Segment Information - Geographical Segment Revenue (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue		$ 7,411	$ 6,700
Domestic [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue		2,363	1,722
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	[1]	$ 5,048	$ 4,978

[1] Revenue from the Central Banks, consisting of a consortium of central banks around the world, is classified as international revenue. Reporting revenue by country for this customer is not practicable.