Note 15 - Segment Reporting and Sales by Major Customer - Schedule of Revenue by Major Customers by Reporting Segments (Details)	9 Months Ended
Jan. 31, 2023	Jan. 31, 2022
Revenue Benchmark [Member] \| Customer Concentration Risk [Member] \| Aerospace Products [Member]
Aerospace Products – two customers in the nine months ended January 31, 2023, two customers in the nine months ended January 31, 2022	24.80%	25.20%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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