Major Customers Who Accounted for 10% or More of Net Product and Engineering Revenue (Detail)	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011		Jul. 31, 2010
Philips
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	14.00%	13.00%		15.00%
L-3
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	12.00%		[1]		[1]
Toshiba
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	10.00%	11.00%		12.00%

[1] Total net revenue was less than 10% in this fiscal year.