Statement of Stockholders' Equity (Deficit) - USD ($) shares in Thousands, $ in Thousands	Junior Series A Convertible Preferred Stock	Common stock	Additional paid-in Capital	Accumulated Deficit.	Accumulated Other Comprehensive Loss	Total
Balance at Dec. 31, 2011	$ 3,000	$ 1		$ (105,488)		$ (102,487)
Balance (in shares) at Dec. 31, 2011	3,000	1,451
Increase (Decrease) in Stockholders' Equity
Issuance of common stock			$ 2			2
Issuance of common stock (in shares)		19
Issuance of Junior Series A Preferred Stock			640			640
Preferred Stock dividends			(642)	(6,421)		(7,063)
Net loss				(14,562)		(14,562)
Balance at Dec. 31, 2012	$ 3,000	$ 1		(126,471)		(123,470)
Balance (in shares) at Dec. 31, 2012	3,000	1,470
Increase (Decrease) in Stockholders' Equity
Issuance of common stock		$ 21	174,310			174,331
Issuance of common stock (in shares)		21,038
Issuance of common stock from offering, net		$ 9	175,546			175,555
Issuance of common stock from offering, net (in shares)		8,740
Issuance of common stock upon conversion of Junior Series A Preferred Stock	$ (3,000)					(3,000)
Issuance of common stock upon conversion of Junior Series A Preferred Stock (in shares)	(3,000)
Reclassification of warrant liability			2,179			2,179
Reclassification of preferred stock issuance costs			(1,804)			(1,804)
Exercise of stock options/warrants			94			94
Exercise of stock options/warrants (in shares)		165
Share-based compensation			2,871			2,871
Preferred Stock dividends			(457)	(5,434)		(5,891)
Net loss				(51,145)		(51,145)
Balance at Dec. 31, 2013		$ 31	352,739	(183,050)		169,720
Balance (in shares) at Dec. 31, 2013		31,413
Increase (Decrease) in Stockholders' Equity
Net loss						(93,672)
Balance at Jun. 30, 2014						138,940
Balance at Dec. 31, 2013		$ 31	352,739	(183,050)		169,720
Balance (in shares) at Dec. 31, 2013		31,413
Increase (Decrease) in Stockholders' Equity
Net loss						(85,120)
Balance at Sep. 30, 2014						153,092
Balance at Dec. 31, 2013		$ 31	352,739	(183,050)		169,720
Balance (in shares) at Dec. 31, 2013		31,413
Increase (Decrease) in Stockholders' Equity
Issuance of common stock from offering, net		$ 2	55,407			55,409
Issuance of common stock from offering, net (in shares)		1,900
Exercise of stock options/warrants		$ 1	2,948			2,949
Exercise of stock options/warrants (in shares)		682
Share-based compensation			13,040			13,040
Excess tax benefit from share-based compensation			4,256			4,256
Net loss				(116,772)		(116,772)
Unrealized gain on available for sale securities, net of taxes					$ (65)	(65)
Balance at Dec. 31, 2014		$ 34	428,390	(299,822)	(65)	128,537
Balance (in shares) at Dec. 31, 2014		33,995
Balance at Jun. 30, 2014						138,940
Increase (Decrease) in Stockholders' Equity
Net loss						8,552
Balance at Sep. 30, 2014						153,092
Increase (Decrease) in Stockholders' Equity
Net loss						(31,652)
Balance at Dec. 31, 2014		$ 34	$ 428,390	$ (299,822)	$ (65)	$ 128,537
Balance (in shares) at Dec. 31, 2014		33,995