Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Total
Beginning balance (in shares) at Dec. 31, 2016	258,000
Beginning balance at Dec. 31, 2016	$ 8	$ 308,784	$ (316,308)	$ (7,516)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 0	1,138	0	1,138
Issuance of common stock and warrants (in shares)	245,000
Issuance of common stock and warrants	$ 7	10,726	0	10,733
Issuance of common stock due to the vesting of restricted stock, net of shares withheld to cover taxes (in shares)	4,000
Proceeds from exercise of warrants	$ 0	289	0	289
Issuance costs related to common stock and warrants	0	(1,392)	0	(1,392)
Reclassification of warrant liabilities to equity	0	798	0	798
Net income (loss)	$ 0	0	321	321
Ending balance (in shares) at Dec. 31, 2017	507,000
Ending balance at Dec. 31, 2017	$ 15	320,343	(315,987)	4,371
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 0	1,301	0	1,301
Issuance of common stock and warrants (in shares)	390,000
Issuance of common stock and warrants	$ 12	4,780	0	4,792
Issuance of common stock due to the vesting of restricted stock, net of shares withheld to cover taxes (in shares)	10,000
Proceeds from exercise of warrants (in shares)	35,000
Proceeds from exercise of warrants	$ 1	1,274	0	1,275
Issuance costs related to common stock and warrants	0	(690)	0	(690)
Amendment of equity classified warrants	0	293	0	293
Reclassification of warrant liabilities to equity	$ 0	472	0	472
Net income (loss)			(9,242)	(9,242)
Ending balance (in shares) at Dec. 31, 2018	942,000
Ending balance at Dec. 31, 2018	$ 28	$ 327,773	$ (325,229)	$ 2,572