STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 693,931	$ 698,257
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	489,206	415,821
Amortization	54,653	50,471
Stock based compensation	17,818	26,690
Net gain on sale of vehicles and equipment exchange	(7,163)	(1,353)
Loss on intangible asset abandonment	23,122	805
Deferred income taxes	30,000	180,000
Changes in working capital components:
Trade receivables	120,635	(297,519)
Inventories	(444,030)	(263,809)
Prepaid expenses and other assets	(42,060)	(18,958)
Income tax refund receivable	59,322	(59,322)
Accounts payable	44,390	107,702
Accrued liabilities	58,074	(38,681)
Income taxes payable	84,052	(6,572)
Net cash provided by operating activities	1,181,950	793,532
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(566,519)	(621,598)
Proceeds from sale of equipment and vehicles	59,500	10,200
Purchases of intangibles	(56,770)	(60,470)
Purchases of short-term investments	(1,857,990)	(2,446,359)
Proceeds from sale of short-term investments	2,250,054	2,829,346
Net cash used in investing activities	(171,725)	(288,881)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repurchase of common stock		(2,079)
Cash dividend paid	(1,998,475)
Proceeds from exercise of stock options	89,028	73,210
Net cash provided by (used in) financing activities	(1,909,447)	71,131
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(899,222)	575,782
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR	1,867,165	1,291,383
CASH AND CASH EQUIVALENTS AT END OF YEAR	967,943	1,867,165
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for income taxes, net of refunds received of $61,650 and $4,090, respectively	177,626	230,894
SUPPLEMENTAL SCHEDULE OF NONCASH OPERATING AND INVESTING ACTIVITIES
Equipment transferred from inventory to property, plant and equipment		$ 227,039