Property and Equipment - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 3,410	$ 3,121
Less: accumulated depreciation and amortization	(2,742)	(2,652)
Property and equipment, net	668	469
Machinery and Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,642	1,614
Computer Equipment and Software [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	236	251
Office Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	230	215
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,290	996
Construction in Progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 12	$ 45

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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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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