Convertible Note - Finance Expense Related to the Convertible Notes (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Debt Instrument [Line Items]
Amortization of debt discount	$ 785	$ 424	$ 2,313	$ (654)	$ 3,260
the “Notes” \| Convertible Debt
Debt Instrument [Line Items]
Amortization of debt discount	0	0	0	0	3,605
Amortization of debt issuance costs	826	0	2,511	0	333
Total finance expense recognized	$ 826	$ 0	$ 2,511	$ 0	$ 3,938

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