XML 54 R43.htm IDEA: XBRL DOCUMENT v3.19.1
Stock-Based Compensation - Additional Information (Detail)
3 Months Ended 12 Months Ended
Jan. 01, 2019
shares
Mar. 31, 2019
USD ($)
Milestone
$ / shares
shares
Mar. 31, 2018
USD ($)
$ / shares
shares
Mar. 31, 2017
shares
Dec. 31, 2018
shares
Sep. 20, 2018
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Total number of options outstanding   11,493,302        
Common stock available for issuance under stock option plan   2,821,785        
Stock-based compensation expense | $   $ 44,116,000 $ 15,817,000      
Weighted average grant date fair value per share | $ / shares   $ 98.23 $ 125.80      
2011 Stock Option Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Options granted   0        
2014 Stock Option Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Common stock shares annual increase added to plan 1,875,530          
2014 Stock Option 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 Stock Option Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Total number of shares reserved for issuance           1,200,000
Restricted Stock Units [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Restricted stock units granted   354,111   32,500    
Share based compensation granted under plan vest period       2 years    
Fair value of restricted stock units vested | $   $ 2,000,000 $ 2,600,000      
Stock-based compensation expense | $   $ 58,000 $ 168,000      
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   354,111 33,600      
Performance Shares [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Options granted   0 323,753      
Total unrecognized stock-based compensation expense | $   $ 49,500,000        
Number of shares outstanding and unvested stock options   745,454        
Performance-Based Stock Options [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Milestones not achieved | Milestone   1        
Stock-based compensation expense | $   $ 14,200,000 $ 0      
Stock Options [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Options granted   1,179,861        
Total number of options outstanding   8,282,047     7,530,767  
Stock-based compensation expense | $   $ 43,564,000 15,381,000      
Total unrecognized stock-based compensation expense | $   $ 342,800,000        
Weighted average period of unrecognized compensation costs   2 years 10 months 28 days        
Intrinsic value of options exercised | $   $ 26,700,000 $ 47,700,000