Note 11 - Fair Value (Details) (USD $)	3 Months Ended	12 Months Ended								3 Months Ended				3 Months Ended	12 Months Ended
	Aug. 31, 2013	May 31, 2014	Aug. 31, 2014	May 31, 2013	Aug. 31, 2014 Contingent Consideration Liability [Member]	Aug. 31, 2014 Term Loan Facility [Member]	May 31, 2014 Term Loan Facility [Member]	Aug. 31, 2014 Notes Payable, Other Payables [Member]	May 31, 2014 Notes Payable, Other Payables [Member]	Aug. 31, 2013 LIFECODES [Member]	Aug. 31, 2014 LIFECODES [Member]	May 31, 2014 LIFECODES [Member]	May 31, 2013 LIFECODES [Member]	Aug. 31, 2014 Cash and Cash Equivalents [Member] Geographic Concentration Risk [Member] UNITED STATES	May 31, 2014 Cash and Cash Equivalents [Member] Geographic Concentration Risk [Member] UNITED STATES
Note 11 - Fair Value (Details) [Line Items]
Cash and Cash Equivalents, at Carrying Value	$ 24,002,000	$ 23,621,000	$ 17,355,000	$ 29,388,000
Concentration Risk, Percentage														15.00%	19.00%
Long-term Debt, Fair Value						656,700,000	656,700,000	442,800,000	446,300,000
Business Combination, Contingent Consideration, Liability		11,300,000	11,579,000	4,504,000							11,600,000	0	4,500,000
Accrued Liabilities					(200,000)
Other Liabilities, Noncurrent		23,833,000	24,095,000		11,400,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	$ (1,320,000)	$ 4,638,000								$ 1,300,000