Summary of Significant Accounting Policies, Income Tax, Leases, Property and Equipment, Impairment of Long-lived Assets and Fair Value Measurements (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) ft²	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Income tax [Abstract]
Provision for uncertain tax positions	$ 0	$ 0
Impairment of long-lived assets [Abstract]
Impairment charges	0	0	$ 0
Fair value measurements [Abstract]
Transfers into of Level 3	0	0
Transfers out of Level 3	0	0
Recurring [Member] | Money Market Funds [Member]
Fair value measurements [Abstract]
Assets at fair value	$ 331,000,000	$ 191,900,000
Leasehold Improvements [Member]
Property and equipment [Abstract]
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember
Laboratory Equipment [Member] | Minimum [Member]
Property and equipment [Abstract]
Useful lives	3 years
Laboratory Equipment [Member] | Maximum [Member]
Property and equipment [Abstract]
Useful lives	5 years
Office Equipment and Other Assets [Member] | Minimum [Member]
Property and equipment [Abstract]
Useful lives	3 years
Office Equipment and Other Assets [Member] | Maximum [Member]
Property and equipment [Abstract]
Useful lives	5 years
United Kingdom [Member]
Leases [Abstract]
Area leased for office space | ft²	123,000
United States [Member]
Leases [Abstract]
Area leased for office space | ft²	20,000