Convertible Senior Secured Notes (Details) - USD ($) $ in Thousands, shares in Millions	3 Months Ended	6 Months Ended		32 Months Ended
	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Details of Notes reflected in balance sheet
Remaining outstanding balance		$ 5,699		$ 7,085
Loss on extinguishment of debt	$ 241	382	$ 2,375
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		(1,962)	(25,300)	(81,463)
Conversion of debt to equity - accretion of debt discount and deferred financing costs		424		25,003
Accretion of debt discount and deferred financing costs		152		5,151
Remaining outstanding balance		$ 5,699		$ 7,085
Shares of common stock issued in conversion of Notes		0.4
Loss on extinguishment of debt		$ 400	$ 2,400