Condensed Consolidated Statements of Stockholders' Equity (unaudited) - USD ($) $ in Thousands	Total	Series D Convertible Preferred Stock	Series E Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2020	$ 22,569			$ 51	$ 220,307	$ (197,789)
Balance, Shares at Dec. 31, 2020				50,821,361
Balance at Mar. 31, 2021	23,503			$ 57	232,871	(209,425)
Balance, Shares at Mar. 31, 2021				56,879,679
Balance at Dec. 31, 2020	22,569			$ 51	220,307	(197,789)
Balance, Shares at Dec. 31, 2020				50,821,361
Issuance of common stock, net of issuance costs	13,474			$ 8	13,466
Issuance of common stock, net of issuance costs, shares				7,709,306
Issuance of common stock through employee stock purchase plan ("ESPP")	5				5
Issuance of common stock through employee stock purchase plan ("ESPP"), shares				4,206
Issuance of common stock through release of restricted stock units ("RSUs"), shares				248,111
Stock-based compensation	1,827				1,827
Net loss	(25,608)					(25,608)
Balance at Jun. 30, 2021	12,267			$ 59	235,605	(223,397)
Balance, Shares at Jun. 30, 2021				58,782,984
Balance at Mar. 31, 2021	23,503			$ 57	232,871	(209,425)
Balance, Shares at Mar. 31, 2021				56,879,679
Issuance of common stock, net of issuance costs	1,771			$ 2	1,769
Issuance of common stock, net of issuance costs, shares				1,650,988
Issuance of common stock through employee stock purchase plan ("ESPP")	5				5
Issuance of common stock through employee stock purchase plan ("ESPP"), shares				4,206
Issuance of common stock through release of restricted stock units ("RSUs"), shares				248,111
Stock-based compensation	960				960
Net loss	(13,972)					(13,972)
Balance at Jun. 30, 2021	12,267			$ 59	235,605	(223,397)
Balance, Shares at Jun. 30, 2021				58,782,984
Balance at Dec. 31, 2021	$ 18,868			$ 83	265,237	(246,452)
Balance, Shares at Dec. 31, 2021	82,969,421			82,969,421
Balance at Mar. 31, 2022	$ 11,616			$ 90	269,791	(258,265)
Balance, Shares at Mar. 31, 2022				89,774,309
Balance at Dec. 31, 2021	$ 18,868			$ 83	265,237	(246,452)
Balance, Shares at Dec. 31, 2021	82,969,421			82,969,421
Issuance of convertible preferred stock and warrants, net of issuance costs, shares		1,436	1,436
Conversion of preferred stock into common stock				$ 18	(18)
Conversion of preferred stock into common stock, shares		(1,436)	(1,436)	17,950,860
Issuance of common stock, net of issuance costs	$ 3,944			$ 7	3,937
Issuance of common stock, net of issuance costs, shares				6,804,888
Stock-based compensation	1,177				1,177
Net loss	(20,248)					(20,248)
Balance at Jun. 30, 2022	$ 3,741			$ 108	270,333	(266,700)
Balance, Shares at Jun. 30, 2022	107,725,169			107,725,169
Balance at Mar. 31, 2022	$ 11,616			$ 90	269,791	(258,265)
Balance, Shares at Mar. 31, 2022				89,774,309
Issuance of convertible preferred stock and warrants, net of issuance costs, shares		1,436	1,436
Conversion of preferred stock into common stock				$ 18	(18)
Conversion of preferred stock into common stock, shares		(1,436)	(1,436)	17,950,860
Stock-based compensation	560				560
Net loss	(8,435)					(8,435)
Balance at Jun. 30, 2022	$ 3,741			$ 108	$ 270,333	$ (266,700)
Balance, Shares at Jun. 30, 2022	107,725,169			107,725,169