CONSOLIDATED STATEMENTS OF CHANGES IN REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Preferred Stock [Member] Series A 12% Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Deficit [Member]	Total
Ending balance at Dec. 31, 2020					$ 1,723
Ending balance (in shares) at Dec. 31, 2020					176
Beginning balance at Dec. 31, 2019	$ 537	$ 56	$ 259,673	$ (216,394)	$ 43,872
Beginning balance (in shares) at Dec. 31, 2019	1,327,500	56,894,642
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Series A 12% convertible preferred stock dividend			61	(61)
Series A 12% convertible preferred stock dividend (in shares)		26.300
Series C super dividend redeemable convertible preferred stock dividend			76	(76)
Series C super dividend redeemable convertible preferred stock dividend (in shares)		33,416
Issuance of common stock			44		44
Issuance of common stock (in shares)		14,452
Conversion of Convertible Preferred to common	$ (10)		11		1
Conversion of Convertible Preferred to common (in shares)	(25,000)	4,553
Issuance of common stock for stock option exercises			219		$ 219
Issuance of common stock for stock option exercises (in shares)		84,624			84,624
Stock-based compensation expense			1,799		$ 1,799
Stock-based compensation expense (in shares)		19,068
Net loss				(23,465)	(23,465)
Ending balance at Dec. 31, 2020	$ 527	$ 56	261,883	(239,996)	22,470
Ending balance (in shares) at Dec. 31, 2020	1,302,500	57,077,055
Ending balance at Dec. 31, 2021					$ 1,723
Ending balance (in shares) at Dec. 31, 2021					176
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Series A 12% convertible preferred stock dividend			79	(79)
Series A 12% convertible preferred stock dividend (in shares)		26,050
Series C super dividend redeemable convertible preferred stock dividend			92	(92)
Series C super dividend redeemable convertible preferred stock dividend (in shares)		31,112
Issuance of common stock		$ 1	3,863		$ 3,864
Issuance of common stock (in shares)		845,214
Issuance of common stock for warrant exercises		$ 2	2,948		$ 2,950
Issuance of common stock for warrant exercises (in shares)		1,180,240
Issuance of common stock for stock option exercises (in shares)		148,941			148,941
Stock-based compensation expense			2,136		$ 2,136
Stock-based compensation expense (in shares)		32,693
Net loss				(30,527)	(30,527)
Ending balance at Dec. 31, 2021	$ 527	$ 59	$ 271,001	$ (270,694)	$ 893
Ending balance (in shares) at Dec. 31, 2021	1,302,500	59,341,305