Convertible Senior Notes - Interest Expenses (Details) - Convertible senior notes - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Debt
Contractual interest expense	$ 943	$ 943	$ 1,887	$ 1,887
Amortization of debt issuance costs	226	225	449	446
Total interest expense	$ 1,169	$ 1,168	$ 2,336	$ 2,333

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

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