Cash Flow Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Apr. 28, 2013	Apr. 29, 2012	May 01, 2011
Cash Flow Supplemental Disclosures [Line Items]
Value of shares of common stock surrendered to satisfy withholding tax liabilities and the cost of stock options exercised			$ 563
Number of options exercised	23,025	59,400	229,974
Performance Based Restricted Stock Units Vested And Stock Options Exercised During Period [Member]
Cash Flow Supplemental Disclosures [Line Items]
Number of shares of common stock surrendered to satisfy withholding tax liabilities and the cost of stock options exercised			60,415
Value of shares of common stock surrendered to satisfy withholding tax liabilities and the cost of stock options exercised			$ 563
Stock Options [Member]
Cash Flow Supplemental Disclosures [Line Items]
Number of options exercised			110,500
Performance Based Restricted Stock Units [Member]
Cash Flow Supplemental Disclosures [Line Items]
Number of units vested			40,000