Schedule of Consideration Transferred and Fair Value Assigned to Assets Acquired And Liabilities Assumed (Detail) - USD ($)		9 Months Ended
	Dec. 07, 2015	Feb. 29, 2016	May. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 244,144,000	$ 238,999,000
CryoScience
Business Acquisition [Line Items]
Accounts receivable		2,271,000
Inventories		5,686,000
Prepaid expenses		211,000
Intangible assets		5,260,000
Property, plant and equipment		13,400,000
Total identifiable assets		26,828,000
Accounts payable		(2,801,000)
Other accrued items		(310,000)
Net assets		23,717,000
Goodwill		6,570,000
Purchase price		30,287,000
Purchase price	$ 30,287,000	30,287,000
Plus: estimated working capital deficit	$ 1,069,000	1,069,000
Cash paid at closing		$ 31,356,000