Schedule of Valuation and Qualifying Accounts (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Allowance, Credit Loss
Balance at beginning of year	$ 140,000	$ 140,000
Charges to statement of income	4,895	0
Write-offs	(4,895)	0
Balance at end of year	140,000	140,000
SEC Schedule, 12-09, Reserve, Inventory
Balance at beginning of year	579,000	564,000
Charges to statement of income	(15,477)	0
Write-offs	(106,523)	(2,870)
Balance at end of year	$ 457,000	$ 579,000

Amount of valuation and qualifying accounts and reserves.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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Amount of increase in valuation and qualifying accounts and reserves from charge to cost and expense.

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Amount of decrease in valuation and qualifying accounts and reserves.

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