Nature of Business and Summary of Significant Accounting Policies Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	May 02, 2020	Apr. 27, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Precontract costs	$ 1,582	$ 857
Minimum
Product Warranty Liability [Line Items]
Standard parts warranty period	1 year
Installation warranty period	1 year
Maximum
Product Warranty Liability [Line Items]
Standard parts warranty period	5 years
Installation warranty period	10 years