Note 11 - Fair Value (Details) (USD $)					9 Months Ended	12 Months Ended	3 Months Ended		9 Months Ended
	Feb. 28, 2014	May 31, 2013	Feb. 28, 2013	May 31, 2012	Feb. 28, 2014 Geographic Concentration Risk [Member] UNITED STATES	May 31, 2013 Geographic Concentration Risk [Member] UNITED STATES	Nov. 30, 2013 LIFECODES [Member]	Aug. 31, 2013 LIFECODES [Member]	Feb. 28, 2014 LIFECODES [Member]	May 31, 2013 LIFECODES [Member]	Mar. 22, 2013 LIFECODES [Member]	Feb. 28, 2014 Notes Payable, Other Payables [Member]	May 31, 2013 Notes Payable, Other Payables [Member]	Feb. 28, 2014 Term Loan [Member]	May 31, 2013 Term Loan [Member]
Note 11 - Fair Value (Details) [Line Items]
Cash and Cash Equivalents, at Carrying Value	$ 26,028,000	$ 29,388,000	$ 19,520,000	$ 18,578,000
Concentration Risk, Percentage					17.00%	38.00%
Long-term Debt, Fair Value												451,300,000	452,300,000	662,400,000	669,100,000
Business Combination, Contingent Consideration, Liability		4,504,000							0	4,500,000	4,400,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability							$ (3,300,000)	$ (1,300,000)	$ (4,500,000)