Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net income	$ 3,568,802	$ 3,026,909
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	413,447	390,269
Change in fair value of derivative instrument	172,278	(8,041)
(Gain)/Loss on disposition of long-term assets	16,341	(44,889)
Depreciation and amortization	1,923,936	1,795,379
Deferred income taxes	(308,889)	(696,569)
Excess tax benefit from employee stock plans	(16,067)	(19,670)
Changes in operating assets and liabilities:
Trade accounts receivable, net	842,995	(589,435)
Other receivables	(130,329)	47,421
Inventories	(1,339,741)	(603,719)
Prepaid income taxes	47,440	(66,391)
Prepaid expenses, other	32,944	(231,019)
Accounts payable	252,873	758,978
Compensation and related expenses	(61,286)	(227,579)
Other accrued expenses	76,972	(4,666)
Accrued product warranties	(85,395)	(1,738)
Accrued income taxes	435,550	503,719
Deferred revenue	588,028	385,608
Net cash provided by operating activities	6,429,899	4,414,567
Cash flows from investing activities:
Proceeds from maturities of marketable securities	205,000	5,254,639
Purchases of property, plant and equipment	(998,706)	(1,308,243)
Proceeds from sale of property and equipment	55,315	116,234
Cash paid for patents and other intangible assets	(372,504)	(669,154)
Other	(2,230)	(2,259)
Net cash provided by (used in) investing activities	(1,113,125)	3,391,217
Cash flows from financing activities:
Proceeds from the revolving lines of credit	18,383,528	4,757,484
Payments on the revolving lines of credit	(18,143,489)	(7,532,789)
Payments on notes payable and seller financed note payable	(1,641,199)	(1,453,660)
Proceeds from the exercise of stock options	284,568	256,212
Excess tax benefit from employee stock plans	16,067	19,670
Dividends paid	(1,865,089)	(1,798,208)
Net cash used in financing activities	(2,965,614)	(5,751,291)
Effect of exchange rate changes on cash and cash equivalents	(343,547)	24,407
Net increase in cash and cash equivalents	2,007,613	2,078,900
Cash and cash equivalents:
Beginning of period	4,132,953	2,415,416
End of period	6,140,566	4,494,316
Supplemental disclosures of cash flow information:
Cash paid during the period for income taxes	1,067,365	1,166,483
Cash paid during the period for interest	151,949	221,299
Supplemental schedule of noncash investing and financing activities:
Dividends accrued	624,062	610,404
Purchases of prepaid expenses, fixed assets and intangibles in accounts payable	$ 173,665	$ 217,344