Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Accrued compensation and related benefits	$ 11,804	$ 5,344
Accrued freelancer costs	967	622
Accrued indirect taxes	2,670	2,401
Accrued vendor expenses	8,826	5,485
Accrued payment processing fees	961	832
Operating lease liability, current	2,969	3,214
Other	569	444
Total accrued expenses and other current liabilities	$ 28,766	$ 18,342