Note 2 - Business Combinations (Details) - Assets Acquired and Liabilities Assumed (USD $)				0 Months Ended	12 Months Ended				0 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2012	Mar. 22, 2013 LIFECODES [Member]	May 31, 2013 LIFECODES [Member]	May 31, 2014 LIFECODES [Member]	Jan. 31, 2014 LIFECODES [Member]	Mar. 22, 2013 LIFECODES [Member]	Aug. 19, 2011 Immucor Inc [Member]	Aug. 19, 2011 Immucor Inc [Member]
Note 2 - Business Combinations (Details) - Assets Acquired and Liabilities Assumed [Line Items]
Cash on hand								$ 2,558,000		$ 322,963,000
Accounts receivable								7,697,000		66,781,000
Inventories								16,800,000		60,000,000
Property and equipment								13,432,000		64,683,000
Intangible assets							3,500,000	33,240,000		779,860,000
Goodwill	851,563,000	1,003,463,000	966,338,000				1,100,000	36,889,000		972,295,000
Current liabilities								(4,669,000)		(53,429,000)
Deferred revenue										(4,107,000)
Deferred tax assets and liabilities - net								(15,197,000)		(273,962,000)
Other assets and liabilities - net								(146,000)		4,303,000
Total				90,604,000					1,939,387,000
Less: Contingent consideration liability	(11,300,000)	(4,504,000)			(4,500,000)	0		(4,400,000)
Total cash purchase price				$ 86,204,000	$ 87,300,000