CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accounts receivable, allowances	$ 2,502	$ 2,700
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, 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
Treasury stock (in shares)	14,620,175	14,620,175
Class A Common
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)	92,242,152	91,617,450
Common stock, outstanding (in shares)	77,621,977	76,997,275
Class B Common
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)	78,331,591	78,331,591
Common stock, outstanding (in shares)	78,331,591	78,331,591