Equipment and Leasehold Improvements - Components of Equipment and Leasehold Improvements (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 19,801	$ 19,393
Less: Accumulated depreciation and amortization	(17,663)	(16,929)
Property, Plant and Equipment, Net, Total	2,138	2,464
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	14,095	13,737
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	766	752
Office Furniture [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	110	110
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	4,760	4,749
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 70	$ 45