CONDENSED BALANCE SHEETS (USD $)	Jun. 30, 2013	Dec. 31, 2012
CURRENT ASSETS:
Cash and cash equivalents	$ 1,269,476	$ 967,943
Short-term investments	829,654	1,442,939
Trade receivables, less allowance of $43,000 in 2013 and 2012	2,383,791	2,060,312
Inventories	2,432,751	2,678,864
Prepaid expenses and other assets	176,574	124,983
Income taxes receivable	17,925
Deferred income taxes	142,000	142,000
Total current assets	7,252,171	7,417,041
PROPERTY, PLANT, AND EQUIPMENT, at cost:
Land and building	6,090,942	6,063,965
Machinery and equipment	3,487,070	3,219,598
Office equipment	738,711	700,062
Vehicles	237,488	237,488
Gross property, plant, and equipment, at cost	10,554,211	10,221,113
Less accumulated depreciation	5,031,197	4,759,235
Net property, plant, and equipment, at cost	5,523,014	5,461,878
INTANGIBLE ASSETS, less accumulated amortization of $508,555 in 2013 and $482,107 in 2012	338,671	305,357
Total assets	13,113,856	13,184,276
CURRENT LIABILITIES:
Accounts payable	317,071	593,922
Accrued compensation	207,322	265,822
Other accrued liabilities	75,957	81,635
Income taxes payable		82,152
Total current liabilities	600,350	1,023,531
DEFERRED INCOME TAXES	431,000	366,000
Total liabilities	1,031,350	1,389,531
STOCKHOLDERS' EQUITY:
Preferred stock, par value $.10 per share; authorized 250,000 shares; issued none
Common stock, par value $.10 per share; authorized 4,750,000 shares; issued and outstanding 2,008,836 shares in 2013 and 1,998,475 shares in 2012	200,884	199,848
Additional paid-in capital	2,551,870	2,470,507
Retained earnings	9,329,752	9,124,390
Total stockholders' equity	12,082,506	11,794,745
Total liabilities and stockholders' equity	$ 13,113,856	$ 13,184,276