CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 3,476,957	$ 2,415,416
Marketable securities, current	3,502,410	5,495,556
Trade accounts receivable, less allowance for doubtful accounts of $182,381 in 2013 and $303,839 in 2012	10,599,741	10,407,649
Other receivables	95,330	244,081
Inventories	6,246,788	6,344,982
Prepaid income taxes	427,715	279,964
Prepaid expenses, other	923,540	799,124
Deferred income taxes	926,081	926,081
Total current assets	26,198,562	26,912,853
Marketable securities, noncurrent		210,440
Property, plant and equipment, net of accumulated depreciation of $6,972,360 in 2013 and $6,876,028 in 2012	5,727,175	5,350,310
Goodwill	8,504,968	8,729,438
Investment in affiliated company	3,204,001	3,303,750
Intangible assets, net	11,984,052	12,381,614
Other assets	250,108	308,996
Deferred income taxes	116,897	22,370
TOTAL ASSETS	55,985,763	57,219,771
Current liabilities:
Current maturities of long-term notes payable	2,511,471	2,566,154
Revolving lines of credit	4,581,459	5,327,515
Accounts payable	3,129,997	2,893,225
Compensation and related expenses	3,058,516	3,510,272
Other accrued expenses	862,017	868,199
Accrued product warranties	245,269	240,621
Accrued income taxes	223,798	36,139
Dividends payable	608,038	579,386
Deferred revenue	778,249	472,185
Total current liabilities	15,998,814	16,493,696
Notes payable	3,650,617	3,926,863
Obligations to former employees	73,823	76,161
Deferred income taxes	2,404,610	2,576,396
Accrued income taxes	290,203	265,207
Total noncurrent liabilities	6,419,253	6,844,627
Total liabilities	22,418,067	23,338,323
Stockholders' equity:
Capital stock - undesignated. Authorized 3,000,000 shares; none issued and outstanding in 2013 and 2012
Common stock - $0.10 par value. Authorized 22,000,000 shares; issued and outstanding 5,527,616 shares in 2013 and 5,517,966 shares in 2012	552,762	551,797
Additional paid-in capital	3,975,025	3,738,968
Retained earnings	30,476,398	30,217,977
Accumulated other comprehensive loss	(1,436,489)	(627,294)
Total stockholders' equity	33,567,696	33,881,448
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 55,985,763	$ 57,219,771