CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2020		59,901,306
Beginning balance at Dec. 31, 2020	$ 16,617	$ 6	$ 537,370	$ (520,759)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock units	115		115
Stock-based compensation costs	507		507
Net loss	(9,688)			(9,688)
Ending balance (in shares) at Mar. 31, 2021		59,901,306
Ending balance at Mar. 31, 2021	7,551	$ 6	537,992	(530,447)
Beginning balance (in shares) at Dec. 31, 2021		60,433,395
Beginning balance at Dec. 31, 2021	(68,494)	$ 6	540,823	(609,323)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock and warrants (in shares)		136,370,064
Issuance of common stock and warrants	189,412	$ 14	189,398
Vesting of restricted stock units	37		37
Stock-based compensation costs	391		391
Net loss	(22,060)			(22,060)
Ending balance (in shares) at Mar. 31, 2022		196,803,459
Ending balance at Mar. 31, 2022	$ 99,286	$ 20	$ 730,649	$ (631,383)