FAIR VALUE MEASUREMENTS - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Mar. 31, 2024
ASSETS:
Cash and cash equivalents	$ 398,361	$ 389,674
Available-for-sale securities	15,642	22,946
Equity investment in Napatech	13,909	11,507
Derivative financial instruments		11
Total assets	427,912	424,138
LIABILITIES:
Derivative financial instruments	(324)	(74)
Total liabilities	(324)	(74)
U.S. government and municipal obligations
ASSETS:
Available-for-sale securities	2,002	11,491
Commercial paper
ASSETS:
Available-for-sale securities	13,130	8,648
Certificates of deposit
ASSETS:
Available-for-sale securities	510	2,807
Level 1
ASSETS:
Cash and cash equivalents	373,633	381,829
Equity investment in Napatech	13,909	11,507
Derivative financial instruments		0
Total assets	389,544	402,321
LIABILITIES:
Derivative financial instruments	0	0
Total liabilities	0	0
Level 1 | U.S. government and municipal obligations
ASSETS:
Available-for-sale securities	2,002	8,985
Level 1 | Commercial paper
ASSETS:
Available-for-sale securities	0	0
Level 1 | Certificates of deposit
ASSETS:
Available-for-sale securities	0	0
Level 2
ASSETS:
Cash and cash equivalents	24,728	7,845
Equity investment in Napatech	0	0
Derivative financial instruments		11
Total assets	38,368	21,817
LIABILITIES:
Derivative financial instruments	(324)	(74)
Total liabilities	(324)	(74)
Level 2 | U.S. government and municipal obligations
ASSETS:
Available-for-sale securities	0	2,506
Level 2 | Commercial paper
ASSETS:
Available-for-sale securities	13,130	8,648
Level 2 | Certificates of deposit
ASSETS:
Available-for-sale securities	510	2,807
Level 3
ASSETS:
Cash and cash equivalents	0	0
Equity investment in Napatech	0	0
Derivative financial instruments		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
Level 3 | Certificates of deposit
ASSETS:
Available-for-sale securities	$ 0	$ 0