Details of Certain Financial Statement Components and Supplemental Disclosures of Cash Flow Information and Non-Cash Activities - Components of Property and Equipment (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 12,841,000	$ 12,841,000
Less: accumulated depreciation and amortization	(9,350,000)	(7,290,000)
Property and Equipment, Net	3,491,000	5,551,000
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	11,571,000	11,571,000
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	1,065,000	1,065,000
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 205,000	$ 205,000