Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Initial Public Offering	Follow On Public Offering	Private Placement	At The Market Offering	Redeemable Convertible Preferred Stock	Series A Redeemable Convertible Preferred Stock	Series B Redeemable Convertible Preferred Stock	Series B Redeemable Convertible Preferred Stock License Agreement	Common Stock	Common Stock Initial Public Offering	Common Stock Follow On Public Offering	Common Stock Private Placement	Common Stock At The Market Offering	Additional Paid-In Capital	Additional Paid-In Capital Initial Public Offering	Additional Paid-In Capital Follow On Public Offering	Additional Paid-In Capital Private Placement	Additional Paid-In Capital At The Market Offering	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Redeemable convertible preferred stock, beginning balance at Dec. 31, 2017						$ 26,084
Redeemable convertible preferred stock, beginning balance, shares at Dec. 31, 2017						4,379,916
Issuance of redeemable convertible preferred stock, value							$ 14,651	$ 93,844	$ 3,812
Issuance of redeemable convertible preferred stock, shares							1,414,811	7,081,452	263,615
Redeemable convertible preferred stock, ending balance at Dec. 31, 2018						$ 138,391
Redeemable convertible preferred stock, ending balance, shares at Dec. 31, 2018						13,139,794
Beginning balance at Dec. 31, 2017	$ (15,739)														$ 432					$ (1)	$ (16,170)
Beginning balance, shares at Dec. 31, 2017										1,263,416
Issuance of common stock upon exercise of stock options	28														28
Issuance of common stock upon exercise of stock options, shares										19,591
Early exercised common stock options, shares										70,583
Repurchase of early exercised shares, shares										(17,900)
Vesting of early exercised common stock options and restricted stock	189														189
Stock-based compensation	950														950
Other comprehensive income (loss)	(30)																			(30)
Net loss	(34,346)																				(34,346)
Ending balance at Dec. 31, 2018	(48,948)														1,599					(31)	(50,516)
Ending balance, shares at Dec. 31, 2018										1,335,690
Conversion of redeemable convertible preferred stock into common stock						$ (138,391)
Conversion of redeemable convertible preferred stock into common stock, shares						(13,139,794)
Conversion of redeemable convertible preferred stock into common stock	138,391									$ 1					138,390
Conversion of redeemable convertible preferred stock into common stock, shares										13,139,794
Issuance of common stock, net of issuance cost		$ 50,247									$ 1					$ 50,246
Issuance of common stock, net of issuance costs, shares											5,750,000
Issuance of common stock upon exercise of stock options	$ 307														307
Issuance of common stock upon exercise of stock options, shares										135,563
Early exercised common stock options, shares										2,112
Repurchase of early exercised shares, shares	(23,698)									(23,698)
Vesting of early exercised common stock options and restricted stock	$ 114														114
Stock-based compensation	2,168														2,168
Other comprehensive income (loss)	96																			96
Net loss	(41,975)																				(41,975)
Ending balance at Dec. 31, 2019	100,400									$ 2					192,824					65	(92,491)
Ending balance, shares at Dec. 31, 2019										20,339,461
Issuance of common stock, net of issuance cost			$ 100,664	$ 19,988	$ 6,582							$ 1					$ 100,663	$ 19,988	$ 6,582
Issuance of common stock, net of issuance costs, shares												7,166,667	1,333,333	410,896
Issuance of common stock upon exercise of stock options	1,202														1,202
Issuance of common stock upon exercise of stock options, shares										256,583
Employee stock purchase plan (ESPP) purchase	$ 326														326
Employee stock purchase plan (ESPP) purchase, shares										40,794
Repurchase of early exercised shares, shares	(10,518)									(10,518)
Vesting of early exercised common stock options and restricted stock	$ 56														56
Stock-based compensation	3,609														3,609
Other comprehensive income (loss)	(58)																			(58)
Net loss	(34,495)																				(34,495)
Ending balance at Dec. 31, 2020	$ 198,274									$ 3					$ 325,250					$ 7	$ (126,986)
Ending balance, shares at Dec. 31, 2020										29,537,216