CONDENSED CONSOLIDATED STATEMENTSOF COMPREHENSIVE LOSS (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net loss	$ (12,968)	$ (28,659)
Changes in foreign currency translation adjustments:
Change during period	(29)	28
Reclassification of adjustments to net loss due to dissolution of Personalis (Shanghai) Ltd	199
Net changes in foreign currency translation adjustments	170	28
Change in unrealized gain (loss) on available-for-sale debt securities	(73)	429
Comprehensive loss	$ (12,871)	$ (28,202)