Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 7,850	$ 8,785
Investments	1,041	45
Trade receivables, less allowance for doubtful accounts of $11	934	1,036
Inventories	1,721	1,695
Other current assets	204	159
Income tax receivable	15	0
Total current assets	11,765	11,720
Deferred income tax asset, net	207	203
Intangible assets, net	424	489
Property and equipment, net	1,038	1,063
Total assets	13,434	13,475
Current liabilities
Current maturities of financing lease	6	5
Accounts payable	198	129
Accrued expenses	411	431
Total current liabilities	615	565
Long-term liabilities
Financing lease, net of current maturities	16	19
Total long-term liabilities	16	19
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	2,033	2,030
Retained earnings	10,431	10,522
Total stockholders' equity	12,803	12,891
Total liabilities and stockholders' equity	$ 13,434	$ 13,475