Quarterly report pursuant to Section 13 or 15(d)

Summary of Unvested Stock Option Activity (Detail)

v3.5.0.2
Summary of Unvested Stock Option Activity (Detail) - $ / shares
 3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Weighted Average Grant Date Fair Value        
Granted $ 1.13 $ 1.22 $ 0.99 $ 1.45
Stock Options        
Shares        
Beginning Balance     1,717,000  
Granted     1,978,000  
Vested     (964,000)  
Forfeited or cancelled     (194,000)  
Ending Balance 2,537,000   2,537,000  
Weighted Average Grant Date Fair Value        
Beginning Balance     $ 2.33  
Granted     1.39  
Vested     2.18  
Forfeited or cancelled     2.08  
Ending Balance $ 1.68   $ 1.68