CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Short-term investments, allowance for credit losses	$ 275	$ 0
Accounts receivable, allowance for credit losses	$ 5,776	$ 3,920
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0.000001	$ 0.000001
Preferred stock, authorized shares	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock
Common stock, par value (in dollars per share)	$ 0.000001	$ 0.000001
Class A common stock
Common stock
Common stock, authorized shares	1,000,000,000	1,000,000,000
Common stock, shares issued	40,865,000	40,305,000
Common stock, shares outstanding	40,865,000	40,305,000
Class B common stock
Common stock
Common stock, authorized shares	95,000,000	95,000,000
Common stock, shares issued	5,170,000	5,171,000
Common stock, shares outstanding	5,170,000	5,171,000