Subsequent Events (Details) - Subsequent Events [Member] - USD ($) $ / shares in Units, $ in Millions		1 Months Ended
	Oct. 22, 2023	Oct. 31, 2023
Immunovant, Inc. [Member] | Underwritten Public Offering [Member]
Subsequent Events [Abstract]
Net proceeds of common stock		$ 466.6
Roche Transaction [Member]
Subsequent Events [Abstract]
Consideration to be received in cash	$ 7,100.0
Consideration to be received from milestone	$ 150.0
Pfizer [Member] | Telavant Holdings, Inc [Member]
Subsequent Events [Abstract]
Ownership percentage	25.00%
RSL [Member] | Immunovant, Inc. [Member]
Subsequent Events [Abstract]
Ownership percentage	55.00%
RSL [Member] | Telavant Holdings, Inc [Member]
Subsequent Events [Abstract]
Ownership percentage	75.00%
RSL [Member] | Roche Transaction [Member]
Subsequent Events [Abstract]
Consideration to be received in cash	$ 5,200.0
Consideration to be received from milestone	$ 110.0
Common Stock [Member] | Roivant participation of Immunovant Stock offering [Member]
Subsequent Events [Abstract]
Common shares purchased by RSL (in shares)		1,526,316
Option purchase additional shares of common stock (in shares)		1,105,500
Sale price (in dollars per share)		$ 38
Common Stock [Member] | Immunovant, Inc. [Member] | Underwritten Public Offering [Member]
Subsequent Events [Abstract]
Common shares issued (in shares)		8,475,500
Common Stock [Member] | Immunovant, Inc. [Member] | Private Placement [Member]
Subsequent Events [Abstract]
Common shares purchased by RSL (in shares)		4,473,684
Sale price (in dollars per share)		$ 38