Convertible Senior Secured Notes (Details) - USD ($) $ in Thousands, shares in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Details of Notes reflected in balance sheet
Carrying value	$ 8,068		$ 8,068		$ 26,947
Loss on extinguishment of debt	25	$ 860	2,400	$ 2,592
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			(26,335)	(13,400)	(53,941)
Conversion of debt to equity - accretion of debt discount	6,863		6,863		17,926
Accretion of debt discount			593		4,568
Carrying value	$ 8,068		$ 8,068		$ 26,947
Shares of common stock issued in conversion of Notes			5.0
Shares of common stock issued in settlement of the interest make-whole provision			0.5
Loss on extinguishment of debt			$ 2,400	$ 2,600