XML 83 R50.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Stock-Based Compensation - Additional Information (Detail)
12 Months Ended
Jan. 01, 2019
shares
Dec. 31, 2019
USD ($)
Milestone
$ / shares
shares
Dec. 31, 2018
USD ($)
Milestone
$ / shares
shares
Dec. 31, 2017
USD ($)
Milestone
$ / shares
shares
Dec. 31, 2016
USD ($)
Dec. 31, 2015
Sep. 20, 2018
shares
Jul. 02, 2014
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Share based compensation granted under plan vested period   4 years            
Share based compensation, vest period   1 year            
Share based compensation, term of plan   10 years            
Stock-based compensation expense | $   $ 153,231,000 $ 101,963,000 $ 35,534,000        
Weighted average grant date fair value per share | $ / shares   $ 82.39 $ 109.92 $ 41.94        
Share option, weighted-average forfeiture rates   13.70% 10.70% 13.30%        
Total number of shares reserved   10,651,531            
Common stock available for issuance under stock option plan   2,155,175            
Non-employees [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Share based compensation, term of plan     10 years          
2011 Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Options granted   0            
2014 Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Common stock shares annual increase added to plan 1,875,530              
Milestones achieved | Milestone   1 1 0        
2014 Plan [Member] | Milestone Three [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Percentage of performance based grants that were achieved     33.00%   50.00% 35.00%    
2014 Plan [Member] | Milestone Two [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Percentage of performance based grants that were achieved     20.00% 33.00%        
2014 Plan [Member] | Consultant [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Stock-based compensation expense | $         $ 0      
2014 Plan [Member] | Maximum [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Percentage of increase on outstanding shares of Common stock   4.00%            
2016 Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Total number of shares reserved for issuance             1,200,000  
Shares of common stock initially authorized for issuance under this plan             1,200,000  
2014 Employee Stock Purchase Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Total number of shares reserved for issuance               282,000
Shares of common stock initially authorized for issuance under this plan               282,000
Number of shares issued under the plan   105,160            
Accrued expenses | $   $ 700,000            
Total number of shares available for issuance   176,840            
Restricted Stock Units Vest One Year Anniversary [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Restricted stock units cliff vesting percentage   25.00%            
Restricted Stock Units [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Restricted stock units granted   393,539   32,500        
Share based compensation granted under plan vested period       2 years        
Fair value of restricted stock units vested | $   $ 2,000,000.0 $ 2,600,000 $ 0        
Restricted stock units granted   60,868            
Outstanding and unvested performance restricted stock units   333,243 82,700          
Stock-based compensation expense | $   $ 10,992,000 $ 651,000 $ 617,000        
Restricted Stock Units [Member] | Restricted Stock Units Vest One Year Anniversary [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Restricted stock units cliff vesting percentage       50.00%        
Restricted stock units vesting period month and year       2018-02        
Restricted Stock Units [Member] | Restricted Stock Units Vest Two Year Anniversary [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Restricted stock units cliff vesting percentage       50.00%        
Restricted stock units vesting period month and year       2019-02        
Performance Restricted Stock Units [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Restricted stock units granted     71,400          
Fair value of restricted stock units vested | $   $ 11,100,000 $ 0          
Percentage Of Milestone Achieved   18.00%            
Outstanding and unvested performance restricted stock units   333,243            
Total unrecognized stock-based compensation expense | $   $ 52,600,000            
Performance Restricted Stock Units [Member] | Milestones [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Restricted stock units granted     33,600          
Performance Restricted Stock Units [Member] | Commercial Milestones [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Restricted stock units granted   393,539 37,800          
Performance Shares [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Total unrecognized stock-based compensation expense | $   $ 35,700,000            
Options granted   0 524,003 449,208        
Number of shares outstanding and unvested stock options   485,595            
Performance-Based Stock Options [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Stock-based compensation expense | $   $ 0 $ 0 $ 0        
Performance-Based Stock Options [Member] | Consultant [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Stock-based compensation expense | $     6,900,000          
Performance Milestone [Member] | 2014 Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Stock-based compensation expense | $   16,300,000 4,400,000          
Stock Options [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Total unrecognized stock-based compensation expense | $   $ 283,400,000            
Options granted   2,215,606            
Stock-based compensation expense | $   $ 140,517,000 100,342,000 34,525,000        
Weighted average period of unrecognized compensation costs   2 years 5 months 8 days            
Intrinsic value of options exercised | $   $ 119,100,000 $ 98,300,000 $ 77,700,000        
Total number of shares reserved   8,163,113 7,530,767