Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Summary of Cash and Cash Equivalents

Cash and cash equivalents consist of the following at December 31, 2021 and 2020 (in thousands):

	December 31,
	2021		2020
Cash and cash equivalents:
Cash	$	13,465	$	344
Money market funds		16,523		34,698
	$	29,988	$	35,042

Summary of Estimated Useful Lives of Assets

These amounts are depreciated using the straight-line method over the estimated useful lives of the assets as follows:

Laboratory equipment	4 years
Computer equipment	3 years
Software	5 years
Leasehold improvements	Shorter of useful life or remaining term of related lease

Summary 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 data):

	Years Ended December 31,
	2021			2020			2019
Numerator:
Net loss	$	(48,663	)	$	(32,845	)	$	(47,339	)
Net loss attributable to common stockholders	$	(48,663	)	$	(32,845	)	$	(47,339	)
Denominator:
Weighted-average common shares –    basic and diluted		67,956,739			32,506,679			22,180,868
Net loss per share attributable to common    stockholders –basic and diluted	$	(0.72	)	$	(1.01	)	$	(2.13	)

Summary of Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss per Share

The following table sets forth the potentially dilutive securities that have been excluded from the calculation of diluted net loss per share because to include them would be anti-dilutive (in common stock equivalent shares):

	Years Ended December 31,
	2021		2020		2019
Stock options		6,765,837		4,110,691		3,915,591
Restricted stock units		—		620,277		517,750
Warrants		10,687,912		9,040		9,040
Common stock issuable upon conversion of outstanding debt		2,439,024		2,439,024		—
Total		19,892,773		7,179,032		4,442,381