CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Revenues	$ 21,553	$ 17,548	$ 34,629	$ 25,619
Operating expenses:
Research and development	41,523	36,455	83,002	71,305
General and administrative	17,927	14,597	34,046	31,715
Total operating expenses	59,450	51,052	117,048	103,020
Loss from operations	(37,897)	(33,504)	(82,419)	(77,401)
Interest and other income, net	1,932	3,148	3,480	4,842
Net loss	(35,965)	(30,356)	(78,939)	(72,559)
Net loss attributable to non-controlling interest	(36)	(72)	(97)	(125)
Net loss attributable to Sangamo Therapeutics, Inc. stockholders	$ (35,929)	$ (30,284)	$ (78,842)	$ (72,434)
Basic and diluted net loss per share attributable to Sangamo Therapeutics, Inc. stockholders (in dollars per share)	$ (0.26)	$ (0.26)	$ (0.62)	$ (0.67)
Shares used in computing basic and diluted net loss per share attributable to Sangamo Therapeutics, Inc. stockholders (in shares)	138,977	114,382	127,519	108,360