Cover - shares	6 Months Ended
	Sep. 30, 2020	Nov. 11, 2020
Entity Addresses [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-37418
Entity Registrant Name	Axovant Gene Therapies Ltd.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	85-3863315
Entity Address, Address Line One	11 Times Square
Entity Address, Address Line Two	33rd Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10036
City Area Code	(877)
Local Phone Number	746-4891
Entity Information, Former Legal or Registered Name	Axovant Gene Therapies Ltd.
Title of 12(b) Security	Common Stock, par value $0.00001 per share
Trading Symbol	SIOX
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		48,467,922
Entity Central Index Key	0001636050
Amendment Flag	false
Current Fiscal Year End Date	--03-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Former Address
Entity Addresses [Line Items]
Entity Address, Address Line One	Clarendon House
Entity Address, Address Line Two	2 Church Street
Entity Address, City or Town	Hamilton
Entity Address, Postal Zip Code	HM 11
Entity Address, Country	BM