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)

v3.3.1.900
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, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Outstanding        
Shares 1,256,478 1,466,238 1,945,497 2,099,364
Weighted average remaining life (in years) 5 years      
Weighted average exercise price (in usd per share) $ 14.50 $ 10.85 $ 7.57 $ 5.97
Exercisable        
Shares 1,014,817 1,192,708 1,586,354  
Weighted average remaining life (in years) 4 years 2 months 12 days      
Weighted average exercise price (in usd per share) $ 10.58 $ 7.57 $ 5.66  
$ 3.50 - $ 5.12        
Share-based Compensation Arrangement by Share-based Payment Award        
Exercise price, lower range (in usd per share) 3.50      
Exercise price, upper range (in usd per share) $ 5.12      
Outstanding        
Shares 458,470      
Weighted average remaining life (in years) 3 years 3 months 18 days      
Weighted average exercise price (in usd per share) $ 3.86      
Exercisable        
Shares 458,470      
Weighted average remaining life (in years) 3 years 3 months 18 days      
Weighted average exercise price (in usd per share) $ 3.86      
$ 6.63 - $ 7.30        
Share-based Compensation Arrangement by Share-based Payment Award        
Exercise price, lower range (in usd per share) 6.63      
Exercise price, upper range (in usd per share) $ 7.30      
Outstanding        
Shares 125,041      
Weighted average remaining life (in years) 1 year 2 months 12 days      
Weighted average exercise price (in usd per share) $ 6.75      
Exercisable        
Shares 125,041      
Weighted average remaining life (in years) 1 year 2 months 12 days      
Weighted average exercise price (in usd per share) $ 6.75      
$10.16 - $18.03        
Share-based Compensation Arrangement by Share-based Payment Award        
Exercise price, lower range (in usd per share) 10.16      
Exercise price, upper range (in usd per share) $ 18.03      
Outstanding        
Shares 426,869      
Weighted average remaining life (in years) 5 years 7 months 6 days      
Weighted average exercise price (in usd per share) $ 13.51      
Exercisable        
Shares 358,240      
Weighted average remaining life (in years) 5 years 4 months 24 days      
Weighted average exercise price (in usd per share) $ 13.51      
$30.00 - $47.37        
Share-based Compensation Arrangement by Share-based Payment Award        
Exercise price, lower range (in usd per share) 30.00      
Exercise price, upper range (in usd per share) $ 47.37      
Outstanding        
Shares 228,848      
Weighted average remaining life (in years) 8 years 10 months 24 days      
Weighted average exercise price (in usd per share) $ 38.42      
Exercisable        
Shares 55,816      
Weighted average remaining life (in years) 8 years 2 months 12 days      
Weighted average exercise price (in usd per share) $ 40.01      
$60.68 - $60.68        
Share-based Compensation Arrangement by Share-based Payment Award        
Exercise price, lower range (in usd per share) 60.68      
Exercise price, upper range (in usd per share) $ 60.68      
Outstanding        
Shares 17,250      
Weighted average remaining life (in years) 9 years 2 months 12 days      
Weighted average exercise price (in usd per share) $ 60.68      
Exercisable        
Shares 17,250      
Weighted average remaining life (in years) 9 years 2 months 12 days      
Weighted average exercise price (in usd per share) $ 60.68