Business acquisition, number of free shares held by the holders.

No definition available.

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- Definition

Business acquisition number of shares owned by sellers under block transaction.

+ References

No definition available.

+ Details

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Namespace Prefix:	sgmo_
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- Definition

Business acquisition, percentage of equity interests expected to acquire.

+ References

No definition available.

+ Details

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- Definition

Business acquisition, percentage of share capital and voting rights held by sellers.

+ References

No definition available.

+ Details

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Namespace Prefix:	sgmo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

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- Definition

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6613-128477

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6578-128477

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

+ Details

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Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

Name:	us-gaap_PlanNameAxis=sgmo_TwoThousandEighteenEquityIncentivePlanMember
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Subsequent Events - Additional Information (Detail) - TxCell S.A. [Member] - EUR (€) € / shares in Units, € in Millions	Jul. 20, 2018	Nov. 01, 2018	Oct. 01, 2018
Subsequent Event [Line Items]
Percentage of share capital and voting rights owned after completion of offer	95.00%
Share Purchase Agreement and Tender Offer Agreement [Member]
Subsequent Event [Line Items]
Percentage of equity interests expected to acquire	100.00%
Consideration payable	€ 72
Share Purchase Agreement [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Purchase price per share		€ 2.58	€ 2.58
Number of shares owned by sellers			13,519,036
Percentage of share capital and voting rights held by sellers			53.00%
Percentage of share capital and voting rights owned after completion of offer			80.00%
Tender Offer Agreement [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Number of free shares held by the holders		495,396
Tender Offer Agreement [Member] \| Subsequent Event [Member] \| 2018 Equity Incentive Plan [Member]
Subsequent Event [Line Items]
Number of common stock available for grant		150,000