Property and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,534	$ 1,516
Less: Accumulated depreciation	(426)	(346)
Property And Equipment, net	1,108	1,170
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	500	500
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	75	75
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	72	72
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	62	60
Research equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	667	667
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 158	$ 142