Note 5 - Property, Plant, and Equipment - Schedule of Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	Apr. 30, 2023	Apr. 30, 2022
Property, plant, and equipment, gross	$ 84,593	$ 81,624
Accumulated depreciation	(25,526)	(22,778)
Total property, plant and equipment	59,067	58,846
Construction in Progress [Member]
Property, plant, and equipment, gross	0	6,417
Land [Member]
Property, plant, and equipment, gross	4,751	4,751
Building and Building Improvements [Member]
Property, plant, and equipment, gross	47,867	40,962
Aircraft [Member]
Property, plant, and equipment, gross	8,515	8,719
Machinery and Equipment [Member]
Property, plant, and equipment, gross	5,547	4,917
Furniture and Fixtures [Member]
Property, plant, and equipment, gross	13,881	11,826
Leasehold Improvements [Member]
Property, plant, and equipment, gross	$ 4,032	$ 4,032