CONDENSED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Income) Loss	Accumulated Deficit	Convertible Preferred Stock
Beginning Balance at Dec. 31, 2019	$ (25,482)	$ 1	$ 1,179	$ (2)	$ (26,660)
Temporary Equity, Beginning Balance, Shares at Dec. 31, 2019						27,283,973
Temporary Equity, Beginning Balance at Dec. 31, 2019						$ 59,815
Beginning Balance, Shares at Dec. 31, 2019		1,600,601
Vesting of shares of common stock subject to repurchase	13		13
Vesting of shares of common stock subject to repurchase, Shares		17,494
Issuance of common stock upon exercise of stock option, net of repurchase	1		1
Issuance of common stock upon exercise of stock option, net of repurchase, Shares		2,871
Share-based compensation expense	482		482
Unrealized gain (loss) on short-term investments	(2)			(2)
Net loss	(8,706)				(8,706)
Ending Balance at Mar. 31, 2020	(33,694)	$ 1	1,675	(4)	(35,366)
Temporary Equity, Ending Balance, Shares at Mar. 31, 2020						27,283,973
Temporary Equity, Ending Balance at Mar. 31, 2020						$ 59,815
Ending Balance, Shares at Mar. 31, 2020		1,620,966
Beginning Balance at Dec. 31, 2020	321,220	$ 3	439,235	3	(118,021)
Beginning Balance, Shares at Dec. 31, 2020		32,627,963
Vesting of shares of common stock subject to repurchase	9		9
Vesting of shares of common stock subject to repurchase, Shares		15,802
Issuance of common stock upon exercise of stock option, net of repurchase	$ 756		756
Issuance of common stock upon exercise of stock option, net of repurchase, Shares	155,322	154,489
Share-based compensation expense	$ 3,347		3,347
Unrealized gain (loss) on short-term investments	31			31
Net loss	(19,373)				(19,373)
Ending Balance at Mar. 31, 2021	$ 305,990	$ 3	$ 443,347	$ 34	$ (137,394)
Ending Balance, Shares at Mar. 31, 2021		32,798,254