Debt - Components of The Notes (Details) - 1.75% Convertible Senior Notes due 2023 - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Principal	$ 143,750	$ 143,750
Less: debt discount, net of amortization	(19,840)	(21,231)
Less: debt issuance costs, net of amortization	(2,618)	(2,803)
Net carrying amount of the convertible senior notes	$ 121,292	$ 119,716

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount, after accumulated amortization, of debt discount (premium).

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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