Note 3 - Income Taxes - Components of Deferred Tax Liabilities and Assets (Details) - USD ($) $ in Thousands	Apr. 30, 2017	Apr. 30, 2016
Deferred tax liabilities:
Depreciation
Deferred tax assets:
Depreciation	309	80
Accounts receivable allowance	43	31
Inventory and other allowances	467	859
Vacation accruals	106	93
NOL carryforward		41
Total gross deferred tax assets	925	1,104
Less valuation allowance
Net deferred tax assets	$ 925	$ 1,104