Annual report pursuant to Section 13 and 15(d)

Stock Incentive Plan - Additional Information (Details)

v3.19.3.a.u2
Stock Incentive Plan - Additional Information (Details)
$ / shares in Units, $ in Thousands
 1 Months Ended 2 Months Ended 12 Months Ended
Dec. 01, 2017
shares
Nov. 30, 2019
USD ($)
Sep. 30, 2019
shares
Dec. 31, 2019
USD ($)
vote
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Dec. 31, 2017
USD ($)
$ / shares
shares
Dec. 31, 2011
Dec. 31, 2016
$ / shares
Dec. 31, 2010
$ / shares
shares
May 31, 2010
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Preferred stock, shares authorized (in shares)       5,000,000 5,000,000          
Preferred stock, par value (in usd per share) | $ / shares       $ 0.0001 $ 0.0001          
Granted (in shares)       1,330,000 518,000 390,000        
Total intrinsic value of options exercised | $       $ 7,154 $ 5,588 $ 808        
Exercise of stock options, net (in shares)       916,000 909,000 401,000        
Exercised (in usd per share) | $ / shares       $ 7.362 $ 7.367 $ 4.935        
Exercise of stock options, net | $       $ 6,742 $ 6,696 $ 1,977        
Withholding tax on compensation from exercise of stock options | $   $ 2,292                
Weighted average exercise price (in usd per share) | $ / shares       $ 10.524 $ 8.050 $ 7.367   $ 7.300    
Stock Options                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Options vesting period             5 years      
Ratable vesting percentage       33.33%            
Weighted average exercise price (in usd per share) | $ / shares       $ 6.33 $ 5.20 $ 2.93        
Stock-based compensation expense | $       $ 1,620 $ 1,258 $ 1,293        
Non-vested stock options unrecognized compensation expense | $       $ 9,486            
Non-vested stock options unrecognized compensation expense, weighted-average period of recognition       2 years 8 months 1 day            
Stock Options | Minimum                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Options vesting period       3 years            
Class A Common Stock                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Common stock, shares authorized (in shares)       500,000,000 500,000,000          
Common stock, par value (in usd per share) | $ / shares       $ 0.0001 $ 0.0001          
Number of votes per share | vote       1            
Class B Common Stock                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Common stock, shares authorized (in shares)       144,000,000 144,000,000          
Common stock, par value (in usd per share) | $ / shares       $ 0.0001 $ 0.0001          
Number of votes per share | vote       5            
Common stock, shares issuable upon conversion (in shares)       1            
Preferred Stock                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Preferred stock, shares authorized (in shares)       5,000,000            
Preferred stock, par value (in usd per share) | $ / shares       $ 0.0001            
2000 Stock Incentive Plan                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Common stock, par value (in usd per share) | $ / shares                 $ 0.0001  
Shares reserved for future issuance (in shares)                 28,500,000  
2000 Stock Incentive Plan | Stock Options | Maximum                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Options vesting period       10 years            
2010 Stock Incentive Plan | Stock Options                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Shares available for grant (in shares)       5,717,000            
Options vesting period       10 years            
2010 Stock Incentive Plan | Class A Common Stock                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Shares reserved for future issuance (in shares)                   10,000,000
Granted (in shares)       5,217,000            
2017 Employee Stock Purchase Plan | Stock Options                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Number of allocated shares (up to) (in shares) 200,000                  
Discount from fair value of stock (percent) 5.00%                  
Stock issued during period (in shares)       49,000 51,000          
Shares withheld for future purchases       100,000 0          
Chief Executive Officer | Class A Common Stock                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Exercise of stock options, net (in shares)     600,000              
2019 Stock Option Grants | Stock Options                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Exercise term upon termination       90 days            
2019 Stock Option Grants | 2010 Stock Incentive Plan | Stock Options                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Granted (in shares)       1,000,000            
Options vesting period       3 years            
Expiration period       10 years