Note 12 - Leases - Future Minimum Payments (Details) - USD ($)		Jan. 31, 2020	May 01, 2019
2020 *	[1]	$ 354,000
2021		1,432,000
2022		1,506,000
2023		1,597,000
2024		1,634,000
Thereafter		5,265,000
Total undiscounted future minimum lease payments		11,788,000
Less: difference between undiscounted lease payments & the present value of future lease payments		2,144,000
Operating Lease, Liability, Total		$ 9,644,000	$ 10,340,000

[1] Excludes the nine months ended January 31, 2020