Debt - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Debt Instrument [Line Items]
Interest Expense	$ 3,484	$ 3,396
Convertible Senior Notes \| Convertible debt
Debt Instrument [Line Items]
Contractual interest expense	81	81
Amortization of debt discount	3,032	2,810
Amortization of issuance costs	288	269
Interest Expense	$ 3,401	$ 3,160

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

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