Leases - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) ft² option	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Lessee, Lease, Description [Line Items]
Tenant improvements (up to)	$ 9,500
Tenant improvement allowance receivable reimbursable by the landlord	1,300
Increase in right-of-use asset	0	$ 169
Increase in lease liability	104	$ (141)
Operating lease right-of-use assets	11,473		$ 10,154
Finance lease right-of-use assets	$ 300		$ 300
Washington | Office space, principal executive offices and laboratory
Lessee, Lease, Description [Line Items]
Square feet of office space leased | ft²	33,300
Number of option to extend leases | option	2
Lease agreement extended period	5 years
Washington | Office Space, additional offices and laboratory
Lessee, Lease, Description [Line Items]
Square feet of office space leased | ft²	6,272
Lease agreement extended period	28 months
Increase in right-of-use asset	$ 1,600
Increase in lease liability	$ 1,600