ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023 USD ($) $ / shares	Sep. 30, 2023 USD ($) $ / shares
Change in Accounting Estimate [Line Items]
Capital resources	$ 132.1	$ 132.1
Letter of credit established as a deposit	1.5	1.5
Kite Pharma, Inc. \| Change In Agreement Estimate, March 2023
Change in Accounting Estimate [Line Items]
Increase in revenue		8.9
Decrease in net loss		$ 8.9
Decreased net loss per share, basic (in dollars per share) \| $ / shares		$ 0.05
Decreased net loss per share, diluted (in dollars per share) \| $ / shares		$ 0.05
Kite Pharma, Inc. \| Change In Estimate, September 2023
Change in Accounting Estimate [Line Items]
Increase in revenue	4.9	$ 4.9
Decrease in net loss	$ 4.9	$ 4.9
Decreased net loss per share, basic (in dollars per share) \| $ / shares	$ 0.03	$ 0.03
Decreased net loss per share, diluted (in dollars per share) \| $ / shares	$ 0.03	$ 0.03

Increase (Decrease) In Earnings Per Share, Basic

No definition available.

Name:	sgmo_IncreaseDecreaseInEarningsPerShareBasic
Namespace Prefix:	sgmo_
Data Type:	dtr-types1:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Increase (Decrease) In Earnings Per Share, Diluted

+ References

No definition available.

+ Details

Name:	sgmo_IncreaseDecreaseInEarningsPerShareDiluted
Namespace Prefix:	sgmo_
Data Type:	dtr-types1:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Increase (Decrease) In Net Income (Loss) Attributable To Parent

+ References

No definition available.

+ Details

Name:	sgmo_IncreaseDecreaseInNetIncomeLossAttributableToParent
Namespace Prefix:	sgmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Increase (Decrease) In Revenue From Contract With Customer, Excluding Assessed Tax

+ References

No definition available.

+ Details

Name:	sgmo_IncreaseDecreaseInRevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	sgmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(9))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_CashCashEquivalentsAndShortTermInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

+ Details

Name:	us-gaap_ChangeInAccountingEstimateLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	srt_CounterpartyNameAxis=sgmo_KitePharmaIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ChangeInAccountingEstimateByTypeAxis=sgmo_ChangeInAgreementEstimateMarch2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ChangeInAccountingEstimateByTypeAxis=sgmo_ChangeInAgreementEstimateSeptember2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: