Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Property Plant and equipment gross	$ 1,953	$ 1,974
Less accumulated depreciation and amortization	(1,869)	(1,877)
Total	84	97
Laboratory and manufacturing equipment
Property Plant And Equipment [Line Items]
Property Plant and equipment gross	591	591
Computer equipment and software
Property Plant And Equipment [Line Items]
Property Plant and equipment gross	1,179	1,179
Office furniture and equipment
Property Plant And Equipment [Line Items]
Property Plant and equipment gross	$ 183	183
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property Plant and equipment gross		$ 21

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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