Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - 6 months ended Jun. 30, 2016 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Series A Preferred Stock [Member]
Beginning Balance at Dec. 31, 2015	$ 31,696	$ 53	$ 274,891	$ (47)	$ (243,203)	$ 2
Beginning Balance, shares at Dec. 31, 2015		52,730,799				2,093,155
Stock-based compensation	7,457		7,457
Exercise of stock options	$ 225		225
Exercise of stock options, shares	112,425	112,425
Vesting of restricted stock awards	$ 0	$ 0	0	0	0	$ 0
Vesting of restricted stock awards, shares		104,025
Common stock issuance upon retirement	2,460	$ 1	2,459
Common stock issuance upon retirement, shares		663,221
Equity financing costs	40		40
Net loss	(35,219)				(35,219)
Ending Balance at Jun. 30, 2016	$ 6,659	$ 54	$ 285,072	$ (47)	$ (278,422)	$ 2
Ending Balance, shares at Jun. 30, 2016		53,610,470				2,093,155