Note 4 - Disaggregation of Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2025	Jan. 31, 2024	Jan. 31, 2025	Jan. 31, 2024
Revenues from customers	$ 21,174	$ 18,960	$ 62,363	$ 55,746
Percentage of Completion Contracts [Member]
Revenues from customers	7,419	4,756	20,038	15,369
Transferred at Point in Time [Member]
Revenues from customers	13,755	14,204	42,325	40,377
Casino [Member]
Revenues from customers	6,845	7,319	20,943	21,816
Sportsbook [Member]
Revenues from customers	1,838	1,457	4,281	3,471
Casino Non-gaming [Member]
Revenues from customers	1,130	1,153	3,476	3,400
Professional Services [Member]
Revenues from customers	0	12	0	64
Aircraft Modification [Member]
Revenues from customers	8,061	5,402	22,337	16,967
Aircraft Avionics [Member]
Revenues from customers	915	810	2,200	2,332
Special Mission Electronics [Member]
Revenues from customers	2,385	2,807	9,126	7,696
Professional Services [Member]
Revenues from customers	9,813	9,941	28,700	28,751
Professional Services [Member] | Percentage of Completion Contracts [Member]
Revenues from customers	0	0	0	0
Professional Services [Member] | Transferred at Point in Time [Member]
Revenues from customers	9,813	9,941	28,700	28,751
Professional Services [Member] | Casino [Member]
Revenues from customers	6,845	7,319	20,943	21,816
Professional Services [Member] | Sportsbook [Member]
Revenues from customers	1,838	1,457	4,281	3,471
Professional Services [Member] | Casino Non-gaming [Member]
Revenues from customers	1,130	1,153	3,476	3,400
Professional Services [Member] | Professional Services [Member]
Revenues from customers	0	12	0	64
Professional Services [Member] | Aircraft Modification [Member]
Revenues from customers	0	0	0	0
Professional Services [Member] | Aircraft Avionics [Member]
Revenues from customers	0	0	0	0
Professional Services [Member] | Special Mission Electronics [Member]
Revenues from customers	0	0	0	0
Aerospace Products [Member]
Revenues from customers	11,361	9,019	33,663	26,995
Aerospace Products [Member] | Percentage of Completion Contracts [Member]
Revenues from customers	7,419	4,756	20,038	15,369
Aerospace Products [Member] | Transferred at Point in Time [Member]
Revenues from customers	3,942	4,263	13,625	11,626
Aerospace Products [Member] | Casino [Member]
Revenues from customers	0	0	0	0
Aerospace Products [Member] | Sportsbook [Member]
Revenues from customers	0	0	0	0
Aerospace Products [Member] | Casino Non-gaming [Member]
Revenues from customers	0	0	0	0
Aerospace Products [Member] | Professional Services [Member]
Revenues from customers	0	0	0	0
Aerospace Products [Member] | Aircraft Modification [Member]
Revenues from customers	8,061	5,402	22,337	16,967
Aerospace Products [Member] | Aircraft Avionics [Member]
Revenues from customers	915	810	2,200	2,332
Aerospace Products [Member] | Special Mission Electronics [Member]
Revenues from customers	2,385	2,807	9,126	7,696
North America [Member]
Revenues from customers	13,862	15,104	47,175	48,098
North America [Member] | Professional Services [Member]
Revenues from customers	9,813	9,941	28,700	28,751
North America [Member] | Aerospace Products [Member]
Revenues from customers	4,049	5,163	18,475	19,347
Europe [Member]
Revenues from customers	6,687	2,255	13,330	3,873
Europe [Member] | Professional Services [Member]
Revenues from customers	0	0	0	0
Europe [Member] | Aerospace Products [Member]
Revenues from customers	6,687	2,255	13,330	3,873
Asia [Member]
Revenues from customers	593	876	1,521	1,235
Asia [Member] | Professional Services [Member]
Revenues from customers	0	0	0	0
Asia [Member] | Aerospace Products [Member]
Revenues from customers	593	876	1,521	1,235
Australia and Other [Member]
Revenues from customers	32	725	337	2,540
Australia and Other [Member] | Professional Services [Member]
Revenues from customers	0	0	0	0
Australia and Other [Member] | Aerospace Products [Member]
Revenues from customers	$ 32	$ 725	$ 337	$ 2,540