Customer Financing (Detail)	3 Months Ended
	Jul. 27, 2019 USD ($) finance_agreement	Jul. 28, 2018 USD ($)	Apr. 27, 2019 USD ($)	Apr. 28, 2018 USD ($)
Customer Financing [Line Items]
Maximum credit financed for equipment purchases for any one customer	$ 1,000,000
Number of customer financing contracts | finance_agreement	2
Financing contracts sold under ASC 860	$ 66,303,000	$ 47,310,000
Revenues from Sale of Financing Contracts	7,346,000	2,491,000
Cash and cash equivalents	109,781,000	$ 91,476,000	$ 95,646,000	$ 62,984,000
Current receivables of finance contracts not yet sold	16,844,000		48,559,000
Finance contracts receivable sold and outstanding	565,756,000
Deferred purchase price	$ 110,753,000		121,657,000
Bad debt write-offs, percentage (less than)	1.00%
Unsettled Financing Arrangements
Customer Financing [Line Items]
Cash and cash equivalents	$ 32,983,000		$ 34,016,000
The Bank of Tokyo-Mitsubishi UFJ, Ltd.
Customer Financing [Line Items]
Percentage of principal amount of financing contracts held as collateral (at least)	9.50%
Capacity under agreement	$ 525,000,000
Fifth Third Bank
Customer Financing [Line Items]
Percentage of principal amount of financing contracts held as collateral (at least)	11.00%
Capacity under agreement	$ 100,000,000