Geographic Information and Concentrations of Risk - Net Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 80,689	$ 55,891	$ 137,529	$ 104,447
United States and Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	69,080	41,459	111,430	74,953
South Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	5,856	8,558	14,094	16,927
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 5,753	$ 5,874	$ 12,005	$ 12,567