Accounts Receivable - Allowance for Doubtful Accounts (Detail) - Allowance for doubtful accounts [Member] - USD ($) $ in Thousands |
9 Months Ended | |
|---|---|---|
Jan. 29, 2017 |
Jan. 31, 2016 |
|
| Valuation and Qualifying Accounts Disclosure [Line Items] | ||
| Beginning balance | $ (1,088) | $ (851) |
| Provision for bad debts | 239 | (93) |
| Net write-offs, net of recoveries | 452 | 130 |
| Ending balance | $ (397) | $ (814) |