Major Customers Who Accounted for 10% or More of Net Product and Engineering Revenue (Detail) (Total Net Revenue)	3 Months Ended			6 Months Ended
	Jan. 31, 2014	Jan. 31, 2013		Jan. 31, 2014	Jan. 31, 2013
Philips
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	16.00%	13.00%		17.00%	15.00%
L-3
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	13.00%	12.00%		11.00%	11.00%
Toshiba
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	14.00%	11.00%		12.00%	11.00%
Siemens AG
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	10.00%		[1]	10.00%		[1]

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