Inventories (Detail) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Inventory [Line Items]
Purchased components	$ 755,578	$ 716,848
Finished goods	273,576	334,434
Inventories	$ 1,029,154	$ 1,051,282

Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

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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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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of unprocessed items to be consumed in the manufacturing or production process.

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