Warranty Reserves Estimated Cost (Details) - USD ($)	3 Months Ended	6 Months Ended
	Oct. 29, 2016	Oct. 29, 2016	Oct. 31, 2015	Jul. 30, 2016	Apr. 30, 2016	Jul. 31, 2015	Apr. 30, 2015
Standard Product Warranty Accrual, Preexisting, Increase (Decrease)	$ (179,000)	$ 1,228,000	$ (424,000)
Standard Product Warranty Accrual	3,688,000	3,688,000	$ 2,338,000	$ 5,223,000	$ 4,134,000	$ 2,029,000	$ 2,653,000
UAS
Standard Product Warranty Accrual, Preexisting, Increase (Decrease)		1,407,000
Standard Product Warranty Accrual	$ 865,000	865,000
Product Warranty Expense		$ 1,114,000