Commitments and Contingencies - Schedule of Additional Information Related to Operating Leases (Details)	12 Months Ended
	Dec. 31, 2021 ft²
Lessee Lease Description [Line Items]
Lease arrangement, contractual expiration period, beginning year	2024-04
Lease arrangement, contractual expiration period, ending year	2031-11
Seattle, WA
Lessee Lease Description [Line Items]
Approximate Square Footage	48,086
Commencement Dates, Beginning	2019-03
Commencement Dates, Ending	2020-09
Lease arrangement, contractual expiration period, beginning year	2026-12
Lease arrangement, contractual expiration period, ending year	2028-04
Cambridge, MA
Lessee Lease Description [Line Items]
Approximate Square Footage	59,639
Commencement Dates, Beginning	2019-03
Commencement Dates, Ending	2020-05
Lease arrangement, contractual expiration period, beginning year	2025-11
Lease arrangement, contractual expiration period, ending year	2028-02
South San Francisco, CA
Lessee Lease Description [Line Items]
Approximate Square Footage	66,075
Commencement Dates, Beginning	2019-12
Commencement Dates, Ending	2021-11
Lease arrangement, contractual expiration period, beginning year	2024-04
Lease arrangement, contractual expiration period, ending year	2030-04
Fremont, CA
Lessee Lease Description [Line Items]
Approximate Square Footage	163,193
Commencement Dates, Beginning	2021-07
Lease arrangement, contractual expiration period, ending year	2031-11