Basis of Presentation (Property and Equipment) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Summary of Property and equipment
Property and equipment , gross	$ 3,087	$ 3,129
Less accumulated depreciation and amortization	(2,682)	(2,643)
Total property and equipment, net	405	486
Lab and office equipment
Summary of Property and equipment
Property and equipment , gross	2,182	2,232
Leasehold improvements
Summary of Property and equipment
Property and equipment , gross	273	273
Computer equipment and software
Summary of Property and equipment
Property and equipment , gross	$ 632	$ 624