Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Accounts receivable, allowances	$ 5,000	$ 5,000
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	500,000	500,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	5,000,000	5,000,000
Common stock, shares issued (in shares)	2,110,013	2,110,013
Common stock, shares outstanding (in shares)	1,746,449	1,845,160