Condensed Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents	$ 6,429	$ 6,713
Investments	3,052	3,056
Trade receivables, less allowance for doubtful accounts of $11	1,323	1,005
Inventories	1,720	1,663
Other current assets	171	188
Income tax receivable	81	3
Total current assets	12,776	12,628
Deferred income tax asset, net	226	208
Intangible assets, net	13	38
Property and equipment, net	981	1,017
Total assets	13,996	13,891
Current liabilities
Current maturities of financing lease	6	6
Accounts payable	319	349
Accrued expenses	769	342
Total current liabilities	1,094	697
Long-term liabilities
Financing lease, net of current maturities	3	6
Total long-term liabilities	3	6
Commitments and contingencies
Stockholders' equity
Common stock par value $0.10 per share; authorized 10,000,000 shares; 3,395,521 shares issued and outstanding	339	339
Additional paid-in capital	2,043	2,041
Retained earnings	10,515	10,808
Accumulated other comprehensive gain (unrealized gain on available-for-sale securities, net of income tax)	2	0
Total stockholders' equity	12,899	13,188
Total liabilities and stockholders' equity	$ 13,996	$ 13,891