Note 1 - Nature of Operations, Organization and Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2018	Apr. 30, 2017
Duration after Which Invoices Are Considered to Be Doubtful	90 days
Allowance for Doubtful Accounts Receivable, Ending Balance	$ 112	$ 112
Duration During Which Inventory If Inactive Taken as Obsolete	5 years
Inventory Valuation Reserves, Ending Balance	$ 571	1,177
Period for Payment Due	30 days
Cash, Uninsured Amount	$ 3,750	2,312
Research and Development Expense, Total	1,763	1,479
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	$ 5,426	5,012
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	$ 1,459
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

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Represents the duration during which inventory if inactive taken as obsolete.

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Period for payment due from invoice date after shipment for revenue recognition of products sold.

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For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of valuation reserve for inventory.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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