Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ / shares in Thousands	Sep. 30, 2021	Dec. 31, 2020
Allowance for doubtful accounts	$ 100,000	$ 100,000
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, shares issued (in shares)	5,868,000	5,791,000
Common stock, shares outstanding (in shares)	5,868,000	5,791,000

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

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