Convertible Senior Secured Notes (Details) - USD ($) $ in Thousands, shares in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Details of Notes reflected in balance sheet
Carrying value	$ 8,762		$ 8,762		$ 26,947
Loss on extinguishment of debt	241	$ 39	2,375	$ 1,732
7.50% Convertible Senior Secured Notes due 2019
Details of Notes reflected in balance sheet
Gross proceeds					90,000
Initial value of interest make-whole derivative reported as debt discount					(9,270)
Conversion option reported as debt discount and APIC					(22,336)
Conversion of debt to equity - principal			(25,335)	(9,700)	(53,941)
Conversion of debt to equity - accretion of debt discount	6,669		6,669		17,926
Accretion of debt discount			481		4,568
Carrying value	$ 8,762		$ 8,762		$ 26,947
Shares of common stock issued in conversion of Notes			4.8
Shares of common stock issued in settlement of the interest make-whole provision			0.5
Loss on extinguishment of debt			$ 2,400	$ 1,700