Debt - Summary of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Debt Instrument [Line Items]
Amortization of debt discount	$ 2,815	$ 2,978
Senior Notes \| 2023 Convertible Notes
Debt Instrument [Line Items]
Contractual interest expense	1,581	1,581
Amortization of debt discount	2,348	2,225
Total	$ 3,929	$ 3,806
Effective interest rate (as a percent)	5.45%

Amount of amortization expense attributable to debt discount (premium) and debt issuance costs.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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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 of the cost of borrowed funds accounted for as interest expense for debt.

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Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

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