Revenue - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	May 31, 2023	Feb. 28, 2019	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Disaggregation Of Revenue [Line Items]
Revenue from collaboration agreement			$ 37,919,000	$ 47,830,000	$ 124,492,000	$ 130,110,000
Deferred revenue			99,534,000		99,534,000		$ 122,714,000
Medicare Reimbursements
Disaggregation Of Revenue [Line Items]
Revenue from collaboration agreement			1,900,000	1,100,000	4,600,000	4,000,000
Medicare Reimbursements | Immune Medicine Service Revenue
Disaggregation Of Revenue [Line Items]
Revenue from collaboration agreement					400,000	300,000
Medicare Reimbursements | MRD Service Revenue
Disaggregation Of Revenue [Line Items]
Revenue from collaboration agreement					4,200,000	3,700,000
MRD Development Agreements | Maximum
Disaggregation Of Revenue [Line Items]
Additional milestone payment receivable			399,500,000		399,500,000
Genentech Collaboration Agreement
Disaggregation Of Revenue [Line Items]
Revenue from collaboration agreement	$ 7,700,000		8,000,000	$ 20,400,000	34,700,000	$ 46,500,000
Non-refundable upfront payments received		$ 300,000,000.0			300,000,000.0
Additional transaction price of regulatory milestone	$ 10,000,000
Genentech Collaboration Agreement | Regulatory Milestones
Disaggregation Of Revenue [Line Items]
Additional transaction price of regulatory milestone					$ 10,000,000.0
Genentech Collaboration Agreement | Maximum
Disaggregation Of Revenue [Line Items]
Revenue recognition expected period					9 years
Genentech Collaboration Agreement | Maximum | Regulatory Milestones
Disaggregation Of Revenue [Line Items]
Expected revenue through milestone payments			75,000,000.0		$ 75,000,000.0
Genentech Collaboration Agreement | Maximum | Development Milestones
Disaggregation Of Revenue [Line Items]
Expected revenue through milestone payments			300,000,000.0		300,000,000.0
Genentech Collaboration Agreement | Maximum | Commercial Milestones
Disaggregation Of Revenue [Line Items]
Expected revenue through milestone payments			1,430,000,000		1,430,000,000
Genentech Collaboration Agreement | Minimum
Disaggregation Of Revenue [Line Items]
Expected revenue through milestone payments			$ 1,800,000,000		$ 1,800,000,000
Revenue recognition expected period					8 years