FAIR VALUE MEASUREMENTS - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Mar. 31, 2023
ASSETS:
Cash and cash equivalents	$ 279,944	$ 386,794
Available-for-sale securities	46,590	41,144
Equity investment in Napatech	6,021
Derivative financial instruments	5	59
Total assets	332,560	427,997
LIABILITIES:
Derivative financial instruments	(230)	(1,429)
Total liabilities	(230)	(1,429)
U.S. government and municipal obligations
ASSETS:
Available-for-sale securities	20,230	17,735
Commercial paper
ASSETS:
Available-for-sale securities	18,989	19,136
Corporate bonds
ASSETS:
Available-for-sale securities		310
Certificate of deposits
ASSETS:
Available-for-sale securities	7,371	3,963
Level 1
ASSETS:
Cash and cash equivalents	270,901	370,455
Equity investment in Napatech	6,021
Derivative financial instruments	0	0
Total assets	294,632	388,500
LIABILITIES:
Derivative financial instruments	0	0
Total liabilities	0	0
Level 1 | U.S. government and municipal obligations
ASSETS:
Available-for-sale securities	17,710	17,735
Level 1 | Commercial paper
ASSETS:
Available-for-sale securities	0	0
Level 1 | Corporate bonds
ASSETS:
Available-for-sale securities		310
Level 1 | Certificate of deposits
ASSETS:
Available-for-sale securities	0	0
Level 2
ASSETS:
Cash and cash equivalents	9,043	16,339
Equity investment in Napatech	0
Derivative financial instruments	5	59
Total assets	37,928	39,497
LIABILITIES:
Derivative financial instruments	(230)	(49)
Total liabilities	(230)	(49)
Level 2 | U.S. government and municipal obligations
ASSETS:
Available-for-sale securities	2,520	0
Level 2 | Commercial paper
ASSETS:
Available-for-sale securities	18,989	19,136
Level 2 | Corporate bonds
ASSETS:
Available-for-sale securities		0
Level 2 | Certificate of deposits
ASSETS:
Available-for-sale securities	7,371	3,963
Level 3
ASSETS:
Cash and cash equivalents	0	0
Equity investment in Napatech	0
Derivative financial instruments	0	0
Total assets	0	0
LIABILITIES:
Derivative financial instruments	0	(1,380)
Total liabilities	0	(1,380)
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
Level 3 | Corporate bonds
ASSETS:
Available-for-sale securities		0
Level 3 | Certificate of deposits
ASSETS:
Available-for-sale securities	$ 0	$ 0