Geographic Information and Concentrations of Risk - Schedule of Geographic Concentration of Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets by Geographic Concentration, Total	$ 161,373	$ 162,256
United States and Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets by Geographic Concentration, Total	81,769	79,809
South Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets by Geographic Concentration, Total	53,610	56,937
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets by Geographic Concentration, Total	$ 25,994	$ 25,510