DEBT - Schedule of Convertible Senior Notes due in 2028 (Details) - Convertible Notes - Convertible Senior Notes Due 2028 - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2021
Debt Instrument [Line Items]
Amortization of debt discount	$ 4,929	$ 11,412
Amortization of debt issuance costs	235	550
Total interest cost recognized	$ 5,164	$ 11,962

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