Quarterly report pursuant to Section 13 or 15(d)

Organization and Description of Business - Additional Information (Detail)

v3.3.0.814
Organization and Description of Business - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2015
Sep. 30, 2014
Sep. 30, 2015
Sep. 30, 2014
Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]          
Net loss $ (5,865) $ (5,961) $ (9,550) $ (19,195)  
Cash flows from operating activities     (18,128) $ (13,642)  
Accumulated deficit (390,309)   (390,309)   $ (380,759)
Cash, cash equivalents and marketable securities $ 46,900   $ 46,900