FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	$ 102,989	$ 112,531	$ 121,848
Accumulated gross unrealized gain, before tax	18	60
Accumulated gross unrealized loss, before tax	(6)	0
Cash, cash equivalents and debt securities available-for-sale, amortized cost	166,470	161,449
Cash, cash equivalents and debt securities available-for-sale	166,482	161,509
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accumulated gross unrealized gain, before tax	0	17
Accumulated gross unrealized loss, before tax	0	0
Cash, cash equivalents and debt securities available-for-sale, amortized cost	101,589	112,959
Cash, cash equivalents and debt securities available-for-sale	101,589	112,976
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	64,881	48,490
Accumulated gross unrealized gain, before tax	18	43
Accumulated gross unrealized loss, before tax	(6)	0
Debt securities, available-for-sale	64,893	48,533
Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	43,131	39,070
Cash and cash equivalents, fair value	43,131	39,070
Money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	58,458	67,712
Cash and cash equivalents, fair value	58,458	67,712
Treasury securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost		6,177
Accumulated gross unrealized gain, before tax		17
Accumulated gross unrealized loss, before tax		0
Debt securities, available-for-sale		6,194
Certificate of deposit | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	8,641	8,641
Cash and cash equivalents, fair value	8,641	8,641
Commercial paper | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	27,412	17,656
Accumulated gross unrealized gain, before tax	1	42
Accumulated gross unrealized loss, before tax	(1)	0
Debt securities, available-for-sale	27,412	17,698
Corporate debt | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost	28,828	22,193
Accumulated gross unrealized gain, before tax	17	1
Accumulated gross unrealized loss, before tax	(5)	0
Debt securities, available-for-sale	28,840	22,194
Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents and debt securities available-for-sale	102,989	112,531
Cash and Cash Equivalents | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents and debt securities available-for-sale	101,589	106,782
Cash and Cash Equivalents | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	1,400	5,749
Cash and Cash Equivalents | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	43,131	39,070
Cash and Cash Equivalents | Money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	58,458	67,712
Cash and Cash Equivalents | Commercial paper | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	1,400	700
Cash and Cash Equivalents | Corporate debt | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	5,049
Restricted Cash (Current & Non-Current)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents and debt securities available-for-sale	8,641	8,641
Restricted Cash (Current & Non-Current) | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents and debt securities available-for-sale	0	0
Restricted Cash (Current & Non-Current) | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	8,641	8,641
Restricted Cash (Current & Non-Current) | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	0	0
Restricted Cash (Current & Non-Current) | Certificate of deposit | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	8,641	8,641
Short-Term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents and debt securities available-for-sale	44,607	40,337
Short-Term Investments | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	6,194
Short-Term Investments | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	44,607	34,143
Short-Term Investments | Treasury securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale		6,194
Short-Term Investments | Commercial paper | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	26,012	16,998
Short-Term Investments | Corporate debt | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	18,595	17,145
Long-Term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents and debt securities available-for-sale	10,245	0
Long-Term Investments | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0	0
Long-Term Investments | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	10,245	0
Long-Term Investments | Treasury securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale		0
Long-Term Investments | Certificate of deposit | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	0
Long-Term Investments | Corporate debt | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale	$ 10,245	$ 0