Convertible Senior Notes - Interest Expenses (Details) - Convertible senior notes - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Debt
Contractual interest expense	$ 943	$ 943
Amortization of debt issuance costs	223	222
Total interest expense	$ 1,166	$ 1,165

Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Name:	us-gaap_InterestExpenseDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration