Quarterly report pursuant to Section 13 or 15(d)

Business Combination and Recapitalization - Additional Information (Detail)

v3.19.3.a.u2
Business Combination and Recapitalization - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 9 Months Ended
Dec. 18, 2019
Sep. 29, 2019
Dec. 31, 2019
Dec. 31, 2019
Mar. 31, 2025
Mar. 31, 2023
May 31, 2019
Mar. 31, 2019
Business Acquisition [Line Items]                
Business combination consideration $ 420.9              
Business acquisition price per share $ 10.00              
Closing of Share Price 13.88              
Business combination per share disclosed in fair value $ 10.00              
Number of securities called by warrants or rights     5,750,000 5,750,000     5,750,000  
Common stock to potential forfeiture in the event that the milestones are not achieved   1,800,000            
Preferred Stock, Shares Issued     0 0        
Business combination costs       $ 2.8        
Common share, shares outstanding     54,655,376 54,655,376       38,590,381
Common Stock, Shares, Issued     56,455,376 56,455,376       38,590,381
Preferred stock, shares outstanding     0 0        
Sponsor [Member]                
Business Acquisition [Line Items]                
Restricted Share For Each Milestone   900,000            
General and Administrative Expense [Member]                
Business Acquisition [Line Items]                
Additional Financial Advisory Fees     $ 2.3 $ 2.3        
Forecast [Member] | Milestone Achievement One [Member]                
Business Acquisition [Line Items]                
Volume-weighted average price         $ 31.50 $ 17.50    
2018 Equity Incentive Plan [Member]                
Business Acquisition [Line Items]                
Options outstanding number 4,408,287   4,188,301 4,188,301        
Common Stock [Member]                
Business Acquisition [Line Items]                
Number of shares issued in business combination 42,080,376     3,500,000        
Earnout shares reserved for issuance 20,000,000              
Common Stock [Member] | Forecast [Member] | Milestone Achievement One [Member]                
Business Acquisition [Line Items]                
Earnout shares reserved for issuance         10,000,000 10,000,000    
Immunovant Sciences Ltd [Member]                
Business Acquisition [Line Items]                
Percentage of business acquisition 100.00%              
Number of shares issued in business combination 42,080,376              
Shares exchange ratio 0.48907%              
Series A Preferred Stock [Member]                
Business Acquisition [Line Items]                
Number of shares issued in business combination 10,000              
Preferred Stock, Shares Issued     10,000 10,000        
Preferred stock, shares outstanding     10,000 10,000        
Series A Preferred Stock [Member] | Roivant Sciences Ltd. (RSL) [Member]                
Business Acquisition [Line Items]                
Number of shares issued in business combination 10,000