Note 14 - Concentration (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2023	Oct. 31, 2022
Revenue from Contract with Customer, Including Assessed Tax	$ 9,610,000	$ 10,066,000	$ 19,353,000	$ 20,010,000
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | One Single Customer [Member]
Concentration Risk, Percentage			33.60%
Revenue from Contract with Customer, Including Assessed Tax			$ 19,353,000