Stock-based Compensation - Stock-based Compensation Expense (Details) - 2014 Stock Plan - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 01, 2020	Jan. 26, 2019	Feb. 01, 2020	Jan. 26, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1.6	$ 0.8	$ 5.6	$ 11.7
RSAs | Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1.3	0.6	3.6	9.7
RSAs | Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	0.0	0.0	0.9	0.9
RSUs | Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 0.3	$ 0.2	$ 1.1	$ 1.1