Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Accounts receivable-trade, allowance for doubtful accounts	$ 9,839	$ 22,642
Other intangibles, accumulated amortization	$ 712,519	$ 710,463
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0024	$ 0.0024
Common stock, shares authorized (in shares)	25,000,000	25,000,000
Common stock, shares issued (in shares)	11,330,340	11,313,692
Common stock, shares outstanding (in shares)	9,154,208	9,270,862
Treasury stock, shares (in shares)	2,176,132	2,042,830