Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Series A Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning Balance at Dec. 31, 2019	$ (4,769)		$ 2	$ 199	$ (4,970)
Beginning balance, shares at Dec. 31, 2019		3,177,744
Beginning balance at Dec. 31, 2019		$ 10,515
Beginning balance, shares at Dec. 31, 2019			2,108,266
Exercise of stock options	45			45
Exercise of stock options, shares			52,706
Stock-based compensation	2			2
Net loss	(2,050)				(2,050)
Ending Balance at Mar. 31, 2020	(6,772)		$ 2	246	(7,020)
Ending balance, shares at Mar. 31, 2020		3,177,744
Ending balance at Mar. 31, 2020		$ 10,515
Ending balance, shares at Mar. 31, 2020			2,160,972
Beginning Balance at Dec. 31, 2019	(4,769)		$ 2	199	(4,970)
Beginning balance, shares at Dec. 31, 2019		3,177,744
Beginning balance at Dec. 31, 2019		$ 10,515
Beginning balance, shares at Dec. 31, 2019			2,108,266
Net loss	(41,911)
Ending Balance at Sep. 30, 2020	20,319		$ 11	67,189	(46,881)
Ending balance, shares at Sep. 30, 2020			11,216,563
Beginning Balance at Mar. 31, 2020	(6,772)		$ 2	246	(7,020)
Beginning balance, shares at Mar. 31, 2020		3,177,744
Beginning balance at Mar. 31, 2020		$ 10,515
Beginning balance, shares at Mar. 31, 2020			2,160,972
Conversion of preferred stocks into common stock	10,515		$ 3	10,512
Conversion of preferred stocks into common stock, shares		(3,177,744)
Conversion of preferred stocks into common stock		$ (10,515)
Conversion of preferred stocks into common stock, shares			3,177,744
Sale of common stock, net of issuance costs	24,016		$ 4	24,012
Sale of common stock, net of issuance costs, shares			4,215,929
Issuance of common stock in connection with reverse merger	31,809		$ 2	31,807
Issuance of common stock in connection with reverse merger, shares			1,656,076
Issuance of common stock upon vesting of restricted stock units, shares			(16,294)
Exercise of stock options	47			47
Exercise of stock options, shares			3,888
Stock-based compensation	24			24
Net loss	(34,761)				(34,761)
Ending Balance at Jun. 30, 2020	24,878		$ 11	66,648	(41,781)
Ending balance, shares at Jun. 30, 2020			11,198,315
Exercise of stock options	166			166
Exercise of stock options, shares			18,248
Stock-based compensation	375			375
Net loss	(5,100)				(5,100)
Ending Balance at Sep. 30, 2020	20,319		$ 11	67,189	(46,881)
Ending balance, shares at Sep. 30, 2020			11,216,563
Beginning Balance at Dec. 31, 2020	58,980		$ 13	110,424	(51,457)
Beginning balance, shares at Dec. 31, 2020		0
Beginning balance, shares at Dec. 31, 2020			12,830,598
Exercise of stock options	27			27
Exercise of stock options, shares			7,655
Stock-based compensation	495			495
Cashless exercise of warrants, shares			673,463
Net loss	(4,804)				(4,804)
Ending Balance at Mar. 31, 2021	54,698		$ 13	110,946	(56,261)
Ending balance, shares at Mar. 31, 2021			13,511,716
Beginning Balance at Dec. 31, 2020	$ 58,980		$ 13	110,424	(51,457)
Beginning balance, shares at Dec. 31, 2020		0
Beginning balance, shares at Dec. 31, 2020			12,830,598
Exercise of stock options, shares	29,575
Net loss	$ (18,367)
Ending Balance at Sep. 30, 2021	43,650		$ 15	113,459	(69,824)
Ending balance, shares at Sep. 30, 2021		0
Ending balance, shares at Sep. 30, 2021			14,754,447
Beginning Balance at Mar. 31, 2021	54,698		$ 13	110,946	(56,261)
Beginning balance, shares at Mar. 31, 2021			13,511,716
Issuance of common stock upon vesting of restricted stock units, shares			5,000
Exercise of stock options	15			15
Exercise of stock options, shares			1,939
Stock-based compensation	1,008			1,008
Cashless exercise of warrants			$ 1	(1)
Cashless exercise of warrants, shares			560,402
Net loss	(5,812)				(5,812)
Ending Balance at Jun. 30, 2021	49,909		$ 14	111,968	(62,073)
Ending balance, shares at Jun. 30, 2021			14,079,057
Exercise of stock options	19			19
Exercise of stock options, shares			19,981
Stock-based compensation	1,473			1,473
Cashless exercise of warrants			$ 1	(1)
Cashless exercise of warrants, shares			655,409
Net loss	(7,751)				(7,751)
Ending Balance at Sep. 30, 2021	$ 43,650		$ 15	$ 113,459	$ (69,824)
Ending balance, shares at Sep. 30, 2021		0
Ending balance, shares at Sep. 30, 2021			14,754,447