Balance Sheet Components - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 496	$ 361
Less: accumulated depreciation	(355)	(309)
Total property and equipment, net	141	52
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	456	$ 361
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	35
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 5

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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