Property, plant, and equipment (Detail) - Schedule Of Property, Plant And Equipment (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012	Jul. 31, 2011
Building and building improvements	$ 4,751	$ 4,320
Machinery and equipment	6,760	6,916
Office furniture and computer equipment	14,879	14,551
Leasehold improvements	4,498	4,694
	30,888	30,481
Accumulated depreciation and amortization	(22,484)	(20,858)
	8,404	9,623
Land and land improvements	712	712
	$ 9,116	$ 10,335