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Collaboration and License Agreements - Additional Information (Details) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended						12 Months Ended
	Mar. 31, 2023 USD ($) geneTherapyProgram $ / shares shares	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($) $ / shares shares	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) non-clinicalStageCompounds	Dec. 31, 2019 USD ($) preclinicalCandidates undisclosedProgram $ / shares shares	Dec. 31, 2022 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Acquired in-process research and development	$ 143.9			$ 0.0
Unrealized gain on equity security investments	2.2			19.9
Equity securities fair value (Level 1)	135.7									$ 102.1
Revenues	$ 420.4			310.6
Collaborative Arrangement \| 2023 Voyager Agreement \| Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Beneficial ownership percentage	19.90%
Collaborative Arrangement \| Heptares
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Acquired in-process research and development							$ 100.0
Research and development			$ 30.0
Potential milestone payments	$ 2,600.0
Agreement termination, minimal contractual time							180 days
Agreement termination, contractual time threshold							90 days
Agreement termination by counterparty, contractual time threshold							365 days
Agreement termination by counterparty, minimal contractual time							120 days
Collaborative Arrangement \| Takeda
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Acquired in-process research and development								$ 120.0
Research and development		$ 5.0
Potential milestone payments	1,900.0
Agreement termination, minimal contractual time								6 months
Agreement termination, contractual time threshold								12 months
Number of non-clinical stage compounds \| non-clinicalStageCompounds								4
Collaborative Arrangement \| Idorsia
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Acquired in-process research and development								$ 45.0
Potential milestone payments	1,700.0
Agreement termination, minimal contractual time								90 days
Agreement termination, due to material breach								90 days
Collaborative Arrangement \| Xenon
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Acquired in-process research and development									$ 36.2
Research and development				$ 7.3			$ 5.4
Potential milestone payments	1,700.0
Agreement termination, contractual time threshold									90 days
Number of preclinical candidates \| preclinicalCandidates									3
Upfront payment									$ 50.0
Share price (in USD per share) \| $ / shares				$ 31.855			$ 19.9755		$ 14.196
Equity securities fair value (Level 3)							$ 4.6		$ 14.1
Milestone payment				$ 15.0			$ 10.0
Equity securities fair value (Level 1)				$ 7.7
Collaborative Arrangement \| Xenon \| Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sale of stock (in shares) \| shares				0.3			0.3		1.4
Collaborative Arrangement \| Voyager
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of undisclosed programs \| undisclosedProgram									2
Unrealized gain on equity security investments	9.3
Equity securities fair value (Level 1)	66.1
Collaborative Arrangement \| 2019 Voyager Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Acquired in-process research and development					$ 5.0	$ 113.1
Potential milestone payments	1,300.0
Agreement termination, minimal contractual time									180 days
Agreement termination, contractual time threshold									1 year
Upfront payment						$ 165.0
Share price (in USD per share) \| $ / shares						$ 11.9625
Equity securities fair value (Level 3)						$ 54.7
Voting restriction period						3 years
Collaborative Arrangement \| 2019 Voyager Agreement \| Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sale of stock (in shares) \| shares						4.2
Collaborative Arrangement \| 2023 Voyager Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Acquired in-process research and development	143.9
Potential milestone payments	$ 6,100.0
Agreement termination, minimal contractual time	180 days
Agreement termination, contractual time threshold	1 year
Upfront payment	$ 175.0
Share price (in USD per share) \| $ / shares	$ 8.88
Equity securities fair value (Level 1)	$ 31.3
Voting restriction period						3 years
Number of gene therapy programs \| geneTherapyProgram	3
Board of directors maximum duration term	10 years
Collaborative Arrangement \| 2023 Voyager Agreement \| Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sale of stock (in shares) \| shares	4.4
Collaborative Arrangement \| MTPC
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Agreement termination, contractual time threshold	180 days
Revenues			$ 20.0
Potential milestone payment receipts	$ 30.0
Collaborative Arrangement \| MTPC \| Patents \| Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Patent term	10 years
Collaborative Arrangement \| AbbVie
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Agreement termination, contractual time threshold	180 days
Potential milestone payment receipts	$ 366.0
Collaborative Arrangement \| AbbVie \| Royalty
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenues	$ 3.7			$ 4.2
Collaborative Arrangement \| AbbVie \| Patents \| Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Patent term	10 years