Note 17. Income Taxes (Detail) - Net Deferred Tax Assets (Liabilities) (USD $)	12 Months Ended
	May 31, 2012	May 31, 2011
Deferred tax liabilities:
Intangibles	$ (277,816,000)	$ (19,282,000)
Property, Plant & Equipment	(4,504,000)	(4,931,000)
Prepaids and other	(324,000)	(346,000)
Deferred tax assets:
Tax Credit carry-forwards	25,109,000	2,736,000
Net operating loss carry-forwards	10,371,000	11,580,000
Compensation expense	3,165,000	5,617,000
Reserves not currently deductible	1,723,000	4,376,000
Inventory	950,000	603,000
Deferred revenue	279,000	2,923,000
Other	2,928,000	6,187,000
	(238,119,000)	9,463,000
Valuation Allowance	(1,888,000)	(2,467,000)
Net deferred tax assets (liabilities)	(240,007,000)	6,996,000
Balance, beginning of period		6,716,000
Change in valuation allowance		2,300,000
Balance, end of period	1,888,000	2,467,000
Change Due to Acquisition [Member]
Deferred tax assets:
Change in valuation allowance	(753,000)
Additions [Member]
Deferred tax assets:
Change in valuation allowance	592,000
Reductions [Member]
Deferred tax assets:
Change in valuation allowance	$ (418,000)	$ (4,249,000)