Annual report pursuant to Section 13 and 15(d)

Stock Plans and Stock-Based Compensation - Summary of Stock Option Activity (Detail)

v3.6.0.2
Stock Plans and Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Shares Subject to Outstanding Options      
Outstanding at the beginning of period 1,804,083 991,010  
Options granted 646,667 845,703  
Options exercised 0 0  
Options forfeited 14,319 15,631  
Options expired 42,043 16,999  
Outstanding as end of period 2,394,388 1,804,083 991,010
Vested and expected to vest 2,351,745    
Exercisable 1,310,883    
Weighted-Average Exercise Price of Options      
Outstanding at the beginning of period $ 7.41 $ 6.09  
Options granted 1.28 9.00  
Options exercised 0 0  
Options forfeited 4.50 4.75  
Options expired 25.01 12.31  
Outstanding as end of period 5.46 $ 7.41 $ 6.09
Vested and expected to vest 5.50    
Exercisable $ 6.15    
Weighted-Average Remaining Contractual Term (Years)      
Outstanding 7 years 9 months 8 years 2 months 27 days 8 years 10 months 28 days
Vested and expected to vest 7 years 8 months 23 days    
Exercisable 7 years 2 months 5 days    
Aggregate Intrinsic Value (In Thousands)      
Outstanding at the beginning of period     $ 4,559
Outstanding as end of period $ 349    
Vested and expected 331    
Exercisable $ 3    
Performance Option [Member]      
Shares Subject to Outstanding Options      
Options granted 327,000    
Options exercised 0    
Outstanding as end of period 327,000    
Weighted-Average Exercise Price of Options      
Options granted $ 1.82    
Outstanding as end of period $ 1.82