Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Trade accounts receivable, allowance for doubtful accounts	$ 637	$ 417
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	17,573,669	10,849,385
Common stock, shares outstanding (in shares)	17,573,669	10,849,385