CASH EQUIVALENTS AND MARKETABLE SECURITIES - Summary of Cash Equivalents and Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
ASSETS
Cash and cash equivalents, at carrying value, total	$ 100,444	$ 178,872
Available-for-sale securities, amortized cost	207,923	286,138
Available-for-sale securities, gross unrealized gains	28	11
Available-for-sale securities, gross unrealized (Losses)	(918)	(304)
Available-for-sale securities, estimated fair value	207,033	285,845
Total cash equivalents and available-for-sale securities, amortized cost	258,743	406,057
Total cash equivalents and available-for-sale securities, gross unrealized gains	28	11
Total cash equivalents and available-for-sale securities, gross unrealized (losses)	(918)	(304)
Total cash equivalents and available-for-sale securities, estimated fair value	257,853	405,764
Money market funds
ASSETS
Cash and cash equivalents, at carrying value, total	50,820	119,919
Cash equivalents, gross unrealized gains	0	0
Cash and cash equivalents accumulated gross unrealized loss before tax	0	0
Cash equivalents, estimated fair value	50,820	119,919
Cash equivalents:
ASSETS
Cash and cash equivalents, at carrying value, total	50,820	119,919
Cash equivalents, gross unrealized gains	0	0
Cash and cash equivalents accumulated gross unrealized loss before tax	0	0
Cash equivalents, estimated fair value	50,820	119,919
U.S. government-sponsored entity debt securities
ASSETS
Available-for-sale securities, amortized cost	18,710	30,700
Available-for-sale securities, gross unrealized gains	0	1
Available-for-sale securities, gross unrealized (Losses)	(293)	(87)
Available-for-sale securities, estimated fair value	18,417	30,614
Commercial paper securities
ASSETS
Available-for-sale securities, amortized cost	101,336	105,792
Available-for-sale securities, gross unrealized gains	22	7
Available-for-sale securities, gross unrealized (Losses)	(193)	(42)
Available-for-sale securities, estimated fair value	101,165	105,757
Corporate debt securities
ASSETS
Available-for-sale securities, amortized cost	11,760	33,723
Available-for-sale securities, gross unrealized gains	0	1
Available-for-sale securities, gross unrealized (Losses)	(90)	(42)
Available-for-sale securities, estimated fair value	11,670	33,682
Asset-backed securities
ASSETS
Available-for-sale securities, amortized cost	24,970	70,807
Available-for-sale securities, gross unrealized gains	2	1
Available-for-sale securities, gross unrealized (Losses)	(180)	(107)
Available-for-sale securities, estimated fair value	24,792	70,701
U.S. treasury bills
ASSETS
Available-for-sale securities, amortized cost	7,950
Available-for-sale securities, gross unrealized gains	0
Available-for-sale securities, gross unrealized (Losses)	(12)
Available-for-sale securities, estimated fair value	7,938
Certificates of deposit
ASSETS
Available-for-sale securities, amortized cost	37,599	45,116
Available-for-sale securities, gross unrealized gains	4	1
Available-for-sale securities, gross unrealized (Losses)	(142)	(26)
Available-for-sale securities, estimated fair value	37,461	$ 45,091
Agency bonds
ASSETS
Available-for-sale securities, amortized cost	5,598
Available-for-sale securities, gross unrealized gains	0
Available-for-sale securities, gross unrealized (Losses)	(8)
Available-for-sale securities, estimated fair value	$ 5,590

Cash and cash equivalents accumulated gross unrealized gain before tax.

No definition available.

Name:	sgmo_CashAndCashEquivalentsAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix:	sgmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Cash and cash equivalents accumulated gross unrealized loss before tax.

+ References

No definition available.

+ Details

Name:	sgmo_CashAndCashEquivalentsAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix:	sgmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cash equivalents and available for sale securities.

+ References

No definition available.

+ Details

Name:	sgmo_CashEquivalentsAndAvailableForSaleSecurities
Namespace Prefix:	sgmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cash equivalents and available for Sale Securities Amortized Cost

+ References

No definition available.

+ Details

Name:	sgmo_CashEquivalentsAndAvailableForSaleSecuritiesAmortizedCost
Namespace Prefix:	sgmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cash equivalents and available for sale securities, gross unrealized gain, before tax.

+ References

No definition available.

+ Details

Name:	sgmo_CashEquivalentsAndAvailableForSaleSecuritiesGrossUnrealizedGainBeforeTax
Namespace Prefix:	sgmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Cash equivalents and available for sale securities, gross unrealized loss, before Tax

+ References

No definition available.

+ Details

Name:	sgmo_CashEquivalentsAndAvailableForSaleSecuritiesGrossUnrealizedLossBeforeTax
Namespace Prefix:	sgmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

+ Details

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

- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

+ Details

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

- Definition

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

+ Details

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

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

+ Details

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

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3044-108585

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124098289&loc=d3e6676-107765

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(1))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CashEquivalentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommercialPaperMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=sgmo_USGovernmentSponsoredAgencyBondMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: