Consolidated Balance Sheets (Parentheticals) - USD ($) $ / shares in Thousands, $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts receivable, allowance	$ 35	$ 34
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	43,000,000	43,000,000
Common stock, shares issued (in shares)	19,238,081	19,125,521
Common stock, shares outstanding (in shares)	19,238,081	19,125,521