FAIR VALUE MEASUREMENTS - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Mar. 31, 2021
ASSETS:
Cash and cash equivalents	$ 487,168	$ 467,176
Available-for-sale securities	6,737	9,277
Derivative financial instruments	18	57
Total assets	493,923	476,510
LIABILITIES:
Derivative financial instruments	(38)	(191)
Total liabilities	(38)	(191)
U.S. government and municipal obligations
ASSETS:
Available-for-sale securities	1,039	3,578
Commercial paper
ASSETS:
Available-for-sale securities	5,698	5,699
Level 1
ASSETS:
Cash and cash equivalents	487,168	467,176
Derivative financial instruments	0	0
Total assets	488,207	469,715
LIABILITIES:
Derivative financial instruments	0	0
Total liabilities	0	0
Level 1 | U.S. government and municipal obligations
ASSETS:
Available-for-sale securities	1,039	2,539
Level 1 | Commercial paper
ASSETS:
Available-for-sale securities	0	0
Level 2
ASSETS:
Cash and cash equivalents	0	0
Derivative financial instruments	18	57
Total assets	5,716	6,795
LIABILITIES:
Derivative financial instruments	(38)	(191)
Total liabilities	(38)	(191)
Level 2 | U.S. government and municipal obligations
ASSETS:
Available-for-sale securities	0	1,039
Level 2 | Commercial paper
ASSETS:
Available-for-sale securities	5,698	5,699
Level 3
ASSETS:
Cash and cash equivalents	0	0
Derivative financial instruments	0	0
Total assets	0	0
LIABILITIES:
Derivative financial instruments	0	0
Total liabilities	0	0
Level 3 | U.S. government and municipal obligations
ASSETS:
Available-for-sale securities	0	0
Level 3 | Commercial paper
ASSETS:
Available-for-sale securities	$ 0	$ 0