Segments and Geographic Information - Summary of Significant Revenues in Following Regions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	$ 7,128	$ 9,472
North America [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	6,277	8,583
Asia [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	538	540
Europe [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	290	325
All Other Regions [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	$ 23	$ 24