CONVERTIBLE SENIOR NOTES AND CAPPED CALL - Interest Expense (Details) - Convertible Debt - Convertible Senior Notes - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Debt Instrument [Line Items]
Contractual interest expense	$ 1,813	$ 1,572
Amortization of debt discount	16,664	13,901
Amortization of issuance costs	234	145
Total interest expense	$ 18,711	$ 15,618

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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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

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