Condensed Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Series A Redeemable Convertible Preferred Stock	Series B Redeemable Convertible Preferred Stock	Series C Redeemable Convertible Preferred Stock	Series D Redeemable Convertible Preferred Stock
Beginning balance at Dec. 31, 2019	$ (106,373)	$ 7	$ 2,967	$ (109,347)
Beginning balance, shares at Dec. 31, 2019		4,059,909
Beginning balance at Dec. 31, 2019						$ 24,967	$ 55,151	$ 80,192
Beginning balance, shares at Dec. 31, 2019						6,225,719	6,786,896	7,377,480
Exercise of stock options	$ 49		49
Exercise of stock options (in shares)	43,657	28,837
Issuance of common stock related to early exercised stock options		14,819
Vesting of early exercised stock options	$ 128		128
Issuance of preferred stock									$ 109,875
Issuance of preferred stock, net of issuance cost (in shares)									8,220,242
Stock-based compensation expense	372		372
Net Loss	(27,142)			(27,142)
Ending balance at Mar. 31, 2020	(132,966)	$ 7	3,516	(136,489)
Ending balance, shares at Mar. 31, 2020		4,103,565
Ending balance at Mar. 31, 2020						$ 24,967	$ 55,151	$ 80,192	$ 109,875
Ending balance, shares at Mar. 31, 2020						6,225,719	6,786,896	7,377,480	8,220,242
Beginning balance at Dec. 31, 2020	345,843	$ 54	544,353	(198,564)
Beginning balance, shares at Dec. 31, 2020		51,071,593
Exercise of stock options	$ 487		487
Exercise of stock options (in shares)	267,208	267,208
Vesting of early exercised stock options	$ 9		9
Stock-based compensation expense	1,865		1,865
Unrealized losses on investments	(47)				$ (47)
Net Loss	(21,220)			(21,220)
Ending balance at Mar. 31, 2021	$ 326,937	$ 54	$ 546,714	$ (219,784)	$ (47)
Ending balance, shares at Mar. 31, 2021		51,338,801