Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Trade accounts receivable, allowance	$ 937,000	$ 1,354,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	50,000,000	50,000,000
Common stock, issued (in shares)	14,578,146	14,315,586
Common stock, outstanding (in shares)	14,578,146	14,315,586

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

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