Basis of Presentation (Property and Equipment) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Summary of Property and equipment
Property and equipment , gross	$ 5,779	$ 5,669
Less accumulated depreciation and amortization	(4,945)	(4,881)
Property and equipment, Total	834	788
Lab and office equipment [Member]
Summary of Property and equipment
Property and equipment , gross	4,541	4,374
Leasehold improvements [Member]
Summary of Property and equipment
Property and equipment , gross	213	145
Computer equipment and software [Member]
Summary of Property and equipment
Property and equipment , gross	$ 1,025	$ 1,150