CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accounts receivable, allowances
Accounts receivable, allowances (in dollars)	$ 5,817	$ 5,865
Common stock
Common stock, par value (in dollars per share)	$ 0.000005	$ 0.000005
Common stock, authorized (in shares)	900,000,000	900,000,000
Common stock, issued (in shares)	0	0
Common stock, outstanding (in shares)	0	0
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized (in shares)	100,000,000	100,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Class A Common
Common stock
Common stock, par value (in dollars per share)	$ 0.000005	$ 0.000005
Common stock, authorized (in shares)	750,000,000	750,000,000
Common stock, issued (in shares)	75,164,389	72,271,298
Common stock, outstanding (in shares)	63,958,397	64,786,705
Treasury stock
Treasury stock (in shares)	11,205,992	7,508,985
Class B Common
Common stock
Common stock, par value (in dollars per share)	$ 0.000005	$ 0.000005
Common stock, authorized (in shares)	150,000,000	150,000,000
Common stock, issued (in shares)	82,498,213	83,303,628
Common stock, outstanding (in shares)	82,498,213	83,303,628