Convertible 3.75% Senior Notes (Details 3) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Debt Instrument [Line Items]
Interest Expense at 3.75% coupon rate (1)		$ 1,348	$ 0	$ 2,695	$ 0
Debt discount amortization (1)		1,643	$ 0	3,233	0
Amortization of deferred financing costs (1)				397	$ 16
Convertible Notes Payable [Member]
Debt Instrument [Line Items]
Interest Expense at 3.75% coupon rate (1)	[1]	1,347		2,695
Debt discount amortization (1)	[1]	1,643		3,233
Amortization of deferred financing costs (1)	[1]	180		353
Total interest expense		$ 3,170		$ 6,281

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