Condensed Consolidated Balance Sheets - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 5,966,000	$ 6,652,000
Accounts receivable, less allowances of $7,000	985,000	639,000
Short-term investments (Note 2)	1,423,000	0
Inventories, less reserves for obsolescence of $4,848,000, and $4,759,000, respectively (Note 3)	3,948,000	3,518,000
Prepaid expenses and other current assets	139,000	46,000
Total current assets	12,461,000	10,855,000
Property and equipment, net	3,102,000	3,217,000
Other assets (Note 4)	190,000	189,000
Total assets	15,753,000	14,261,000
Current liabilities:
Accounts payable	1,059,000	410,000
Accrued liabilities	494,000	446,000
Total current liabilities	1,553,000	856,000
Long-term debt (Note 5)	0	163,000
Total liabilities	1,553,000	1,019,000
Commitments and contingencies (Note 7)
Shareholders' equity:
Preferred stock, $0.001 par value. Authorized 5,000,000 shares; None issued or outstanding	0	0
Additional paid-in capital	11,150,000	11,071,000
Accumulated other comprehensive income	(91,000)	(66,000)
Retained earnings	3,135,000	2,231,000
Total equity	14,200,000	13,242,000
Total liabilities and equity	15,753,000	14,261,000
Common Class A [Member]
Shareholders' equity:
Common Stock, value, issued	5,000	5,000
Common Class B [Member]
Shareholders' equity:
Common Stock, value, issued	$ 1,000	$ 1,000