Basis of Presentation (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2012	May 31, 2012
Basis of Presentation (Textual) [Abstract]
Assets, liabilities, revenues and expenses of foreign subsidiaries	less than 10% of consolidated amounts
Demonstration equipment	$ 5,024	$ 5,495
Maximum [Member]
Period for demonstration equipment included in other assets	2 years