Convertible Senior Notes - Summary of Convertible Debt (Details) - 1.125% Convertible Senior Notes Due 2026 - Convertible debt - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Principal	$ 345,000	$ 345,000
Unamortized discount	(53,327)	(57,247)
Unamortized issuance costs	(6,662)	(7,152)
Net carrying amount	285,011	280,601
Equity component, net of purchase discounts and issuance costs	$ 58,560	$ 58,560

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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The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

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Amount, after accumulated amortization, of debt discount.

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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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