Condensed Consolidated Statement of Stockholders' Equity - 9 months ended Sep. 30, 2018 - 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	$ 4,896		$ 4,896
Stock-based compensation, Shares	0	0	0	0	0	0	0
Stock option exercises	$ 528		$ 528
Stock option exercises, shares	285,403	285,403
Restricted stock awards		$ 2	(2)
Restricted stock awards, shares		1,733,731
Common stock issuance upon retirement		$ 2	(2)
Common stock issuance upon retirement, shares	2,119,925	2,119,925
Series B issuance, net of issuance costs	$ 47,993		47,993
Series B issuance, net of issuance costs, shares							5,000
Series B conversion to Common Stock		$ 11	(11)
Series B conversion to Common Stock, shares		10,555,556					(1,900)
Series B beneficial conversion feature	(12,500)		12,500		$ (12,500)
Cumulative effect of accounting change	135				135
Net loss	(26,859)				(26,859)
Ending Balance at Sep. 30, 2018	$ 35,570	$ 71	$ 379,824	$ (47)	$ (344,280)	$ 2
Ending Balance, shares at Sep. 30, 2018		70,598,687				2,093,155	3,100