Inventories - Schedule of Inventories (Details) - USD ($)	Jul. 31, 2018	Apr. 30, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 2,774,000	$ 2,450,000
Work in process	483,000	444,000
Finished goods	489,000	463,000
Inventory gross	3,746,000	3,357,000
Less: allowance for obsolete inventory	(96,000)	(90,000)
Totals	$ 3,650,000	$ 3,267,000

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Amount before valuation and LIFO reserves of completed merchandise or goods expected to be sold within one year or operating cycle, if longer.

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Gross amount, as of the balance sheet date, of merchandise, goods, commodities, or supplies held for future sale or to be used in manufacturing, servicing or production process.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount before valuation and LIFO reserves of raw materials expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount of valuation reserve for inventory.

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Amount before valuation and LIFO reserves of merchandise or goods in the production process expected to be completed within one year or operating cycle, if longer.

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