Quarterly report pursuant to Section 13 or 15(d)

Description of Business and Liquidity - Additional Information (Detail)

v3.21.2
Description of Business and Liquidity - Additional Information (Detail)
$ in Thousands
3 Months Ended
Dec. 18, 2019
shares
Jun. 30, 2021
USD ($)
segment
Mar. 31, 2021
USD ($)
Dec. 17, 2019
Business Acquisition [Line Items]        
Number of operating segments | segment   1    
Number of reportable segments | segment   1    
Cash | $   $ 379,005 $ 400,146  
Accumulated deficit | $   $ 229,128 $ 198,657  
Immunovant Sciences Ltd        
Business Acquisition [Line Items]        
Percentage of business acquisition 100.00%      
Immunovant Sciences Ltd | Common stock        
Business Acquisition [Line Items]        
Number of shares issued in business combination (in shares) | shares 42,080,376      
Immunovant Sciences Ltd | Series A  preferred stock | Roivant Sciences Ltd. (RSL)        
Business Acquisition [Line Items]        
Number of shares issued in business combination (in shares) | shares 10,000      
Immunovant Sciences Ltd | Sellers        
Business Acquisition [Line Items]        
Ownership percentage       100.00%