Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	[1]
Accounts receivable allowance	$ 459	$ 343
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)	2,660,330	2,659,628
Common stock, shares outstanding (in shares)	2,660,330	2,659,628

[1] The balance sheet at December 31, 2020 has been derived from the audited financial statements at that date