| Document and Entity Information | Aug. 23, 2019 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Aug. 23, 2019 |
| Entity Registrant Name | Myovant Sciences Ltd. |
| Entity Incorporation, State or Country Code | D0 |
| Entity File Number | 001-37929 |
| Entity Tax Identification Number | 98-1343578 |
| Entity Address, Address Line One | Suite 1, 3rd Floor |
| Entity Address, Address Line Two | 11-12 St. James’s Square |
| Entity Address, City or Town | London |
| Entity Address, Country | GB |
| Entity Address, Postal Zip Code | SW1Y 4LB |
| Country Region | 44 |
| City Area Code | 207 |
| Local Phone Number | 400 3347 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001679082 |
| Title of 12(b) Security | Common Shares, par value $0.000017727 per share |
| Trading Symbol | MYOV |
| Security Exchange Name | NYSE |
