Note 1 - Nature of Operations, Organization and Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2019	Apr. 30, 2018
Duration after Which Invoices Are Considered to Be Doubtful	90 days
Accounts Receivable, Allowance for Credit Loss, Ending Balance	$ 143	$ 112
Duration During Which Inventory If Inactive Taken as Obsolete	5 years
Inventory Valuation Reserves, Ending Balance	$ 718	571
Period for Payment Due	30 days
Cash, Uninsured Amount	$ 5,365	3,750
Research and Development Expense, Total	1,888	1,763
Kansas Expanded Lottery Act Management Contract Privilege Fee [Member]
Finite-Lived Intangible Assets, Gross, Total	5,500	5,500
Gaming Equipment [Member]
Finite-Lived Intangible Assets, Gross, Total	$ 5,646	5,426
Finite-Lived Intangible Asset, Useful Life	3 years
JET Autopilot Intellectual Property [Member]
Finite-Lived Intangible Assets, Gross, Total	$ 1,417	$ 1,417
Finite-Lived Intangible Asset, Useful Life	15 years
Other Miscellaneous Long-Term Assets [Member]
Finite-Lived Intangible Assets, Gross, Total	$ 912
Supplemental Type Certificates [Member]
Finite-Lived Intangible Asset, Useful Life	7 years
Minimum [Member]
Property, Plant and Equipment, Useful Life	3 years
Maximum [Member]
Property, Plant and Equipment, Useful Life	39 years