Note 14. Segment and Geographic Information (Detail) - Sales by Product Group (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended	9 Months Ended
	Feb. 29, 2012	Aug. 19, 2011	Feb. 28, 2011	Feb. 29, 2012	Feb. 28, 2011
Sales by product group	$ 81,370	$ 74,910	$ 83,349	$ 175,795	$ 248,536
Instruments [Member]
Sales by product group	11,362	9,457	10,807	24,439	33,319
Traditional Reagents [Member]
Sales by product group	48,371	42,936	49,605	102,362	148,873
Capture Reagents [Member]
Sales by product group	20,153	21,239	21,539	45,801	62,212
Molecular Immunohematology [Member]
Sales by product group	$ 1,484	$ 1,278	$ 1,398	$ 3,193	$ 4,132