Amount of amortization expense attributable to debt discount (premium) and debt issuance costs.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Convertible Notes (Details 3) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Convertible Notes (Details 3) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Interest expense related to notes
Amortization of discount and debt issuance costs			$ 5,324	$ 5,025
Interest expense	$ 3,287	$ 3,193	9,754	9,497
1.125% Convertible Senior Notes due 2018
Interest expense related to notes
Interest	388	388	1,164	1,164
Amortization of discount and debt issuance costs	1,801	1,699	5,324	5,025
Interest expense	$ 2,189	$ 2,087	$ 6,488	$ 6,189
Convertible Senior Notes \| 1.125% Convertible Senior Notes due 2018
Interest expense related to notes
Convertible notes stated interest rate (as a percent)					1.125%
Debt Instrument, Interest Rate, Effective Percentage		5.50%		5.50%
Convertible Senior Notes \| 1.125% Convertible Senior Notes due 2018
Interest expense related to notes
Convertible notes stated interest rate (as a percent)	1.125%		1.125%
Debt Instrument, Interest Rate, Effective Percentage	5.50%		5.50%