Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities:
Net income (loss)	$ 623,644	$ (238,305)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	144,893	201,634
Stock-based compensation	5,306	7,535
Non-cash life insurance policy reduction / (accretion)		(6,617)
Non-cash other revenue	(86,433)
Non-cash miscellaneous loss	24,618
(Gain) loss on sale of property, plant and equipment	(434,549)	(3,800)
Foreign currency transaction (gain) loss	5,925	341
(Increase) decrease in trade, accounts & notes receivable, and deposits from related parties	(839,989)	(104,767)
(Increase) decrease in inventories	705,371	393,576
(Increase) decrease in refundable income taxes	1,918	(3,550)
(Increase) decrease in prepaid expenses and other current assets	(251,056)	(320,175)
(Increase) decrease in other assets	(49,681)	(6,052)
Increase (decrease) in income taxes payable	42,522	18,664
Increase (decrease) in accounts payable & accrued expenses, deferred revenue, and other noncurrent liabilities	(19,235)	561,297
Net cash provided by (used in) operating activities	(126,746)	499,781
Investing activities:
Purchase of property, plant and equipment	(38,890)	(15,383)
Proceeds from the sale of property, plant and equipment		3,888
Payments received on notes receivables - related parties	49,691	28,326
Net cash provided by investing activities	10,801	16,831
Financing activities:
Proceeds from line of credit borrowings	500,000
Principal payments on long-term borrowings		(108,320)
Net cash provided by (used in) financing activities	500,000	(108,320)
Effect of exchange rate changes on cash and cash equivalents	7,058	(4,240)
Increase (decrease) in cash and cash equivalents	391,113	404,052
Cash and cash equivalents at beginning of period	1,989,974	3,272,788
Cash and cash equivalents at end of period	$ 2,381,087	$ 3,676,840