Note 16 - Segment Reporting and Sales by Major Customer (Details Textual)	12 Months Ended
	Apr. 30, 2023
Number of Operating Segments	2
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | The Five Aerospace Customers [Member]
Concentration Risk, Percentage	33.30%
Number of Major Customers	5
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Top Customer [Member]
Concentration Risk, Percentage	14.30%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Next Top Four Customers [Member] | Minimum [Member]
Concentration Risk, Percentage	1.90%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Next Top Four Customers [Member] | Maximum [Member]
Concentration Risk, Percentage	8.30%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Customer One [Member]
Concentration Risk, Percentage	31.70%
Number of Major Customers	1