Convertible senior notes, 2015 Convertible Notes Interest Expense (Details 3) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Long-term debt
Amortization of debt issuance costs	$ 302	$ 107	$ 0
Convertible debt \| 3.00% Convertible senior notes due 2022
Long-term debt
Contractual interest expense	4,497	1,702
Amortization of debt issuance costs	302	107
Amortization of debt discount	6,065	2,146
Total	$ 10,864	$ 3,955
Effective interest rate of the liability component	11.00%	11.00%

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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

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