FAIR VALUE MEASUREMENTS (Tables)

3 Months Ended

Jun. 30, 2012

Fair Value Disclosures [Abstract]

Fair Value Hierarchy of Financial Assets and Liabilities [Table Text Block]

The following tables represent the Company’s fair value hierarchy for its financial assets and liabilities:

Fair Values as of June 30, 2012:

(in thousands)	Level 1		Level 2		Total
Cash and cash equivalents:
Cash	$	159,846	$	—	$	159,846
U.S. Treasury Bills	25,000		—		25,000
Commercial Paper	—		19,793		19,793
Short-term investments:
U.S. Treasury Bills and Government Agency Securities	1,501		84,070		85,571
Commercial Paper	—		14,129		14,129
Corporate Bonds	—		46,150		46,150
CDs	—		4,884		4,884
Long-term investments:
U.S. Treasury Bills and Government Agency Securities	5,150		5,003		10,153
Corporate Bonds	—		19,157		19,157
Other current assets:
Derivative assets	—		3,029		3,029
Total assets measured at fair value	$	191,497	$	196,215	$	387,712
Accrued liabilities:
Derivative liabilities	$	14	$	580	$	594

Fair Values as of March 31, 2012:

(in thousands)	Level 1		Level 2		Total
Cash and cash equivalents:
Cash	$	147,338	$	—	$	147,338
U.S. Treasury Bills	50,000		—		50,000
Commercial Paper	—		11,997		11,997
Short-term investments:
U.S. Treasury Bills and Government Agency Securities	12,898		48,998		61,896
Commercial Paper	—		20,039		20,039
Corporate Bonds	—		38,356		38,356
CDs	—		4,886		4,886
Long-term investments:
U.S. Treasury Bills and Government Agency Securities	6,647		23,190		29,837
Corporate Bonds	—		25,510		25,510
Other current assets:
Derivative assets	—		2,658		2,658
Total assets measured at fair value	$	216,883	$	175,634	$	392,517
Accrued liabilities:
Derivative liabilities	$	7	$	714	$	721