Convertible 3.75% Senior Notes (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Debt Instrument [Line Items]
Interest Expense at 3.75% coupon rate (1)	$ 1,348		$ 0
Debt discount amortization (1)	1,590		0
Amortization of deferred financing costs (1)	195		8
Convertible Notes Payable [Member]
Debt Instrument [Line Items]
Interest Expense at 3.75% coupon rate (1)	1,348	[1]
Debt discount amortization (1)	1,590	[1]
Amortization of deferred financing costs (1)	173	[1]
Total interest expense	$ 3,111

[1] Included within “Interest and other expense, net” on the Condensed Consolidated Statements of Operations