Note 15 - Segment Reporting and Sales by Major Customer (Details Textual)	3 Months Ended
	Jul. 31, 2023	Jul. 31, 2022
Number of Operating Segments	2
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Number of Major Customers	2	1
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | The Five Aerospace Customers [Member]
Concentration Risk, Percentage	33.80%
Number of Major Customers	5
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Top Customer [Member]
Concentration Risk, Percentage	12.90%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Next Top Four Customers [Member] | Minimum [Member]
Concentration Risk, Percentage	2.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Next Top Four Customers [Member] | Maximum [Member]
Concentration Risk, Percentage	10.90%