Note 4 - Disaggregation of Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2023	Jul. 31, 2022
Revenues from customers	$ 17,185	$ 15,304
Percentage of Completion Contracts [Member]
Revenues from customers	5,213	3,251
Transferred at Point in Time [Member]
Revenues from customers	11,972	12,053
Casino [Member]
Revenues from customers	7,198	7,816
Sportsbook [Member]
Revenues from customers	701	0
Casino Non-gaming [Member]
Revenues from customers	1,090	1,077
Professional Services [Member]
Revenues from customers	52	69
Aircraft Modification [Member]
Revenues from customers	5,483	3,836
Aircraft Avionics [Member]
Revenues from customers	744	715
Special Mission Electronics [Member]
Revenues from customers	1,917	1,791
Professional Services [Member]
Revenues from customers	9,041	8,962
Professional Services [Member] | Percentage of Completion Contracts [Member]
Revenues from customers	0	0
Professional Services [Member] | Transferred at Point in Time [Member]
Revenues from customers	9,041	8,962
Professional Services [Member] | Casino [Member]
Revenues from customers	7,198	7,816
Professional Services [Member] | Sportsbook [Member]
Revenues from customers	701	0
Professional Services [Member] | Casino Non-gaming [Member]
Revenues from customers	1,090	1,077
Professional Services [Member] | Professional Services [Member]
Revenues from customers	52	69
Professional Services [Member] | Aircraft Modification [Member]
Revenues from customers	0	0
Professional Services [Member] | Aircraft Avionics [Member]
Revenues from customers	0	0
Professional Services [Member] | Special Mission Electronics [Member]
Revenues from customers	0	0
Aerospace Products [Member]
Revenues from customers	8,144	6,342
Aerospace Products [Member] | Percentage of Completion Contracts [Member]
Revenues from customers	5,213	3,251
Aerospace Products [Member] | Transferred at Point in Time [Member]
Revenues from customers	2,931	3,091
Aerospace Products [Member] | Casino [Member]
Revenues from customers	0	0
Aerospace Products [Member] | Sportsbook [Member]
Revenues from customers	0	0
Aerospace Products [Member] | Casino Non-gaming [Member]
Revenues from customers	0	0
Aerospace Products [Member] | Professional Services [Member]
Revenues from customers	0	0
Aerospace Products [Member] | Aircraft Modification [Member]
Revenues from customers	5,483	3,836
Aerospace Products [Member] | Aircraft Avionics [Member]
Revenues from customers	744	715
Aerospace Products [Member] | Special Mission Electronics [Member]
Revenues from customers	1,917	1,791
North America [Member]
Revenues from customers	15,992	14,959
North America [Member] | Professional Services [Member]
Revenues from customers	9,041	8,962
North America [Member] | Aerospace Products [Member]
Revenues from customers	6,951	5,997
Europe [Member]
Revenues from customers	952	183
Europe [Member] | Professional Services [Member]
Revenues from customers	0	0
Europe [Member] | Aerospace Products [Member]
Revenues from customers	952	183
Other [Member]
Revenues from customers	241	162
Other [Member] | Professional Services [Member]
Revenues from customers	0	0
Other [Member] | Aerospace Products [Member]
Revenues from customers	$ 241	$ 162