Organization and Basis of Presentation - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Organization And Basis Of Presentation [Line Items]
Cash and cash equivalents	$ 25,342	$ 36,079	$ 54,059	$ 7,942
Net working capital	21,900
Accumulated deficit	$ (123,311)	$ (125,202)