Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature.

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Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature.

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Face (par) amount of debt instrument at time of issuance.

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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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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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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Debt - Convertible Senior Notes (Details) $ in Thousands	12 Months Ended
Debt - Convertible Senior Notes (Details) $ in Thousands	Dec. 31, 2020 USD ($) numberOfClassesOfReceivables	Oct. 20, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jul. 23, 2018 USD ($)
1.75% Convertible Senior Notes due 2023
Debt Instrument [Line Items]
Aggregate Principal Amount	$ 25,626
Net Carrying Amount	$ 22,482		$ 119,716
1.75% Convertible Senior Notes due 2023 \| Senior Notes
Debt Instrument [Line Items]
Stated Cash Interest Rate	1.75%
Effective Interest Rate	7.25%
Conversion Rate	32.7332
Aggregate Principal Amount	$ 25,626		143,750	$ 143,750
Unamortized Debt Discount	(2,776)		(21,231)
Unamortized Debt Issuance Costs	(368)		(2,803)
Net Carrying Amount	$ 22,482		119,716
Debt Instrument, Convertible, Threshold Consecutive Trading Days \| numberOfClassesOfReceivables	30
Debt Instrument, Convertible, Threshold Trading Days \| numberOfClassesOfReceivables	20
Convertible Senior Notes due 2025
Debt Instrument [Line Items]
Aggregate Principal Amount	$ 661,250
Net Carrying Amount	$ 488,268		$ 0
Convertible Senior Notes due 2025 \| Senior Notes
Debt Instrument [Line Items]
Effective Interest Rate	6.52%
Conversion Rate	13.7920
Aggregate Principal Amount	$ 661,250	$ 661,250
Unamortized Debt Discount	(163,077)
Unamortized Debt Issuance Costs	(9,905)
Net Carrying Amount	$ 488,268