Commitments and Contingencies (Details) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2021 patent	Dec. 31, 2022 USD ($) party	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Other Commitments [Line Items]
Number of parties with patent license agreement | party		4
Royalty expense | $		$ 0.7	$ 0.7	$ 1.1
Percentage of precision oncology testing revenue (as a percent)		0.20%	0.20%	0.40%
TwinStrand Biosciences And University Of Washington vs. Guardant Health, Inc.
Other Commitments [Line Items]
Gain contingency, patents allegedly infringed upon, number | patent	4