Note 15 - Segment Reporting and Sales by Major Customer - Professional Services (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2022	Jul. 31, 2021
Revenues from customers	$ 15,304	$ 17,745
Interest expense	723	614
Depreciation and amortization	771	702
Operating income (loss)	1,625	4,022
Gaming [Member]
Revenues from customers	8,893	9,255
Interest expense	642	548
Depreciation and amortization	626	578
Operating income (loss)	2,642	3,544
Aircraft Modification [Member]
Revenues from customers	3,836	5,782
Interest expense	66	55
Depreciation and amortization	53	45
Operating income (loss)	54	1,143
Aircraft Avionics [Member]
Revenues from customers	715	875
Interest expense	0	0
Depreciation and amortization	2	2
Operating income (loss)	48	(19)
Special Mission Electronics [Member]
Revenues from customers	1,791	1,762
Interest expense	7	6
Depreciation and amortization	39	33
Operating income (loss)	616	503
Product and Service, Other [Member]
Revenues from customers	69	71
Interest expense	8	5
Depreciation and amortization	51	44
Operating income (loss)	$ (1,735)	$ (1,149)