Note 16 - Concentration (Details Textual) - USD ($)	12 Months Ended
Apr. 30, 2024	Apr. 30, 2023	Apr. 30, 2022
Revenue from Contract with Customer, Including Assessed Tax	$ 37,487,000	$ 39,695,000	$ 40,525,000
Customer Concentration Risk [Member] \| Revenue Benchmark [Member] \| One Single Customer [Member]
Concentration Risk, Percentage	32.20%	33.90%	33.00%
Revenue from Contract with Customer, Including Assessed Tax	$ 37,487,000	$ 39,695,000	$ 40,525,000

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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+ Details