Product Information Table (Detail)	3 Months Ended			6 Months Ended
	Jan. 31, 2013	Jan. 31, 2012		Jan. 31, 2013	Jan. 31, 2012
Product Information [Line Items]
Percentage of net product and engineering revenue	67.00%	64.00%		69.00%	65.00%
Philips
Product Information [Line Items]
Percentage of net product and engineering revenue	13.00%	15.00%		15.00%	15.00%
L-3
Product Information [Line Items]
Percentage of net product and engineering revenue	12.00%			11.00%
Toshiba
Product Information [Line Items]
Percentage of net product and engineering revenue	11.00%			11.00%	11.00%
Siemens Ag
Product Information [Line Items]
Percentage of net product and engineering revenue		11.00%	[1]		11.00%	[1]

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