Income Taxes - Schedule of Deferred Tax Assets (Liabilities) (Details) - USD ($)	Apr. 30, 2019	Apr. 30, 2018
Income Tax Disclosure [Abstract]
Depreciation	$ (141,000)	$ (161,000)
Inventory valuation	26,000	26,000
Allowance for doubtful accounts	3,000	2,000
263A adjustment		58,000
Accrued vacation	28,000	30,000
Accumulated unrealized (gain)/loss on investments	(1,114,000)	(910,000)
Net deferred tax assets (liabilities)	$ (1,198,000)	$ (955,000)