Annual report pursuant to Section 13 and 15(d)

Description of Business - Additional Information (Details)

v3.3.1.900
Description of Business - Additional Information (Details) - USD ($)
$ in Thousands
Dec. 31, 2015
Dec. 31, 2014
Description Of Business [Abstract]    
Accumulated deficit $ (1,140,083) $ (1,119,477)
Cash, cash equivalents and marketable securities $ 66,300