Senior Convertible Notes - Schedule of Interest Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Interest Expense Debt [Roll Forward]
Interest payable on Senior Convertible Debenture, beginning of period	$ 1,988
Interest payable on Senior Convertible Debenture, end of period	2,474	$ 1,988
Convertible Senior Notes Due 2019
Interest Expense Debt [Roll Forward]
Interest payable on Senior Convertible Debenture, beginning of period	1,988	4,969	$ 2,222	$ 6,250	$ 2,500
Accrued interest expense	486	2,982	2,747	3,388	3,750
Interest Payment		(5,963)		(7,416)
Interest payable on Senior Convertible Debenture, end of period	$ 2,474	$ 1,988	$ 4,969	$ 2,222	$ 6,250