Customer Financing (Detail)	3 Months Ended		9 Months Ended
	Jan. 29, 2022 USD ($)	Jan. 23, 2021 USD ($)	Jan. 29, 2022 USD ($) financingAgreement	Jan. 23, 2021 USD ($)	Apr. 24, 2021 USD ($)
Customer Financing [Line Items]
Maximum credit financed for equipment purchases for any one customer	$ 1,000,000		$ 1,000,000
Number of customer financing contracts | financingAgreement			2
Financing contracts sold			$ 225,300,000	$ 245,552,000
Gain on sale of financing contracts	(663,000)	$ 926,000	(2,278,000)	(2,075,000)
Proceeds from Receivables sold			327,205,000	291,074,000
Cash and cash equivalents	165,044,000		165,044,000		$ 143,244,000
Current receivables of finance contracts not yet sold	65,191,000		65,191,000		50,638,000
Finance contracts receivable sold and outstanding	571,629,000		$ 571,629,000
Bad debt write-offs, percentage (less than)			1.00%
Unsettled Financing Arrangements
Customer Financing [Line Items]
Cash and cash equivalents	40,787,000		$ 40,787,000		$ 36,771,000
Customer Finance Contracts
Customer Financing [Line Items]
Gain on sale of financing contracts	(5,143,000)	$ (1,484,000)	$ (8,433,000)	$ (212,000)
The Bank of Tokyo-Mitsubishi UFJ, Ltd.
Customer Financing [Line Items]
Percentage of principal amount of financing contracts held as collateral (at least)			15.00%
Capacity under agreement	525,000,000		$ 525,000,000
Fifth Third Bank
Customer Financing [Line Items]
Percentage of principal amount of financing contracts held as collateral (at least)			15.00%
Capacity under agreement	$ 100,000,000		$ 100,000,000