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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative accounting adjustment from adoption of new standard net of tax | ASU 2014-09 [Member]	$ 0	$ 0	$ 0	$ (234)	$ (234)
Cumulative accounting adjustment from adoption of new standard net of tax | ASU 2017-11 [Member]	0	0	2,614	(2,547)	67
Beginning balance at Dec. 31, 2017	$ 4	$ 4	223,829	(203,957)	19,880
Beginning balance (in shares) at Dec. 31, 2017	36,182	4,304,425
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 0	$ 0	904	0	904
Conversion of convertible preferred stock into common stock	$ (3)	$ 10	(7)	0	0
Conversion of convertible preferred stock into common stock (in shares)	(26,214)	9,744,916
Sale of common stock, net of offering costs of $2,336	$ 0	$ 16	14,648	0	14,664
Sale of common stock, net of offering costs (in shares)	0	15,893,745
Net loss			0	(4,033)	(4,033)
Ending balance at Dec. 31, 2018	$ 1	$ 30	241,988	(210,771)	31,248
Ending 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