v3.26.1
Share-Based Compensation and Other Compensation Plans - Narrative (Details)
$ / shares in Units, $ in Thousands
 1 Months Ended 12 Months Ended
Dec. 23, 2025
USD ($)
shares
Jul. 31, 2024
tranche
Apr. 30, 2026
shares
Jul. 31, 2024
USD ($)
tranche
$ / shares
shares
Nov. 30, 2021
shares
Mar. 31, 2026
USD ($)
tranche
$ / shares
shares
Mar. 31, 2025
USD ($)
shares
Mar. 31, 2024
USD ($)
shares
Sep. 30, 2021
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Performance of grant date   5 years              
Term of trailing trading days, weighted average price use to calculate performance condition of PSUs   30 days              
Research and development expense           $ 681,812 $ 550,413 $ 439,909  
General and administrative expenses           610,466 591,410 416,133  
Cash Bonus Program                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Research and development expense           900 5,800 9,900  
General and administrative expenses           $ 4,500 $ 21,200 35,600  
Compensation-related expenses               $ 79,700  
Employee Stock                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Percentage of stock purchase price equal to lower of closing price under ESPP                 85.00%
Percentage of maximum contribution of base salary                 15.00%
Maximum amount of contribution of base salary                 $ 25
Issuance of the company's common shares under employee stock purchase plan (in shares) | shares           121,724 118,640 140,227  
Share-based compensation expense           $ 400 $ 500 $ 500  
Stock options and performance stock options                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Grant date fair value of options vested           $ 86,810 $ 100,639 $ 157,359  
Performance Stock Units                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares) | shares           0 0 0  
Restricted Stock Units                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Remaining weighted-average service period           3 years 1 month 2 days      
Grant date fair value of options vested           $ 53,600 $ 49,300 $ 49,100  
Share-based payment arrangement, nonvested award, excluding option, cost not yet recognized, amount           $ 115,800      
Restricted Stock Units | President and Chief Investment Officer                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares) | shares       1,836,547          
Restricted Stock Units | Chief Executive Officer                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Aggregate grant date fair value       $ 72,700          
Granted (in shares) | shares       2,754,821          
Performance Restricted Stock Units (at max)                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Remaining weighted-average service period           1 year 14 days      
Grant date fair value of options vested           $ 0 0 0  
Share-based payment arrangement, nonvested award, excluding option, cost not yet recognized, amount           $ 205,400      
Number of vesting tranches meeting share price hurdles | tranche           5      
Number of tranches available for vesting | tranche   6   6   6      
Period of trailing trading days, weighted average trading price used to calculate performance condition           30 days      
Performance stock units performance condition satisfied (in shares) | shares           28,051,785      
PSUs holding period before common shares may be sold by executive       2 years          
Performance Restricted Stock Units (at max) | First Tranche                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Share price (in dollars per share) | $ / shares       $ 15.00   $ 15.00      
Performance Restricted Stock Units (at max) | Second Tranche                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Share price (in dollars per share) | $ / shares       17.50   17.50      
Performance Restricted Stock Units (at max) | Third Tranche                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Share price (in dollars per share) | $ / shares       20.00   20.00      
Performance Restricted Stock Units (at max) | Fourth Tranche                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Share price (in dollars per share) | $ / shares       22.50   22.50      
Performance Restricted Stock Units (at max) | Fifth Tranche                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Share price (in dollars per share) | $ / shares       $ 25.00   25.00      
Performance Restricted Stock Units (at max) | President and Chief Investment Officer                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Aggregate grant date fair value       $ 363,300          
Granted (in shares) | shares       17,000,000          
Performance Restricted Stock Units (at max) | Chief Executive Officer                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares) | shares       14,450,000          
Stock Options | President and Chief Operating Officer                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Aggregate grant date fair value       $ 2,900          
Stock Options | President and Chief Investment Officer                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares) | shares       0          
Stock Options | Chief Executive Officer                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares) | shares       0          
CVARs | March 2020 CVAR Grants                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Cap (in dollars per share) | $ / shares           $ 12.68      
Number of shares outstanding (in shares) | shares           0      
CVARs | March 2020 CVAR Grants | Subsequent Event                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of shares issued (in shares) | shares     422,216            
CVARs | November 2021 CVAR Grants                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Share-based compensation arrangement by share-based payment award, equity instruments other than options, vested in period, fair value           $ 1,500 5,900 6,200  
CVARs | First Tranche | March 2020 CVAR Grants                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Hurdle price (in dollars per share) | $ / shares           $ 6.40      
CVARs | First Tranche | March 2020 CVAR Grants | Minimum                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Hurdle price (in dollars per share) | $ / shares           6.40      
CVARs | First Tranche | March 2020 CVAR Grants | Maximum                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Hurdle price (in dollars per share) | $ / shares           9.20      
CVARs | Second Tranche | March 2020 CVAR Grants                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Hurdle price (in dollars per share) | $ / shares           $ 11.50      
Employee Stock                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
ESPP initial offering period                 3 months
ESPP additional offering period                 6 months
Priovant Share Exchange                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares) | shares 1,746,194                
Share-based compensation expense $ 25,200                
Research and development expense 8,300                
General and administrative expenses $ 16,900                
One-Time Cash Retention Awards                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
General and administrative expenses           $ 14,800 86,400    
RSL 2021 EIP                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Common shares reserved for future issuance (in shares) | shares           217,186,782      
Common stock, capital shares reserved for future issuance, outstanding share, percentage           5.00%      
Equity incentive plan term           10 years      
Common shares available for future grants (in shares) | shares           60,944,783      
RSL 2021 EIP | CVARs                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares) | shares         6,317,350        
RSL 2021 EIP | CVARs | November 2021 CVAR Grants                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of shares issued (in shares) | shares           297,795      
RSL Equity Plans | Stock options and performance stock options                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares) | shares           2,264,315      
RSL Equity Plans | Restricted Stock Units                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares) | shares           6,473,525      
RSL Equity Plans | Performance Restricted Stock Units (at max)                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares) | shares           11,900,000      
RSL Equity Plans | Stock Options                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Unrecognized compensation expense           $ 30,300      
Remaining weighted-average service period           1 year 7 months 24 days      
RSL 2015 EIP | CVARs                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Share-based compensation arrangement by share-based payment award, equity instruments other than options, vested in period, fair value               2,100  
RSL 2015 EIP | CVARs | March 2020 CVAR Grants                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of service-vested shares (in shares) | shares           17,548,368      
Subsidiary Equity Incentive Plans                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Unrecognized compensation expense           $ 97,000      
Share-based compensation expense           $ 83,400 $ 56,100 $ 54,900