CASH, CASH EQUIVALENTS AND MARKETABLE SECURITIES - Summary of Marketable Securities Classified as Short-term and Long-term (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Cash, Cash Equivalents and Marketable Securities [Line Items]
Amortized Cost	$ 50,414	$ 77,339
Unrealized Gains	168	17
Fair Value	50,582	77,356
U.S. government and municipal obligations
Cash, Cash Equivalents and Marketable Securities [Line Items]
Fair Value	31,341	27,622
Commercial paper
Cash, Cash Equivalents and Marketable Securities [Line Items]
Fair Value	14,644	48,722
Corporate bonds
Cash, Cash Equivalents and Marketable Securities [Line Items]
Fair Value	4,597	1,012
Short-term marketable securities
Cash, Cash Equivalents and Marketable Securities [Line Items]
Amortized Cost	47,852	76,332
Unrealized Gains	117	12
Fair Value	47,969	76,344
Short-term marketable securities | U.S. government and municipal obligations
Cash, Cash Equivalents and Marketable Securities [Line Items]
Amortized Cost	28,621	27,610
Unrealized Gains	107	12
Fair Value	28,728	27,622
Short-term marketable securities | Commercial paper
Cash, Cash Equivalents and Marketable Securities [Line Items]
Amortized Cost	14,644	48,722
Unrealized Gains	0	0
Fair Value	14,644	48,722
Short-term marketable securities | Corporate bonds
Cash, Cash Equivalents and Marketable Securities [Line Items]
Amortized Cost	4,587
Unrealized Gains	10
Fair Value	4,597
Long-term marketable securities
Cash, Cash Equivalents and Marketable Securities [Line Items]
Amortized Cost	2,562	1,007
Unrealized Gains	51	5
Fair Value	2,613	1,012
Long-term marketable securities | U.S. government and municipal obligations
Cash, Cash Equivalents and Marketable Securities [Line Items]
Amortized Cost	2,562
Unrealized Gains	51
Fair Value	$ 2,613
Long-term marketable securities | Corporate bonds
Cash, Cash Equivalents and Marketable Securities [Line Items]
Amortized Cost		1,007
Unrealized Gains		5
Fair Value		$ 1,012