Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 1,057	$ 963
Treasury bills	7,697	7,711
Available-for-sale securities	45	45
Trade receivables, less allowance for doubtful accounts of $11	896	902
Inventories	1,618	1,552
Other current assets	155	141
Income tax receivable	0	45
Total current assets	11,468	11,359
Deferred income tax asset	192	182
Intangible assets, net	565	800
Property and equipment, net	1,050	1,074
Total assets	13,275	13,415
Current liabilities
Contingent earn-out	0	150
Current maturity of financing lease	5	0
Accounts payable	116	178
Accrued expenses	405	380
Total current liabilities	526	708
Long-term liabilities
Financing lease, net of current maturities	24	0
Total long-term liabilities	24	0
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	2,019	2,004
Retained earnings	10,335	10,352
Accumulated other comprehensive gain (unrealized gain on available-for-sale securities, net of income tax)	32	12
Total stockholders' equity	12,725	12,707
Total liabilities and stockholders' equity	$ 13,275	$ 13,415