Debt and Commitments (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Interest expense on convertible notes	$ 1,777	$ 4,269
Coupon [Member] | Convertible Debt [Member] | 3.375% Convertible Notes [Member]
Debt Instrument [Line Items]
Interest expense on convertible notes	1,046	1,878
Debt discount amortization [Member] | Convertible Debt [Member] | 3.375% Convertible Notes [Member]
Debt Instrument [Line Items]
Interest expense on convertible notes	$ 731	$ 2,391