FAIR VALUE MEASUREMENTS - Schedule of Financial Assets and Liabilities (Detail) (USD $)	Jun. 30, 2014	Mar. 31, 2014
ASSETS:
Cash and cash equivalents	$ 88,974,000	$ 102,076,000
Marketable securities	145,470,000	116,718,000
Derivative financial instruments	358,000	368,000
Total assets	234,802,000	219,162,000
LIABILITIES:
Contingent purchase consideration	(4,369,000)	(4,291,000)
Contingent contractual non-compliance liability		(49,000)
Derivative financial instruments	(102,000)	(139,000)
Total liabilities	(4,471,000)	(4,479,000)
U.S. government and municipal obligations
ASSETS:
Marketable securities	115,494,000	91,757,000
Commercial paper
ASSETS:
Marketable securities	23,882,000	14,581,000
Corporate bonds
ASSETS:
Marketable securities	6,094,000	10,380,000
Level 1
ASSETS:
Cash and cash equivalents	88,974,000	82,079,000
Derivative financial instruments	0	0
Total assets	135,997,000	114,451,000
LIABILITIES:
Contingent purchase consideration	0	0
Contingent contractual non-compliance liability		0
Derivative financial instruments	0	0
Total liabilities	0	0
Level 1 | U.S. government and municipal obligations
ASSETS:
Marketable securities	40,929,000	21,992,000
Level 1 | Commercial paper
ASSETS:
Marketable securities	0	0
Level 1 | Corporate bonds
ASSETS:
Marketable securities	6,094,000	10,380,000
Level 2
ASSETS:
Cash and cash equivalents	0	19,997,000
Derivative financial instruments	358,000	368,000
Total assets	98,805,000	104,711,000
LIABILITIES:
Contingent purchase consideration	0	0
Contingent contractual non-compliance liability		0
Derivative financial instruments	(102,000)	(139,000)
Total liabilities	(102,000)	(139,000)
Level 2 | U.S. government and municipal obligations
ASSETS:
Marketable securities	74,565,000	69,765,000
Level 2 | Commercial paper
ASSETS:
Marketable securities	23,882,000	14,581,000
Level 2 | Corporate bonds
ASSETS:
Marketable securities	0	0
Level 3
ASSETS:
Cash and cash equivalents	0	0
Derivative financial instruments	0	0
Total assets	0	0
LIABILITIES:
Contingent purchase consideration	(4,369,000)	(4,291,000)
Contingent contractual non-compliance liability	0	(49,000)
Derivative financial instruments	0	0
Total liabilities	(4,369,000)	(4,340,000)
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	$ 0