CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Preferred Stock [Member] Convertible Preferred Stock - Series C [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Total
Beginning balance at Dec. 31, 2019	$ 1	$ 33	$ 243,180	$ (214,561)	$ 28,653
Beginning balance (in shares) at Dec. 31, 2019	2,103	32,932,273
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 0	$ 0	430	0	430
Conversion of convertible preferred stock into common stock	$ (1)	$ 1	0	0	0
Conversion of convertible preferred stock into common stock (in shares)	(2,103)	782,089
Net loss	$ 0	$ 0	0	(1,035)	(1,035)
Ending balance at Mar. 31, 2020	$ 0	$ 34	243,610	(215,596)	28,048
Ending balance (in shares) at Mar. 31, 2020	0	33,714,362
Beginning balance at Dec. 31, 2020	$ 0	$ 34	244,831	(218,973)	25,892
Beginning balance (in shares) at Dec. 31, 2020	0	33,801,045
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 0	$ 0	662	0	662
Issuance of restricted stock	$ 0	$ 0	0	0	0
Issuance of restricted stock (in shares)	0	16,260
Net loss	$ 0	$ 0	0	(2,418)	(2,418)
Ending balance at Mar. 31, 2021	$ 0	$ 34	$ 245,493	$ (221,391)	$ 24,136
Ending balance (in shares) at Mar. 31, 2021	0	33,817,305