CONDENSED BALANCE SHEETS (unaudited) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 3,902	$ 7,646
Investments	6,026	2,036
Trade receivables, less allowance for credit losses of $11	1,066	1,161
Inventories	1,836	1,745
Other current assets	279	214
Income tax receivable	136	11
Total current assets	13,245	12,813
Deferred income tax asset, net	198	256
Property and equipment, net	907	975
Total assets	14,350	14,044
Current liabilities
Current maturities of financing lease	1	6
Accounts payable	261	274
Accrued expenses	559	350
Total current liabilities	821	630
Commitments and contingencies
Stockholders' equity
Common stock par value $0.10 per share; authorized 10,000,000 shares; 3,428,021 shares issued and outstanding	342	342
Additional paid-in capital	2,201	2,163
Retained earnings	10,988	10,908
Accumulated other comprehensive income (loss) (unrealized income (loss) on available-for-sale securities, net of income tax)	(2)	1
Total stockholders' equity	13,529	13,414
Total liabilities and stockholders' equity	$ 14,350	$ 14,044