Note 7 - Goodwill (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 19, 2011		May 31, 2012		May 31, 2011		May 31, 2010
Increase (Decrease) in Restricted Cash		[1]		[1]	$ (4,256,000)	[1]		[1]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Asset			2,900,000
Other Income			4,300,000
BioArray [Member]
Increase (Decrease) in Restricted Cash					$ 7,200,000

[1] In fiscal 2011, the Company accrued the release of escrowed funds related to the acquisition of BioArray. In accordance with the contingent consideration guidance in Accounting Standards Codification ("ASC") 805 "Business Combinations," $2.9 million of the $7.2 million returned to the Company was recorded to Goodwill as it relates to items that were predefined as contingent items in the agreement pursuant to which the Acquisition occurred (the "Acquisition Agreement") and are considered measurement period adjustments. The $2.9 million appears in the Non-cash Investing and Financing Activities on the Consolidated Statement of Cash Flows. The remaining $4.3 million was recorded to Other Income as it is not considered a measurement period adjustment and appears as an adjustment to net income in the operating activities of the Consolidated Statement of Cash Flows. The funds were received by the Company during fiscal 2012.