DEBT - Summary of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Long-term Debt, Unclassified [Abstract]
Stated coupon interest	$ 2,557	$ 1,476	$ 5,170	$ 4,778
Amortization of debt discount, and royalty rights	48	125	118	5,511
Total interest expense	$ 2,605	$ 1,601	$ 5,288	$ 10,289

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