FAIR VALUE MEASUREMENTS - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Mar. 31, 2016
ASSETS:
Cash and cash equivalents	$ 210,870	$ 210,711
Marketable securities	124,052	141,364
Derivative financial instruments	116	191
Contingently returnable consideration	8,341	16,131
Total assets	343,379	368,397
LIABILITIES:
Contingent purchase consideration	(4,674)	(7,293)
Derivative financial instruments	(93)	(158)
Total liabilities	(4,767)	(7,451)
U.S. government and municipal obligations
ASSETS:
Marketable securities	97,338	123,328
Commercial paper
ASSETS:
Marketable securities	26,714	16,172
Corporate bonds
ASSETS:
Marketable securities		1,864
Level 1
ASSETS:
Cash and cash equivalents	210,870	210,711
Derivative financial instruments	0	0
Contingently returnable consideration	0
Total assets	236,481	253,691
LIABILITIES:
Contingent purchase consideration	0	0
Derivative financial instruments	0	0
Total liabilities	0	0
Level 1 | U.S. government and municipal obligations
ASSETS:
Marketable securities	25,611	41,116
Level 1 | Commercial paper
ASSETS:
Marketable securities	0	0
Level 1 | Corporate bonds
ASSETS:
Marketable securities		1,864
Level 2
ASSETS:
Cash and cash equivalents	0	0
Derivative financial instruments	116	191
Contingently returnable consideration	0
Total assets	98,557	98,575
LIABILITIES:
Contingent purchase consideration	0	0
Derivative financial instruments	(93)	(158)
Total liabilities	(93)	(158)
Level 2 | U.S. government and municipal obligations
ASSETS:
Marketable securities	71,727	82,212
Level 2 | Commercial paper
ASSETS:
Marketable securities	26,714	16,172
Level 2 | Corporate bonds
ASSETS:
Marketable securities		0
Level 3
ASSETS:
Cash and cash equivalents	0	0
Derivative financial instruments	0	0
Contingently returnable consideration	8,341	16,131
Total assets	8,341	16,131
LIABILITIES:
Contingent purchase consideration	(4,674)	(7,293)
Derivative financial instruments	0	0
Total liabilities	(4,674)	(7,293)
Level 3 | U.S. government and municipal obligations
ASSETS:
Marketable securities	0	0
Level 3 | Commercial paper
ASSETS:
Marketable securities	$ 0	0
Level 3 | Corporate bonds
ASSETS:
Marketable securities		$ 0