Acquisition of Ceregene - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Oct. 31, 2013 USD ($) shares	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) Candidate	Mar. 31, 2015 USD ($)
Business Acquisition [Line Items]
Impairment charge		$ 1,870,000
Goodwill		1,585,000	$ 1,585,000
Ceregene, Inc. [Member]
Business Acquisition [Line Items]
Common stock, transferred, shares | shares	100,000
Sangamo shares of common stock	$ 1,200,000
Contingent earn-out	1,500,000
Fair value of contingent earn-out liability	1,800,000			$ 0
Number of clinical product candidates | Candidate			2
Estimated fair values of in-process research and development	1,900,000
Impairment charge		$ 1,900,000
Goodwill	$ 1,600,000