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, 2018	$ 1	$ 30	$ 241,988	$ (210,771)	$ 31,248
Beginning balance (in shares) at Dec. 31, 2018	9,968	29,943,086
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 0	$ 0	1,195	0	1,195
Conversion of convertible preferred stock into common stock	$ 0	$ 3	(3)	0	0
Conversion of convertible preferred stock into common stock (in shares)	(7,865)	2,923,791
Exercise of stock options	$ 0	$ 0	0	0	0
Exercise of stock options (in shares)	0	36,410
Issuance of restricted stock	$ 0	$ 0	0	0	0
Issuance of restricted stock (in shares)	0	28,986
Net loss	$ 0	$ 0	0	(3,790)	(3,790)
Ending balance at Dec. 31, 2019	$ 1	$ 33	243,180	(214,561)	28,653
Ending balance (in shares) at Dec. 31, 2019	2,103	32,932,273
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 0	$ 0	1,633	0	1,633
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
Exercise of stock options	$ 0	$ 0	18	0	18
Exercise of stock options (in shares)	0	15,000
Issuance of restricted stock	$ 0	$ 0	0	0	0
Issuance of restricted stock (in shares)	0	71,683
Net loss	$ 0	$ 0	0	(4,412)	(4,412)
Ending balance at Dec. 31, 2020	$ 0	$ 34	$ 244,831	$ (218,973)	$ 25,892
Ending balance (in shares) at Dec. 31, 2020	0	33,801,045