Income Taxes - Components of Loss before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Domestic	$ (72,164)	$ (47,218)	$ (41,985)
Foreign	(23,499)	(4,607)	(4,734)
Loss before income taxes	$ (95,663)	$ (51,825)	$ (46,719)