v3.7.0.1
Organization and Summary of Significant Accounting Policies - Additional Information (Detail)
$ in Thousands
1 Months Ended 6 Months Ended
Jan. 31, 2017
Jun. 30, 2017
USD ($)
Segment
Jun. 30, 2016
USD ($)
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]      
Number of operating segment | Segment   1  
Cash, cash equivalents and marketable securities   $ 127,000  
Proceeds from issuance of common stock, net   88,200  
Cash used in operating activities   42,642 $ 52,561
Percentage of reduction in global workforce 40.00%    
Cowen      
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]      
Proceeds from issuance of common stock, net   $ 88,200