Balance Sheet Components - Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Distribution fees	$ 30,692	$ 20,360
Traffic acquisition cost	7,602	5,278
Prefunded liability	5,425	5,429
Operating lease liabilities	3,727	3,168
Liability related to purchased intangible asset	2,250	1,000
Interest payable	1,157	282
Marketing expenses	946	2,164
Other	11,835	12,351
Total other current liabilities	$ 63,634	$ 50,032