Stock-Based Compensation - Stock Option Activity by Range of Exercise Prices (Detail) (USD $)	12 Months Ended
	Apr. 28, 2013	Apr. 29, 2012	May 01, 2011	May 02, 2010
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	182,825	209,475	268,875	498,849
Options Outstanding, Weighted-Average Remaining Contractual Life	4 years 4 months 24 days
Options Outstanding, Weighted-Average Exercise Price	$ 6.99	$ 7.22	$ 6.81	$ 5.87
Options Exercisable, Number Exercisable	169,825
Options Exercisable, Weighted-Average Exercise Price	$ 7.23
Exercise Prices Range 1.88 to 1.88 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 1.88
Range of Exercise Prices, upper limit	$ 1.88
Options Outstanding, Number Outstanding	40,000
Options Outstanding, Weighted-Average Remaining Contractual Life	5 years 8 months 12 days
Options Outstanding, Weighted-Average Exercise Price	$ 1.88
Options Exercisable, Number Exercisable	32,000
Options Exercisable, Weighted-Average Exercise Price	$ 1.88
Exercise Prices Range 4.59 to 5.41 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 4.59
Range of Exercise Prices, upper limit	$ 5.41
Options Outstanding, Number Outstanding	6,000
Options Outstanding, Weighted-Average Remaining Contractual Life	2 years 9 months 18 days
Options Outstanding, Weighted-Average Exercise Price	$ 4.86
Options Exercisable, Number Exercisable	6,000
Options Exercisable, Weighted-Average Exercise Price	$ 4.86
Exercise Prices Range 7.08 to 7.27 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 7.08
Range of Exercise Prices, upper limit	$ 7.27
Options Outstanding, Number Outstanding	27,125
Options Outstanding, Weighted-Average Remaining Contractual Life	4 years 4 months 24 days
Options Outstanding, Weighted-Average Exercise Price	$ 7.12
Options Exercisable, Number Exercisable	22,125
Options Exercisable, Weighted-Average Exercise Price	$ 7.13
Exercise Prices Range 8.75 to 9.57 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 8.75
Range of Exercise Prices, upper limit	$ 9.57
Options Outstanding, Number Outstanding	101,700
Options Outstanding, Weighted-Average Remaining Contractual Life	3 years 10 months 24 days
Options Outstanding, Weighted-Average Exercise Price	$ 8.81
Options Exercisable, Number Exercisable	101,700
Options Exercisable, Weighted-Average Exercise Price	$ 8.81
Exercise Prices Range 10.11 to 12.13 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 10.11
Range of Exercise Prices, upper limit	$ 12.13
Options Outstanding, Number Outstanding	8,000
Options Outstanding, Weighted-Average Remaining Contractual Life	5 years 8 months 12 days
Options Outstanding, Weighted-Average Exercise Price	$ 10.62
Options Exercisable, Number Exercisable	8,000
Options Exercisable, Weighted-Average Exercise Price	$ 10.62