Note 14 - Concentration (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2024	Jan. 31, 2023	Jan. 31, 2024	Jan. 31, 2023
Revenue from Contract with Customer, Including Assessed Tax	$ 9,131,000	$ 9,967,000	$ 28,484,000	$ 29,977,000
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | One Single Customer [Member]
Concentration Risk, Percentage			32.70%
Revenue from Contract with Customer, Including Assessed Tax			$ 28,484,000