Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts Receivable, allowance	$ 7,980	$ 7,223
Property and equipment, accumulated depreciation	$ 13,280	$ 12,326
Common Class A | Common Stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	180,000,000	180,000,000
Common stock, shares issued	17,754,416	17,696,991
Common stock, shares outstanding	17,754,416	17,696,991
Common Class B | Common Stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	1,000	1,000
Common stock, shares issued	1	1
Common stock, shares outstanding	1	1