FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Dec. 31, 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 December 31, 2012:

(in thousands)	Level 1		Level 2		Total
Cash and cash equivalents:
Cash	$	146,965	$	—	$	146,965
U.S. Treasury Bills	39,997		—		39,997
Commercial paper	—		9,694		9,694
Short-term investments:
U.S. Treasury Bills and Government Agency Securities	21,503		44,055		65,558
Commercial paper	—		28,390		28,390
Corporate bonds	—		36,294		36,294
CDs	—		2,003		2,003
Long-term investments:
U.S. Treasury Bills and Government Agency Securities	28,181		35,798		63,979
Corporate bonds	—		14,634		14,634
CDs	—		1,006		1,006
Other current assets:
Derivative assets	—		421		421
Total assets measured at fair value	$	236,646	$	172,295	$	408,941
Accrued liabilities:
Derivative liabilities	$	1	$	1,334	$	1,335

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