Accrued Expenses and Other Current Liabilities (Details) (USD $)	Jan. 31, 2012	Jul. 31, 2011	Jan. 31, 2011	Jul. 31, 2010
Accrued Expenses and Other Current Liabilities [Abstract]
Accrued wages and benefits	$ 12,681,000	$ 19,751,000
Accrued warranty obligations	8,852,000	9,120,000	9,731,000	10,562,000
Accrued commissions and royalties	4,093,000	3,295,000
Accrued business acquisition payments	1,070,000	726,000
Other	9,731,000	16,966,000
Accrued expenses and other current liabilities	$ 36,427,000	$ 49,858,000