Note 10 - Deferred Revenue (Details) - Deferred Revenue (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012
Deferred Revenue Arrangement [Line Items]
Balance at beginning of year	$ 3,037	$ 13,575
Foreign currency translation adjustment	29	(173)
Balance at end of year	2,413	3,037
Less current portion	(2,252)	(2,606)
Deferred revenue, net of current portion	161	431
Fair value adjustments relating to the Immucor Acquisition		(8,532)
Additions to deferred revenue from new contracts	7,843	7,621
Prior to Acquisition [Member]
Deferred Revenue Arrangement [Line Items]
Revenue recognized		(936)
Current Period [Member]
Deferred Revenue Arrangement [Line Items]
Revenue recognized	$ (8,496)	$ (8,518)