Note 2 - Business Combinations (Details) - Summarized Results of Operations (Lifecodes Acquisition [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
Aug. 31, 2013	Aug. 31, 2012
Lifecodes Acquisition [Member]
Note 2 - Business Combinations (Details) - Summarized Results of Operations [Line Items]
Net sales	$ 96,044	$ 96,252
Net loss	$ (7,760)	$ (11,606)

The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(2)-(3)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

Name:	us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration