Major Customers Who Accounted for 10% or More of Net Product and Engineering Revenue (Parenthetical) (Detail)	3 Months Ended		9 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2013	Apr. 30, 2012
Product Information [Line Items]
Percentage of net product and engineering revenue	67.00%	72.00%	68.00%	67.00%
Maximum
Product Information [Line Items]
Percentage of net product and engineering revenue	10.00%