Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 6,826	$ 4,676
Trade accounts receivable, net	6,466	3,964
Inventories, net	9,441	13,513
Prepaid expenses and other current assets	1,878	1,733
Total current assets	24,611	23,886
Property, plant and equipment, net	3,566	3,964
Right-of-use (ROU) asset	2,887	2,885
Investment in securities	2,014	2,635
Deferred tax assets, net	4,300	4,373
Other assets	112	197
Total assets	37,490	37,940
Current liabilities:
Accounts payable	5,119	5,310
Accrued compensation and related taxes	1,635	1,271
Accrued warranty expense	791	1,248
Accrued other expenses and other current liabilities	307	479
Dividends payable	250	252
Short-term lease liability	525	369
Note payable-current portion	82	78
Deferred revenue	757	369
Total current liabilities	9,466	9,376
Note payable, net of current portion	247	328
Long-term lease liability	2,702	2,606
Deferred revenue	2,551	2,354
Total liabilities	14,966	14,664
Commitments and contingencies
Stockholders' equity:
Preferred stock; $1.00 par value; 1,000,000 authorized shares: none issued or outstanding	0	0
Common stock; $.60 par value; 20,000,000 authorized shares; 13,962,366 and 13,929,381 issued and 12,511,966 and 12,596,923 outstanding shares at December 31, 2020 and 2019, respectively	8,377	8,357
Additional paid-in capital	26,346	26,095
Retained earnings	(6,797)	(6,043)
Treasury stock, at cost, 1,450,400 and 1,332,458 shares at December 31, 2020 and 2019, respectively	(5,402)	(5,133)
Total stockholders' equity	22,524	23,276
Total liabilities and stockholders' equity	$ 37,490	$ 37,940