Annual report pursuant to Section 13 and 15(d)

Stock Option and Purchase Plans - Summary of Weighted Average Exercise Prices and Contractual Lives for Outstanding and Exercisable Stock Options (Detail)

v3.6.0.2
Stock Option and Purchase Plans - Summary of Weighted Average Exercise Prices and Contractual Lives for Outstanding and Exercisable Stock Options (Detail) - $ / shares
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Outstanding        
Shares (in shares) 1,338,273 1,444,954 1,686,178 2,237,325
Weighted average remaining life (in years) 4 years 9 months 18 days      
Weighted average exercise price (in usd per share) $ 14.85 $ 12.61 $ 9.43 $ 6.58
Exercisable        
Shares (in shares) 1,091,561 1,167,040 1,371,614  
Weighted average remaining life (in years) 3 years 10 months 24 days      
Weighted average exercise price (in usd per share) $ 11.03 $ 9.20 $ 6.58  
$ 3.04 - $ 4.45        
Share-based Compensation Arrangement by Share-based Payment Award        
Exercise price, lower range (in usd per share) 3.04      
Exercise price, upper range (in usd per share) $ 4.45      
Outstanding        
Shares (in shares) 471,841      
Weighted average remaining life (in years) 2 years 6 months      
Weighted average exercise price (in usd per share) $ 3.29      
Exercisable        
Shares (in shares) 471,841      
Weighted average remaining life (in years) 2 years 6 months      
Weighted average exercise price (in usd per share) $ 3.29      
$ 5.77 - $ 6.35        
Share-based Compensation Arrangement by Share-based Payment Award        
Exercise price, lower range (in usd per share) 5.77      
Exercise price, upper range (in usd per share) $ 6.35      
Outstanding        
Shares (in shares) 45,166      
Weighted average remaining life (in years) 6 months      
Weighted average exercise price (in usd per share) $ 6.01      
Exercisable        
Shares (in shares) 45,166      
Weighted average remaining life (in years) 6 months      
Weighted average exercise price (in usd per share) $ 6.01      
$ 8.83 - $15.68        
Share-based Compensation Arrangement by Share-based Payment Award        
Exercise price, lower range (in usd per share) 8.83      
Exercise price, upper range (in usd per share) $ 15.68      
Outstanding        
Shares (in shares) 459,138      
Weighted average remaining life (in years) 4 years 7 months 6 days      
Weighted average exercise price (in usd per share) $ 11.73      
Exercisable        
Shares (in shares) 431,370      
Weighted average remaining life (in years) 4 years 6 months      
Weighted average exercise price (in usd per share) $ 11.81      
$ 26.09 - $41.19        
Share-based Compensation Arrangement by Share-based Payment Award        
Exercise price, lower range (in usd per share) 26.09      
Exercise price, upper range (in usd per share) $ 41.19      
Outstanding        
Shares (in shares) 342,288      
Weighted average remaining life (in years) 8 years 6 months      
Weighted average exercise price (in usd per share) $ 33.93      
Exercisable        
Shares (in shares) 123,344      
Weighted average remaining life (in years) 7 years 10 months 24 days      
Weighted average exercise price (in usd per share) $ 33.05      
$ 52.77 - $52.77        
Share-based Compensation Arrangement by Share-based Payment Award        
Exercise price, lower range (in usd per share) 52.77      
Exercise price, upper range (in usd per share) $ 52.77      
Outstanding        
Shares (in shares) 19,840      
Weighted average remaining life (in years) 8 years 2 months 12 days      
Weighted average exercise price (in usd per share) $ 52.77      
Exercisable        
Shares (in shares) 19,840      
Weighted average remaining life (in years) 8 years 2 months 12 days      
Weighted average exercise price (in usd per share) $ 52.77