Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	[1]
Accounts receivable, allowance for doubtful accounts	$ 253	$ 221
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	31,466,508	19,503,558
Common stock, shares outstanding (in shares)	31,466,508	19,503,558

[1] The condensed consolidated balance sheet as of December 31, 2017 has been derived from the audited consolidated financial statements as of that date.