Convertible Notes - Schedule of Interest Expense (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Senior Notes Due 2019 [Member]	Sep. 30, 2014 Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Contractual interest expense			$ 1,797	$ 2,995
Amortization of debt issuance costs			922	1,533
Amortization of debt discount	14,504	0	7,802	12,971
Debt Instrument, Interest Expense, Total			$ 10,521	$ 17,499