Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2018	$ 49,456	$ 21	$ 167,040	$ (117,605)
Balance, Shares at Dec. 31, 2018		20,809,025
Issuance of common stock, net of issuance costs	11,980	$ 4	11,976
Issuance of common stock, net of issuance costs, shares		3,875,848
Exercise of common stock options	36		36
Exercise of common stock options, shares		24,399
Issuance of common stock through employee stock purchase plan ("ESPP")	76		76
Issuance of common stock through employee stock purchase plan ("ESPP"), shares		25,737
Stock-based compensation	2,989		2,989
Net loss	(47,339)			(47,339)
Balance at Dec. 31, 2019	17,198	$ 25	182,117	(164,944)
Balance, Shares at Dec. 31, 2019		24,735,009
Issuance of common stock, net of issuance costs	34,096	$ 25	34,071
Issuance of common stock, net of issuance costs, shares		25,343,290
Exercise of common stock options	17		17
Exercise of common stock options, shares		11,928
Issuance of common stock through employee stock purchase plan ("ESPP")	52		52
Issuance of common stock through employee stock purchase plan ("ESPP"), shares		43,095
Issuance of common stock through release of restricted stock units ("RSUs")		$ 1	(1)
Issuance of common stock through release of restricted stock units ("RSUs"), shares		688,039
Stock-based compensation	4,051		4,051
Net loss	(32,845)			(32,845)
Balance at Dec. 31, 2020	$ 22,569	$ 51	220,307	(197,789)
Balance, Shares at Dec. 31, 2020	50,821,361	50,821,361
Issuance of common stock including for warrants net of issuance cost	$ 41,273	$ 31	41,242
Issuance of common stock shares including for warrants net of issuance cost, shares		31,497,400
Issuance of common stock through employee stock purchase plan ("ESPP")	18		18
Issuance of common stock through employee stock purchase plan ("ESPP"), shares		30,383
Issuance of common stock through release of restricted stock units ("RSUs")		$ 1	(1)
Issuance of common stock through release of restricted stock units ("RSUs"), shares		620,277
Stock-based compensation	3,671		3,671
Net loss	(48,663)			(48,663)
Balance at Dec. 31, 2021	$ 18,868	$ 83	$ 265,237	$ (246,452)
Balance, Shares at Dec. 31, 2021	82,969,421	82,969,421