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Convertible Notes (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Debt Instrument [Line Items]
Other assets	$ 3,749	$ 2,165
Convertible notes, long-term	124,443	119,418
1.125% Convertible Senior Notes due 2018
Debt Instrument [Line Items]
Principal amount of convertible notes	138,000
Convertible Senior Notes
Debt Instrument [Line Items]
Total convertible notes	124,443	119,418
Convertible notes, short-term	0	0
Convertible notes, long-term	$ 124,443	$ 119,418
Convertible Senior Notes \| 1.125% Convertible Senior Notes due 2018
Debt Instrument [Line Items]
Convertible notes stated interest rate (as a percent)	1.125%	1.125%	1.125%
Principal amount of convertible notes	$ 138,000	$ 138,000
Unamortized discount	(12,496)	(17,099)
Unamortized Debt Issuance Expense	(1,061)	(1,483)
Total convertible notes	$ 124,443	119,418
Adjustments for New Accounting Pronouncement [Member]
Debt Instrument [Line Items]
Other assets		2,165
Convertible notes, long-term		119,418
Scenario, Previously Reported [Member] \| Adjustments for New Accounting Pronouncement [Member]
Debt Instrument [Line Items]
Other assets		3,648
Convertible notes, long-term		120,901
Scenario, Adjustment [Member] \| Adjustments for New Accounting Pronouncement [Member]
Debt Instrument [Line Items]
Other assets		(1,483)
Convertible notes, long-term		$ (1,483)