Intangible Assets and Goodwill - Schedule of Goodwill Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Apr. 29, 2017	Apr. 30, 2016	May 02, 2015
Goodwill [Roll Forward]
Beginning balance	$ 1.7	$ 1.7	$ 13.0
Impairment	0.0	0.0	(11.1)
Foreign currency translation	(0.1)	0.0	(0.2)
Ending balance	1.6	1.7	1.7
Interface
Goodwill [Roll Forward]
Beginning balance	0.7	0.7	12.0
Impairment	0.0	0.0	(11.1)
Foreign currency translation	(0.1)	0.0	(0.2)
Ending balance	0.6	0.7	0.7
Power Products
Goodwill [Roll Forward]
Beginning balance	1.0	1.0	1.0
Impairment	0.0	0.0	0.0
Foreign currency translation	0.0	0.0	0.0
Ending balance	$ 1.0	$ 1.0	$ 1.0