Akero Therapeutics (AKRO) 10-Q 13 May 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	May 07, 2021
Document and Entity Information
Document Type	10-Q
Document Period End Date	Mar. 31, 2021
Entity Registrant Name	Akero Therapeutics, Inc.
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	AKRO
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		34,826,078
Entity Central Index Key	0001744659
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 187,960	$ 187,242
Short-term marketable securities	62,024	81,145
Prepaid expenses and other current assets	5,792	2,958
Total current assets	255,776	271,345
Property and equipment, net	120	131
Right of use asset	1,612	1,662
Other assets, noncurrent	115	201
Total assets	257,623	273,339
Current liabilities:
Accounts payable	4,605	3,428
Accrued expenses and other current liabilities	5,531	9,683
Total current liabilities	10,136	13,111
Operating lease liability, noncurrent	1,467	1,516
Total liabilities	11,603	14,627
Commitments and contingencies (Note 11)
Stockholders’ equity:
Common stock, $0.0001 par value, 150,000,000 shares authorized as of March 31, 2021 and December 31, 2020; 34,770,319 and 34,741,649 shares issued and outstanding as of March 31, 2021 and December 31, 2020, respectively	4	4
Additional paid-in capital	470,635	468,238
Accumulated other comprehensive loss	(2)	(3)
Accumulated deficit	(224,617)	(209,527)
Total stockholders’ equity	246,020	258,712
Total liabilities and stockholders’ equity	$ 257,623	$ 273,339

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Condensed Consolidated Balance Sheets
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	34,770,319	34,741,649
Common stock, shares outstanding	34,770,319	34,741,649

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating expenses:
Research and development	$ 10,602	$ 8,791
General and administrative	4,526	3,588
Total operating expenses	15,128	12,379
Loss from operations	(15,128)	(12,379)
Other income:
Other income	38	493
Net loss	(15,090)	(11,886)
Net unrealized gain on short-term marketable securities	1	51
Comprehensive loss	$ (15,089)	$ (11,835)
Net loss per common share, basic and diluted	$ (0.43)	$ (0.42)
Weighted-average number of shares used in computing net loss per common share, basic and diluted	34,744,275	28,499,475

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Common Stock	Additional Paid-In-Capital	Accumulated Other Comprehensive Gain (Loss)	Accumulated Deficit	Total
Balance at beginning at Dec. 31, 2019	$ 3	$ 259,049	$ (6)	$ (130,320)	$ 128,726
Balance at beginning (in shares) at Dec. 31, 2019	28,567,837
Exercise of stock options		112			112
Exercise of stock options (in shares)	103,385
Vesting of restricted stock		30			30
Stock-based compensation expense		1,238			1,238
Disgorgement of stockholders' short-swing profits, net		52			52
Net unrealized gain on short-term marketable securities			51		51
Net loss				(11,886)	(11,886)
Balance at ending at Mar. 31, 2020	$ 3	260,481	45	(142,206)	118,323
Balance at ending (in shares) at Mar. 31, 2020	28,671,222
Balance at beginning at Dec. 31, 2019	$ 3	259,049	(6)	(130,320)	128,726
Balance at beginning (in shares) at Dec. 31, 2019	28,567,837
Net loss					(79,207)
Balance at ending at Dec. 31, 2020	$ 4	468,238	(3)	(209,527)	258,712
Balance at ending (in shares) at Dec. 31, 2020	34,741,649
Exercise of stock options		24			$ 24
Exercise of stock options (in shares)	28,670				28,670
Vesting of restricted stock		9			$ 9
Stock-based compensation expense		2,364			2,364
Net unrealized gain on short-term marketable securities			1		1
Net loss				(15,090)	(15,090)
Balance at ending at Mar. 31, 2021	$ 4	$ 470,635	$ (2)	$ (224,617)	$ 246,020
Balance at ending (in shares) at Mar. 31, 2021	34,770,319

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (15,090)	$ (11,886)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	2,364	1,237
Depreciation	11
Non-cash lease expense	50	54
Net amortization of premiums and discounts on short-term investments	121	(103)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(2,787)	724
Accounts payable	1,177	588
Accrued expenses and other current liabilities	(4,143)	(1,877)
Operating lease liability	(49)	(54)
Net cash used in operating activities	(18,346)	(11,317)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of short-term marketable securities		(24,781)
Proceeds from maturities of short-term marketable securities	19,000	18,500
Net cash provided by (used in) investing activities	19,000	(6,281)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the exercise of stock options	24	112
Proceeds from the disgorgement of stockholders' short-swing profits, net		52
Net cash provided by financing activities	24	164
Net increase (decrease) in cash, cash equivalents and restricted cash	678	(17,434)
Cash, cash equivalents and restricted cash at the beginning of the period	187,390	64,848
Cash, cash equivalents and restricted cash at the end of the period	188,068	47,414
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING INFORMATION:
Net unrealizable gain (loss) on marketable securities	$ 1	$ 51

Nature of the business and basi

Nature of the business and basis of presentation	3 Months Ended
	Mar. 31, 2021
Nature of the business and basis of presentation
Nature of the business and basis of presentation	1. Nature of the business and basis of presentation Akero Therapeutics, Inc., together with its wholly owned subsidiary Akero Securities Corporation, (“Akero” or the “Company”) is a cardio-metabolic nonalcoholic steatohepatitis, or NASH, company dedicated to developing pioneering medicines designed to restore metabolic balance and improve overall health. NASH is a severe form of nonalcoholic fatty liver disease, or NAFLD, characterized by inflammation and fibrosis in the liver that can progress to cirrhosis, liver failure, cancer and death. The Company’s lead product candidate, efruxifermin, or EFX, is an analog of fibroblast growth factor 21, or FGF21, which is an endogenously expressed hormone that protects against cellular stress and regulates metabolism of lipids, carbohydrates and proteins throughout the body. The Company conducted a Phase 2a clinical trial, the BALANCED study, to evaluate EFX in the treatment of biopsy-confirmed NASH patients. The main portion of this study in NASH patients with F1-F3 fibrosis showed EFX’s potential to reverse fibrosis, resolve NASH, improve liver health, improve glycemic control and improve lipoprotein profile. An expansion cohort in F4 NASH patients with compensated cirrhosis showed comparable results. The Company initiated a Phase 2b clinical trial, the HARMONY study, to evaluate EFX in the treatment of NASH patients with F2/F3 fibrosis in February 2021 and randomized the first patient in March 2021. Initiation of a second Phase 2b clinical trial in F4 NASH patients with compensated cirrhosis, the SYMMETRY study, is planned for the second half of 2021. Based on clinical data to date, the Company believes EFX has the potential to be a highly-differentiated, best-in-class FGF21 analog and foundational NASH monotherapy. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, completion and success of clinical testing, development by competitors of new technological innovations, compliance with governmental regulations, dependence on key personnel and protection of proprietary technology and the ability to secure additional capital to fund operations. EFX will require extensive clinical testing prior to regulatory approval and commercialization. These efforts require significant amounts of additional capital, adequate personnel, and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s drug development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. Basis of presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company after elimination of all intercompany accounts and transactions. All adjustments necessary for the fair presentation of the Company’s condensed consolidated financial statements for the periods have been reflected. Liquidity In accordance with Accounting Standards Update (“ASU”) No. 2014‑15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205‑40) , the Company has evaluated whether there are certain conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the consolidated financial statements are issued. Since its inception, the Company has funded its operations primarily with proceeds from sales of redeemable convertible preferred stock and most recently with proceeds from its initial public offering (“IPO”) in June 2019 and a follow-on public offering of its common stock in July 2020 . The Company has incurred recurring losses since its inception, including net losses of $15,090 and $11,886 for the three months ended March 31, 2021 and 2020, respectively, and net losses of $79,207 and $43,755 for the years ended December 31, 2020 and 2019, respectively. In addition, as of March 31, 2021, the Company had an accumulated deficit of $224,617. The Company expects to continue to generate operating losses for the foreseeable future. As of May 13, 2021, the issuance date of these condensed consolidated financial statements, the Company expects that its existing cash, cash equivalents and short-term marketable securities of $249,984 as of March 31, 2021, will be sufficient to fund its operating expenses and capital expenditure requirements for at least 12 months from the issuance date of these condensed consolidated financial statements. The Company expects that it will require additional funding beyond this time to complete the clinical development of EFX, commercialize EFX, if it receives regulatory approval, and pursue in-licenses or acquisitions of other product candidates. If the Company is unable to obtain funding, the Company will be forced to delay, reduce or eliminate some or all of its research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect its business prospects, or the Company may be unable to continue operations. Although management continues to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all.

Fair value of financial assets

Fair value of financial assets and liabilities	3 Months Ended
	Mar. 31, 2021
Fair value of financial assets and liabilities
Fair value of financial assets and liabilities	3. Fair value of financial assets and liabilities Certain assets and liabilities of the Company are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: · Level 1—Quoted prices in active markets for identical assets or liabilities. · Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. · Level 3—Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The following is a summary of our financial assets measured at fair value on a recurring basis as of March 31, 2021 and December 31, 2020: March 31, 2021 Total Level 1 Level 2 Level 3 Money market funds $ 162,416 $ 162,416 $ — $ — Commercial paper 33,976 — 33,976 — Corporate debt securities 28,048 — 28,048 — $ 224,440 $ 162,416 $ 62,024 $ — December 31, 2020 Total Level 1 Level 2 Level 3 Money market funds $ 158,023 $ 158,023 $ — $ — Commercial paper 47,955 — 47,955 — Corporate debt securities 33,190 — 33,190 — $ 239,168 $ 158,023 $ 81,145 $ — Commercial paper and corporate debt securities were valued by the Company using quoted prices in active markets for similar securities, which represent a Level 2 measurement within the fair value hierarchy. The carrying values of the Company’s prepaid expenses and other current assets, accounts payable and accrued expenses approximate their fair values due to the short-term nature of these assets and liabilities. During the three months ended March 31, 2021 and the twelve months ended December 31, 2020, there were no transfers between Level 1, Level 2 and Level 3.

Short-term marketable securitie

Short-term marketable securities	3 Months Ended
	Mar. 31, 2021
Short-term marketable securities
Short-term marketable securities	4 . Short-term marketable securities The following is a summary of short-term marketable securities as of March 31, 2021 and December 31, 2020 : March 31, 2021 Amortized cost Gross unrealized gains Gross unrealized losses Fair value Money market funds $ 162,416 $ — $ — $ 162,416 Commercial paper 33,976 — — 33,976 Corporate debt securities 28,050 — (2) 28,048 $ 224,442 $ — $ (2) $ 224,440 Cash equivalents $ 162,416 Short-term marketable securities 62,024 $ 224,440 December 31, 2020 Amortized cost Gross unrealized gains Gross unrealized losses Fair value Money market funds $ 158,023 $ — $ — $ 158,023 Commercial paper 47,955 — — 47,955 Corporate debt securities 33,193 — (3) 33,190 $ 239,171 $ — $ (3) $ 239,168 Cash equivalents $ 158,023 Short-term marketable securities 81,145 $ 239,168

Accrued expenses and other curr

Accrued expenses and other current liabilities	3 Months Ended
	Mar. 31, 2021
Accrued expenses and other current liabilities
Accrued expenses and other current liabilities	5. Accrued expenses and other current liabilities The following is a summary of accrued expenses and other current liabilities as of March 31, 2021 and December 31, 2020 : March 31, 2021 December 31, 2020 Accrued external research and development expenses $ 3,923 $ 8,740 Accrued employee compensation and benefits 965 495 Accrued legal and professional fees 306 154 Short-term lease liability and other 337 294 $ 5,531 $ 9,683

Stockholder's equity (deficit)

Stockholder's equity (deficit)	3 Months Ended
	Mar. 31, 2021
Stockholder’s equity (deficit)
Stockholder’s equity (deficit)	6. Stockholder’s equity (deficit) Common stock As of March 31, 2021 and December 31, 2020, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue 150,000,000 shares of $0.0001 par value common stock. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. The holders of common stock, voting exclusively and as a separate class, have the exclusive right to vote for the election of directors of the Company. Common stockholders are entitled to receive dividends, as may be declared by the board of directors. Through March 31, 2021, no cash dividends had been declared or paid. On June 24, 2019, the Company completed its IPO at which time the Company issued 6,612,500 shares of common stock, including the exercise in full by the underwriters of their option to purchase up to 862,500 additional shares of common stock, at a public offering price of $16.00 per share. The Company received $98,394, net of underwriting discounts and commissions, but before deducting offering costs paid by the Company, which were $2,942. Upon the closing of the IPO, all outstanding shares of convertible preferred stock converted into 21,056,136 shares of common stock. On July 10, 2020, the Company completed a follow-on public offering at which time the Company issued 6,012,390 shares of common stock, including the exercise in full by the underwriters of their option to purchase up to 784,224 additional shares of common stock, at a public offering price of $36.00 per share. The Company received $203,460 net of underwriting discounts and commissions, but before deducting offering costs paid by the Company, which were $906. As of March 31, 2021 and December 31, 2020, there were 34,770,319 and 34,741,649 shares of common stock issued and outstanding, respectively. The following shares of common stock were reserved for issuance as follows: March 31, 2021 December 31, 2020 Options outstanding under the 2018 Stock Option and Grant Plan 2,119,349 2,148,019 Options outstanding under the 2019 Stock Option and Incentive Plan 1,758,356 1,585,293 Options available for future grant 3,344,146 2,127,544 2019 Employee Stock Purchase Plan 891,379 543,963 Total 8,113,230 6,404,819 Undesignated preferred stock The Company’s fourth amended and restated certificate of incorporation authorizes the Company to issue up to 10,000,000 shares of undesignated preferred stock, par value $0.0001 per share. There were no undesignated preferred shares issued or outstanding as of March 31, 2021. Restricted common stock In March 2017, the Company issued an aggregate of 226,400 shares of restricted common stock under restricted stock agreements with the founders. Pursuant to the terms of the agreements, the restricted common stock was initially subject to a vesting schedule over a four-year period commencing in January 2017 and culminating in January 2021. In March 2018, the Company amended the restricted stock agreements such that the restricted common stock became subject to a vesting schedule over a two-year period commencing in May 2018 and culminating in June 2020. As of March 31, 2021, all restricted stock issued to the founders is fully vested. In April, June and July 2019, the Company amended certain option grant agreements granted under the Company’s 2018 Stock Option and Grant Plan to allow the holders the right to early exercise unvested options, subject to a repurchase right held by the Company equal to the lesser of the original exercise price per share or the fair value of the shares on the repurchase date. The unvested shares issued as a result of the early exercise are deemed restricted stock pursuant to a restricted stock agreement and a vesting schedule identical to the vesting schedule of the original grant agreement. The proceeds related to unvested restricted common stock are recorded as liabilities until the stock vests, at which point they are reclassified to additional paid-in capital. Common shares issued for the early exercise of options are included in issued and outstanding shares. The following table summarizes restricted stock activity since December 31, 2020: Grant-Date Fair Number of Shares Value Unvested restricted common stock as of December 31, 2020 33,614 0.62 Shares vesting (14,889) 0.62 Unvested restricted common stock as of March 31, 2021 18,725 $ 0.62 As of March 31, 2021, there were 18,725 shares of unvested restricted common stock from the early exercise of stock options.

Stock-based awards

Stock-based awards	3 Months Ended
	Mar. 31, 2021
Stock-based awards
Stock-based awards	7. Stock-based awards 2018 Stock option and grant plan The Company’s 2018 Stock Option and Grant Plan (the “2018 Plan”) provided for the Company to grant incentive stock options or nonqualified stock options, restricted stock awards and other stock-based awards to employees, directors and consultants of the Company. The 2018 Plan was administered by the board of directors or, at the discretion of the board of directors, by a committee of the board of directors. The exercise prices, vesting and other restrictions were determined at the discretion of the board of directors, or its committee if so delegated. The total number of shares of common stock that could have been issued under the 2018 Plan was 3,071,960 shares, of which 107,635 shares remained available for grant on June 18, 2019, the date that the Company’s 2019 Stock Option and Incentive Plan (the “2019 Plan”) became effective. Upon the effectiveness of the 2019 Plan, the 107,635 remaining shares available under the 2018 Plan were transferred and became available for issuance under the 2019 Plan. Shares of common stock underlying outstanding awards under the 2018 Plan that are forfeited, cancelled, held back upon exercise or settlement of an award to satisfy the exercise price or tax withholding, reacquired by the Company prior to vesting, satisfied without the issuance of stock, expire or are otherwise terminated (other than by exercise) will be added to the shares of common stock available for issuance under the 2019 Plan. 2019 Stock option and incentive plan The 2019 Plan was adopted and approved by the Company’s board of directors in May 2019 and by the Company’s stockholders in June 2019. The 2019 Plan became effective on June 18, 2019 and replaced the Company’s 2018 Plan on that date. The 2019 Plan allows the board of directors or the compensation committee of the board of directors to make equity-based incentive awards to the Company’s officers, employees, directors or other key persons (including consultants). The number of shares initially reserved for issuance under the 2019 Plan was 2,572,457, which included the 107,635 shares transferred from the 2018 Plan, and shall be cumulatively increased on each January 1 by 4% of the number of shares of the Company’s common stock outstanding on the immediately preceding December 31 or such lesser number of shares determined by the Company’s board of directors or compensation committee of the board of directors. The 2019 Plan was increased by 1,389,665 shares on January 1, 2021 and by 1,142,713 shares on January 1, 2020. The 2019 Plan is administered by the board of directors or, at the discretion of the board of directors, by a committee of the board of directors. The exercise prices, vesting and other restrictions are determined at the discretion of the board of directors, or its committee if so delegated, except that the exercise price per share of stock options may not be less than 100% of the fair market value of the share of common stock on the date of grant and the term of stock option may not be greater than ten years. All incentive options granted to any person possessing more than 10% of the total combined voting power of all classes of shares may not have an exercise price of less than 110% of the fair market value of the common stock on the grant date. Stock options granted to employees, officers, members of the board of directors and consultants will typically vest over a four-year period. Shares that are expired, terminated, surrendered or canceled under the 2019 Plan without having been fully exercised will be available for future awards. 2019 Employee stock purchase plan The 2019 Employee Stock Purchase Plan (the “2019 ESPP”) was adopted and approved by the Company’s board of directors in May 2019 and by the Company’s stockholders in June 2019. The 2019 ESPP became effective on June 18, 2019, at which time 273,869 shares were reserved for issuance. The 2019 ESPP provides that the number of shares reserved and available for issuance will automatically increase each January 1, beginning on January 1, 2020 and each January 1 through January 1, 2029, by the least of (i) 1% of the outstanding number of shares of the Company’s common stock on the immediately preceding December 31, (ii) 410,803 shares or (iii) such number of shares as determined by the compensation committee. The 2019 ESPP was increased by 347,416 shares on January 1, 2021 and by 285,678 shares on January 1, 2020. Stock option valuation The assumptions that the Company used to determine the grant-date fair value of stock options granted to employees, directors and consultants as follows, presented on a weighted average basis: Three Months Ended March 31, 2021 2020 Expected term (in years) 6.00 6.00 Expected volatility 70.44 % % Weighted average risk-free interest rate 0.59 % % Expected dividend yield 0.00 % % Stock options The following table summarizes the Company’s stock option activity since December 31, 2020: Weighted- Weighted- Average Average Aggregate Exercise remaining Intrinsic Number Price per contractual Value of Options Share term (years) (000's) Balance outstanding, December 31, 2020 3,733,312 $ 12.15 8.53 $ 52,498 Options granted 173,063 $ 25.99 Options exercised (28,670) $ 0.85 Balance outstanding, March 31, 2021 3,877,705 $ 12.85 8.36 $ 62,711 Exercisable, March 31, 2021 1,310,142 $ 8.80 8.02 $ 26,473 Vested and expected to vest, March 31, 2021 3,877,705 $ 12.85 8.36 $ 62,711 The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The weighted average grant-date fair value per share of stock options granted during the three months ended March 31, 2021 was $16.08. Stock-based compensation The following table summarizes the Company’s stock-based compensation expense during the three months ended March 31, 2021 and 2020: Three Months Ended March 31, 2021 2020 Classified within research and development expense $ 1,645 $ 368 Classified within general and administrative expense 719 869 Total stock-based compensation expense $ 2,364 $ 1,237 As of March 31, 2021, total unrecognized compensation cost related to unvested stock options was $23,608, which is expected to be recognized over a weighted average period of 2.3 years. In April, June and July 2019, certain option holders early exercised options to purchase 491,207 shares of common stock, at an average exercise price of $0.65 per share, for cash proceeds of $321 (See Note 6). Stock-based compensation expense related to these options will continue to be recognized over the requisite service period of the awards based on the grant-date fair value which was determined using the Black-Scholes option-pricing model.

Amgen license agreement

Amgen license agreement	3 Months Ended
	Mar. 31, 2021
Amgen license agreement
Amgen license agreement	8. Amgen license agreement In June 2018, the Company entered into a license agreement (the “Amgen Agreement”) with Amgen, Inc. (“Amgen”) pursuant to which the Company was granted an exclusive license to certain patents and intellectual property related to a long-acting FGF21 analog in order to commercially develop, manufacture, use and distribute FGF21 as a treatment for NASH and other serious metabolic diseases. The Amgen Agreement provides the Company with exclusive global rights to the licensed products and the right to grant sublicenses that cover EFX to third parties. In exchange for these rights, the Company made an upfront payment of $5,000 and issued 2,653,333 shares of Series A Preferred Stock with a fair value of $1,353 to Amgen. Amgen was also entitled to maintain a 10% ownership interest of the outstanding shares of the Company’s common stock, on a fully diluted and converted basis, through the second closing of the Company’s Series A Preferred Stock financing. In November 2018, in connection with the second closing of the Company’s Series A Preferred Stock financing, the Company issued 3,205,128 shares of Series A Preferred Stock to Amgen for a total value of $7,404, satisfying its anti-dilution obligation under the Amgen Agreement. Under the Amgen Agreement, the Company made a milestone payment in August 2019 of $2,500 in connection with dosing the first patient in the BALANCED study and is obligated to pay Amgen $7,500 in connection with dosing the first patient in a Phase 3 clinical trial, up to $30,000 in connection with marketing approvals, and aggregate milestone payments of up to $75,000 upon the achievement of specified commercial milestones for all products licensed under the Amgen Agreement. Under the Amgen Agreement, the Company is obligated to pay Amgen tiered royalties ranging from a low to high single-digit percentages on annual net sales of the licensed products, beginning on the first commercial sale of such licensed products in each country and expiring on a country-by-country basis on the latest of (i) the expiration of the last valid patent claim covering such licensed products in such country, (ii) the loss of regulatory exclusivity in such country, and (iii) ten years after the first commercial sale of such licensed product in such country. The royalty payments are subject to reduction under specified conditions set forth in the Amgen Agreement. The Company is solely responsible for all development, manufacturing, and commercial activities and costs of the licensed products, including clinical studies or other tests necessary to support the use of a licensed product. The Company is also responsible for costs related to the filing, prosecution and maintenance of the licensed patent rights. The Amgen Agreement will remain in effect until the expiration of the royalty term in all countries for all licensed products. The Amgen Agreement may be terminated by either party with at least 90 days' notice in the event of material breach by the other party that remains uncured for 90 days, by either party for insolvency or bankruptcy of the other party and immediately by Amgen if the Company challenges the licensed patents. The Company may also terminate the Amgen Agreement with 90 days' written notice for discretionary reasons such as scientific, technical, regulatory or commercial issues , as defined in the Amgen Agreement. During the three months ended March 31, 2021 and 2020, the Company did not record any research and development expense in connection with the Amgen Agreement.

Income taxes

Income taxes	3 Months Ended
	Mar. 31, 2021
Income taxes
Income taxes	9. Income taxes During the three months ended March 31, 2021 and 2020, the Company did not record any income tax benefits for the net operating losses incurred or for the research and development tax credits generated in each period due to its uncertainty of realizing a benefit from those items. All of the Company’s operating losses since inception have been generated in the United States. On March 27, 2020, the Coronavirus Aid, Relief and Economic Security (CARES) Act, (the “Act”) was signed into law. The Act includes provisions relating to refundable payroll tax credits, deferment of the employer portion of certain payroll taxes, net operating loss carryback periods, alternative minimum tax credit refunds, modifications to the net interest deduction limitations and technical corrections to tax depreciation methods for qualified improvement property. The Company analyzed the provisions of the Act and determined there was no significant impact to its income tax provision for the three months ended March 31, 2021.

Net loss per share

Net loss per share	3 Months Ended
	Mar. 31, 2021
Net loss per share
Net loss per share	10. Net loss per share Basic and diluted net loss per share attributable to common stockholders was calculated as follows: Three Months Ended March 31, 2021 2020 Numerator: Net loss $ (15,090) $ (11,886) Denominator: Weighted average common shares outstanding, basic and diluted 34,744,275 28,499,475 Net loss per share, basic and diluted $ (0.43) $ (0.42) The Company excluded 9,761 shares and 77,223 shares of restricted common stock, presented on a weighted average basis, from the calculations of basic net loss per share for the three months ended March 31, 2021 and 2020, respectively, because those shares had not vested. The Company’s potentially dilutive securities, which include stock options and unvested restricted common stock, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: Three Months Ended March 31, 2021 2020 Options to purchase common stock 3,877,705 3,095,450 Unvested restricted common stock 18,725 93,532 3,896,430 3,188,982

Commitments and contingencies

Commitments and contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and contingencies
Commitments and contingencies	11. Commitments and contingencies COVID-19 Pandemic In March 2020, the novel strain of coronavirus (“COVID-19”) was declared a pandemic by the World Health Organization. Efforts to contain the spread of COVID-19 intensified and the United States, Europe and Asia implemented severe travel restrictions, social distancing requirements, stay-at-home orders and delayed the commencement of non-COVID-19-related clinical trials, among other restrictions. The Company’s financial results for the three months ended March 31, 2021 were not significantly impacted by COVID-19, however despite vaccination efforts, the Company cannot at this time predict the specific extent, duration, or full impact that the COVID-19 pandemic will have on its financial condition, operations, and business plans for 2021, including the timing and enrollment of patients in its planned clinical trials and other expected milestones of its product candidate. Operating lease In February 2020, the Company entered into a seven-year agreement to occupy 6,647 square feet of office space in South San Francisco, California. The lease commenced on July 10, 2020 when the Company took occupancy of the leased space and the lease was determined to be operating classified. Under the agreement, the Company is required to make approximately $2,300 in total minimum payments during the term. The Company is also required to pay its proportionate share of building operating and tax costs after the first year under lease which are not included in the measurement of the lease and treated as variable lease cost and expensed when incurred. As of March 31, 2021, maturities of the Company’s operating lease liability was as follows: 2021 (remaining) $ 228 2022 312 2023 321 2024 331 2025 341 2026 and thereafter 559 Total future minimum lease payments 2,092 Less imputed interest (437) Present value of operating lease liabilities $ 1,655 As of March 31, 2021, the total lease liability was $1,655, of which $1,467 was noncurrent and $188 was short-term and classified within “Accrued expenses and other current liabilities” on the condensed consolidated balance sheet. For the three months ended March 31, 2021 and 2020, the components of operating lease cost were as follows: Three Months Ended March 31, 2021 March 31, 2020 Lease cost: Statement of Operations Classification: Operating lease cost General and administrative expense $ 81 $ 59 Variable operating lease cost General and administrative expense — 27 Short-term lease cost Research and development expense — 8 Total operating lease cost $ 81 $ 94 Other information: Cash paid for amounts included in the measurement of operating lease liability $ 75 $ 59 Weighted average remaining lease term, in years 6.3 1.0 Weighted average discount rate Research and manufacturing commitments The Company has entered into agreements with contract research organizations and contract manufacturing organizations to provide services in connection with its nonclinical studies and clinical trials and to manufacture clinical development materials. As of March 31, 2021, the Company had non-cancelable purchase commitments under these agreements totaling $11,153. Indemnification agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors and its executive officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company is not currently aware of any indemnification claims and has not accrued any liabilities related to such obligations in its condensed consolidated financial statements as of March 31, 2021. Legal proceedings The Company is not a party to any litigation and does not have contingency reserves established for any litigation liabilities. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to such legal proceedings.

Subsequent events

Subsequent events	3 Months Ended
	Mar. 31, 2021
Subsequent events
Subsequent events	12. Subsequent event The Company evaluated subsequent events through May 13, 2021, the date on which these financial statements were issued. Based on this evaluation, it was determined that no subsequent events occurred that require recognition or disclosure in its financial statements for the three months ended March 31, 2021.

Summary of significant accounti

Summary of significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 2021
Summary of significant accounting policies
Unaudited interim financial statements	Unaudited interim financial statements The accompanying unaudited condensed consolidated financial statements have been prepared by the Company in accordance with GAAP for interim financial reporting and as required by Regulation S-X, Rule 10‑01. The unaudited condensed consolidated financial statements have been prepared on the same basis as the Company’s audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the Company’s financial position as of March 31, 2021 and the results of its operations and its cash flows for the three months ended March 31, 2021 and 2020 and the condensed consolidated statement of stockholders’ equity (deficit) as of March 31, 2021. The financial data and other information disclosed in these notes related to the three months ended March 31, 2021 and 2020 are unaudited. The results for the three months ended March 31, 2021 are not necessarily indicative of results to be expected for the year ending December 31, 2021, any other interim periods, or any future year or period.
Use of estimates	Use of estimates The preparation of the Company's condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the accrual of research and development expenses, the valuations of common stock and the valuation allowance for deferred tax assets. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates when there are changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates.
Cash and cash equivalents	Cash and cash equivalents The Company considers all highly liquid investments with original maturities of three months or less at the time of purchase to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market accounts.
Short-term marketable securities	Short-term marketable securities The Company invests in short-term marketable securities, primarily money market funds, commercial paper, U.S. treasury securities and corporate debt securities. The Company classifies its short-term marketable securities as available-for-sale securities and reports them at fair value in short-term marketable securities on the condensed consolidated balance sheets with related unrealized gains and losses included within accumulated other comprehensive gain (loss) on the condensed consolidated balance sheets. The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in other income on the condensed consolidated statements of operations and comprehensive loss. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in other income. The Company regularly reviews all its investments for other-than-temporary declines in estimated fair value. This review includes the consideration of the cause of the impairment, including the creditworthiness of the security issuers, the number of securities in an unrealized loss position, the severity and duration of the unrealized losses, whether the Company has the intent to sell the securities and whether it is more likely than not that the Company will be required to sell the securities before the recovery of their amortized cost basis. When the Company determines that the decline in estimated fair value of an investment is below the amortized cost basis and the decline is other-than-temporary, the carrying value of the security will be reduced and a loss will be recorded for the amount of such decline.
Restricted cash	Restricted cash As of March 31, 2021 and December 31, 2020, the Company was required to maintain a separate cash balance of $108 for the benefit of the landlord in connection with the Company’s Gateway office space lease in South San Francisco, California (the “Gateway Lease”), which is classified within other assets (non-current) on the condensed consolidated balance sheets (see Note 11). As of December 31, 2020, the Company was required to maintain a separate cash balance of $40 to collateralize corporate credit cards with a bank, which is classified within other assets (non-current) on the condensed consolidated balance sheet.
Concentrations of credit risk	Concentrations of credit risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash, cash equivalents and short-term marketable securities. Periodically, the Company maintains deposits in accredited financial institutions in excess of federally insured limits. The Company deposits its cash investments in financial institutions that it believes have high credit quality and has not experienced any losses on such accounts and does not believe it is exposed to any unusual credit risk beyond the normal credit risk associated with commercial banking relationships. At March 31, 2021 and December 31, 2020, all of the Company's cash, cash equivalents and short-term investments were held at one accredited financial institution.
Property and equipment	Property and equipment Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation is provided using the straight-line method over the estimated useful lives of the assets, which is three years for furniture and equipment. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the improvements. Depreciation and amortization begins at the time the asset is placed in service.
Leases	Leases The Company determines whether an arrangement is or contains a lease at inception by assessing whether the arrangement contains an identified asset and whether the Company has the right to control the identified asset. Right-of-use, or ROU, assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Lease liabilities are recognized at the lease commencement date based on the present value of future lease payments over the lease term. ROU assets are based on the measurement of the lease liability and are further adjusted by any lease payments made prior to or on lease commencement, lease incentives received and initial direct costs incurred, as applicable. The Company has elected to not recognize leases with a lease term of one year or less on its balance sheet. Operating lease costs included in the measurement of the lease are recognized on a straight-line basis over the lease term. Variable lease costs are expensed as incurred as an operating expense. The Company determines the lease classification and the present value of future lease payments at the time of the lease commencement using an incremental borrowing rate that it estimates based upon the Company’s credit risk and term of the lease. The interest rate implicit in lease contracts has not historically been readily determinable and the Company must therefore use the appropriate incremental borrowing rate to measure its leases. To estimate the incremental borrowing rate, a credit rating applicable to the Company is estimated using a synthetic credit rating analysis since the Company does not currently have a rating agency-based credit rating.
Research and development costs	Research and development costs Research and development costs are expensed as incurred. Research and development expenses consist of costs incurred to discover, research and develop drug candidates, including personnel expenses, stock-based compensation expense, third-party license fees and external costs including fees paid to consultants, contract manufacturing organizations, or CMOs, and clinical research organizations, or CROs, in connection with drug product manufacturing, nonclinical studies and clinical trials, and other related clinical trial fees, such as for investigator grants, patient screening, laboratory work, clinical trial database management, clinical trial material management and statistical compilation and analysis. Non-refundable prepayments for goods or services that will be used or rendered for future research and development activities are recorded as prepaid expenses. Such amounts are recognized as an expense as the goods are delivered or the related services are performed, or until it is no longer expected that the goods will be delivered or the services rendered. Costs incurred i n obtaining technology licenses are charged immediately to research and development expense if the technology licensed has not reached technological feasibility and has no alternative future uses.
Research contract costs and accruals	Research contract costs and accruals The Company has entered into various research and development and other agreements with commercial firms, researchers and others for provisions of goods and services. These agreements are generally cancelable, and the related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies or clinical trials, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ materially from the Company's estimates.
Stock-based compensation	Stock-based compensation The Company measures all stock-based awards granted to employees and nonemployees based on the fair value on the date of the grant and recognizes compensation expense for those awards over the requisite service period, which is generally the vesting period of the respective award, on a straight-line basis. The Company accounts for forfeitures as they occur. The Company estimates the fair value of stock option grants using the Black-Scholes option pricing model. Prior to the Company’s initial public offering, the exercise price for all stock options granted was at the estimated fair value of the underlying common stock as determined on the date of grant by the Company’s board of directors. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model, which requires inputs based on certain subjective assumptions, including the expected stock price volatility, the expected term of the option, the risk-free interest rate for a period that approximates the expected term of the option, and the Company's expected dividend yield. The Company went public in June 2019 and accordingly, lacks sufficient company-specific historical and implied volatility information for its shares traded in the public markets. Therefore, it estimates its expected share price volatility based on the historical volatility of publicly traded peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded share price. The expected term of the Company's stock options has been determined utilizing the "simplified" method for awards that qualify as "plain-vanilla" options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends on common stock and does not expect to pay any cash dividends in the foreseeable future. The fair value of each common stock award is estimated on the date of grant based on the fair value of the Company's common stock on that same date. Compensation expense for purchases under the Employee Stock Purchase Plan is recognized based on the fair value of the common stock estimated based on the closing price of our common stock as reported on the date of offering, less the purchase discount percentage provided for in the plan. The Company classifies stock-based compensation expense in its condensed consolidated statement of operations and comprehensive loss in the same manner in which the award recipient's payroll costs are classified or in which the award recipient's service payments are classified.
Comprehensive loss	Comprehensive loss Comprehensive loss includes net loss as well as other changes in stockholders' equity (deficit) that result from transactions and economic events other than those with stockholders. The Company’s comprehensive loss is comprised of net loss and changes in unrealized gains and losses on its short-term marketable securities .
Emerging growth company	Emerging growth company The Company is an emerging growth company as defined in the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”). Under the JOBS Act, companies have extended transition periods available for complying with new or revised accounting standards. The Company has elected this exemption to delay adopting new or revised accounting standards until such time as those standards apply.
Recently issued accounting pronouncements and pronouncements not yet adopted	Recently adopted accounting pronouncements On January 1, 2021, the Company adopted Accounting Standard Update No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (ASU 2019-12), which simplifies the accounting for income taxes. ASU 2019-12 was effective beginning January 1, 2021. The adoption of this new standard did not have a material impact on our condensed consolidated financial statements. Recently issued accounting pronouncements not yet adopted In June 2016, the FASB issued No. ASU 2016-13, Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 requires measurement and recognition of expected credit losses for financial assets. In November 2019, the FASB issued No. ASU 2019-10 to modify the effective date for ASU 2016-13 for other public business entities includes smaller reporting companies, as defined by the SEC. This guidance will become effective for the Company beginning in the first quarter of 2023. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of ASU 2016-13 will have on its condensed consolidated financial statements.

Fair value of financial asset_2

Fair value of financial assets and liabilities (Tables)	3 Months Ended
	Mar. 31, 2021
Fair value of financial assets and liabilities
Summary of assets that are measured at fair value on a recurring basis	March 31, 2021 Total Level 1 Level 2 Level 3 Money market funds $ 162,416 $ 162,416 $ — $ — Commercial paper 33,976 — 33,976 — Corporate debt securities 28,048 — 28,048 — $ 224,440 $ 162,416 $ 62,024 $ — December 31, 2020 Total Level 1 Level 2 Level 3 Money market funds $ 158,023 $ 158,023 $ — $ — Commercial paper 47,955 — 47,955 — Corporate debt securities 33,190 — 33,190 — $ 239,168 $ 158,023 $ 81,145 $ —

Short-term marketable securit_2

Short-term marketable securities (Tables)	3 Months Ended
	Mar. 31, 2021
Short-term marketable securities
Summary of short-term marketable securities	March 31, 2021 Amortized cost Gross unrealized gains Gross unrealized losses Fair value Money market funds $ 162,416 $ — $ — $ 162,416 Commercial paper 33,976 — — 33,976 Corporate debt securities 28,050 — (2) 28,048 $ 224,442 $ — $ (2) $ 224,440 Cash equivalents $ 162,416 Short-term marketable securities 62,024 $ 224,440 December 31, 2020 Amortized cost Gross unrealized gains Gross unrealized losses Fair value Money market funds $ 158,023 $ — $ — $ 158,023 Commercial paper 47,955 — — 47,955 Corporate debt securities 33,193 — (3) 33,190 $ 239,171 $ — $ (3) $ 239,168 Cash equivalents $ 158,023 Short-term marketable securities 81,145 $ 239,168

Accrued expenses and other cu_2

Accrued expenses and other current liabilities (Tables)	3 Months Ended
	Mar. 31, 2021
Accrued expenses and other current liabilities
Schedule of accrued expenses and other current liabilities	March 31, 2021 December 31, 2020 Accrued external research and development expenses $ 3,923 $ 8,740 Accrued employee compensation and benefits 965 495 Accrued legal and professional fees 306 154 Short-term lease liability and other 337 294 $ 5,531 $ 9,683

Stockholder's equity (deficit)

Stockholder's equity (deficit) (Tables)	3 Months Ended
	Mar. 31, 2021
Stockholder’s equity (deficit)
Schedule of common stock reserved for issuance	March 31, 2021 December 31, 2020 Options outstanding under the 2018 Stock Option and Grant Plan 2,119,349 2,148,019 Options outstanding under the 2019 Stock Option and Incentive Plan 1,758,356 1,585,293 Options available for future grant 3,344,146 2,127,544 2019 Employee Stock Purchase Plan 891,379 543,963 Total 8,113,230 6,404,819
Summary of restricted stock activity	Grant-Date Fair Number of Shares Value Unvested restricted common stock as of December 31, 2020 33,614 0.62 Shares vesting (14,889) 0.62 Unvested restricted common stock as of March 31, 2021 18,725 $ 0.62

Stock-based awards (Tables)

Stock-based awards (Tables)	3 Months Ended
	Mar. 31, 2021
Stock-based awards
Schedule of assumptions used to determine grant-date fair value of stock options granted	Three Months Ended March 31, 2021 2020 Expected term (in years) 6.00 6.00 Expected volatility 70.44 % % Weighted average risk-free interest rate 0.59 % % Expected dividend yield 0.00 % %
Summary of stock option activity	Weighted- Weighted- Average Average Aggregate Exercise remaining Intrinsic Number Price per contractual Value of Options Share term (years) (000's) Balance outstanding, December 31, 2020 3,733,312 $ 12.15 8.53 $ 52,498 Options granted 173,063 $ 25.99 Options exercised (28,670) $ 0.85 Balance outstanding, March 31, 2021 3,877,705 $ 12.85 8.36 $ 62,711 Exercisable, March 31, 2021 1,310,142 $ 8.80 8.02 $ 26,473 Vested and expected to vest, March 31, 2021 3,877,705 $ 12.85 8.36 $ 62,711
Summary of stock-based compensation expense	Three Months Ended March 31, 2021 2020 Classified within research and development expense $ 1,645 $ 368 Classified within general and administrative expense 719 869 Total stock-based compensation expense $ 2,364 $ 1,237

Net loss per share (Tables)

Net loss per share (Tables)	3 Months Ended
	Mar. 31, 2021
Net loss per share
Schedule of basic and diluted net loss per share attributable to common stockholders	Three Months Ended March 31, 2021 2020 Numerator: Net loss $ (15,090) $ (11,886) Denominator: Weighted average common shares outstanding, basic and diluted 34,744,275 28,499,475 Net loss per share, basic and diluted $ (0.43) $ (0.42)
Schedule of computation of diluted net loss per share attributable to common stockholders	Three Months Ended March 31, 2021 2020 Options to purchase common stock 3,877,705 3,095,450 Unvested restricted common stock 18,725 93,532 3,896,430 3,188,982

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2021
Commitments and contingencies
Schedule of maturity of the Company’s operating lease liabilities	2021 (remaining) $ 228 2022 312 2023 321 2024 331 2025 341 2026 and thereafter 559 Total future minimum lease payments 2,092 Less imputed interest (437) Present value of operating lease liabilities $ 1,655
Schedule of components of operating lease expense	Three Months Ended March 31, 2021 March 31, 2020 Lease cost: Statement of Operations Classification: Operating lease cost General and administrative expense $ 81 $ 59 Variable operating lease cost General and administrative expense — 27 Short-term lease cost Research and development expense — 8 Total operating lease cost $ 81 $ 94 Other information: Cash paid for amounts included in the measurement of operating lease liability $ 75 $ 59 Weighted average remaining lease term, in years 6.3 1.0 Weighted average discount rate

Nature of the business and ba_2

Nature of the business and basis of presentation (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Nature of the business and basis of presentation
Net loss	$ 15,090	$ 11,886	$ 79,207	$ 43,755
Accumulated deficit	224,617		$ 209,527
Cash, cash equivalents and short-term marketable securities	$ 249,984

Summary of significant accoun_2

Summary of significant accounting policies - Restricted cash (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Summary of significant accounting policies
Separate cash balance for the landlord	$ 108	$ 108
Separate cash balance to collateralize corporate credit cards with a bank		$ 40

Summary of significant accoun_3

Summary of significant accounting policies - Property and equipment (Details)	3 Months Ended
	Mar. 31, 2021
Furniture and equipment
Property and equipment
Estimated useful lives	3 years

Fair value of financial asset_3

Fair value of financial assets and liabilities - Recurring (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 224,440	$ 239,168
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	162,416	158,023
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	33,976	47,955
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	28,048	33,190
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	162,416	158,023
Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	162,416	158,023
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	62,024	81,145
Level 2 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	33,976	47,955
Level 2 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 28,048	$ 33,190

Fair value of financial asset_4

Fair value of financial assets and liabilities - Textual (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Fair value of financial assets and liabilities
Transfers from level 1 to level 2, Assets	$ 0	$ 0
Transfers from level 2 to level 1, Assets	0	0
Transfers from level 1 to level 2, Liabilities	0	0
Transfers from level 2 to level 1, Liabilities	0	0
Transfers into level 3 Assets	0	0
Transfers out of level 3 Assets	0	0
Transfers into level 3 liabilities	0	0
Transfers out of level 3 liabilities	$ 0	$ 0

Short-term marketable securit_3

Short-term marketable securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized cost	$ 224,442	$ 239,171
Gross unrealized losses	(2)	(3)
Fair value	224,440	239,168
Cash equivalents	162,416	158,023
Short-term marketable securities	62,024	81,145
Total	224,440	239,168
Money market funds
Debt Securities, Available-for-sale [Line Items]
Amortized cost	162,416	158,023
Fair value	162,416	158,023
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized cost	33,976	47,955
Fair value	33,976	47,955
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized cost	28,050	33,193
Gross unrealized losses	(2)	(3)
Fair value	$ 28,048	$ 33,190

Accrued expenses and other cu_3

Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accrued expenses and other current liabilities
Accrued external research and development expenses	$ 3,923	$ 8,740
Accrued employee compensation and benefits	965	495
Accrued legal and professional fees	306	154
Short-term lease liability and other	337	294
Total accrued expenses and other current liabilities	$ 5,531	$ 9,683

Stockholder's equity (deficit_2

Stockholder's equity (deficit) - Common stock (Details) $ / shares in Units, $ in Thousands	Jul. 10, 2020USD ($)$ / sharesshares	Jun. 24, 2019USD ($)$ / sharesshares	Mar. 31, 2021Vote$ / sharesshares	Dec. 31, 2020$ / sharesshares	Jun. 18, 2019shares
Class of Stock
Common stock, shares authorized			150,000,000	150,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.0001	$ 0.0001
Number of votes per share | Vote			1
Cash dividend declared | $ / shares			$ 0
Common stock, shares issued			34,770,319	34,741,649
Common stock, shares outstanding			34,770,319	34,741,649
Common stock were reserved for issuance
Options available for future grant			8,113,230	6,404,819
Options to purchase common stock
Common stock were reserved for issuance
Options available for future grant			3,344,146	2,127,544
2018 Stock option and grant plan
Common stock were reserved for issuance
Options available for future grant			2,119,349	2,148,019	107,635
2019 Stock Option and Incentive plan
Common stock were reserved for issuance
Options available for future grant			1,758,356	1,585,293
2019 Employee Stock Purchase Plan
Common stock were reserved for issuance
Options available for future grant			891,379	543,963
IPO
Class of Stock
Number of shares issued		6,612,500
Public offering price | $ / shares		$ 16
Proceeds received, net of underwriting discounts and commissions | $		$ 98,394
Offering costs | $		$ 2,942
Number of shares converted		21,056,136
Follow Up Public Offering
Class of Stock
Number of shares issued	6,012,390
Public offering price | $ / shares	$ 36
Proceeds received, net of underwriting discounts and commissions | $	$ 203,460
Offering costs | $	$ 906
Over allotment | Maximum
Class of Stock
Number of shares issued	784,224	862,500

Stockholder's equity (deficit_3

Stockholder's equity (deficit) - Undesignated preferred stock and Restricted common stock (Details) - $ / shares	1 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2021
Restricted stock
Class of Stock
Shares issued (in shares)		226,400
Stock options vesting period	2 years	4 years
Undesignated Preferred Stock
Class of Stock
Preferred stock, par value (in dollars per share)			$ 0.0001
Preferred stock, shares issued			0
Preferred stock, shares outstanding			0
Undesignated Preferred Stock | Maximum
Class of Stock
Preferred stock, shares authorized			10,000,000

Stockholder's equity (deficit_4

Stockholder's equity (deficit) - Restricted stock activity (Details)	3 Months Ended
	Mar. 31, 2021USD ($)shares
Number of Shares
Beginning balance of unvested restricted common stock | shares	33,614
Shares vesting | shares	(14,889)
Ending balance of unvested restricted common stock | shares	18,725
Grant-Date Fair Value
Beginning balance of unvested restricted common stock | $	$ 0.62
Shares vesting | $	0.62
Ending balance of unvested restricted common stock | $	$ 0.62

Stockholder's equity (deficit_5

Stockholder's equity (deficit) - Restricted stock activity narrative (Details) - shares	Mar. 31, 2021	Dec. 31, 2020
Number of Shares
Unvested restricted common stock	18,725	33,614

Stock-based awards - Textual (D

Stock-based awards - Textual (Details) - shares	Jun. 18, 2019	Jun. 30, 2019	Mar. 31, 2021	Jan. 31, 2021	Dec. 31, 2020	Jan. 31, 2020
Share-based awards
Number of shares remained available for grant			8,113,230		6,404,819
2018 Stock option and grant plan
Share-based awards
Number of shares of common stock issued	3,071,960
Number of shares remained available for grant	107,635		2,119,349		2,148,019
2019 Stock option and incentive plan
Share-based awards
Number of shares remained available for grant	107,635
Number of shares initially reserved for issuance		2,572,457
Number of additional shares reserved for issuance				1,389,665		1,142,713
Percent of shares reserved and available for issuance automatically increase annually on January 1		4.00%
Percentage of exercise price per share of stock options		100.00%
Percentage of minimum exercise price, holding more than 10% of voting power		110.00%
Stock options vesting period		4 years
2019 Employee stock purchase plan
Share-based awards
Number of shares initially reserved for issuance	273,869
Number of additional shares reserved for issuance				347,416		285,678
Percent of shares reserved and available for issuance automatically increase annually on January 1		1.00%
Number of shares reserved and available for issuance automatically increase annually on January 1 (in shares)		410,803
Maximum | 2019 Stock option and incentive plan
Share-based awards
Term of stock option		10 years

Stock-based awards - Stock opti

Stock-based awards - Stock option valuation (Details)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Assumptions to determine grant-date fair value of stock options granted
Expected term (in years)	6 years	6 years
Expected volatility	70.44%	80.60%
Weighted average risk-free interest rate	0.59%	1.63%
Expected dividend yield	0.00%	0.00%

Stock based awards - Stock opti

Stock based awards - Stock option activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Number of Options
Balance Outstanding, Beginning of the period (in shares)	3,733,312
Options granted ( in shares)	173,063
Options exercised ( in shares)	(28,670)
Balance Outstanding, End of the period (in shares)	3,877,705	3,733,312
Exercisable ( in shares)	1,310,142
Vested and expected to vest ( in shares)	3,877,705
Weighted-Average Exercise Price per Share
Weighted-average exercise price, Beginning of the period (in dollars per share)	$ 12.15
Weighted-average exercise price, Granted (in dollars per share)	25.99
Weighted-average exercise price, Exercised (in dollars per share)	0.85
Weighted-average exercise price, End of the period (in dollars per share)	12.85	$ 12.15
Weighted-average exercise price, Exercisable ( in dollars per share )	8.80
Weighted-average exercise price, Vested and expected to vest at end of the period (in dollars per share)	$ 12.85
Weighted-Average remaining contractual term (years) and Aggregate Intrinsic Value
Weighted-average remaining contractual term outstanding (in years)	8 years 4 months 10 days	8 years 6 months 11 days
Weighted-average remaining contractual term , Options Exercisable(in years)	8 years 7 days
Weighted-average remaining contractual term vested and expected to vest (in years)	8 years 4 months 10 days
Aggregate Intrinsic Value Balance outstanding	$ 62,711	$ 52,498
Aggregate Intrinsic Value Exercisable	26,473
Aggregate Intrinsic Value Vested and Expected to vest	$ 62,711
Weighted average grant-date fair value per share of stock options granted	$ 16.08

Stock based awards - Stock-base

Stock based awards - Stock-based compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			3 Months Ended
	Jul. 31, 2019	Jun. 30, 2019	Apr. 30, 2019	Mar. 31, 2021	Mar. 31, 2020
Stock-based compensation
Total stock-based compensation expense				$ 2,364	$ 1,237
Total unrecognized compensation cost related to unvested stock-based awards				$ 23,608
Weighted average period of recognition for unrecognized compensation cost				2 years 3 months 18 days
Common Stock
Stock-based compensation
Issuance of restricted common stock upon early exercise of stock options (in shares)	491,207	491,207	491,207
Exercise price of common stock purchase	$ 0.65	$ 0.65	$ 0.65
Proceeds from the early exercise of stock options in exchange for restricted common stock	$ 321	$ 321	$ 321
Research and development expense
Stock-based compensation
Total stock-based compensation expense				$ 1,645	368
General and administrative expense
Stock-based compensation
Total stock-based compensation expense				$ 719	$ 869

Amgen license agreement (Detail

Amgen license agreement (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended
	Aug. 31, 2019	Nov. 30, 2018	Jun. 30, 2018	Mar. 31, 2021	Mar. 31, 2020
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development expense				$ 10,602	$ 8,791
Amgen Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Initial fair value of the anti-dilution right liability		$ 7,404
Payment for clinical trail	$ 2,500
Obligation for payment in connection with dosing of the first patient	7,500
Amgen Agreement | Maximum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Aggregate milestone payments upon the achievement of specified commercial milestones	75,000
Payment in connection with dosing of the first patient	$ 30,000
Amgen Agreement | Amgen
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Ownership interest of the outstanding shares (as a percent)			10.00%
Amgen Agreement | Research and development expense
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development expense				$ 0	$ 0
Amgen Agreement | Amgen
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Upfront payment			$ 5,000
Amgen Agreement | Series A Preferred Stock
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Share Issued under agreement		3,205,128
Amgen Agreement | Series A Preferred Stock | Amgen
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Share Issued under agreement			2,653,333
Share Issued value under agreement			$ 1,353

Income taxes - Current income t

Income taxes - Current income tax provision (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Current income tax provision:
Income tax benefit related to operating losses and research and development tax credits	$ 0	$ 0

Net loss per share - Basic and

Net loss per share - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net loss	$ (15,090)	$ (11,886)	$ (79,207)	$ (43,755)
Denominator:
Weighted average common shares outstanding, basic and diluted	34,744,275	28,499,475
Net loss per share, basic and diluted	$ (0.43)	$ (0.42)
Number of weighted average restricted common stock	9,761	77,223

Net loss per share - Anti-Dilut

Net loss per share - Anti-Diluted (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive shares excluded from the calculation of diluted earnings per share, total	3,896,430	3,188,982
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive shares excluded from the calculation of diluted earnings per share, total	3,877,705	3,095,450
Unvested restricted common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive shares excluded from the calculation of diluted earnings per share, total	18,725	93,532

Commitments and contingencies_2

Commitments and contingencies (Details) $ in Thousands	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Jul. 10, 2020ft²	Feb. 29, 2020USD ($)
Commitments and contingencies
Lease agreement term				7 years
Square feet of office | ft²			6,647
Minimum payments during the term				$ 2,300
Non-cancelable purchase commitments with contract research organizations and contract manufacturing organizations	$ 11,153
Total lease liability	$ 1,655
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:PrepaidExpenseAndOtherAssetsCurrent us-gaap:OperatingLeaseLiabilityNoncurrent
Operating lease liability, noncurrent	$ 1,467	$ 1,516
Short-term Liabilities	$ 188
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Prepaid Expense and Other Assets, Current

Commitments and contingencies -

Commitments and contingencies - Maturities Of Operating Leases (Details) $ in Thousands	Mar. 31, 2021USD ($)
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2021 (remaining)	$ 228
2022	312
2023	321
2024	331
2025	341
2026 and thereafter	559
Total future minimum lease payments	2,092
Less imputed interest	(437)
Present value of operating lease liabilities	$ 1,655

Commitments and contingencies_3

Commitments and contingencies - Components of operating lease expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating lease expense:
Total operating lease cost	$ 81	$ 94
Other information:
Cash paid for amounts included in the measurement of operating lease liability	$ 75	$ 59
Weighted average remaining lease term, in years	6 years 3 months 18 days	1 year
Weighted average discount rate	7.60%	8.00%
General and administrative expense
Operating lease expense:
Operating lease cost	$ 81	$ 59
Variable operating lease cost		27
Research and development expense
Operating lease expense:
Short-term lease cost		$ 8