Long-Term Debt (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
3.00% Convertible Notes [Member]
Contractual interest expense and the discount amortization
Year-to-date contractual interest expense	$ 0	$ 1,839	$ 3,450
Year-to-date discount amortization	$ 0	$ 1,810	$ 3,251
Effective interest rate of liability component	0.00%	8.60%	8.60%
2.25% Convertible Notes [Member]
Contractual interest expense and the discount amortization
Year-to-date contractual interest expense	$ 0	$ 1,875	$ 4,112
Year-to-date discount amortization	$ 0	$ 5,366	$ 7,530
Effective interest rate of liability component	0.00%	7.70%	7.70%
3.00% Convertible Notes due 2020
Contractual interest expense and the discount amortization
Effective interest rate of liability component	8.25%