Stockholders' Equity - Additional Information (Details) - USD ($)
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Feb. 16, 2016
Jul. 23, 2014
Mar. 13, 2014
Dec. 10, 2012
Jun. 30, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Common stock, shares authorized (in shares) 100,000,000 100,000,000            
Common stock, shares issued (in shares) 58,276,447 57,374,907            
Common stock, shares outstanding (in shares) 58,276,447 57,374,907            
Common stock, par value (in dollars per share) $ 0.001 $ 0.001            
Preferred stock, shares authorized (in shares) 5,000,000 5,000,000,000            
Preferred stock, shares issued (in shares) 0 0            
Preferred stock, shares outstanding (in shares) 0 0            
Preferred stock, par value (in dollars per share) $ 0.001 $ 0.001            
Weighted average fair value of stock options granted (in dollars per share) $ 3.10 $ 4.45 $ 5.15          
Dividend yield 0.00% 0.00% 0.00%          
Expected life (in years) 5 years 5 years 5 years          
Volatility determination period (in years) 5 years              
Fair value of stock options exercised $ 1,100,000 $ 1,700,000            
2010 Employee Stock Purchase Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Shares of common stock available for issuance (in shares) 197,000             1,000,000
Incentive Stock Option [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Unrecognized compensation cost $ 7,100,000              
Weighted average recognition period of unrecognized compensation cost 1 year 10 months 10 days              
Incentive Stock Option [Member] | 1998 Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Shares of common stock available for issuance (in shares) 5,850,000              
Incentive Stock Option [Member] | 2000 Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Shares of common stock available for issuance (in shares) 10,000,000              
Increase in number of shares of common stock available for issuance (in shares) 4,150,000              
Incentive Stock Option [Member] | 2009 Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Shares of common stock available for issuance (in shares) 2,400,000              
Increase in number of shares of common stock available for issuance (in shares) 6,000,000              
Incentive Stock Option [Member] | Amended 2009 Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Shares of common stock available for issuance (in shares) 23,817,744              
Increase in number of shares of common stock available for issuance (in shares) 4,250,000              
Stock option term 10 years              
Restricted Stock Units (RSUs) [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Unrecognized compensation cost $ 9,300,000              
Weighted average recognition period of unrecognized compensation cost 2 years 9 months 20 days              
2012 Stock Repurchase Program [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Amount authorized for repurchase $ 74,000,000.0     $ 64,000,000.0 $ 50,000,000.0 $ 40,000,000 $ 30,000,000  
Increase to purchase price limit of stock repurchase program       $ 14,000,000        
Stock repurchased during period (in shares) 1,518,349              
Remaining authorized repurchase amount $ 20,100,000