Income Taxes - Schedule of Deferred Tax Assets (liabilities) (Details) - USD ($)	Apr. 30, 2017	Apr. 30, 2016
Income Tax Disclosure [Abstract]
Inventory valuation	$ 31,000	$ 30,000
Allowance for doubtful accounts	1,000
263A adjustment	77,000	98,000
Accrued vacation	38,000	34,000
Accumulated unrealized (gain)/loss on investments	(890,000)	(249,000)
Net deferred tax assets (liabilities)	(743,000)	(87,000)
Depreciation	(163,000)	(191,000)
Net deferred long-term tax assets (liabilities)	$ 906,000	$ 278,000