DEBT - Interest Expense (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
Feb. 29, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Effective interest rate		4.31%	4.31%	4.31%	4.31%
Convertible debt
Debt Instrument [Line Items]
Interest rate	0.75%
Contractual interest expense (0.75% coupon)		$ 1,125	$ 0	$ 2,700	$ 0
Amortization of debt discount		3,807	0	9,060	0
Amortization of issuance costs		565	0	1,345	0
Interest expense		$ 5,497	$ 0	$ 13,105	$ 0

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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Amount of amortization expense attributable to debt issuance costs.

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The rate of interest that was being paid on the original debt issue that is being converted in the noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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

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Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

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