CONSOLIDATED AND CONDENSED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Accounts receivable allowance for doubtful accounts	$ 3,230	$ 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 unit)	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	42,973,798	37,002,874
Common stock, shares outstanding	42,973,798	37,002,874
Class B common stock
Common stock, par value (in dollars per unit)	$ 0.001	$ 0.001
Common stock, shares authorized	164,000,000	164,000,000
Common stock, shares issued	40,773,291	46,179,192
Common stock, shares outstanding	40,773,291	46,179,192