Leases - Narrative (Details) $ in Thousands			1 Months Ended				12 Months Ended
	Apr. 01, 2026 USD ($) $ / ft²	Oct. 01, 2016 USD ($) ft² $ / ft²	Nov. 30, 2021 USD ($) $ / ft²	Sep. 30, 2020 ft² $ / ft²	Sep. 30, 2019 ft² lease_term $ / ft²	Jul. 31, 2018 ft² $ / ft²	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Lessee, Lease, Description [Line Items]
Letter of credit							$ 1,725	$ 1,258	$ 34
Operating lease, expense							43,400	43,900	$ 34,500
Letter of credit
Lessee, Lease, Description [Line Items]
Letter of credit							32,800	$ 30,000
Seattle, Washington
Lessee, Lease, Description [Line Items]
Lease building space (in sq ft) | ft²				22,188	22,188	36,126
Annual lease rent per square foot (in dollars per sq ft) | $ / ft²				62.80	62.80	54.00
Lease rent, annual increase percentage				2.50%	2.50%	2.50%
Lessee, operating lease, term of contract extension					16 months
Lease extension terms					5 years
Lessee, operating lease, number of contracts | lease_term					2
60 Binney Street lease
Lessee, Lease, Description [Line Items]
Lease building space (in sq ft) | ft²		253,108
Annual lease rent per square foot (in dollars per sq ft) | $ / ft²		72.50	90.00
Lease payments base annual rent		$ 18,400	$ 22,800
Lease rent, annual increase percentage		1.75%	3.00%
Collateralized letter of credit		$ 13,800
Decrease in letter of credit under the terms of the lease		9,200
Landlord contribution for cost of construction and tenant improvements		$ 42,400	$ 19,100
60 Binney Street lease | Letter of credit
Lessee, Lease, Description [Line Items]
Letter of credit			25,000
60 Binney Street lease | Forecast
Lessee, Lease, Description [Line Items]
Annual lease rent per square foot (in dollars per sq ft) | $ / ft²	118.41
Lease payments base annual rent	$ 30,000
Lease rent, annual increase percentage	3.00%
Office and Laboratory Space Lease | Seattle, Washington | Letter of credit
Lessee, Lease, Description [Line Items]
Letter of credit			$ 5,000
Construction-in-progress | Cambridge, Massachusetts
Lessee, Lease, Description [Line Items]
Reimbursement received							$ 18,700