Cover Page - USD ($)	12 Months Ended
	Mar. 31, 2021	May 06, 2021	Sep. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Mar. 31, 2021
Current Fiscal Year End Date	--03-31
Document Transition Report	false
Entity File Number	001-37929
Entity Registrant Name	Myovant Sciences Ltd.
Entity Incorporation, State or Country Code	D0
Entity Tax Identification Number	98-1343578
Entity Address, Address Line Two	Suite 1, 3rd Floor
Entity Address, Address Line One	11-12 St. James’s Square
Entity Address, City or Town	London
Entity Address, Postal Zip Code	SW1Y 4LB
Entity Address, Country	GB
Country Region	44
City Area Code	207
Local Phone Number	400 3351
Title of 12(b) Security	Common Shares, $0.000017727 par value per share
Trading Symbol	MYOV
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 559,121,548
Entity Common Stock, Shares Outstanding		91,480,278
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement for the 2021 Annual General Meeting of Shareholders (the “2021 Proxy Statement”) to be filed with the Securities and Exchange Commission pursuant to Regulation 14A not later than 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein.
Entity Central Index Key	0001679082
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY