CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 2,924,722	$ 2,415,416
Marketable securities, current	2,415,718	5,495,556
Trade accounts receivable, less allowance for doubtful accounts of $229,125 in 2013 and $303,839 in 2012	11,705,461	10,407,649
Other receivables	173,650	244,081
Inventories	6,698,433	6,344,982
Prepaid income taxes	499,725	279,964
Prepaid expenses, other	848,669	799,124
Deferred income taxes	926,081	926,081
Total current assets	26,192,459	26,912,853
Marketable securities, noncurrent		210,440
Property, plant and equipment, net of accumulated depreciation of $7,229,163 in 2013 and $6,876,028 in 2012	5,788,854	5,350,310
Goodwill	8,616,039	8,729,438
Investment in affiliated company	3,251,750	3,303,750
Intangible assets, net	12,082,874	12,381,614
Other assets	237,991	308,996
Deferred income taxes		22,370
TOTAL ASSETS	56,169,967	57,219,771
Current liabilities:
Current maturities of long-term notes payable	2,562,544	2,566,154
Revolving lines of credit	4,420,000	5,327,515
Accounts payable	3,516,183	2,893,225
Compensation and related expenses	3,238,622	3,510,272
Other accrued expenses	896,587	868,199
Accrued product warranties	240,550	240,621
Accrued income taxes	306,492	36,139
Dividends payable	610,251	579,386
Deferred revenue	931,224	472,185
Total current liabilities	16,722,453	16,493,696
Notes payable	2,612,961	3,926,863
Obligations to former employees	74,971	76,161
Deferred income taxes	2,017,211	2,576,396
Accrued income taxes	291,585	265,207
Total noncurrent liabilities	4,996,728	6,844,627
Total liabilities	21,719,181	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 5,547,737 shares in 2013 and 5,517,966 shares in 2012	554,774	551,797
Additional paid-in capital	4,262,348	3,738,968
Retained earnings	30,667,415	30,217,977
Accumulated other comprehensive loss	(1,033,751)	(627,294)
Total stockholders' equity	34,450,786	33,881,448
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 56,169,967	$ 57,219,771