Note 2 - Disaggregation of Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2023	Apr. 30, 2022
Revenues	$ 75,182	$ 71,517
Percentage of Completion Contracts [Member]
Revenues	22,500	19,507
Transferred at Point in Time [Member]
Revenues	52,682	52,010
Casino [Member]
Revenues	30,564	32,455
Sportsbook [Member]
Revenues	2,738	0
Casino Non-gaming [Member]
Revenues	4,456	4,358
Professional Services [Member]
Revenues	283	378
Aircraft Modification [Member]
Revenues	24,016	21,399
Aircraft Avionics [Member]
Revenues	2,324	2,373
Special Mission Electronics [Member]
Revenues	10,801	10,554
Professional Services Segment [Member]
Revenues	38,041	37,191
Professional Services Segment [Member] | Percentage of Completion Contracts [Member]
Revenues	0	0
Professional Services Segment [Member] | Transferred at Point in Time [Member]
Revenues	38,041	37,191
Professional Services Segment [Member] | Casino [Member]
Revenues	30,564	32,455
Professional Services Segment [Member] | Sportsbook [Member]
Revenues	2,738	0
Professional Services Segment [Member] | Casino Non-gaming [Member]
Revenues	4,456	4,358
Professional Services Segment [Member] | Professional Services [Member]
Revenues	283	378
Professional Services Segment [Member] | Aircraft Modification [Member]
Revenues	0	0
Professional Services Segment [Member] | Aircraft Avionics [Member]
Revenues	0	0
Professional Services Segment [Member] | Special Mission Electronics [Member]
Revenues	0	0
Aerospace Products [Member]
Revenues	37,141	34,326
Aerospace Products [Member] | Percentage of Completion Contracts [Member]
Revenues	22,500	19,507
Aerospace Products [Member] | Transferred at Point in Time [Member]
Revenues	14,641	14,819
Aerospace Products [Member] | Casino [Member]
Revenues	0	0
Aerospace Products [Member] | Sportsbook [Member]
Revenues	0	0
Aerospace Products [Member] | Casino Non-gaming [Member]
Revenues	0	0
Aerospace Products [Member] | Professional Services [Member]
Revenues	0	0
Aerospace Products [Member] | Aircraft Modification [Member]
Revenues	24,016	21,399
Aerospace Products [Member] | Aircraft Avionics [Member]
Revenues	2,324	2,373
Aerospace Products [Member] | Special Mission Electronics [Member]
Revenues	10,801	10,554
North America [Member]
Revenues	68,544	66,449
North America [Member] | Professional Services Segment [Member]
Revenues	38,041	37,191
North America [Member] | Aerospace Products [Member]
Revenues	30,503	29,258
Europe [Member]
Revenues	1,095	2,803
Europe [Member] | Professional Services Segment [Member]
Revenues	0	0
Europe [Member] | Aerospace Products [Member]
Revenues	1,095	2,803
Middle East [Member]
Revenues	4,614	934
Middle East [Member] | Professional Services Segment [Member]
Revenues	0	0
Middle East [Member] | Aerospace Products [Member]
Revenues	4,614	934
Asia [Member]
Revenues	929	1,331
Asia [Member] | Professional Services Segment [Member]
Revenues	0	0
Asia [Member] | Aerospace Products [Member]
Revenues	$ 929	$ 1,331