Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ / shares in Thousands, $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Allowance for doubtful accounts	$ 114	$ 35
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)	19,291,102	19,238,081
Common stock, shares outstanding (in shares)	19,291,102	19,238,081

Amount of allowance for credit loss on accounts receivable, classified as current.

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