Accounts Receivable - Allowance for Returns and Allowances and Discounts Accounts (Detail) (Reserve for returns and allowances and discounts [Member], USD $) In Thousands, unless otherwise specified	9 Months Ended
Jan. 27, 2013	Jan. 29, 2012
Reserve for returns and allowances and discounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	$ (478)	$ (577)
Provision for returns, allowances and discounts	(2,146)	(1,929)
Credits issued	2,044	1,966
Ending balance	$ (580)	$ (540)

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e24092-122690

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Total of the deductions in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, representing receivables written off as uncollectible and portions of the reserves utilized, respectively.

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