CONSOLIDATED STATEMENTS OF CHANGES IN REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (loss)	Accumulated Deficit
Balance at Dec. 31, 2018	$ (104,820)				$ 3	$ (104,823)
Balance (in shares) at Dec. 31, 2018		96,385,795
Balance at Dec. 31, 2018		$ 165,902
Balance (in shares) at Dec. 31, 2018			300,597
Share-based compensation expense	2,390			$ 2,390
Accretion of redeemable convertible preferred stock to redemption value	(7,178)	7,178		(2,581)		(4,597)
Conversion of redeemable convertible preferred stock into common stock	173,080	$ (173,080)	$ 19	173,061
Conversion of redeemable convertible preferred stock into common stock, shares		(96,385,795)	19,061,502
Sale of common stock in initial public offering, net of issuance costs of $7.3 million	58,021		$ 6	58,015
Sale of common stock in initial public offering, net of issuance costs, shares			5,445,690
Exercise of stock options	$ 10			10
Exercise of stock options, shares	3,778		3,778
Unrealized gain (loss) on short-term investments	$ 35				35
Net loss	(51,930)					(51,930)
Balance at Dec. 31, 2019	$ 69,608		$ 25	230,895	38	(161,350)
Balance (in shares) at Dec. 31, 2019	24,811,567		24,811,567
Issuance of common stock warrants	$ 4,712			4,712
Share-based compensation expense	5,536			5,536
Exercise of stock options	$ 506			506
Exercise of stock options, shares	164,575		164,575
Unrealized gain (loss) on short-term investments	$ (26)				(26)
Net loss	(74,218)					(74,218)
Balance at Dec. 31, 2020	$ 6,118		$ 25	$ 241,649	$ 12	$ (235,568)
Balance (in shares) at Dec. 31, 2020	24,811,567		24,976,142