Fair Value Disclosures (Tables)

12 Months Ended

May 31, 2014

Fair Value Disclosures [Abstract]

Schedule of fair value of financial instruments measured on a recurring basis

These financial instruments measured at fair value on a recurring basis are summarized below:

	As of May 31, 2014
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash and cash equivalents	$	513,288	$	—	$	—	$	513,288
Total assets at fair value	$	513,288	$	—	$	—	$	513,288
Current accrued liabilities	$	—	$	286	$	—	$	286
Total liabilities at fair value	$	—	$	286	$	—	$	286

	As of May 31, 2013
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash and cash equivalents	$	352,273	$	—	$	—	$	352,273
Marketable securities:
U.S. municipal bonds	—		5,680		—		5,680
Accounts receivable, net	—		39		—		39
Total assets at fair value	$	352,273	$	5,719	$	—	$	357,992