Note 14 - Segment Reporting and Sales by Major Customer - Professional Services (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020
Revenues	$ 61,480	$ 65,871
Interest expense	3,138	4,368
Depreciation and amortization	3,542	4,165
Gain on sale of airplanes		642
Gaming [Member]
Revenues	29,951	27,967
Interest expense	2,847	4,060
Depreciation and amortization	3,060	3,740
Gain on sale of airplanes
Aircraft Modification [Member]
Revenues	21,750	18,142
Interest expense	251	297
Depreciation and amortization	191	168
Gain on sale of airplanes		642
Aircraft Avionics [Member]
Revenues	2,583	5,396
Interest expense
Depreciation and amortization	7	8
Gain on sale of airplanes
Special Mission Electronics [Member]
Revenues	6,942	14,050
Interest expense	27	1
Depreciation and amortization	135	111
Gain on sale of airplanes
Product and Service, Other [Member]
Revenues	254	316
Interest expense	13	10
Depreciation and amortization	$ 149	138
Gain on sale of airplanes