Related Party Transactions - Additional Information (Details)				1 Months Ended	3 Months Ended	9 Months Ended	30 Months Ended
	Nov. 12, 2020 USD ($) $ / shares	Jun. 17, 2020	Dec. 27, 2019 USD ($)	Jun. 30, 2019 USD ($) ft²	Dec. 31, 2020 USD ($) $ / shares	Dec. 31, 2020 USD ($) $ / shares	Mar. 31, 2023 USD ($)	Apr. 01, 2023 USD ($)	Mar. 31, 2020 $ / shares
Related Party Transaction [Line Items]
Common shares, par value \| $ / shares					$ 0.000037453	$ 0.000037453			$ 0.000037453
Lease payment obligations					$ 5,664,000	$ 5,664,000
Durham, North Carolina \| RSI
Related Party Transaction [Line Items]
Area of office space \| ft²				2,784
Lease payment obligations				$ 600,000
Lease agreement, expiration date				2025-07
Subsidiaries \| Market Access Services Agreement
Related Party Transaction [Line Items]
Initial term of the market access services agreement		3 years
Initial Term Of Market Access Services Agreement Extended Period		1 year
Notice Period Intent To Terminate The Agreement		9 months
Related Party Transaction Selling General And Administrative Expenses From Transactions With Related Party					600,000	1,100,000
Due to Related Parties					200,000	200,000
Sunovion \| Sunovion Co Promotion Agreement
Related Party Transaction [Line Items]
Co-promotion expenses incurred by Sunovion					$ 0	$ 0
Sunovion \| Sunovion Co Promotion Agreement \| Scenario Forecast
Related Party Transaction [Line Items]
Due to Related Parties								$ 108,000,000
Sunovion \| Minimum \| Sunovion Co Promotion Agreement \| Scenario Forecast
Related Party Transaction [Line Items]
Co-promotion expenses incurred by Sunovion							$ 60,000,000
Merger Agreement \| Sumitovant
Related Party Transaction [Line Items]
Amount of Merger agreement termination fee.	$ 13,620,000
Merger Agreement \| Sumitovant \| Parent Company
Related Party Transaction [Line Items]
Common shares, par value \| $ / shares	$ 0.000037453
Merger agreement terms and conditions	Subject to the terms and conditions set forth in the Merger Agreement, at the effective time of the Merger (the “Effective Time”), (i) each share of USL’s common stock, par value $0.000037453 per share, issued and outstanding immediately prior to the Effective Time (other than Excluded Shares, Parent Owned Shares and shares for which shareholders have sought appraisal rights under the applicable laws of Bermuda (as each term is defined below)) will automatically cease to exist, and each holder of a common share will cease to have any rights with respect thereto, except for the right to receive the Per Share Merger Consideration; (ii) any common share owned by USL as a treasury share and any common share owned directly by any direct or indirect wholly-owned subsidiary of USL (each, an “Excluded Share”), in each case as of immediately prior to the Effective Time, will be canceled, be no longer outstanding, and will automatically cease to exist, and no consideration will be delivered in exchange therefor; and (iii) each common share that is owned directly by Sumitovant as of immediately prior to the Effective Time (each, a “Parent Owned Share”) will remain outstanding and will constitute a common share of the Surviving Company.
Merger agreement description	In addition, immediately prior to the Effective Time, (i) each option to purchase common shares that is outstanding and unexercised, whether vested or unvested, that has an exercise price per common share that is less than the Per Share Merger Consideration will be canceled and converted into the right to receive the Per Share Merger Consideration, net of the applicable exercise price, (ii) each option to purchase common shares that is outstanding and unexercised, whether vested or unvested, that has an exercise price per common share that is equal to or greater than the Per Share Merger Consideration will be canceled without payment, (iii) each SAR that is outstanding and unexercised, whether vested or unvested, that has a strike price per common share that is less than the Per Share Merger Consideration will be canceled and converted into the right to receive the Per Share Merger Consideration, net of the applicable strike price, (iv) each SAR that is outstanding and unexercised, whether vested or unvested, that has an exercise price per common share that is equal to or greater than the Per Share Merger Consideration will be canceled without payment, and (v) each then-outstanding time-based restricted share unit of USL and each common share granted by USL that is subject to a restriction on transfer that lapses at the end of a specified period or periods (whether vested or unvested) that has not been settled in common shares of USL prior to the Effective Time will be canceled and the holder thereof will have the right to receive a single lump sum cash payment, without interest, equal to the Per Share Merger Consideration, less any applicable withholding for taxes. The respective obligations of USL, Sumitovant and Merger Sub to effect the Merger are subject to the satisfaction, or to the extent permitted by applicable law, waiver of several customary conditions, including: (i) the receipt of the General Shareholder Approval and the Public Shareholder Approval, (ii) the absence of any law, injunction, judgment or other legal restraint that prohibits the consummation of the Merger, (iii) the accuracy of each party’s representations and warranties (subject to certain qualifications), (iv) each party’s compliance in all material respects with its obligations contained in the Merger Agreement and (v) the absence of a material adverse effect on USL.
Investor Rights Agreement \| Sumitovant
Related Party Transaction [Line Items]
Aggregate net offering price of common shares held by related party			$ 5,000,000
Investor Rights Agreement \| Sumitomo Dainippon Pharma Co.
Related Party Transaction [Line Items]
Description of protection conditions of minority shareholders						These protections include, among other things: (i) a requirement for a minimum of three independent directors on the Board (each of whom cannot be removed by Sumitomo Dainippon Pharma or certain of its affiliates without the approval of a majority of the minority shareholders); (ii) a requirement that the audit committee of the Board (the “Audit Committee”) be comprised solely of independent directors; (iii) the appointment of Mr. Pierre Legault as the Company’s lead independent director; (iv) a requirement that any transaction proposed by Sumitomo Dainippon Pharma or certain of its affiliates that would increase Sumitomo Dainippon Pharma’s beneficial ownership to over 76% of the Total Voting Power be approved by the Audit Committee (if occurring prior to December 27, 2021) and, if such transaction would increase Sumitomo Dainippon Pharma’s beneficial ownership to over 80% of the Total Voting Power, a majority of the Company’s minority shareholders must vote on such matter; and (v) a requirement that any related person transactions between Sumitomo Dainippon Pharma or certain of its affiliates and the Company be approved by the Audit Committee, consistent with the Company’s existing Related Person Transactions Policy.
Amounts of transactions with related party			$ 0
Investor Rights Agreement \| Sumitomo Dainippon Pharma Co. \| Minimum
Related Party Transaction [Line Items]
Percentage of ownership rights			50.00%
Investor Rights Agreement \| Sumitomo Dainippon Pharma Co. \| Maximum
Related Party Transaction [Line Items]
Percentage of ownership rights			90.00%

Urovant Sciences Ltd. 10-Q