Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Series A Preferred Stock [Member]	Series B Preferred Stock [Member]
Beginning Balance at Dec. 31, 2017	$ 8,877	$ 56	$ 313,922	$ (47)	$ (305,056)	$ 2
Beginning Balance, shares at Dec. 31, 2017		55,904,072				2,093,155
Stock-based compensation	$ 2,921		$ 2,921
Stock-based compensation, Shares	0	0	0	0	0	0	0
Stock option exercises	$ 130		$ 130
Stock option exercises, shares		63,295
Restricted stock awards		$ 1	(1)
Restricted stock awards, shares		1,038,957
Common stock issuance upon retirement		$ 2	(2)
Common stock issuance upon retirement, shares		1,640,198
Cumulative effect of accounting change	135				$ 135
Net loss	(10,709)				(10,709)
Ending Balance at Mar. 31, 2018	1,354	$ 59	316,970	$ (47)	(315,630)	$ 2
Ending Balance, shares at Mar. 31, 2018		58,646,522				2,093,155
Beginning Balance at Dec. 31, 2018	29,742	$ 71	381,004	$ (47)	$ (351,288)	$ 2
Beginning Balance, shares at Dec. 31, 2018		70,793,725				2,093,155	3,100
Stock-based compensation	$ 1,141		$ 1,141
Stock-based compensation, Shares	0	0	0	0	0	0	0
Stock option exercises	$ 472		$ 472
Stock option exercises, shares	150,275	150,275
Restricted stock awards		$ (1)	1
Restricted stock awards, shares		500,366
Series B conversion to Common Stock		$ 4	(4)
Series B conversion to Common Stock, shares		3,888,888				0	(700)
Net loss	$ (3,833)				$ (3,833)
Ending Balance at Mar. 31, 2019	$ 27,522	$ 74	$ 382,614	$ (47)	$ (355,121)	$ 2
Ending Balance, shares at Mar. 31, 2019		75,333,254				2,093,155	2,400