FAIR VALUE MEASUREMENTS (Tables)

6 Months Ended

Sep. 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 September 30, 2012:

(in thousands)	Level 1		Level 2		Total
Cash and cash equivalents:
Cash	$	122,790	$	—	$	122,790
U.S. Treasury Bills	74,991		—		74,991
Commercial Paper	—		10,148		10,148
Short-term investments:
U.S. Treasury Bills and Government Agency Securities	1,504		73,791		75,295
Commercial Paper	—		25,721		25,721
Corporate Bonds	—		46,601		46,601
CDs	—		4,883		4,883
Long-term investments:
U.S. Treasury Bills and Government Agency Securities	5,116		19,064		24,180
Corporate Bonds	—		13,589		13,589
CDs	—		1,006		1,006
Other current assets:
Derivative assets	—		1,726		1,726
Total assets measured at fair value	$	204,401	$	196,529	$	400,930
Accrued liabilities:
Derivative liabilities	$	4	$	1,005	$	1,009

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