 per share, respectively. The fair value of options is estimated using the Black-Scholes option pricing model, which takes into account inputs such as the exercise price, the estimated fair value of the underlying common stock at the grant date, expected term, expected stock price volatility, risk-free interest rate and dividend yield. The fair value of stock options during the three months ended March 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. 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, 2020 2019 Expected term (in years) 6.2 6.2 Expected stock price volatility 89.0 % 91.0 % Risk-free interest rate 1.32 % 2.47 % Expected dividend yield 0 % 0 %

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	9 . Related party transactions IntellectMap provides 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 three months ended March 31, 2020 and 2019 were $0.1 million and $0.1 million, respectively.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	1 0 . Subsequent events COVID-19 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 indefinitely 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, which was planned for the first half of 2020, due to concerns with patient enrollment. This trial was expected to enroll up to 70 patients and contribute to the safety database for avasopasem in patients with HNC receiving radiotherapy. As a result, the target enrollment for the ROMAN trial was increased to approximately 450 patients in order to ensure the Company is positioned to maintain the planned size of the safety database in a timely manner, with completion of enrollment now expected in the first half of 2021 and data now expected in the second half of 2021, subject to the continuing impact of the COVID-19 pandemic on its business. With this change in the ROMAN trial, the Company anticipates that the assumptions underlying its calculation of interest expense on the royalty purchase liability will change. 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. Amendment to Royalty Agreement with Blackstone Life Sciences (Formerly Known as Clarus Ventures) On May 11, 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. 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 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. On May 11, 2020, as partial consideration for the Amendment, the Company issued two warrants to the Blackstone Purchaser to purchase an aggregate of 550,661 shares of the Company’s common stock at an exercise price equal to $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 date of each respective warrant.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 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 $179.8 million as of March 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, 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 (as defined below) and Amendment No. 1 to the Royalty Agreement, will enable the Company to fund its operating expenses On November 12, 2019, the Company completed an initial public offering (IPO) of its common stock, which resulted in the issuance and sale of 5,000,000 shares of its common stock at a public offering price of $12.00 per share, generating net proceeds of $53.1 million after deducting underwriting discounts and other offering costs.
Basis of Presentation and Consolidation	Basis of presentation and consolidation The accompanying unaudited interim consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (U.S. GAAP) for interim financial information. Any reference in these notes to applicable guidance is meant to refer to U.S. GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (FASB). In the opinion of management, the accompanying interim consolidated financial statements include all normal and recurring adjustments (which consist primarily of accruals, estimates and assumptions that impact the financial statements) considered necessary to present fairly the Company’s financial position as of March 31, 2020 and its results of operations for the three months ended March 31, 2020 and 2019, and statements of changes in redeemable convertible preferred stock and stockholder’s equity (deficit) and cash flows for the three months ended March 31, 2020 and 2019. Operating results for the three months ended March 31, 2020 are not necessarily indicative of the results that may be expected for the year ending December 31, 2020, 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, 2019, included in the Company’s annual report on Form 10-K and filed with the SEC on March 10, 2020.
Use of Estimates	Use of estimates The preparation of unaudited interim consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the unaudited interim consolidated financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Estimates and assumptions are periodically reviewed and the effects of revisions are reflected in the unaudited interim consolidated financial statements in the period they are determined to be necessary. Significant areas that require management’s estimates include the fair value of common stock, prior to the IPO, share-based compensation assumptions, royalty purchase liability assumptions and accrued clinical trial expense. The full extent to which the COVID-19 pandemic will directly or indirectly impact our business, results of operations and financial condition, including manufacturing, clinical trials, research and development costs and employee-related amounts, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain or treat COVID-19, as well as the economic impact on local, regional, national and international customers and markets. Management has made estimates regarding the impact of COVID-19 within the Company’s financial disclosures and there may be changes to those estimates in future periods. Actual results may differ from these estimates.
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: March 31, 2020 2019 Stock options 4,557,673 3,142,879 Redeemable convertible preferred stock — 19,061,502 4,557,673 22,204,381 Amounts in the above table reflect the common stock equivalents for the redeemable convertible preferred stock.
Recent Accounting Pronouncements	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

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 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: March 31, 2020 2019 Stock options 4,557,673 3,142,879 Redeemable convertible preferred stock — 19,061,502 4,557,673 22,204,381

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 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): March 31, 2020 (Level 1) (Level 2) (Level 3) Assets Money market funds and U.S. Treasury obligations (included in cash equivalents) $ 19,946 $ — $ — Short-term investments $ 98,939 $ — $ — 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 $ 93,934 $ — $ —

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2020
Property Plant And Equipment [Abstract]
Schedule of Property Plant and Equipment	Property and equipment consist of (amounts in thousands): March 31, 2020 December 31, 2019 Laboratory equipment $ 786 $ 748 Computer hardware and software 218 218 Leasehold improvements 262 262 Furniture and fixtures 147 147 Property and equipment, gross 1,413 1,375 Less: Accumulated depreciation (521 ) (441 ) Property and equipment, net $ 892 $ 934

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of (amounts in thousands): March 31, 2020 December 31, 2019 Compensation and related benefits $ 726 $ 1,160 Research and development expenses 4,842 3,882 Professional fees and other expenses 155 410 $ 5,723 $ 5,452

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2020
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, 2020 2019 Operating Leases Operating lease right-of-use assets $ 745 $ 815 Other current liabilities 285 297 Operating lease liabilities 472 534 Total operating lease liabilities $ 757 $ 831
Summary of Components of Lease Expense	The components of lease expense were as follows: Three months ended March 31, 2020 2019 Operating lease costs Operating lease rental expense $ 74 $ 52 Interest on lease liabilities 10 14 Total operating lease liabilities $ 84 $ 66
Summary of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases was as follows: Three months ended March 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 84 $ 66 Right-of-use assets obtained in exchange for lease obligation Operating leases — 1,084
Summary of Future Minimum Rental Payments Under Non Cancelable Operating Leases	Future minimum rental payments under the Company’s non-cancelable operating leases were as follows as of March 31, 2020 (amounts in thousands): Remainder of 2020 $ 248 2021 259 2022 260 2023 44 Total 811 Less: imputed interest (54 ) $ 757

Share-based Compensation (Table

Share-based Compensation (Tables)	3 Months Ended
	Mar. 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 three months ended March 31, 2020 and 2019 (in thousands): Three months ended March 31, 2020 2019 Research and development $ 594 $ 238 General and administrative 616 261 $ 1,210 $ 499
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, 2020: Shares Weighted average exercise price per share Weighted- average remaining contractual life (years) Outstanding at January 1, 2020 3,537,946 $ 5.17 Granted 1,028,230 14.40 Exercised (8,503 ) 1.07 Forfeited — — Outstanding at March 31, 2020 4,557,673 $ 7.26 7.7 Vested and exercisable at March 31, 2020 2,189,443 $ 3.06 5.9 Vested and expected to vest at March 31, 2020 4,557,673 $ 7.26 7.7
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, 2020 2019 Expected term (in years) 6.2 6.2 Expected stock price volatility 89.0 % 91.0 % Risk-free interest rate 1.32 % 2.47 % Expected dividend yield 0 % 0 %

Organization and description _2

Organization and description of business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 09, 2019	Nov. 12, 2019	Mar. 31, 2020	Dec. 31, 2019
Organization And Description Of Business [Line Items]
Date of incorporation			Nov. 19, 2012
Accumulated deficit			$ (179,767)	$ (161,350)
Expected payments to be received from royalty purchase agreement			$ 57,500
Common stock, shares issued (shares)			24,820,070	24,811,567
Redeemable Convertible Preferred Stock
Organization And Description Of Business [Line Items]
Shares issued upon conversion		19,061,502
IPO
Organization And Description Of Business [Line Items]
Common stock, shares issued (shares)		5,000,000
Public offering price		$ 12
Net proceeds from stock offering		$ 53,100
Over-allotment option
Organization And Description Of Business [Line Items]
Common stock, shares issued (shares)	445,690
Public offering price	$ 12
Net proceeds from stock offering	$ 5,000

Basis of Presentation and Sig_4

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, 2020	Mar. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities excluded from computation of earnings per share	4,557,673	22,204,381
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities excluded from computation of earnings per share	4,557,673	3,142,879
Redeemable Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive Securities excluded from computation of earnings per share		19,061,502

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 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	$ 19,946	$ 17,447
Level 1 | Short- Term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	98,939	93,934
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 | Short- Term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	0	0
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 | Short- Term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 0	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020USD ($)
Fair Value Disclosures [Abstract]
Changes in valuation techniques	$ 0

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,413	$ 1,375
Less: Accumulated depreciation	(521)	(441)
Property and equipment, net	892	934
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	786	748
Computer Hardware and Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	218	218
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	262	262
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 147	$ 147

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Property Plant And Equipment [Abstract]
Depreciation	$ 80,000	$ 46,000

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Compensation and related benefits	$ 726	$ 1,160
Research and development expenses	4,842	3,882
Professional fees and other expenses	155	410
Accrued expenses	$ 5,723	$ 5,452

Royalty Purchase Liability - Ad

Royalty Purchase Liability - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended
	Feb. 29, 2020	Apr. 30, 2019	Nov. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Royalty Purchase Liability [Line Items]
Total agreed amount of royalty purchase price				$ 64,346		$ 43,251
Royalty purchase price				20,000
Noncash interest expense				1,095	$ 439
Royalty Agreements
Royalty Purchase Liability [Line Items]
Total agreed amount of royalty purchase price			$ 80,000
Royalty purchase price				60,000
Noncash interest expense				$ 1,100	$ 400
Effective interest rate				8.70%
Outstanding amount of royalty agreement				$ 20,000
Period of notice for termination of royalty agreement				2 days
Royalty Agreements | First Tranche
Royalty Purchase Liability [Line Items]
Royalty purchase price			$ 20,000
Royalty Agreements | Second Tranche
Royalty Purchase Liability [Line Items]
Royalty purchase price		$ 20,000
Royalty Agreements | Third Tranche
Royalty Purchase Liability [Line Items]
Royalty purchase price	$ 20,000

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Lessee Lease Description [Line Items]
Operating lease liability, non current	$ 472	$ 534
Operating lease, right-of-use asset	745	$ 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	3 years
ASC 842 | Laboratory Space
Lessee Lease Description [Line Items]
Non-cancelable operating lease, term	10 months 24 days

Leases - Summary of Balance She

Leases - Summary of Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease right-of-use assets	$ 745	$ 815
Other current liabilities	285	297
Operating lease liabilities	472	534
Total operating lease liabilities	$ 757	$ 831

Leases - Summary of Components

Leases - Summary of Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Leases [Abstract]
Operating lease rental expense	$ 74	$ 52
Interest on lease liabilities	10	14
Total operating lease liabilities	$ 84	$ 66

Leases - Summary of Supplementa

Leases - Summary of Supplemental Cash Flow Information Related to Lease (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Leases [Abstract]
Operating cash flows from operating leases	$ 84	$ 66
Right-of-use assets obtained in exchange for lease obligation
Operating leases		$ 1,084

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Rental Payments Under Non Cancelable Operating Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Remainder of 2020	$ 248
2021	259
2022	260
2023	44
Total	811
Less: imputed interest	(54)
Operating lease liabilities	$ 757	$ 831

Share-based Compensation - Addi

Share-based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Nov. 30, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost		$ 19.1
Estimated recognition weighted-average amortization period		3 years 6 months
Aggregate intrinsic value of options outstanding		$ 16.6
Aggregate intrinsic value of options exercisable		$ 14.3
Weighted-average grant-date fair values of options granted		$ 10.72	$ 5.45
Expected dividend yield		0.00%	0.00%
2019 Incentive Award Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
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
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
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				3,038,259
Vesting period		4 years
Term of award		10 years

Share-based Compensation - Summ

Share-based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 1,210	$ 499
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	594	238
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total share-based compensation expense	$ 616	$ 261

Share-based Compensation - Su_2

Share-based Compensation - Summary of Activity Related to Stock Option Grants (Details)	3 Months Ended
	Mar. 31, 2020$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Outstanding beginning balance | shares	3,537,946
Shares, Granted | shares	1,028,230
Shares, Exercised | shares	(8,503)
Shares, Outstanding ending balance | shares	4,557,673
Shares, Vested and exercisable | shares	2,189,443
Shares, Vested and expected to vest | shares	4,557,673
Weighted average exercise price per share, Outstanding beginning balance | $ / shares	$ 5.17
Weighted average exercise price per share, Granted | $ / shares	14.40
Weighted average exercise price per share, Exercised | $ / shares	1.07
Weighted average exercise price per share, Outstanding ending balance | $ / shares	7.26
Weighted average exercise price per share, Vested and exercisable | $ / shares	3.06
Weighted average exercise price per share, Vested and expected to vest | $ / shares	$ 7.26
Weighted average remaining contractual life, Outstanding	7 years 8 months 12 days
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 8 months 12 days

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)	3 Months Ended
	Mar. 31, 2020	Mar. 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	89.00%	91.00%
Risk-free interest rate	1.32%	2.47%
Expected dividend yield	0.00%	0.00%

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
IntellectMap
Related Party Transaction [Line Items]
Advisory services fees	$ 0.1	$ 0.1

Subsequent events - Additional

Subsequent events - Additional Information (Details) $ / shares in Units, $ in Thousands	May 11, 2020USD ($)Warrant$ / sharesshares	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Nov. 30, 2018USD ($)
Subsequent Event [Line Items]
Total agreed amount of royalty purchase price		$ 64,346	$ 43,251
Amended Royalty Agreements | Subsequent Event
Subsequent Event [Line Items]
Outstanding amount of royalty agreement	$ 37,500
Total agreed amount of royalty purchase price	$ 117,500
Number of warrants issued | Warrant	2
Class of warrant, shares issued | shares	550,661
Common stock, exercise price per share | $ / shares	$ 13.62
Amended Royalty Agreements | Subsequent Event | Fifth Tranche
Subsequent Event [Line Items]
Outstanding amount of royalty agreement	$ 20,000
Royalty Agreements
Subsequent Event [Line Items]
Outstanding amount of royalty agreement		$ 20,000
Total agreed amount of royalty purchase price				$ 80,000