CONDENSED BALANCE SHEETS - USD ($)	Mar. 31, 2017	Dec. 31, 2016
CURRENT ASSETS:
Cash and cash equivalents	$ 608,340	$ 1,048,713
Short-term investments	3,338,000	3,246,000
Trade receivables, less allowance of $60,000 in 2017 and $54,000 in 2016	1,930,959	2,336,501
Inventories	2,232,534	1,986,172
Prepaid expenses and other assets	391,835	361,905
Income taxes receivable	280,540	66,181
Total current assets	8,782,208	9,045,472
PROPERTY, PLANT, AND EQUIPMENT, at cost:
Land and building	9,201,846	9,189,743
Machinery and equipment	4,909,952	4,884,814
Office equipment	1,590,032	1,566,856
Vehicles	272,144	272,144
Gross property, plant, and equipment, at cost	15,973,974	15,913,557
Less accumulated depreciation	(7,213,464)	(7,001,162)
Net property, plant, and equipment, at cost	8,760,510	8,912,395
INTANGIBLE ASSETS, less accumulated amortization of $155,552 in 2017 and $149,072 in 2016	339,329	338,127
Total assets	17,882,047	18,295,994
CURRENT LIABILITIES:
Current portion of long-term debt, net	128,182	127,303
Accounts payable	842,140	730,386
Accrued compensation	242,469	388,600
Other accrued liabilities	92,743	67,088
Total current liabilities	1,305,534	1,313,377
LONG-TERM LIABILITIES
Long-term debt, less current portion, net	3,044,789	3,077,457
Deferred income taxes	446,000	446,000
Total long-term liabilities	3,490,789	3,523,457
Total liabilities	4,796,323	4,836,834
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY:
Preferred stock, par value $.10 per share; authorized 250,000 shares: none issued
Common stock, par value $.10 per share; authorized 4,750,000 shares; issued and outstanding 2,018,753 shares in 2017 and 2016	201,875	201,875
Additional paid-in capital	2,737,467	2,732,006
Retained earnings	10,146,382	10,525,279
Total stockholders' equity	13,085,724	13,459,160
Total liabilities and stockholders' equity	$ 17,882,047	$ 18,295,994