Details of Certain Financial Statement Components and Supplemental Disclosures of Cash Flow Information and Non-Cash Activities - Components of Property and Equipment (Detail) - USD ($)	Sep. 26, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 316,000	$ 13,181,000
Less: accumulated depreciation and amortization	(316,000)	(12,948,000)
Property and Equipment, Net		233,000
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	316,000	11,911,000
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross		1,065,000
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross		$ 205,000

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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