Organization and Basis of Presentation (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 15,751	$ 25,342	$ 8,484	$ 36,079
Net working capital	12,600
Accumulated deficit	$ 136,679	$ 123,311