CONVERTIBLE SENIOR NOTES AND CAPPED CALL - Interest Expense (Details) - Convertible Debt - Convertible Senior Notes - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Debt Instrument [Line Items]
Contractual interest expense	$ 1,572	$ 156
Amortization of debt discount	13,901	1,343
Amortization of issuance costs	145	11
Total interest expense	$ 15,618	$ 1,510

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

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