Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	[1]
Accounts receivable allowance	$ 325	$ 335
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)	2,657,530	2,657,530
Common stock, shares outstanding (in shares)	2,657,530	2,657,530

[1] The balance sheet at December 31, 2019 has been derived from the audited financial statements at that date