Shareholders' Equity and Share-Based Compensation - Share-Based Compensation Expense by Award Type (Details) - USD ($) $ in Thousands	12 Months Ended
	May 02, 2020	Apr. 27, 2019	Apr. 28, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 2,265	$ 2,479	$ 2,635
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	492	593	763
Restricted Stock and Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	1,341	1,446	1,442
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 432	$ 440	$ 430