Schedule of Valuation and Qualifying Accounts (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-09, Allowance, Credit Loss
Balance at beginning of year	$ 170,000	$ 140,000
Charges to statement of income	0	35,774
Write-offs	0	(5,774)
Balance at end of year	170,000	170,000
SEC Schedule, 12-09, Reserve, Inventory
Balance at beginning of year	600,000	457,000
Charges to statement of income	41,308	155,058
Write-offs	(29,308)	(12,058)
Balance at end of year	$ 612,000	$ 600,000