Segment, Customer Concentration and Geographical Information - Company Revenue in Different Geographic Locations (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue from External Customer [Line Items]
Total revenues	$ 16,443	$ 12,629	$ 43,743	$ 38,883
Americas [Member] | Reportable Geographical Components [Member]
Revenue from External Customer [Line Items]
Total revenues	15,825	12,045	41,323	37,451
EMEA [Member] | Reportable Geographical Components [Member]
Revenue from External Customer [Line Items]
Total revenues	$ 618	581	$ 2,420	1,411
Asia Pacific [Member] | Reportable Geographical Components [Member]
Revenue from External Customer [Line Items]
Total revenues		$ 3		$ 21