Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 139,465	$ (226,147)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	758,834	836,877
Amortization	36,485	38,265
Stock based compensation	13,634	23,561
Net loss (gain) on sale and disposal of plant and equipment	1,230	(28,689)
Deferred income taxes	39,000	(302,000)
Changes in working capital components:
Trade receivables	(24,955)	146,241
Inventories	39,477	(99,893)
Prepaid expenses and other assets	(207,120)	193,663
Income tax receivable	(652)	64,003
Accounts payable	325,668	(408,526)
Accrued expenses	103,699	(32,666)
Net cash provided by operating activities	1,224,765	204,689
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of plant and equipment	(543,145)	(230,089)
Proceeds from sales of equipment		32,635
Purchases of intangibles assets	(49,970)	(38,977)
Purchases of short-term investments	(5,615,000)	(3,875,000)
Proceeds on sale of short-term investments	5,815,000	4,226,000
Net cash (used in) provided by investing activities	(393,115)	114,569
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment on long-term debt	(138,213)	(139,690)
Repurchase of common stock		(300,466)
Proceeds from exercise of stock options		1,885
Net cash used in financing activities	(138,213)	(438,271)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	693,437	(119,013)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	929,700	1,048,713
CASH AND CASH EQUIVALENTS AT END OF PERIOD	1,623,137	929,700
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest	78,112	70,990
Cash paid for income taxes, net	$ 7,652	$ 60,003