UNAUDITED CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2013	$ 354,583	$ 0	$ 7	$ (10,311)	$ 519,625	$ (154,738)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options	906		1		905
Compensation under employee stock compensation plan	4,665				4,665
Net loss	(45,132)					(45,132)
Balance at Jun. 30, 2014	315,022	0	8	(10,311)	525,195	(199,870)
Balance at Dec. 31, 2014	216,805	0	8	(10,679)	529,682	(302,206)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Series A convertible preferred stock and warrants	6,570				6,570
Accrued dividends on preferred stock	(2,258)
Deemed dividends on preferred stock	(3,350)
Compensation under employee stock compensation plan	3,454				3,454
Surrender of stock to satisfy minimum tax withholding	(34)			(36)	2
Net loss	(264,481)					(264,481)
Balance at Jun. 30, 2015	$ (43,294)	$ 0	$ 8	$ (10,715)	$ 534,100	$ (566,687)