Unaudited Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Allowance for doubtful accounts	$ 671	$ 631
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	16,646,323	16,630,597
Common stock, shares outstanding (in shares)	16,646,323	16,630,597

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

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