Geographic Information and Concentrations of Risk - Net Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 90,240	$ 62,716	$ 227,769	$ 167,163
United States and Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	77,208	47,378	188,638	122,331
South Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	6,836	9,237	20,930	26,164
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 6,196	$ 6,101	$ 18,201	$ 18,668