Quarterly report pursuant to Section 13 or 15(d)

Summary of Unvested Stock Option Activity (Detail)

v3.8.0.1
Summary of Unvested Stock Option Activity (Detail) - $ / shares
shares in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Weighted Average Grant Date Fair Value        
Granted $ 0.86 $ 1.13 $ 0.39 $ 0.99
Stock Options        
Shares        
Beginning Balance     3,259  
Granted     1,355  
Vested     (921)  
Forfeited or cancelled     (494)  
Ending Balance 3,199   3,199  
Weighted Average Grant Date Fair Value        
Beginning Balance     $ 1.16  
Granted     0.86  
Vested     1.08  
Forfeited or cancelled     1.03  
Ending Balance $ 1.08   $ 1.08