Subsequent Events	3 Months Ended
Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	NOTE 11—SUBSEQUENT EVENTS In April 2019, the Company closed an underwritten public offering in which it sold 12,650,000 shares of its common stock at a price to the public of $11.50 per share, including 1,650,000 shares sold pursuant to the exercise in full of the underwriters’ option to purchase additional shares. The net proceeds to Sangamo from the offering, after deducting underwriting discounts and commissions and estimated offering expenses, were approximately $136.2 million.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

Name:	us-gaap_SubsequentEventsTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration