Long-Term Debt, Funding Agreement with NovaQuest (Details) - USD ($) $ in Thousands		1 Months Ended	6 Months Ended	16 Months Ended	71 Months Ended
	Oct. 31, 2018	May 31, 2022	Sep. 30, 2023	Sep. 30, 2023	Apr. 30, 2028	Mar. 31, 2023	Aug. 31, 2018
Carrying Balance of Debt Issued [Abstract]
Less: current portion			$ (28,120)	$ (28,120)		$ (26,940)
Total long-term debt, net			$ 188,911	188,911		180,700
Dermavant [Member] | Funding Agreement with NovaQuest [Member]
Funding Agreement with NovaQuest [Abstract]
Face amount	$ 17,500						$ 100,000
Proceeds from issuance of debt	$ 117,500
Frequency of periodic payment			quarterly
Periodic payment				44,100
Quarterly payments made		$ 7,300
Carrying Balance of Debt Issued [Abstract]
Fair value of long-term debt			$ 217,031	217,031		207,640
Less: current portion			(28,120)	(28,120)		(26,940)
Total long-term debt, net			$ 188,911	$ 188,911		$ 180,700
Dermavant [Member] | Funding Agreement with NovaQuest [Member] | Forecast [Member]
Funding Agreement with NovaQuest [Abstract]
Frequency of periodic payment					quarterly
Periodic payment					$ 176,300
Debt instrument, term					6 years
Dermavant [Member] | Funding Agreement with NovaQuest [Member] | Maximum [Member]
Funding Agreement with NovaQuest [Abstract]
Debt instrument, term	15 years
Maximum milestone payment obligation	$ 440,600						141,000
Right to offset of commercial milestones payment							$ 88,100