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 |
9 Months Ended | 12 Months Ended |
|---|---|---|
Apr. 30, 2017 |
Jul. 31, 2016 |
|
| L-3 | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Percentage of net accounts receivable | 12.00% | 17.00% |
| Philips | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Percentage of net accounts receivable | 21.00% | 15.00% |