Convertible Senior Notes - Schedule of Interest Expense Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Amortization of debt discount and issuance costs	$ 33,283	$ 52,733	$ 53,394
2022 Notes
Debt Instrument [Line Items]
Amortization of debt issuance cost	1,606	1,531	860
Amortization of debt discount	$ 31,677	30,159	16,921
Effective interest rate of the liability component (in percent)	4.75%
2018 Notes
Debt Instrument [Line Items]
Amortization of debt issuance cost	$ 0	1,131	1,911
Amortization of debt discount	$ 0	$ 19,912	$ 33,702
Effective interest rate of the liability component (in percent)	6.50%

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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