Major Customers Who Accounted for 10% or More of Net Product and Engineering Revenue (Detail) (Sales Revenue, Net)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013		Jul. 31, 2012
Philips
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	16.00%	15.00%		14.00%
L-3
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	11.00%	12.00%		12.00%
Toshiba
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	12.00%	10.00%		10.00%
Siemens AG
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	11.00%		[1]		[1]

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