CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net loss	$ (257,831)	$ (192,278)	$ (178,297)
Foreign currency translation adjustment	2,848	(4,606)	(8,351)
Net pension gain (loss)	(163)	786	(716)
Unrealized gain (loss) on marketable securities, net of tax	1,124	(597)	(339)
Comprehensive loss	(254,022)	(196,695)	(187,703)
Comprehensive loss attributable to non-controlling interest	0	0	(11)
Comprehensive loss attributable to Sangamo Therapeutics, Inc.	$ (254,022)	$ (196,695)	$ (187,692)