Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts	$ 209	$ 577
Common Class A [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	10,000,000	10,000,000
Common stock, issued (in shares)	3,412,805	3,388,624
Common stock, outstanding (in shares)	3,412,805	3,388,624