Collaboration and License Agreements - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2021	Dec. 31, 2020	Jul. 31, 2020
Acceleron Collaboration Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenues		$ 0.3
Deferred Revenue	$ 0.0		$ 0.0
MyoKardia Collaboration and License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Non refundable upfront payment received	10.0
Deferred Revenue			0.2
Reimbursement Payment Received	7.7		7.2
Unbilled accounts receivable related to reimbursable research and development cost			0.5
Upfront payment							$ 10.0
Payment for prepaid research funding	$ 2.5		$ 2.5				2.5
Prepaid research funding payment received						$ 2.5
MyoKardia Collaboration and License Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment for certain identified targets							298.5
Milestone payment for certain other identified targets							$ 150.0
MyoKardia Collaboration and License Agreement | Clinical and Regulatory Milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate amount receivable on achievement of milestone				$ 2.5	$ 2.5