0001558370-21-016637 | 10-Q | XBRL Viewer

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Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2021	Nov. 30, 2021
Document and Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-40969
Entity Registrant Name	ENTRADA THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	84-3983399
Entity Address, Address Line One	6 Tide Street
Entity Address, City or Town	Boston
Entity Address State Or Province	MA
Entity Address, Postal Zip Code	02210
City Area Code	857
Local Phone Number	520-9158
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
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	TRDA
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		31,212,856
Entity Central Index Key	0001689375
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 122,172	$ 39,045
Prepaid expenses and other current assets	1,353	904
Total current assets	123,525	39,949
Property and equipment, net	5,901	3,037
Other non-current assets	2,969	541
Total assets	132,395	43,527
Current liabilities:
Accounts payable	2,278	1,602
Accrued expenses and other current liabilities	4,880	1,757
Total current liabilities	7,158	3,359
Deferred rent, net of current portion	339
Total liabilities	7,497	3,359
Commitments and contingencies (Note 9)
Redeemable convertible preferred stock, par value $0.0001 (Note 6)	197,489	81,658
Stockholders' deficit:
Common stock, par value $0.0001; 172,000,000 and 113,259,306 shares authorized as of September 30, 2021 and December 31, 2020, respectively; 1,684,294 and 1,283,545 shares issued as of September 30, 2021 and December 31, 2020, respectively; 1,547,774 and 1,244,139 shares outstanding as of September 30, 2021 and December 31, 2020, respectively
Additional paid-in capital	2,631	1,021
Accumulated deficit	(75,222)	(42,511)
Total stockholders' deficit	(72,591)	(41,490)
Total liabilities, redeemable convertible preferred stock and stockholders' deficit	$ 132,395	$ 43,527

CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
CONDENSED BALANCE SHEETS
Redeemable convertible preferred stock, par value per share (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, par value per share (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares, authorized	172,000,000	113,259,306
Common stock, shares, issued	1,684,294	1,283,545
Common stock, shares, outstanding	1,547,774	1,244,139

CONDENSED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
CONDENSED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating expenses:
Research and development	$ 10,513	$ 5,700	$ 23,564	$ 14,446
General and administrative	3,851	1,273	9,103	3,568
Total operating expenses	14,364	6,973	32,667	18,014
Loss from operations	(14,364)	(6,973)	(32,667)	(18,014)
Other income (expense):
Interest and other income (expense), net	(66)	(17)	(44)	164
Total other income (expense), net	(66)	(17)	(44)	164
Net loss	$ (14,430)	$ (6,990)	$ (32,711)	$ (17,850)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (9.78)	$ (6.13)	$ (24.18)	$ (16.55)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (9.78)	$ (6.13)	$ (24.18)	$ (16.55)
Weighted-average common shares outstanding, basic (in shares)	1,475,170	1,139,647	1,352,721	1,078,783
Weighted-average common shares outstanding, diluted (in shares)	1,475,170	1,139,647	1,352,721	1,078,783

CONDENSED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' DEFICIT - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Series A Redeemable Convertible Preferred Stock	Series B Redeemable Convertible Preferred Stock	Total
Beginning Balances at Dec. 31, 2019						$ 31,816
Beginning Balances (in shares) at Dec. 31, 2019						37,269,149
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of redeemable convertible preferred stock, net of issuance costs				$ 24,978
Issuance of redeemable convertible preferred stock, net of issuance costs (in shares)				24,015,368
Ending Balances at Mar. 31, 2020						$ 56,794
Ending Balances (in shares) at Mar. 31, 2020						61,284,517
Beginning Balances at Dec. 31, 2019		$ 470	$ (15,988)			$ (15,518)
Beginning Balances (in shares) at Dec. 31, 2019	1,004,310
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options		1				1
Issuance of common stock upon exercise of stock options (in shares)	522
Vesting of restricted common stock (in shares)	27,866
Vesting of early exercised options		3				3
Vesting of early exercised options (in shares)	3,352
Stock-based compensation		78				78
Net loss			(4,686)			(4,686)
Ending Balances at Mar. 31, 2020		552	(20,674)			(20,122)
Ending Balances (in shares) at Mar. 31, 2020	1,036,050
Beginning Balances at Dec. 31, 2019						$ 31,816
Beginning Balances (in shares) at Dec. 31, 2019						37,269,149
Ending Balances at Sep. 30, 2020						$ 81,658
Ending Balances (in shares) at Sep. 30, 2020						85,299,885
Beginning Balances at Dec. 31, 2019		470	(15,988)			$ (15,518)
Beginning Balances (in shares) at Dec. 31, 2019	1,004,310
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss						(17,850)
Ending Balances at Sep. 30, 2020		790	(33,838)			(33,048)
Ending Balances (in shares) at Sep. 30, 2020	1,153,633
Beginning Balances at Mar. 31, 2020						$ 56,794
Beginning Balances (in shares) at Mar. 31, 2020						61,284,517
Ending Balances at Jun. 30, 2020						$ 56,794
Ending Balances (in shares) at Jun. 30, 2020						61,284,517
Beginning Balances at Mar. 31, 2020		552	(20,674)			$ (20,122)
Beginning Balances (in shares) at Mar. 31, 2020	1,036,050
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options		83				83
Issuance of common stock upon exercise of stock options (in shares)	54,452
Vesting of restricted common stock (in shares)	27,866
Vesting of early exercised options		3				3
Vesting of early exercised options (in shares)	3,700
Stock-based compensation		74				74
Net loss			(6,174)			(6,174)
Ending Balances at Jun. 30, 2020		712	(26,848)			(26,136)
Ending Balances (in shares) at Jun. 30, 2020	1,122,068
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of redeemable convertible preferred stock, net of issuance costs				$ 24,864
Issuance of redeemable convertible preferred stock, net of issuance costs (in shares)				24,015,368
Ending Balances at Sep. 30, 2020						$ 81,658
Ending Balances (in shares) at Sep. 30, 2020						85,299,885
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted common stock (in shares)	27,865
Vesting of early exercised options		3				$ 3
Vesting of early exercised options (in shares)	3,700
Stock-based compensation		75				75
Net loss			(6,990)			(6,990)
Ending Balances at Sep. 30, 2020		790	(33,838)			(33,048)
Ending Balances (in shares) at Sep. 30, 2020	1,153,633
Beginning Balances at Dec. 31, 2020				$ 79,597		$ 81,658
Beginning Balances (in shares) at Dec. 31, 2020				82,879,139		85,299,885
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of redeemable convertible preferred stock, net of issuance costs					$ 115,831
Issuance of redeemable convertible preferred stock, net of issuance costs (in shares)					53,522,099
Ending Balances at Mar. 31, 2021						$ 197,489
Ending Balances (in shares) at Mar. 31, 2021						138,821,984
Beginning Balances at Dec. 31, 2020		1,021	(42,511)			$ (41,490)
Beginning Balances (in shares) at Dec. 31, 2020	1,244,139
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options		29				29
Issuance of common stock upon exercise of stock options (in shares)	16,453
Vesting of restricted common stock (in shares)	4,326
Vesting of early exercised options		8				8
Vesting of early exercised options (in shares)	6,529
Stock-based compensation		164				164
Net loss			(8,380)			(8,380)
Ending Balances at Mar. 31, 2021		1,222	(50,891)			(49,669)
Ending Balances (in shares) at Mar. 31, 2021	1,271,447
Beginning Balances at Dec. 31, 2020				$ 79,597		$ 81,658
Beginning Balances (in shares) at Dec. 31, 2020				82,879,139		85,299,885
Ending Balances at Sep. 30, 2021				$ 79,597	$ 115,831	$ 197,489
Ending Balances (in shares) at Sep. 30, 2021				82,879,139	53,522,099	138,821,984
Beginning Balances at Dec. 31, 2020		1,021	(42,511)			$ (41,490)
Beginning Balances (in shares) at Dec. 31, 2020	1,244,139
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss						(32,711)
Ending Balances at Sep. 30, 2021		2,631	(75,222)			(72,591)
Ending Balances (in shares) at Sep. 30, 2021	1,547,774
Beginning Balances at Mar. 31, 2021						$ 197,489
Beginning Balances (in shares) at Mar. 31, 2021						138,821,984
Ending Balances at Jun. 30, 2021						$ 197,489
Ending Balances (in shares) at Jun. 30, 2021						138,821,984
Beginning Balances at Mar. 31, 2021		1,222	(50,891)			$ (49,669)
Beginning Balances (in shares) at Mar. 31, 2021	1,271,447
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options		212				212
Issuance of common stock upon exercise of stock options (in shares)	119,359
Vesting of restricted common stock (in shares)	4,327
Vesting of early exercised options		18				18
Vesting of early exercised options (in shares)	10,592
Stock-based compensation		326				326
Net loss			(9,901)			(9,901)
Ending Balances at Jun. 30, 2021		1,778	(60,792)			(59,014)
Ending Balances (in shares) at Jun. 30, 2021	1,405,725
Ending Balances at Sep. 30, 2021				$ 79,597	$ 115,831	$ 197,489
Ending Balances (in shares) at Sep. 30, 2021				82,879,139	53,522,099	138,821,984
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options		106				$ 106
Issuance of common stock upon exercise of stock options (in shares)	57,661
Vesting of restricted common stock (in shares)	2,884
Vesting of early exercised options		170				170
Vesting of early exercised options (in shares)	81,504
Stock-based compensation		577				577
Net loss			(14,430)			(14,430)
Ending Balances at Sep. 30, 2021		$ 2,631	$ (75,222)			$ (72,591)
Ending Balances (in shares) at Sep. 30, 2021	1,547,774

CONDENSED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' DEFICIT (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Sep. 30, 2020	Mar. 31, 2020
Series A Redeemable Convertible Preferred Stock
Stock issuance costs		$ 136	$ 22
Series B Redeemable Convertible Preferred Stock
Stock issuance costs	$ 420

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (32,711)	$ (17,850)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	753	228
Loss on disposal of property and equipment	153	7
Stock-based compensation expense	1,068	227
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(449)	(1,902)
Other non-current assets	(1,923)	(544)
Accounts payable	311	709
Accrued expenses and other current liabilities	2,138	221
Deferred rent	339	(42)
Net cash used in operating activities	(30,321)	(18,946)
Cash flows from investing activities:
Purchases of property and equipment	(3,258)	(874)
Sale of property and equipment		7
Net cash used in investing activities	(3,258)	(867)
Cash flows from financing activities:
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs	115,831	49,842
Proceeds from exercise of stock options	347	84
Proceeds from the early exercise of stock options	528	14
Net cash provided by financing activities	116,706	49,940
Net increase in cash and cash equivalents	83,127	30,127
Cash and cash equivalents at beginning of period	39,045	16,844
Cash and cash equivalents at end of period	122,172	46,971
Supplemental cash flow disclosures:
Deferred financing costs in accounts payable and accrued expenses	505
Purchases of property and equipment included in accounts payable and accrued expenses	832	616
Vesting of restricted stock subject to repurchase		1
Vesting of options early exercised subject to repurchase	$ 195	$ 8

Nature of the Business and Basis of Presentation

9 Months Ended

Sep. 30, 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

Organization

Entrada Therapeutics, Inc. (Entrada or the Company) aims to transform the lives of patients and become the world’s foremost intracellular therapeutics company by establishing Endosomal Escape Vehicle (EEV^TM) therapeutics as a new class of medicines. The Company was incorporated in Delaware on September 22, 2016 and its principal offices are located in Boston, Massachusetts.

Initial Public Offering

In November 2021, the Company completed its initial public offering (IPO) in which the Company issued and sold 10,436,250 shares of its common stock, including 1,361,250 shares pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a public offering price of $20.00 per share, for aggregate gross proceeds of $208.7 million. The Company received approximately $190.9 million in net proceeds, after deducting underwriting discounts and estimated offering expenses payable by the Company. In connection with the IPO, all outstanding shares of the Company’s redeemable convertible preferred stock converted into 19,185,183 shares of the Company’s common stock (see Note 11).

On October 22, 2021, in connection with the Company’s IPO, the Company effected a 1-for-7.235890014 reverse stock split of the Company’s common stock. All common shares, stock options, and per share information presented in the accompanying financial statements and notes thereto have been adjusted, where applicable, to reflect the reverse stock split on a retroactive basis for all periods presented, including reclassification of par and additional paid-in capital amounts. The per share par value and authorized number of shares of the Company’s common stock were not adjusted as a result of the reverse stock split.

Liquidity and Capital Resources

Since its inception, the Company has devoted substantially all of its resources to its research and development efforts relating to its proprietary, highly versatile and modular EEV platform (EEV Platform), advancing development of its portfolio of programs and general and administrative support for these operations, including raising capital. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, technical risks associated with the successful research, development and manufacturing of therapeutic candidates, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, and the ability to secure additional capital to fund operations. Therapeutic candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts will require significant amounts of additional capital, adequate personnel and infrastructure. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize revenue from product sales.

The Company has incurred losses since its inception, including losses of $14.4 million and $7.0 million for the three months ended September 30, 2021 and 2020, respectively and $32.7 million and $17.9 million for the nine months ended September 30, 2021 and 2020, respectively. As of September 30, 2021, the Company had an accumulated deficit of $75.2 million. To date, the Company has funded its operations primarily through the sale of equity securities. The Company expects to continue to generate operating losses and negative operating cash flows for the foreseeable future.

The Company expects that its cash and cash equivalents of $122.2 million as of September 30, 2021 will be sufficient to fund its operations and capital expenditure requirements for at least the next twelve months from the date of issuance of these financial statements. The Company will need additional financing beyond the IPO proceeds to support its continuing operations and pursue its business strategy and may pursue additional cash resources through a combination of equity offerings, debt financings, collaborations, strategic alliances, licensing, or other arrangements. The Company may be unable to raise additional funds or enter into such other agreements when needed or on favorable terms or at all. The inability to raise capital as and when needed would have a negative impact on the Company’s

financial condition and its ability to pursue its business strategy. The Company will need to generate significant revenue to achieve profitability, and it may never do so.

Basis of Presentation

The accompanying condensed financial statements are unaudited and have been prepared in conformity with generally accepted accounting principles in the United States of America (GAAP). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Update (ASU) of the Financial Accounting Standards Board (FASB). The condensed financial statements have been prepared on the same basis as the audited annual financial statements. Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. These condensed financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position as of September 30, 2021, and results of operations for the interim periods ended September 30, 2021 and 2020.

The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year. These condensed financial statements should be read in conjunction with the audited financial statements as of and for the years ended December 31, 2020 and 2019, and the notes thereto, included in the Company’s final prospectus related to the IPO, dated October 25, 2021 and filed with the Securities and Exchange Commission (the SEC) pursuant to Rule 424(b)(4) on November 1, 2021 (Final Prospectus).

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2021

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

The Company’s significant accounting policies are disclosed in the audited financial statements for the years ended December 31, 2020 and 2019 included in the Final Prospectus. Since the date of those financial statements, there have been no changes to the Company’s significant accounting policies.

Deferred Offering Costs

The Company capitalizes incremental legal, professional accounting and other third-party fees that are directly associated with the IPO as other non-current assets until the IPO is consummated. After consummation of the IPO, these costs will be recorded in stockholders’ deficit as a reduction of additional paid-in-capital generated as a result of the offering. As of September 30, 2021, the Company included $2.2 million in other non-current assets. The IPO was completed in November 2021 and all deferred offering costs were subsequently recorded within stockholders’ equity as a reduction of additional paid-in-capital generated from the offering.

Fair Value Measurements

9 Months Ended

Sep. 30, 2021

Fair Value Measurements

Fair Value Measurements

3. Fair Value Measurements

The following tables present the Company’s fair value hierarchy for its assets and liabilities that are measured at fair value on a recurring basis and indicate the level within the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value (in thousands):


	Fair Value Measurements at
	September 30, 2021
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	121,922	$	—	$	—	$	121,922
Total	$	121,922	$	—	$	—	$	121,922


	Fair Value Measurements at
	December 31, 2020
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	38,795	$	—	$	—	$	38,795
Total	$	38,795	$	—	$	—	$	38,795

Cash equivalents consisted of money market funds and are classified within Level 1 of the fair value hierarchy because they are valued using quoted market prices in active markets.

- Definition

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

+ References + Details

Property and Equipment, Net

9 Months Ended

Sep. 30, 2021

Property and Equipment, Net

Property and Equipment, Net

4. Property and Equipment, Net

Property and equipment, net consisted of the following at September 30, 2021 and December 31, 2020 (in thousands):


	September 30,		December 31,
	2021		2020
Laboratory equipment	$	5,336	$	2,121
Furniture and fixtures		24		18
Computer equipment		37		22
Leasehold improvements		1,556		1,253
		6,953		3,414
Less: Accumulated depreciation		(1,052)		(377)
	$	5,901	$	3,037

Depreciation expense for the three months ended September 30, 2021 and 2020 was $0.3 million and $0.1 million, respectively. Depreciation expense for the nine months ended September 30, 2021 and 2020 was $0.8 million and $0.2 million, respectively.

Accrued Expenses and Other Current Liabilities

9 Months Ended

Sep. 30, 2021

Accrued Expenses and Other Current Liabilities

Accrued Expenses and Other Current Liabilities

5. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following at September 30, 2021 and December 31, 2020 (in thousands):


	September 30,		December 31,
	2021		2020
Accrued employee compensation and benefits	$	2,752	$	1,482
Accrued external research and development expenses		1,004		125
Accrued issuance costs		495		—
Accrued general and administrative professional service expenses		301		35
Other		328		115
	$	4,880	$	1,757

Redeemable Convertible Preferred Stock and Common Stock

9 Months Ended

Sep. 30, 2021

Redeemable Convertible Preferred Stock and Common Stock

Redeemable Convertible Preferred Stock and Common Stock

6. Redeemable Convertible Preferred Stock and Common Stock

Redeemable Convertible Preferred Stock

On October 27, 2016, the Company entered into a Series Seed Preferred Stock Purchase Agreement, whereby the Company issued an aggregate of 691,641 shares of Series Seed redeemable convertible preferred stock (Series Seed Preferred Stock) at a purchase price of $0.8675 per share for aggregate proceeds of $0.6 million. On March 3, 2017, the Company entered into a second closing of Series Seed Preferred Stock, whereby the Company issued 576,368 shares at a purchase price of $0.8675 per share for aggregate proceeds of $0.5 million. On May 16, 2017, the Company completed the milestone closing of Series Seed Preferred Stock upon the satisfaction of stated milestones pursuant to the Series Seed Preferred Stock Purchase Agreement. In connection with this milestone closing, a total of 1,152,737 shares of Series Seed Preferred Stock were issued at a purchase price of $0.8675, for aggregate gross proceeds of $1.0 million. The Company incurred issuance costs of less than $0.1 million in connection with each of these closings.

On December 14, 2018, the Company entered into a Series A Preferred Stock Purchase Agreement, whereby the Company issued an aggregate of 34,848,403 shares of Series A redeemable convertible preferred stock (Series A Preferred Stock), 24,015,368 of which were issued at a purchase price of $1.041 per share for gross cash proceeds of $25.0 million, and 10,833,035 of which were issued in satisfaction of principal and interest on convertible notes outstanding held by the Company of $9.0 million. Pursuant to the Series A Preferred Stock Purchase Agreement, the Company also agreed to issue up to an additional 24,015,368 shares at a price of $1.041 per share upon the achievement of certain specified milestones.

The conditional issuance of 24,015,368 additional shares of Series A Preferred Stock was based on the achievement of defined milestones pursuant to which the investors were required to purchase, and the Company to sell, is referred to herein as the preferred stock tranche liability. The Company concluded that the preferred stock tranche liability met the definition of a freestanding financial instrument, as the obligation was legally detachable and separately exercisable from the initial issuance of the Series A Preferred Stock. Therefore, the Company allocated the net proceeds between the preferred stock tranche liability and the Series A Preferred Stock. Since the Series A Preferred Stock underlying the preferred stock tranche liability was contingently redeemable upon the occurrence of a deemed liquidation event, the preferred stock tranche liability was classified as a liability under ASC Topic 480, Distinguishing Liabilities from Equity, and was initially recorded at fair value. The preferred stock tranche liability was then remeasured at fair value at each reporting period and settlement date. The Company incurred issuance costs of $0.3 million which, together with the preferred stock tranche liability, were recorded as a discount to the Series A Preferred Stock.

The Company released the corresponding preferred stock tranche liability as of December 31, 2019 and recorded $6.3 million to Other Income for the year ended 2019 given the Company did not meet the milestones. Subsequently, on January 22, 2020, upon waiver of stated milestones in the Series A Preferred Stock Purchase Agreement, the Company issued 24,015,368 shares of Series A Preferred Stock at a purchase price of $1.041 per share for aggregate proceeds of $25.0 million. The Company incurred issuance costs of less than $0.1 million. Pursuant to the Amended and Restated Series A Preferred Stock Purchase Agreement, on August 12, 2020, the Company agreed to issue an additional 24,015,368 shares of Series A Preferred Stock at a purchase price of $1.041 per share for aggregate proceeds of $25.0 million. The Company incurred issuance costs of $0.1 million.

On March 29, 2021, the Company entered into a Series B Preferred Stock Purchase Agreement, whereby the Company issued an aggregate of 53,522,099 shares of Series B redeemable convertible preferred stock (Series B Preferred Stock, together with the Series Seed Preferred Stock and Series A Preferred Stock, Preferred Stock) at a price of $2.172 per share for gross cash proceeds of $116.2 million. The Company incurred issuance costs of $0.4 million. As part of the issuance of Series B Preferred Stock, the liquidation preferences of the Preferred Stock were modified such that, in the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company or a deemed liquidation event, the holders of Preferred Stock then outstanding shall be entitled to be paid out equal to the greater of (i) the applicable original issue price, plus any dividends declared but unpaid thereon, or (ii) such amount per share as would have been payable had all shares of Preferred Stock been converted into common stock.

The Company amended the articles of incorporation upon the issuance of the Series B Preferred Stock and the rights and preferences of the outstanding shares of Series Seed Preferred Stock and Series A Preferred Stock were adjusted. The Company considered if the adjustment to the previously issued shares of Preferred Stock represents an extinguishment or a modification to the outstanding mezzanine classified instruments. The adjustments to the outstanding shares of Preferred Stock were qualitatively insignificant. As a result, the adjustments to the rights and preferences of the outstanding shares of Preferred Stock qualified as a modification and no accounting was required as holders of these classes of equity did not receive any incremental value in the transaction.

Upon issuance of each class of redeemable convertible preferred stock, the Company assessed the embedded conversion and liquidation features of the shares and determined that such features did not require the Company to separately account for these features. The Company also concluded that no beneficial conversion feature existed on the issuance date of each class of redeemable convertible preferred stock.

Preferred Stock consisted of the following at September 30, 2021 and December 31, 2020 (in thousands, except share amounts):


	September 30, 2021
		Preferred Stock					Common Stock
	Preferred Stock	Issued and	Carrying		Liquidation		Issuable Upon
	Authorized	Outstanding	Value		Preference		Conversion
Series Seed preferred stock	2,420,746	2,420,746	$	2,061	$	2,100	334,547
Series A preferred stock	82,879,139	82,879,139		79,597		86,277	11,453,888
Series B preferred stock	53,522,099	53,522,099		115,831		116,250	7,396,748
	138,821,984	138,821,984	$	197,489	$	204,627	19,185,183


	December 31, 2020
		Preferred Stock					Common Stock
	Preferred Stock	Issued and	Carrying		Liquidation		Issuable Upon
	Authorized	Outstanding	Value		Preference		Conversion
Series Seed preferred stock	2,420,746	2,420,746	$	2,061	$	2,100	334,547
Series A preferred stock	82,879,139	82,879,139		79,597		86,277	11,453,888
	85,299,885	85,299,885	$	81,658	$	88,377	11,788,435

As of September 30, 2021, unless noted otherwise, the Preferred Stock have the following rights and preferences:

Conversion Rights

Each share of Preferred Stock is convertible at the option of the holder at any time after the date of issuance. The number of shares of common stock to be issued in the event of a conversion is determined by dividing the original issue price of $0.8675 for the Series Seed Preferred Stock, $1.041 for the Series A Preferred Stock, and $2.172 for the Series B Preferred Stock by the conversion price then in effect. The conversion price for each of the Series Seed Preferred Stock, Series A Preferred Stock, and Series B Preferred Stock was initially $0.8675, $1.041, and $2.172 per share, respectively, subject to adjustment under certain circumstances, including but not limited to certain additional issuances of common shares.

The Preferred Stock automatically convert at either (i) the closing of a firm-commitment underwritten public offering resulting in at least $75 million of net proceeds to the Company, upon which all outstanding Preferred Stock shall automatically be converted into common shares, at the then effective Series Seed conversion price, Series A conversion price, or Series B conversion price, respectively or (ii) at the election of the required majority of Preferred Stock holders, upon which all or any portion of the outstanding Preferred Stock shall automatically be converted into common shares, at the then effective Series Seed conversion price, Series A conversion price, or Series B conversion price, respectively.

Dividends

The holders of Preferred Stock shall be entitled to receive non-cumulative cash dividends, out of any assets legally available therefor, prior and in preference to any declaration or payment of any dividend on shares of common stock (payable other than in common stock or other securities and rights convertible into or entitling the holder thereof to receive, directly or indirectly, additional shares of common stock of the Company) at a rate of eight percent of the applicable original issue price per share of Preferred Stock per annum, payable only when, as and if declared by the Company’s board of directors.

The Company shall not declare, pay or set aside any dividends on shares of any other class or series of capital stock of the Company (other than dividends on shares of common stock payable in shares of common stock) unless (in addition to the obtaining of any consents required otherwise by the Company’s restated certificate of incorporation) the holders of Preferred Stock then outstanding shall first receive, or simultaneously receive, in addition to the eight percent non-cumulative dividend described above, a dividend on each outstanding share of Preferred Stock in an amount at least

equal to the dividend payable on each share of such class or series determined as if all shares of such class or series had been converted into common stock. No dividends were declared or paid through September 30, 2021.

Liquidation Preference

Upon liquidation, dissolution, or winding up of business or a deemed liquidation event, the holders of the Preferred Stock shall be entitled to be paid out the greater of (i) the applicable original issue price, plus any dividends declared but unpaid thereon, or (ii) such amount per share as would have been payable had all shares of Preferred Stock been converted into common stock. If, upon any such event, the assets available for distribution are insufficient to satisfy the liquidation payment to holders of Preferred Stock in full, the holders of Preferred Stock shall share ratably in any distribution of the assets available for distribution in proportion to the respective amounts which would otherwise be payable in respect of the shares held by them upon such distribution if all amounts payable on or with respect to such shares were paid in full.

Voting Rights

Except as provided by law or by other provisions of the instruments pursuant to which each series of Preferred Stock was issued, holders of the Preferred Stock and common stockholders’ vote together as one class on an “as-converted basis”. On any matter presented to the stockholders of the Company for their action or consideration at any meeting of stockholders of the Company, each holder of Series Seed Preferred Stock, Series A Preferred Stock, and Series B Preferred Stock is entitled to cast the number of votes equal to the number of whole shares of common stock into which the shares of Series Seed Preferred Stock, Series A Preferred Stock, and Series B Preferred Stock held by such holder are convertible as of the record date for determining shares entitled to vote on such matter. The holders of the shares of Series A Preferred Stock, exclusively and as a separate class, are entitled to elect three directors of the Company. The holders of the shares of Series B Preferred Stock, exclusively and as a separate class, are entitled to elect one director of the Company. The holders of the shares of common stock and Preferred Stock, exclusively and voting together as a single class, are entitled to elect three directors of the Company.

Common Stock

As of September 30, 2021 and December 31, 2020, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue 172,000,000 and 113,259,306 shares, respectively, of common stock, par value $0.0001 per share.

The holders of common stock are entitled to one vote for each share of common stock. Subject to the payment in full of all preferential dividends to which the holders of the Preferred Stock are entitled, the holders of common stock shall be entitled to receive dividends out of funds legally available. In the event of any voluntary or involuntary liquidation, dissolution, or winding up of the Company, after the payment or provision for payment of all debts and liabilities of the Company and all preferential amounts to which the holders of Preferred Stock are entitled with respect to the distribution of assets in liquidation, the holders of common stock shall be entitled to share ratably in the remaining assets of the Company available for distribution.

As of September 30, 2021, the Company has reserved 19,185,183 shares of common stock for the potential conversion of Preferred Stock and 3,110,588 shares of common stock for the potential exercise of outstanding stock options under the 2016 Plan.

Stock Based Compensation

9 Months Ended

Sep. 30, 2021

Stock Based Compensation

Stock Based Compensation

7. Stock-Based Compensation

2016 Plan

The 2016 Plan provides for the Company to grant incentive stock options or non-qualified stock options, restricted stock, restricted stock units, and other equity awards to employees, directors, and consultants of the Company. The 2016 Plan is administered by the board of directors of the Company 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. Recipients of stock options shall be eligible to purchase shares of the Company’s common stock at an exercise price equal to the estimated fair market value of such stock on the date of grant. The exercise price may be less than fair market value if the stock award is granted pursuant to an assumption or

substitution for another stock award in the event of a merger or sale of the Company. The maximum term of options granted under the 2016 Plan is ten years, and stock options typically vest over a four-year period. The board of directors may assign vesting terms to the stock options granted as deemed appropriate. The 2016 Plan allows for early exercise of all stock option grants if authorized by the board of directors at the time of grant. The shares of common stock issued from the early exercise of stock options are restricted and continue to vest over the original service based vesting condition of the original stock option award. The Company has the option to repurchase any unvested shares at the original purchase price upon any voluntary or involuntary termination. The board of directors may, at its discretion, accelerate unvested awards held by employees in the event of a change of control of the Company unless assumed or substituted by the acquirer or surviving entity.

During the nine months ended September 30, 2021, the Company increased the number of shares of common stock authorized for issuance under the 2016 Plan from 1,997,099 to 3,110,588 shares. As of September 30, 2021, 63,173 shares remained available for future issuance under the 2016 Plan.

Stock-based compensation expense recorded in the statements of operations is as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development expenses	$	182	$	24	$	344	$	78
General and administrative expenses		396		51		724		149
Total	$	578	$	75	$	1,068	$	227

Stock Option Valuation

The following table presents, on a weighted-average basis, the assumptions used in the Black-Scholes option-pricing model to determine the fair value of stock options granted during the nine months ended September 30, 2021 and the year ended December 31, 2020:


	September 30,		December 31,
	2021		2020
Risk‑free interest rate	0.99	%	0.53	%
Expected volatility	74	%	75	%
Expected dividend yield	—		—
Expected term (in years)	6.02		5.99

Early Exercise of Unvested Stock Options

Shares purchased by employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be outstanding shares until those shares vest according to their respective vesting schedules. Cash received from employee exercises of unvested options is included in current liabilities on the balance sheet. Amounts recorded are reclassified to common stock and additional paid-in capital as the shares vest. Vesting can occur in the year of exercise and thereafter. There were 136,520 and 27,869 unvested shares related to early exercises of stock options as of September 30, 2021 and December 31, 2020, respectively. For each of the periods ended September 30, 2021 and December 31, 2020, the liability associated with the unvested early exercise of stock options was $0.4 million and less than $0.1 million, respectively.

Stock Options

The following table summarizes the Company’s stock option activity during the nine months ended September 30, 2021:


		Weighted‑		Weighted‑
		Average		Average	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Shares	Price		Term	Value (2)
				(in years)	(in thousands)
Outstanding as of December 31, 2020	1,625,256	$	1.88
Granted	1,166,904		9.36
Exercised	(401,322)		2.18
Forfeited	(21,275)		3.07
Outstanding as of September 30, 2021	2,369,563	$	5.51	8.99	$	20,029
Vested and exercisable as of September 30, 2021	391,322	$	1.84	7.68	$	4,746
Unvested and exercisable as of September 30, 2021 (1)	1,978,241	$	6.24	9.25	$	15,283
(1) This represents the number of unvested options outstanding as of September 30, 2021 that are expected to vest in the future.
(2) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money as of September 30, 2021.

The aggregate intrinsic value of stock options exercised during the nine months ended September 30, 2021 was $2.3 million. The company received $0.9 million in proceeds for the exercise of these options.

The weighted-average grant-date fair value of stock options granted during the nine months ended September 30, 2021 and 2020 was $6.02 per share and $1.38 per share, respectively. As of September 30, 2021, there was $7.7 million of unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a weighted-average period of 3.3 years.

Restricted Stock Awards

The Company issued restricted stock to its founders and certain officers of the Company. In general, the shares of restricted stock vest over a four-year period, with 25% of the shares vesting after one year, followed by monthly vesting over the remaining three years.

If the holders of the above restricted stock cease to have a business relationship with the Company,

the Company may reacquire any unvested shares of restricted stock held by these individuals for the original purchase price or fair value, whichever is lower at the time of repurchase. The amounts received to date for the purchase price of restricted stock are immaterial. The unvested shares of restricted stock are not considered outstanding shares for accounting purposes until the shares vest.

A summary of unvested restricted stock during the nine months ended September 30, 2021 is as follows:


		Weighted‑
		Average
		Grant‑Date
	Shares	Fair Value
Unvested as of December 31, 2020	11,537	$	0.007
Vested	(11,537)		0.007
Unvested as of September 30, 2021	—	$	—

Income Taxes

9 Months Ended

Sep. 30, 2021

Income Taxes

Income Taxes

8. Income Taxes

Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax basis of assets and liabilities using statutory rates. A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. Due to the uncertainty surrounding the realization of the favorable tax attributes in future tax returns, the Company has recorded a full valuation allowance against the Company’s otherwise recognizable net deferred tax assets.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Commitments and Contingencies

9 Months Ended

Sep. 30, 2021

Commitments and Contingencies

Commitments and Contingencies

9. Commitments and Contingencies

Lease Obligations

The Company leases its facilities under non-cancelable operating leases that expire in November 2023. All of the Company's leases contain escalating rent clauses, which require higher rent payments in future years, and as such, rent expense is recognized on a straight-line basis. See Note 9, "Commitments and Contingencies," in the audited financial statements for the year ended December 31, 2020, and notes thereto, included in the Company’s Final Prospectus for additional information regarding the Company's operating leases.

License Agreement

The Company's significant license agreements are disclosed in Note 9, "Commitments and Contingencies," in the audited financial statements for the year ended December 31, 2020, and notes thereto, included in the Company’s Final Prospectus. Since the date of those financial statements, there have been no changes to its license agreements.

Net Loss per Share

9 Months Ended

Sep. 30, 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 (in thousands, except share and per share amounts):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Numerator:
Net loss attributable to common stockholders	$	(14,430)	$	(6,990)	$	(32,711)	$	(17,850)
Denominator:
Weighted‑average common shares outstanding, basic and diluted		1,475,170		1,139,647		1,352,721		1,078,783
Net loss per share attributable to common stockholders, basic and diluted	$	(9.78)	$	(6.13)	$	(24.18)	$	(16.55)

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 attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect:


	Nine Months Ended September 30,
	2021	2020
Redeemable convertible preferred stock	19,185,183	11,788,435
Unvested restricted common stock	—	23,710
Unvested shares from early exercises	136,520	22,039
Stock options to purchase common stock	2,369,563	1,017,367
	21,691,266	12,851,551

Subsequent Events

9 Months Ended

Sep. 30, 2021

Subsequent Events

Subsequent Events

11. Subsequent Events

The Company has evaluated events occurring after the date of its condensed balance sheet through December 9, 2021, the date the condensed financial statements were available to be issued.

Reverse Stock Split

On October 22, 2021, the Company effected a 1-for-7.235890014 reverse stock split of the Company’s common stock and adjusted the number of shares under the 2016 Plan and the Company’s Amended and Restated Certificate of Incorporation, as well as the share amounts of restricted stock grants under the 2016 Plan and the number of options and exercise prices of options under the plan as a result of the 1-for-7.235890014 reverse stock split. All common shares, stock options, and per share information presented in the accompanying financial statements and notes thereto have been adjusted, where applicable, to reflect the reverse stock split on a retroactive basis for all periods presented, including reclassification of par and additional paid-in capital amounts. The per share par value and authorized number of shares of the Company’s common stock were not adjusted as a result of the reverse stock split.

2021 Stock Option and Incentive Plan

In September 2021, the Company’s board of directors adopted, and in October 2021 the Company’s stockholders approved, the 2021 Stock Option and Incentive Plan (2021 Plan), which became effective as of the date immediately prior to the date of the effectiveness of the registration statement for the IPO. The 2021 Plan allows the board of directors to make equity-based incentive awards to the Company’s officers, employees, directors, and other key persons. Upon effectiveness of the 2021 Plan, the number of shares of common stock reserved for issuance under the 2021 Plan was the sum of (i) 3,902,672 shares; plus (ii) the number of shares under the 2021 Plan which are not needed to fulfill the Company’s obligations for awards issued under the 2021 Plan as a result of forfeiture, expiration, cancellation, termination or net issuances of awards thereunder; plus (iii) the number of shares under the 2016 Plan which are not needed to fulfill the Company’s obligations for awards issued under the 2016 Plan as a result of forfeiture, expiration, cancellation, termination or net issuances of awards thereunder; plus (iv) an annual increase, to be added on January 1st of each year beginning on January 1, 2022 and continuing through and including 2031 by the lesser of (A) 4% of the number of shares of Stock outstanding as of such date and (B) an amount determined by the board of directors. The 2016 Plan was replaced with the 2021 Plan.

2021 Employee Stock Purchase Plan

In September 2021, the Company’s board of directors adopted, and in October 2021 the Company’s stockholders approved, the 2021 Employee Stock Purchase Plan (ESPP), which became effective as of the date immediately prior to the date of the effectiveness of the registration statement for the IPO. The ESPP is administered by the person or persons appointed by the Company’s board of directors for such purpose. The ESPP initially provides participating employees with the opportunity to purchase up to an aggregate of 278,762 shares of common stock. The number of shares of common stock reserved for issuance under the ESPP will automatically increase on January 1st of each year beginning in 2022 and continuing through and including 2031 by the least of (i) 1% of the outstanding number of shares of our common stock of the immediately preceding December, (ii) 557,524 shares or (iii) such number of shares as determined by the ESPP administrator.

Initial Public Offering

In November 2021, the Company completed its IPO in which the Company issued and sold 10,436,250 of its common stock, including 1,361,250 shares pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a public offering price of $20.00 per share, for aggregate gross proceeds of $208.7 million. The Company received approximately $190.9 million in net proceeds after deducting underwriting discounts and estimated offering expenses payable by the Company. In connection with the IPO, all outstanding shares of the Company’s redeemable convertible preferred stock then automatically converted into 19,185,183 shares of the Company’s common stock at the applicable conversion ratio then in effect. Subsequent to the closing of the IPO, there were no shares of redeemable convertible preferred stock outstanding.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2021

Summary of Significant Accounting Policies

Deferred Offering Costs

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2021

Fair Value Measurements

Schedule of fair value hierarchy for assets and liabilities measured at fair value on recurring basis


	Fair Value Measurements at
	September 30, 2021
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	121,922	$	—	$	—	$	121,922
Total	$	121,922	$	—	$	—	$	121,922


	Fair Value Measurements at
	December 31, 2020
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	38,795	$	—	$	—	$	38,795
Total	$	38,795	$	—	$	—	$	38,795

Property and Equipment, Net (Tables)

9 Months Ended

Sep. 30, 2021

Property and Equipment, Net

Schedule of Property and equipment, Net

Property and equipment, net consisted of the following at September 30, 2021 and December 31, 2020 (in thousands):


	September 30,		December 31,
	2021		2020
Laboratory equipment	$	5,336	$	2,121
Furniture and fixtures		24		18
Computer equipment		37		22
Leasehold improvements		1,556		1,253
		6,953		3,414
Less: Accumulated depreciation		(1,052)		(377)
	$	5,901	$	3,037

Accrued Expenses and Other Current Liabilities (Tables)

9 Months Ended

Sep. 30, 2021

Accrued Expenses and Other Current Liabilities

Schedule of accrued expenses and other current liabilities

Accrued expenses and other current liabilities consisted of the following at September 30, 2021 and December 31, 2020 (in thousands):


	September 30,		December 31,
	2021		2020
Accrued employee compensation and benefits	$	2,752	$	1,482
Accrued external research and development expenses		1,004		125
Accrued issuance costs		495		—
Accrued general and administrative professional service expenses		301		35
Other		328		115
	$	4,880	$	1,757

Redeemable Convertible Preferred Stock and Common Stock (Tables)

9 Months Ended

Sep. 30, 2021

Redeemable Convertible Preferred Stock and Common Stock

Schedule of Preferred Stock

Preferred Stock consisted of the following at September 30, 2021 and December 31, 2020 (in thousands, except share amounts):


	September 30, 2021
		Preferred Stock					Common Stock
	Preferred Stock	Issued and	Carrying		Liquidation		Issuable Upon
	Authorized	Outstanding	Value		Preference		Conversion
Series Seed preferred stock	2,420,746	2,420,746	$	2,061	$	2,100	334,547
Series A preferred stock	82,879,139	82,879,139		79,597		86,277	11,453,888
Series B preferred stock	53,522,099	53,522,099		115,831		116,250	7,396,748
	138,821,984	138,821,984	$	197,489	$	204,627	19,185,183


	December 31, 2020
		Preferred Stock					Common Stock
	Preferred Stock	Issued and	Carrying		Liquidation		Issuable Upon
	Authorized	Outstanding	Value		Preference		Conversion
Series Seed preferred stock	2,420,746	2,420,746	$	2,061	$	2,100	334,547
Series A preferred stock	82,879,139	82,879,139		79,597		86,277	11,453,888
	85,299,885	85,299,885	$	81,658	$	88,377	11,788,435

Stock Based Compensation (Tables)

9 Months Ended

Sep. 30, 2021

Stock Based Compensation

Schedule of Stock-based compensation expense

Stock-based compensation expense recorded in the statements of operations is as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development expenses	$	182	$	24	$	344	$	78
General and administrative expenses		396		51		724		149
Total	$	578	$	75	$	1,068	$	227

Schedule of assumptions used in the Black-Scholes option-pricing model to determine the fair value of stock options granted


	September 30,		December 31,
	2021		2020
Risk‑free interest rate	0.99	%	0.53	%
Expected volatility	74	%	75	%
Expected dividend yield	—		—
Expected term (in years)	6.02		5.99

Summary of the stock option activity


		Weighted‑		Weighted‑
		Average		Average	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Shares	Price		Term	Value (2)
				(in years)	(in thousands)
Outstanding as of December 31, 2020	1,625,256	$	1.88
Granted	1,166,904		9.36
Exercised	(401,322)		2.18
Forfeited	(21,275)		3.07
Outstanding as of September 30, 2021	2,369,563	$	5.51	8.99	$	20,029
Vested and exercisable as of September 30, 2021	391,322	$	1.84	7.68	$	4,746
Unvested and exercisable as of September 30, 2021 (1)	1,978,241	$	6.24	9.25	$	15,283
(1) This represents the number of unvested options outstanding as of September 30, 2021 that are expected to vest in the future.
(2) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money as of September 30, 2021.

Summary of unvested restricted stock


		Weighted‑
		Average
		Grant‑Date
	Shares	Fair Value
Unvested as of December 31, 2020	11,537	$	0.007
Vested	(11,537)		0.007
Unvested as of September 30, 2021	—	$	—

Net Loss per Share (Tables)

9 Months Ended

Sep. 30, 2021

Net Loss per Share

Schedule of basic and diluted net loss per share attributable to common stockholders

Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Numerator:
Net loss attributable to common stockholders	$	(14,430)	$	(6,990)	$	(32,711)	$	(17,850)
Denominator:
Weighted‑average common shares outstanding, basic and diluted		1,475,170		1,139,647		1,352,721		1,078,783
Net loss per share attributable to common stockholders, basic and diluted	$	(9.78)	$	(6.13)	$	(24.18)	$	(16.55)

Schedule of antidilutive securities excluded from computation of net loss per share


	Nine Months Ended September 30,
	2021	2020
Redeemable convertible preferred stock	19,185,183	11,788,435
Unvested restricted common stock	—	23,710
Unvested shares from early exercises	136,520	22,039
Stock options to purchase common stock	2,369,563	1,017,367
	21,691,266	12,851,551

Nature of the Business and Basis of Presentation (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended						9 Months Ended
	Oct. 22, 2021	Nov. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2021 USD ($) shares	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2021 USD ($) shares	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) shares
Subsidiary, Sale of Stock [Line Items]
Redeemable convertible preferred stock, shares issued upon conversion \| shares			19,185,183						19,185,183		11,788,435
Net loss			$ 14,430	$ 9,901	$ 8,380	$ 6,990	$ 6,174	$ 4,686	$ 32,711	$ 17,850
Accumulated deficit			75,222						75,222		$ 42,511
Cash and cash equivalents			$ 122,172						$ 122,172		$ 39,045
Subsequent event
Subsidiary, Sale of Stock [Line Items]
Reverse stock split ratio	0.1382
IPO \| Subsequent event
Subsidiary, Sale of Stock [Line Items]
Aggregate shares issued and sold \| shares		10,436,250
Stock price \| $ / shares		$ 20.00
Gross proceeds from issuance of common stock		$ 208,700
Net proceeds from issuance of common stock		$ 190,900
Redeemable convertible preferred stock, shares issued upon conversion \| shares		19,185,183
Over-Allotment Option \| Subsequent event
Subsidiary, Sale of Stock [Line Items]
Shares issued \| shares		1,361,250

Summary of Significant Accounting Policies (Details) $ in Millions	Sep. 30, 2021 USD ($)
Summary of Significant Accounting Policies
Deferred offering cost non-current	$ 2.2

Fair Value Measurements (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets:
Cash equivalents	$ 121,922	$ 38,795
Total	121,922	38,795
Level 1
Assets:
Cash equivalents	121,922	38,795
Total	$ 121,922	$ 38,795

Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 6,953		$ 6,953		$ 3,414
Less: Accumulated depreciation	(1,052)		(1,052)		(377)
Property and Equipment, Net	5,901		5,901		3,037
Depreciation expense	300	$ 100	753	$ 228
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	5,336		5,336		2,121
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	24		24		18
Computer equipment
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	37		37		22
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 1,556		$ 1,556		$ 1,253

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accrued Expenses and Other Current Liabilities
Accrued employee compensation and benefits	$ 2,752	$ 1,482
Accrued external research and development expenses	1,004	125
Accrued issuance costs	495
Accrued general and administrative professional service expenses	301	35
Other	328	115
Total	$ 4,880	$ 1,757

Redeemable Convertible Preferred Stock and Common Stock - Redeemable Convertible Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands								3 Months Ended			7 Months Ended	9 Months Ended
	Mar. 29, 2021	Aug. 12, 2020	Jan. 22, 2020	Dec. 14, 2018	May 16, 2017	Mar. 03, 2017	Oct. 27, 2016	Mar. 31, 2021	Sep. 30, 2020	Mar. 31, 2020	May 16, 2017	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2019
Redeemable Convertible Preferred Stock and Common Stock
Proceeds from issue of redeemable convertible preferred stock												$ 115,831	$ 49,842
Series Seed redeemable convertible preferred stock
Redeemable Convertible Preferred Stock and Common Stock
Shares issued					1,152,737	576,368	691,641
Purchase price (in dollars Per share}					$ 0.8675	$ 0.8675	$ 0.8675				$ 0.8675	$ 0.8675
Proceeds from issue of redeemable convertible preferred stock					$ 1,000	$ 500	$ 600
Series Seed redeemable convertible preferred stock \| Maximum
Redeemable Convertible Preferred Stock and Common Stock
Issuance costs											$ 100
Series A Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock and Common Stock
Shares issued		24,015,368	24,015,368	24,015,368					24,015,368	24,015,368
Purchase price (in dollars Per share}		$ 1.041	$ 1.041	$ 1.041								1.041
Proceeds from issue of redeemable convertible preferred stock		$ 25,000	$ 25,000	$ 25,000
Aggregate shares issued				34,848,403
Issuance costs		$ 100		$ 300
Shares issued in satisfaction of principal and interest on convertible notes				10,833,035
Convertible notes outstanding				$ 9,000
Shares issuable upon achievement of certain specified milestones				24,015,368
Series A Redeemable Convertible Preferred Stock \| Other Income
Redeemable Convertible Preferred Stock and Common Stock
Preferred stock tranche liability														$ 6,300
Series A Redeemable Convertible Preferred Stock \| Maximum
Redeemable Convertible Preferred Stock and Common Stock
Issuance costs			$ 100
Series B Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock and Common Stock
Shares issued	53,522,099							53,522,099
Purchase price (in dollars Per share}	$ 2.172											$ 2.172
Proceeds from issue of redeemable convertible preferred stock	$ 116,200
Issuance costs	$ 400

Redeemable Convertible Preferred Stock and Common Stock - Preferred Stock (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Redeemable Convertible Preferred Stock and Common Stock
Preferred Stock Authorized	138,821,984			85,299,885
Preferred Stock Issued	138,821,984			85,299,885
Preferred stock outstanding	138,821,984	138,821,984	138,821,984	85,299,885	85,299,885	61,284,517	61,284,517	37,269,149
Carrying Value	$ 197,489	$ 197,489	$ 197,489	$ 81,658	$ 81,658	$ 56,794	$ 56,794	$ 31,816
Liquidation Preference	$ 204,627			$ 88,377
Common stock issuable upon conversion	19,185,183			11,788,435
Series Seed redeemable convertible preferred stock
Redeemable Convertible Preferred Stock and Common Stock
Preferred Stock Authorized	2,420,746			2,420,746
Preferred Stock Issued	2,420,746			2,420,746
Preferred stock outstanding	2,420,746			2,420,746
Carrying Value	$ 2,061			$ 2,061
Liquidation Preference	$ 2,100			$ 2,100
Common stock issuable upon conversion	334,547			334,547
Series A Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock and Common Stock
Preferred Stock Authorized	82,879,139			82,879,139
Preferred Stock Issued	82,879,139			82,879,139
Preferred stock outstanding	82,879,139			82,879,139
Carrying Value	$ 79,597			$ 79,597
Liquidation Preference	$ 86,277			$ 86,277
Common stock issuable upon conversion	11,453,888			11,453,888
Series B Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock and Common Stock
Preferred Stock Authorized	53,522,099
Preferred Stock Issued	53,522,099
Preferred stock outstanding	53,522,099
Carrying Value	$ 115,831
Liquidation Preference	$ 116,250
Common stock issuable upon conversion	7,396,748

Redeemable Convertible Preferred Stock and Common Stock - Conversion Right and Dividends (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2021	Mar. 29, 2021	Aug. 12, 2020	Jan. 22, 2020	Dec. 14, 2018	May 16, 2017	Mar. 03, 2017	Oct. 27, 2016
Redeemable Convertible Preferred Stock and Common Stock
Dividend rate (as a percent)	8.00%
Dividends preferred stock	$ 0
Minimum
Redeemable Convertible Preferred Stock and Common Stock
Threshold net proceeds from qualified public offering.	$ 75,000
Series Seed redeemable convertible preferred stock
Redeemable Convertible Preferred Stock and Common Stock
Purchase price (in dollars Per share}	$ 0.8675					$ 0.8675	$ 0.8675	$ 0.8675
Preferred stock, convertible, conversion price (in dollars per share)	0.8675
Series A Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock and Common Stock
Purchase price (in dollars Per share}	1.041		$ 1.041	$ 1.041	$ 1.041
Preferred stock, convertible, conversion price (in dollars per share)	1.041
Series B Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock and Common Stock
Purchase price (in dollars Per share}	2.172	$ 2.172
Preferred stock, convertible, conversion price (in dollars per share)	$ 2.172

Redeemable Convertible Preferred Stock and Common Stock - Voting Rights (Details)	Sep. 30, 2021 Vote
Redeemable Convertible Preferred Stock and Common Stock
Number of directors entitled to be elected	3
Series A Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock and Common Stock
Number of directors entitled to be elected	3
Series B Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock and Common Stock
Number of directors entitled to be elected	1

Redeemable Convertible Preferred Stock and Common Stock - Common Stock (Details)	Sep. 30, 2021 Vote $ / shares shares	Dec. 31, 2020 $ / shares shares
Common Stock Authorized (shares)	172,000,000	113,259,306
Common stock, par value (in dollars per share) \| $ / shares	$ 0.0001	$ 0.0001
Number of votes \| Vote	1
Shares of common stock reserved for issuance	19,185,183
2016 Stock Plan
Shares of common stock reserved for issuance	3,110,588	1,997,099

Stock Based Compensation (Details) - shares	9 Months Ended
Stock Based Compensation (Details) - shares	Sep. 30, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance	19,185,183
2016 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options	10 years
Vesting period	4 years
Shares of common stock reserved for issuance	3,110,588	1,997,099
Shares remaining available for future issuance	63,173

Stock Based Compensation - Compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 578	$ 75	$ 1,068	$ 227
Research and development expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	182	24	344	78
General and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 396	$ 51	$ 724	$ 149

Stock Based Compensation - Stock Option Valuation (Details) - Stock options	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Assumptions used to determine the fair value of stock options granted
Risk-free interest rate (as percentage)	0.99%	0.53%
Expected volatility (as percentage)	74.00%	75.00%
Expected term (in years)	6 years 7 days	5 years 11 months 26 days

Stock Based Compensation - Early Exercise of Unvested Stock Options (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Stock Based Compensation
Unvested shares related to early exercises of stock options	136,520	27,869
Unvested early exercises of stock options	$ 0.4	$ 0.1

Stock Based Compensation - Stock option activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) $ / shares
Aggregate Intrinsic Value
Proceeds from exercise of stock options \| $	$ 347	$ 84
Stock options
Number of Shares
Outstanding at beginning of period (in shares) \| shares	1,625,256
Granted (in shares) \| shares	1,166,904
Exercised (in shares) \| shares	(401,322)
Forfeited (in shares) \| shares	(21,275)
Outstanding at end period (in shares) \| shares	2,369,563
Vested and exercisable (in shares) \| shares	391,322
Unvested and exercisable (in shares) \| shares	1,978,241
Weighted Average Exercise Price
Weighted-Average Exercise Price Outstanding at beginning period (in dollars per share)	$ 1.88
Weighted Average Exercise Price Granted (in dollars per share)	9.36
Weighted Average Exercise Price Exercised (in dollars per share)	2.18
Weighted Average Exercise Price Forfeited (in dollars per share)	3.07
Weighted Average Exercise Price Outstanding at end period (in dollars per share)	5.51
Weighted Average Exercise Price Vested and exercisable (in dollars per share)	1.84
Weighted Average Exercise Price Unvested and exercisable (in dollars per share)	$ 6.24
Weighted Average Contractual Term (in years)
Weighted Average Contractual Term, Outstanding (in years)	8 years 11 months 26 days
Weighted Average Contractual Term, Vested and exercisable (in years)	7 years 8 months 4 days
Weighted Average Contractual Term, Unvested and exercisable (in years)	9 years 3 months
Aggregate Intrinsic Value
Aggregate Intrinsic Value Outstanding \| $	$ 20,029
Aggregate Intrinsic Value Vested and exercisable \| $	4,746
Aggregate Intrinsic Value Unvested and exercisable \| $	15,283
Aggregate intrinsic value of stock options exercised \| $	2,300
Proceeds from exercise of stock options \| $	$ 900
Weighted-average grant-date fair value of stock options granted	$ 6.02	$ 1.38
Unrecognized compensation cost \| $	$ 7,700
Unrecognized compensation cost, weighted-average period for recognition	3 years 3 months 18 days

Stock Based Compensation - Restricted Stock Awards (Details) - Restricted Stock Awards	9 Months Ended
	Sep. 30, 2021 $ / shares shares
Stock-based compensation
Vesting period	4 years
Shares
Unvested balance, at beginning of period (in shares) \| shares	11,537
Vested (in shares) \| shares	(11,537)
Weighted- Average Grant -Date Fair Value
Weighted- Average Grant -Date Fair Value Unvested balance, at beginning of period (in dollars per share) \| $ / shares	$ 0.007
Vested (in dollars per share) \| $ / shares	$ 0.007
Shares vesting after one year
Stock-based compensation
Vesting period	1 year
Vesting percentage	25.00%
Shares vesting after three year
Stock-based compensation
Vesting period	3 years

Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net loss attributable to common stockholders	$ (14,430)	$ (9,901)	$ (8,380)	$ (6,990)	$ (6,174)	$ (4,686)	$ (32,711)	$ (17,850)
Denominator:
Weighted-average common shares outstanding, basic (in shares)	1,475,170			1,139,647			1,352,721	1,078,783
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (9.78)			$ (6.13)			$ (24.18)	$ (16.55)
Numerator:
Net loss attributable to common stockholders	$ (14,430)	$ (9,901)	$ (8,380)	$ (6,990)	$ (6,174)	$ (4,686)	$ (32,711)	$ (17,850)
Denominator:
Weighted-average common shares outstanding, diluted (in shares)	1,475,170			1,139,647			1,352,721	1,078,783
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (9.78)			$ (6.13)			$ (24.18)	$ (16.55)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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+ Details

- Definition

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

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+ Details

Net Loss per Share - Antidilutive securities (Details) - shares	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Net Loss per Share
Antidilutive securities excluded from common stock	21,691,266	12,851,551
Redeemable convertible preferred stock
Net Loss per Share
Antidilutive securities excluded from common stock	19,185,183	11,788,435
Unvested restricted common stock
Net Loss per Share
Antidilutive securities excluded from common stock		23,710
Unvested shares from early exercises
Net Loss per Share
Antidilutive securities excluded from common stock	136,520	22,039
Stock options
Net Loss per Share
Antidilutive securities excluded from common stock	2,369,563	1,017,367

Subsequent event (Details) $ / shares in Units, $ in Millions		1 Months Ended
	Oct. 22, 2021	Nov. 30, 2021 USD ($) $ / shares shares	Oct. 31, 2021 shares	Sep. 30, 2021 shares	Jun. 30, 2021 shares	Mar. 31, 2021 shares	Dec. 31, 2020 shares	Sep. 30, 2020 shares	Jun. 30, 2020 shares	Mar. 31, 2020 shares	Dec. 31, 2019 shares
Subsequent Event [Line Items]
Shares of common stock reserved for issuance				19,185,183
Common stock issuable upon conversion				19,185,183			11,788,435
Preferred stock outstanding				138,821,984	138,821,984	138,821,984	85,299,885	85,299,885	61,284,517	61,284,517	37,269,149
Subsequent event
Subsequent Event [Line Items]
Reverse stock split ratio	0.1382
Preferred stock outstanding		0
Subsequent event \| IPO
Subsequent Event [Line Items]
Aggregate shares issued and sold		10,436,250
Stock price \| $ / shares		$ 20.00
Gross proceeds from issuance of common stock \| $		$ 208.7
Net proceeds from issuance of common stock \| $		$ 190.9
Common stock issuable upon conversion		19,185,183
Subsequent event \| Over-Allotment Option
Subsequent Event [Line Items]
Shares issued		1,361,250
Subsequent event \| 2021 Stock Option and Incentive Plan
Subsequent Event [Line Items]
Shares annual increase percentage			4.00%
Shares of common stock reserved for issuance			3,902,672
Subsequent event \| 2021 Employee Stock Purchase Plan \| ESPP
Subsequent Event [Line Items]
Shares annual increase percentage			1.00%
Stock authorized for issuance			278,762
Shares remaining available for future issuance			557,524