Related Party Transactions (Details)				1 Months Ended	3 Months Ended
		Aug. 01, 2020	Dec. 27, 2019 USD ($) director day	Aug. 31, 2020	Jun. 30, 2022 USD ($) shares	Jun. 30, 2021 USD ($)
Related Party Transaction [Line Items]
Interest expense	[1]				$ 4,200,000	$ 3,505,000
Expenses incurred under agreements					1,163,000	1,323,000
Majority Shareholder | Sunovion Pharmaceuticals Inc. Market Access Services Agreement
Related Party Transaction [Line Items]
Expenses incurred under agreements					$ 1,100,000	1,300,000
Sumitomo Pharma, Co., Ltd. | Majority Shareholder
Related Party Transaction [Line Items]
Number of shares owned (in shares) | shares					50,041,181
Ownership percentage					52.30%
Ownership threshold for appointment of directors			50.00%
Number of independent directors required for audit committee | director			3
Ownership threshold for voting rights			60.00%
Ownership threshold for right of ownership percentage maintenance			50.00%
Sumitovant Biopharma, Inc. | Services Information Sharing Agreement
Related Party Transaction [Line Items]
Expenses incurred under agreements					$ 100,000
Sumitomo Dainippon Pharma, Co., Ltd. | Majority Shareholder | Sunovion Pharmaceuticals Inc. Market Access Services Agreement
Related Party Transaction [Line Items]
Agreement term		3 years
Agreement extension term		1 year
Termination notice period		9 months
MSG | Majority Shareholder | Sunovion Pharmaceuticals Inc. Market Access Services Agreement | Selling, General and Administrative Expenses
Related Party Transaction [Line Items]
Agreement term				2 years
Term Loan | Letter Agreement with Sumitomo Dainippon Pharma, Co., Ltd. | Sumitomo Pharma, Co., Ltd.
Related Party Transaction [Line Items]
Interest expense					3,632,000	$ 2,904,000
Term Loan | Letter Agreement with Sumitomo Dainippon Pharma, Co., Ltd. | Sumitomo Pharma, Co., Ltd. | Majority Shareholder
Related Party Transaction [Line Items]
Maximum borrowing commitment			$ 400,000,000
Facility term			5 years
Notice period for prepayment | day			10
Default interest rate (as a percent)			5.00%
Available borrowing capacity					41,300,000
Outstanding balance					$ 358,700,000
Term Loan | Letter Agreement with Sumitomo Dainippon Pharma, Co., Ltd. | Sumitomo Dainippon Pharma, Co., Ltd. | Majority Shareholder
Related Party Transaction [Line Items]
Repayment period upon change in control			30 days
LIBOR | Term Loan | Letter Agreement with Sumitomo Dainippon Pharma, Co., Ltd. | Sumitomo Pharma, Co., Ltd. | Majority Shareholder
Related Party Transaction [Line Items]
Variable interest rate (as a percent)			3.00%

[1] Includes $3,632 and $2,904 of interest expense under the Sumitomo Pharma Loan Agreement for the three months ended June 30, 2022 and 2021, respectively (see Note 5).