Fair Value Measurements (Tables)

6 Months Ended

Nov. 30, 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 November 30, 2014
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash and cash equivalents	$	826,724	$	—	$	—	$	826,724
Total assets at fair value	$	826,724	$	—	$	—	$	826,724
Current accrued liabilities	$	—	$	274	$	—	$	274
Total liabilities at fair value	$	—	$	274	$	—	$	274

	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