Debt - Interest Expense (Details) - 2025 Notes - Convertible Debt - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Debt Instrument [Line Items]
Contractual interest expense	$ 1,315	$ 1,287
Amortization of debt discount	207	208
Amortization of debt issuance costs	165	166
Total interest expense	$ 1,687	$ 1,661

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 for debt.

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