Accrued Expenses and Other Current Liabilities - Product Warranty Rollforward (Details) - USD ($) |
6 Months Ended | |
|---|---|---|
Jan. 31, 2016 |
Jan. 31, 2015 |
|
| Accrued Liabilities, Current [Abstract] | ||
| Minimum coverage period of product warranty from the date of shipment | 1 year | |
| Changes in Product Warranty Liability | ||
| Accrued warranty obligations, as of the beginning of the period | $ 8,638,000 | $ 8,618,000 |
| Provision for warranty obligations | 2,096,000 | 1,992,000 |
| Charges incurred | (2,110,000) | (2,315,000) |
| Accrued warranty obligations, as of the end of the period | $ 8,624,000 | $ 8,295,000 |