Revenue - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended			9 Months Ended		12 Months Ended
	Jan. 31, 2022	Sep. 30, 2021	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2019
Disaggregation Of Revenue [Line Items]
Revenue			$ 132,000		$ 8,124,000	$ 9,434,000	$ 14,700,000
Collaboration Revenue [Member]
Disaggregation Of Revenue [Line Items]
Revenue			132,000		8,124,000	9,434,000	14,700,000
Neurocrine Biosciences [Member] | Collaboration Revenue [Member]
Disaggregation Of Revenue [Line Items]
Research and development services			132,000		2,031,000	1,938,000	4,990,000
Milestone payments					5,270,000	7,124,000	5,270,000
Pacira BioSciences [Member] | Collaboration Revenue [Member]
Disaggregation Of Revenue [Line Items]
Milestone payments							3,000,000
Development Services Under the Initial Development Program For DTCs [Member] | Neurocrine Biosciences [Member] | Collaboration Revenue [Member]
Disaggregation Of Revenue [Line Items]
Revenue			0		$ 823,000	372,000	1,440,000
License and Collaboration Agreement [Member] | Neurocrine Biosciences [Member]
Disaggregation Of Revenue [Line Items]
Upfront payment received in cash								$ 30,000,000
Upfront payment received in equity investment								20,000,000
Equity investment measured at fair value								16,667,000
Collaborate agreement premium related to equity investment								3,333,000
Transaction price allocated to performance obligations								33,333,000
Milestone Payment Received	$ 15,000,000	$ 10,000,000
Milestone Payment Received in Cash	6,750,000	4,500,000
Milestone Payment Received in Equity Investment	8,250,000	5,500,000
Equity investment measure at fair value	7,876,000	4,730,000
Premium	374,000	770,000
Performance obligation related to milestone	0	0
Revenue	$ 6,750,000	$ 4,500,000
Potential milestone payments receivable			1,667,500,000			$ 1,667,500,000
Percentage of option to co-fund development costs upon achievement of certain milestones						50.00%
License and Collaboration Agreement [Member] | Neurocrine Biosciences [Member] | Regulatory Milestone [Member]
Disaggregation Of Revenue [Line Items]
Potential milestone payments receivable			1,067,500,000			$ 1,067,500,000
License and Collaboration Agreement [Member] | Neurocrine Biosciences [Member] | Sales Based Milestone [Member]
Disaggregation Of Revenue [Line Items]
Potential milestone payments receivable			$ 600,000,000			$ 600,000,000
License and Collaboration Agreement [Member] | Exclusive License to XEN901 and Exclusive License to DTCs [Member] | Neurocrine Biosciences [Member]
Disaggregation Of Revenue [Line Items]
Transaction price allocated to performance obligations								$ 28,807,000
License and Collaboration Agreement [Member] | Development Services Under the Initial Development Program For DTCs [Member] | Neurocrine Biosciences [Member]
Disaggregation Of Revenue [Line Items]
Transaction price allocated to performance obligations				$ 5,025,000
Variable consideration allocated to performance obligation				$ 499,000
Asset Purchase Agreement [Member] | Pacira BioSciences [Member] | XEN402 [Member]
Disaggregation Of Revenue [Line Items]
Milestone payments							1,000,000
Milestone payment due on initiation of Phase 1b clinical trial							$ 2,000,000