CONDENSED CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 60,000.0	$ 60,000.0
Common stock, par value	$ 0.0033	$ 0.0033
Common stock, shares authorized	20,000,000.0	20,000,000.0
Common stock, shares issued	8,107,865	8,089,129
Common stock, shares outstanding	8,107,865	8,089,129
Treasury stock, shares	30,690	30,690