| Cover | Aug. 09, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Aug. 9, 2021 |
| Entity Registrant Name | IMMUNOVANT, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-38906 |
| Entity Tax Identification Number | 83-2771572 |
| Entity Address, Address Line One | 320 West 37th Street |
| Entity Address, City or Town | New York, |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10018 |
| City Area Code | 917 |
| Local Phone Number | 580-3099 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.0001 par value per share |
| Trading Symbol | IMVT |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001764013 |
| Amendment Flag | false |
