Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue:
Precision oncology testing	$ 514,249	$ 392,049	$ 304,312
Development services and other	49,699	57,489	69,341
Total revenue	563,948	449,538	373,653
Costs and operating expenses:
Cost of precision oncology testing	205,528	148,199	110,396
Cost of development services and other	21,524	8,126	12,516
Research and development expense	367,194	373,807	263,221
Sales and marketing expense	295,227	299,828	191,881
General and administrative expense	155,800	163,956	206,640
Other operating expense	83,400	0	0
Total costs and operating expenses	1,128,673	993,916	784,654
Loss from operations	(564,725)	(544,378)	(411,001)
Interest income	35,365	6,069	3,930
Interest expense	(2,578)	(2,577)	(2,577)
Other income (expense), net	53,174	(12,778)	25,178
Fair value adjustments of noncontrolling interest liability	0	(99,785)	0
Loss before provision for income taxes	(478,764)	(653,449)	(384,470)
Provision for income taxes	685	1,139	300
Net loss	(479,449)	(654,588)	(384,770)
Adjustment of redeemable noncontrolling interest	0	0	(20,900)
Net loss attributable to Guardant Health, Inc. common stockholders - basic	(479,449)	(654,588)	(405,670)
Net loss attributable to Guardant Health, Inc. common stockholders - diluted	$ (479,449)	$ (654,588)	$ (405,670)
Net loss per share attributable to Guardant Health, Inc. common stockholders, basic (in usd per share)	$ (4.28)	$ (6.41)	$ (4.00)
Net loss per share attributable to Guardant Health, Inc. common stockholders, diluted (in usd per share)	$ (4.28)	$ (6.41)	$ (4.00)
Weighted-average shares used in computing net loss per share attributable to Guardant Health, Inc. common stockholders, basic (in shares)	111,988	102,178	101,314
Weighted-average shares used in computing net loss per share attributable to Guardant Health, Inc. common stockholders, diluted (in shares)	111,988	102,178	101,314