Inventories (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Components of inventories
Raw materials	$ 2,150,671	$ 998,751
Work-in-process	2,774,628	2,629,570
Finished goods	2,039,186	1,239,168
Inventory, gross	6,964,485	4,867,489
Less: reserve for obsolete inventories	(310,193)	(313,930)
Inventory, net	$ 6,654,292	$ 4,553,559

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 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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