FAIR VALUE MEASUREMENTS - Schedule of Financial Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
ASSETS:
Cash and cash equivalents	$ 104,893	$ 102,076
Marketable securities	159,964us-gaap_AvailableForSaleSecurities	116,718us-gaap_AvailableForSaleSecurities
Derivative financial instruments	15us-gaap_DerivativeAssets	368us-gaap_DerivativeAssets
Total assets	264,872us-gaap_AssetsFairValueDisclosure	219,162us-gaap_AssetsFairValueDisclosure
LIABILITIES:
Contingent consideration	(4,484)	(4,291)
Contingent contractual non-compliance liability		(49)
Derivative financial instruments	(1,664)us-gaap_DerivativeLiabilities	(139)us-gaap_DerivativeLiabilities
Total liabilities	(6,148)us-gaap_LiabilitiesFairValueDisclosure	(4,479)us-gaap_LiabilitiesFairValueDisclosure
U.S. government and municipal obligations
ASSETS:
Marketable securities	145,345	91,757
Commercial paper
ASSETS:
Marketable securities	5,095	14,581
Corporate bonds
ASSETS:
Marketable securities	9,524	10,380
Level 1
ASSETS:
Cash and cash equivalents	104,893	82,079
Derivative financial instruments	0	0
Total assets	160,981	114,451
LIABILITIES:
Contingent 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	46,564	21,992
Level 1 \| Commercial paper
ASSETS:
Marketable securities	0	0
Level 1 \| Corporate bonds
ASSETS:
Marketable securities	9,524	10,380
Level 2
ASSETS:
Cash and cash equivalents	0	19,997
Derivative financial instruments	15	368
Total assets	103,891	104,711
LIABILITIES:
Contingent consideration	0	0
Contingent contractual non-compliance liability		0
Derivative financial instruments	(1,664)	(139)
Total liabilities	(1,664)	(139)
Level 2 \| U.S. government and municipal obligations
ASSETS:
Marketable securities	98,781	69,765
Level 2 \| Commercial paper
ASSETS:
Marketable securities	5,095	14,581
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 consideration	(4,484)	(4,291)
Contingent contractual non-compliance liability		(49)
Derivative financial instruments	0	0
Total liabilities	(4,484)	(4,340)
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

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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