Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accounts receivable, allowance for credit losses	$ 676	$ 309
Other current assets, allowance for credit losses	5	0
Other assets, allowance for credit losses	$ 77	$ 0
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	750,000,000	750,000,000
Common stock, shares issued (in shares)	106,767,000	89,768,000
Common stock, shares outstanding (in shares)	106,767,000	89,768,000
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	133,796,000	151,047,000
Common stock, shares outstanding (in shares)	133,796,000	151,047,000
Class C Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	0	0
Common stock, shares outstanding (in shares)	0	0