Fair Value Measurements (Tables)

3 Months Ended

Aug. 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 August 31, 2014
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash and cash equivalents	$	581,453	$	—	$	—	$	581,453
Total assets at fair value	$	581,453	$	—	$	—	$	581,453
Current accrued liabilities	$	—	$	265	$	—	$	265
Total liabilities at fair value	$	—	$	265	$	—	$	265

	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