CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In-Capital	Accumulated Other Comprehensive Gain (Loss)	Accumulated Deficit
Beginning Balance (in shares) at Dec. 31, 2019		8,480,968
Beginning Balance at Dec. 31, 2019	$ 7,574	$ 85	$ 92,497	$ (28)	$ (84,980)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of warrants (in shares)		221,293
Issuance of common stock upon exercise of warrants	15	$ 2	13
Issuance of common stock and common stock purchase warrants, net of issuance costs (in shares)		950,000
Issuance of common stock and common stock purchase warrants, net of issuance costs	1,990	$ 10	1,980
Issuance of common stock upon restricted stock unit settlement, net of shares withheld for taxes		19,643
Issuance of common stock upon restricted stock unit settlement, net of shares withheld for taxes	(13)		(13)
Stock-based compensation	403		403
Unrealized gain on available-for-sale marketable securities	28			28
Net loss	(4,103)				(4,103)
Ending Balance (in shares) at Mar. 31, 2020		9,671,904
Ending Balance at Mar. 31, 2020	5,894	$ 97	94,880	0	(89,083)
Beginning Balance (in shares) at Dec. 31, 2019		8,480,968
Beginning Balance at Dec. 31, 2019	7,574	$ 85	92,497	(28)	(84,980)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(13,548)
Ending Balance (in shares) at Sep. 30, 2020		31,241,636
Ending Balance at Sep. 30, 2020	18,712	$ 312	116,928	0	(98,528)
Beginning Balance (in shares) at Mar. 31, 2020		9,671,904
Beginning Balance at Mar. 31, 2020	5,894	$ 97	94,880	0	(89,083)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of warrants (in shares)		2,202,863
Issuance of common stock upon exercise of warrants	7	$ 22	(15)
Issuance of common stock and common stock purchase warrants, net of issuance costs (in shares)		14,790,133
Issuance of common stock and common stock purchase warrants, net of issuance costs	18,679	$ 148	18,531
Issuance of common stock upon restricted stock unit settlement, net of shares withheld for taxes		6,673
Issuance of common stock upon restricted stock unit settlement, net of shares withheld for taxes	(4)		(4)
Stock-based compensation	453		453
Net loss	(5,119)				(5,119)
Ending Balance (in shares) at Jun. 30, 2020		26,671,573
Ending Balance at Jun. 30, 2020	19,910	$ 267	113,845	0	(94,202)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of warrants (in shares)		1,113,424
Issuance of common stock upon exercise of warrants	1	$ 11	(10)
Issuance of common stock and common stock purchase warrants, net of issuance costs (in shares)		3,400,418
Issuance of common stock and common stock purchase warrants, net of issuance costs	2,596	$ 34	2,562
Issuance of common stock upon restricted stock unit settlement, net of shares withheld for taxes		56,221
Issuance of common stock upon restricted stock unit settlement, net of shares withheld for taxes	(22)		(22)
Stock-based compensation	553		553
Net loss	(4,326)				(4,326)
Ending Balance (in shares) at Sep. 30, 2020		31,241,636
Ending Balance at Sep. 30, 2020	$ 18,712	$ 312	116,928	0	(98,528)
Beginning Balance (in shares) at Dec. 31, 2020	53,551,461	53,551,461
Beginning Balance at Dec. 31, 2020	$ 27,135	$ 536	132,492	0	(105,893)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of warrants (in shares)		12,444,887
Issuance of common stock upon exercise of warrants	8,969	$ 124	8,845
Issuance of common stock, net of issuance costs of $50 (in shares)		1,083,548
Issuance of common stock, net of issuance costs of $50	1,628	$ 11	1,617
Issuance of common stock upon restricted stock unit settlement, net of shares withheld for taxes		96,350
Issuance of common stock upon restricted stock unit settlement, net of shares withheld for taxes	(52)	$ 1	(53)
Stock-based compensation	469		469
Net loss	(9,005)				(9,005)
Ending Balance (in shares) at Mar. 31, 2021		67,176,246
Ending Balance at Mar. 31, 2021	$ 29,144	$ 672	143,370	0	(114,898)
Beginning Balance (in shares) at Dec. 31, 2020	53,551,461	53,551,461
Beginning Balance at Dec. 31, 2020	$ 27,135	$ 536	132,492	0	(105,893)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (33,407)
Ending Balance (in shares) at Sep. 30, 2021	88,732,346	88,732,346
Ending Balance at Sep. 30, 2021	$ 19,968	$ 887	158,381	0	(139,300)
Beginning Balance (in shares) at Mar. 31, 2021		67,176,246
Beginning Balance at Mar. 31, 2021	29,144	$ 672	143,370	0	(114,898)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock and common stock purchase warrants, net of issuance costs (in shares)		4,768,976
Issuance of common stock and common stock purchase warrants, net of issuance costs	3,937	$ 47	3,890
Stock-based compensation	421		421
Net loss	(11,149)				(11,149)
Ending Balance (in shares) at Jun. 30, 2021		71,945,222
Ending Balance at Jun. 30, 2021	22,353	$ 719	147,681	0	(126,047)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under license agreement (in shares)		2,816,901
Issuance of common stock under license agreement	1,971	$ 28	1,943
Issuance of common stock and common stock purchase warrants, net of issuance costs (in shares)		13,970,223
Issuance of common stock and common stock purchase warrants, net of issuance costs	8,120	$ 140	7,980
Stock-based compensation	777		777
Net loss	$ (13,253)				(13,253)
Ending Balance (in shares) at Sep. 30, 2021	88,732,346	88,732,346
Ending Balance at Sep. 30, 2021	$ 19,968	$ 887	$ 158,381	$ 0	$ (139,300)