Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Allowance for doubtful accounts	$ 351	$ 206
Common Class A [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	10,000,000	10,000,000
Common stock, issued (in shares)	3,388,624	3,346,689
Common stock, outstanding (in shares)	3,388,624	3,346,689

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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