Income Taxes - Schedule of Geographical Breakdown of Loss Before Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
United States	$ (81,670)	$ (89,459)	$ (54,395)
International	910	1,024	758
Loss before provision for (benefit from) income taxes, net	$ (80,760)	$ (88,435)	$ (53,637)