Summary of Net Accounts Receivable Greater Than or Equal to 10% of Net Account Receivable Balance (Detail) (Accounts Receivable, Credit Concentration Risk) (Detail) - Accounts Receivable - Credit Concentration Risk	12 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
L-3
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of net accounts receivable	17.00%	16.00%
Philips
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of net accounts receivable	16.00%	16.00%
Toshiba
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of net accounts receivable		11.00%