Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Accounts receivable allowance	$ 262	$ 222
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	250,000	250,000
Preferred stock, shares outstanding (in shares)	250,000	250,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	9,000,000	9,000,000
Common stock, shares issued (in shares)	2,658,559	2,663,049
Common stock, shares outstanding (in shares)	2,658,559	2,663,049