CONSOLIDATED AND CONDENSED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Accounts receivable allowance for doubtful accounts	$ 3,240	$ 2,545
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Class A common stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	44,145,083	37,002,874
Common stock, shares outstanding	44,145,083	37,002,874
Class B common stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	164,000,000	164,000,000
Common stock, shares issued	39,894,391	46,179,192
Common stock, shares outstanding	39,894,391	46,179,192