Sangamo Therapeutics (SGMO) 10-K 25 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 01, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	SGMO
Entity Registrant Name	SANGAMO BIOSCIENCES INC
Entity Central Index Key	1001233
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		69,170,150
Entity Public Float			$800,449,430

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$6,030	$10,186
Marketable securities	172,932	82,627
Interest receivable	423	338
Accounts receivable	10,368	3,155
Prepaid expenses	623	457
Restricted cash	320	320
Other current assets	183	191
Total current assets	190,879	97,274
Marketable securities, non-current	47,260	38,663
Property and equipment, net	1,479	1,406
Intangible assets, in-process research and development	1,870	1,870
Goodwill	1,585	1,585
Other assets	139	40
Total assets	243,212	140,838
Current liabilities:
Accounts payable and accrued liabilities	8,704	4,380
Accrued compensation and employee benefits	2,853	3,194
Escrow liability	275	275
Deferred revenues	9,050	2,282
Total current liabilities	20,882	10,131
Deferred revenues, non-current	13,149	6,679
Contingent consideration liability	1,800	1,570
Deferred tax liability	748	748
Total liabilities	36,579	19,128
Commitments and contingencies
Stockholders' equity:
Common stock, $0.01 par value; 160,000,000 and 80,000,000 shares authorized as of December 31, 2014 and December 31, 2013, respectively; 69,062,394 and 62,243,892 shares issued and outstanding at December 31, 2014 and December 31, 2013, respectively	690	622
Additional paid-in capital	534,518	423,209
Accumulated deficit	-328,550	-302,133
Accumulated other comprehensive income (loss)	-25	12
Total stockholders' equity	206,633	121,710
Total liabilities and stockholders' equity	$243,212	$140,838

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	160,000,000	80,000,000
Common stock, shares issued	69,062,394	62,243,892
Common stock, shares outstanding	69,062,394	62,243,892

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Collaboration agreements	$43,880	$21,678	$18,186
Research grants	1,990	2,455	3,469
Total revenues	45,870	24,133	21,655
Operating expenses:
Research and development	56,744	36,979	31,709
General and administrative	15,677	13,800	12,144
Change in fair value of contingent liability	230	60
Total operating expenses	72,651	50,839	43,853
Loss from operations	-26,781	-26,706	-22,198
Other income (expense), net	364	82	-66
Net loss	($26,417)	($26,624)	($22,264)
Basic and diluted net loss per share	($0.39)	($0.48)	($0.42)
Shares used in computing basic and diluted net loss per share	67,022	55,974	52,741

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Loss (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net loss	($4,319)	($7,545)	($6,981)	($7,572)	($8,144)	($6,145)	($5,450)	($6,885)	($26,417)	($26,624)	($22,264)
Change in unrealized gain (loss) on available-for-sale securities									-37	-14	14
Comprehensive loss									($26,454)	($26,638)	($22,250)

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income/ (Loss) [Member]
In Thousands, except Share data, unless otherwise specified
Beginning Balances at Dec. 31, 2011	$80,132	$526	$332,839	($253,245)	$12
Beginning Balances, shares at Dec. 31, 2011		52,554,795
Issuance of common stock upon exercise of stock options and in connection with restricted stock units	1,219	3	1,216
Issuance of common stock upon exercise of stock options and in connection with restricted stock units, shares		328,355
Issuance of common stock under employee stock purchase plan	457	2	455
Issuance of common stock under employee stock purchase plan, shares	175,375	175,375
Stock-based compensation	5,338		5,338
Comprehensive loss:
Net unrealized gain (loss) on marketable securities	14				14
Net loss	-22,264			-22,264
Comprehensive loss	-22,250
Ending Balances at Dec. 31, 2012	64,896	531	339,848	-275,509	26
Ending Balances, shares at Dec. 31, 2012		53,058,525
Issuance of common stock in connection with underwritten public offering, net of issuance costs	69,492	70	69,422
Issuance of common stock in connection with underwritten public offering, net of issuance costs, shares		7,015,000
Issuance of common stock upon exercise of stock options and in connection with restricted stock units	6,118	19	6,099
Issuance of common stock upon exercise of stock options and in connection with restricted stock units, shares		1,889,818
Issuance of common stock under employee stock purchase plan	496	1	495
Issuance of common stock under employee stock purchase plan, shares	180,551	180,551
Issuance of common stock in connection with acquisition of Ceregene, Inc.	1,200	1	1,199
Issuance of common stock in connection with acquisition of Ceregene, Inc., shares		99,998
Stock-based compensation	6,146		6,146
Comprehensive loss:
Net unrealized gain (loss) on marketable securities	-14				-14
Net loss	-26,624			-26,624
Comprehensive loss	-26,638
Ending Balances at Dec. 31, 2013	121,710	622	423,209	-302,133	12
Ending Balances, shares at Dec. 31, 2013		62,243,892
Issuance of common stock in connection with underwritten public offering, net of issuance costs	93,796	44	93,752
Issuance of common stock in connection with underwritten public offering, net of issuance costs, shares		4,444,444
Issuance of common stock upon exercise of stock options and in connection with restricted stock units	7,533	23	7,510
Issuance of common stock upon exercise of stock options and in connection with restricted stock units, shares		2,266,855
Issuance of common stock under employee stock purchase plan	848	1	847
Issuance of common stock under employee stock purchase plan, shares	107,203	107,203
Stock-based compensation	9,200		9,200
Comprehensive loss:
Net unrealized gain (loss) on marketable securities	-37				-37
Net loss	-26,417			-26,417
Comprehensive loss	-26,454
Ending Balances at Dec. 31, 2014	$206,633	$690	$534,518	($328,550)	($25)
Ending Balances, shares at Dec. 31, 2014		69,062,394

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Activities:
Net loss	($26,417)	($26,624)	($22,264)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	549	569	660
Amortization of premium on marketable securities	1,098	912	889
Stock-based compensation	9,200	6,146	5,338
Net loss on disposal of property and equipment			123
Change in fair value of contingent consideration liability	230	60
Net changes in operating assets and liabilities:
Restricted cash		-320
Escrow liability		275
Interest receivable	-85	-148	141
Accounts receivable	-7,213	1,008	-3,414
Prepaid expenses and other assets	-258	-160	14
Accounts payable and accrued liabilities	4,324	269	-1,503
Accrued compensation and employee benefits	-341	721	800
Deferred revenues	13,238	-2,190	11,134
Net cash used in operating activities	-5,675	-19,482	-8,082
Investing Activities:
Purchases of marketable securities	-227,802	-118,894	-91,428
Maturities of marketable securities	127,765	51,129	103,470
Acquistion of Ceregene, Inc., net of cash received		79
Purchases of property and equipment	-621	-432	-723
Net cash provided by / (used in) investing activities	-100,658	-68,118	11,319
Financing Activities:
Proceeds from public offering of common stock, net of issuance costs	93,796	69,492
Taxes paid related to net share settlement of equity awards	-4,556	-2,015
Proceeds from issuance of common stock	12,937	8,630	1,676
Net cash provided by financing activities	102,177	76,107	1,676
Net increase / (decrease) in cash and cash equivalents	-4,156	-11,493	4,913
Cash and cash equivalents, beginning of period	10,186	21,679	16,766
Cash and cash equivalents, end of period	6,030	10,186	21,679
Supplemental disclosure of noncash investing activities:
Fair value of shares of common stock issued pursuant to the acquisition of Ceregene Inc.		$1,200

Organization_and_Summary_of_Si

Organization and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Organization and Summary of Significant Accounting Policies	NOTE 1 – ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Sangamo
	Sangamo BioSciences, Inc. (the Company or Sangamo) was incorporated in the State of Delaware on June 22, 1995 and is focused on the research, development and commercialization of novel therapeutic strategies for unmet medical needs. Sangamo’s gene regulation and genome editing technology platform is enabled by the engineering of a class of transcription factors known as zinc finger DNA-binding proteins (ZFPs). Potential applications of Sangamo’s technology include development of human therapeutics, plant agriculture and enhancement of pharmaceutical protein production. Sangamo will require additional financial resources to complete the development and commercialization of its products including ZFP Therapeutics.
	Sangamo is currently working on a number of long-term development projects that will involve experimental technology. The projects may require several years and substantial expenditures to complete and ultimately may be unsuccessful. The Company plans to finance operations with available cash resources, collaborations and strategic partnerships funds, research grants and from the issuance of equity or debt securities. Sangamo believes that its available cash, cash equivalents and investments as of December 31, 2014, along with expected revenues from collaborations, strategic partnerships and research grants, will be adequate to fund its operations at least through 2016. Sangamo will need to raise substantial additional capital to fund subsequent operations and complete the development and commercialization of its products. Additional capital may not be available on terms acceptable to the Company, or at all. If adequate funds are not available, or if the terms of potential funding sources are unfavorable, the Company’s business and ability to develop its technology and ZFP Therapeutic products would be harmed. Furthermore, any sales of additional equity securities may result in dilutions to the Company’s stockholders, and any debt financing may include covenants that restrict the Company’s business.
	Sangamo acquired Ceregene, Inc. (Ceregene) in October 2013. Under the merger agreement, Sangamo obtained Ceregene’s therapeutic programs, including certain intellectual property rights relating to the manufacturing of AAV, and certain toxicology data and safety and efficacy data from Ceregene’s human clinical trials which will enhance and expand the application of Sangamo’s in vivo ZFP Therapeutics, particularly those that target the brain.
	Basis of Presentation
	The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and the accompanying notes. Actual results could differ from those estimates. The consolidated financial statements include the accounts of Sangamo and its wholly owned subsidiaries, Ceregene and Gendaq Limited, after elimination of all intercompany balances and transactions.
	Business Combinations
	The Company accounted for the acquisition of Ceregene in accordance with Accounting Standards Codification (ASC) Topic 805, Business Combinations (ASC Topic 805). ASC Topic 805 establishes principles and requirements for recognizing and measuring the total consideration transferred to and the assets acquired, liabilities assumed and any non-controlling interests in the acquired target in a business combination. ASC Topic 805 also provides guidance for recognizing and measuring goodwill acquired in a business combination; requires purchased in-process research and development to be capitalized at fair value as intangible assets at the time of acquisition; requires acquisition-related expenses and restructuring costs to be recognized separately from the business combination; expands the definition of what constitutes a business; and requires the acquirer to disclose information that users may need to evaluate and understand the financial effect of the business combination.
	Cash and Cash Equivalents
	Sangamo considers all highly liquid investments purchased with original maturities of three months or less at the purchase date to be cash equivalents. Cash and cash equivalents consist of deposits in money market investment accounts, government sponsored entity debt securities, US Treasury debt securities and corporate bank accounts.
	As part of the acquisition of Ceregene, Sangamo was required to set aside $0.3 million in an escrow account until April 1, 2015. The cash held in escrow is recorded as restricted cash.
	Marketable Securities
	Sangamo classifies its marketable securities as available-for-sale and records its investments at estimated fair value based on quoted market prices or observable market inputs of almost identical assets, with the unrealized holding gains and losses included in accumulated other comprehensive income.
	The Company’s investments are subject to a periodic impairment review. The Company recognizes an impairment charge when a decline in the fair value of its investments below the cost basis is judged to be other-than-temporary. The Company considers various factors in determining whether to recognize an impairment charge, including the length of time and extent to which the fair value has been less than the Company’s cost basis, the financial condition and near-term prospects of the investee, and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in the market value. Realized gains and losses on available-for-sale securities are included in other (expense)/income, which is determined using the specific identification method.
	Fair Value Measurements
	The carrying amounts for financial instruments consisting of cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate fair value due to their short maturities. Marketable securities and contingent consideration liabilities are stated at their estimated fair values. The counterparties to the agreements relating to the Company’s investment securities consist of the US Treasury, governmental agencies, various major corporations and financial institutions with high credit standing.
	Property and Equipment
	Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation is calculated using the straight-line method based on the estimated useful lives of the related assets (generally three to five years). For leasehold improvements, amortization is calculated using the straight-line method based on the shorter of the useful life or the lease term. The Company reviews its property and equipment for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable.
	Revenue Recognition
	Revenues from research activities made under strategic partnering agreements and collaborations are recognized as the services are provided when there is persuasive evidence that an arrangement exists, delivery has occurred, the price is fixed or determinable, and collectability is reasonably assured. Revenue generated from research and licensing agreements typically includes upfront signing or license fees, cost reimbursements, research services, minimum sublicense fees, milestone payments and royalties on future licensee’s product sales.
	Multiple Element Arrangements prior to the adoption of ASU No. 2009-13, Revenue Recognition—Multiple Deliverable Revenue Arrangements (ASU 2009-13). For revenue arrangements entered into before January 1, 2011, that include multiple deliverables, the elements of such agreement were divided into separate units of accounting if the deliverables met certain criteria, including whether the fair value of the delivered items could be determined and whether there was evidence of fair value of the undelivered items. In addition, the consideration was allocated among the separate units of accounting based on their fair values, and the applicable revenue recognition criteria are considered separately for each of the separate units of accounting. Prior to the adoption of ASU 2009-13, the Company recognized nonrefundable signing, license or non-exclusive option fees as revenue when rights to use the intellectual property related to the license were delivered and over the period of performance obligations if the Company had continuing performance obligations. The Company estimated the performance period at the inception of the arrangement and reevaluated it each reporting period. Changes to these estimates were recorded on a prospective basis.
	Multiple Element Arrangements after the adoption of ASU 2009-13. ASU 2009-13 amended the accounting standards for certain multiple element revenue arrangements to:
	·	provide updated guidance on whether multiple elements exist, how the elements in an arrangement should be separated, and how the arrangement consideration should be allocated to the separate elements;
	·	require an entity to allocate arrangement consideration to each element based on a selling price hierarchy where the selling price for an element is based on vendor-specific objective evidence (VSOE), if available; third-party evidence (TPE), if available and VSOE is not available; or the best estimate of selling price (ESP), if neither VSOE nor TPE is available; and
	·	eliminate the use of the residual method and require an entity to allocate arrangement consideration using the relative selling price method.
	For revenue agreements with multiple element arrangements, such as license and development agreements, entered into on or after January 1, 2011, the Company allocates revenue to each non-contingent element based on the relative selling price of each element. When applying the relative selling price method, the Company determines the selling price for each deliverable using VSOE of selling price or TPE of selling price. If neither exists the Company uses ESP for that deliverable. Revenue allocated is then recognized when the basic four revenue recognition criteria are met for each element. The collaboration and license agreements entered into with Shire International GmbH, formerly Shire AG, (Shire) in January 2012 and Biogen Idec Inc. (Biogen) in January 2014 were evaluated under these amended accounting standards.
	Additionally, the Company may be entitled to receive certain milestone payments which are contingent upon reaching specified objectives. These milestone payments are recognized as revenue in full upon achievement of the milestone if there is substantive uncertainty at the date the arrangement is entered into that objectives will be achieved and if the achievement is based on the Company’s performance.
	Minimum annual sublicense fees are also recognized as revenue in the period in which such fees are due. Royalty revenues are generally recognized when earned and collectability of the related royalty payment is reasonably assured. The Company recognizes cost reimbursement revenue under collaborative agreements as the related research and development costs for services are rendered. Deferred revenue represents the portion of research or license payments received which have not been earned.
	Sangamo’s research grants are typically multi-year agreements and provide for the reimbursement of qualified expenses for research and development as defined under the terms of the grant agreement. Revenue under grant agreements is recognized when the related qualified research expenses are incurred.
	During 2014, revenues related to Shire and Biogen represented 57% and 28%, respectively, of total revenues. During 2013, revenues related to Shire, Sigma-Aldrich Corporation (Sigma) and Dow AgroSciences LLC (DAS) represented 68%, 9% and 12%, respectively, of total revenues. During 2012, revenues related Shire, Sigma and DAS represented 51%, 11% and 22% of total revenues, respectively.
	Research and Development Expenses
	Research and development costs are expensed as incurred. Research and development expenses consist of direct and research-related allocated overhead costs such as facilities costs, salaries and related personnel costs, and material and supply costs. In addition, research and development expenses include costs related to clinical trials, validation of the Company’s testing processes and procedures and as well as related overhead expenses. Research and development costs incurred in connection with collaborator-funded activities are expensed as incurred. Costs to acquire technologies that are utilized in research and development that have no alternative future use are expensed as incurred.
	Stock-Based Compensation
	The Company measures and recognizes compensation expense for all stock-based payment awards made to Sangamo employees and directors, including employee share options, restricted stuck units (RSUs) and employee share purchases related to the Employee Share Purchase Plan (ESPP), based on estimated fair values at grant date. The fair value of stock-based awards is amortized over the vesting period of the award using a straight-line method.
	To estimate the value of an award, the Company uses the Black-Scholes option pricing model. This model requires inputs such as expected life, expected volatility and risk-free interest rate. These inputs are subjective and generally require significant analysis and judgment to develop. While estimates of expected life and volatility are derived primarily from the Company’s historical data, the risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant commensurate with the expected life assumption. Further, the Company is required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses historical data to estimate pre-vesting option forfeitures and record stock-based compensation expense only for those awards that are expected to vest.
	Indefinite-Lived Intangible Assets
	As part of the Ceregene acquisition the Company recognized indefinite-lived intangible assets for in-process research and development and goodwill as further discussed below. ASC 350 and related updates require companies to test indefinite-lived intangible assets for impairment annually, and more frequently if indicators of impairment exist. ASC 350 includes an optional qualitative assessment for testing indefinite-lived intangible assets for impairment that permits companies to assess whether it is more likely than not (i.e., a likelihood of greater than 50%) that an indefinite-lived intangible asset is impaired. If a company concludes based on the qualitative assessment that it is not more likely than not that the fair value of an indefinite-lived intangible asset or, in the case of goodwill, that the fair value of the related reporting unit, is less than carrying value, it would not have to determine the asset’s or reporting unit’s fair value, as applicable.
	In-Process Research and Development
	Intangible assets related to in-process research and development costs, or IPR&D, are considered to be indefinite-lived until the completion or abandonment of the associated research and development efforts. If and when development is complete, which generally occurs if and when regulatory approval to market a product is obtained, the associated assets would be deemed finite-lived and would then be amortized based on their respective estimated useful lives at that point in time. Prior to completion of the research and development efforts, the assets are considered indefinite-lived. During this period, the assets will not be amortized but will be tested for impairment on an annual basis and between annual tests if the Company becomes aware of any events occurring or changes in circumstances that would indicate a reduction in the fair value of the IPR&D projects below their respective carrying amounts. During the fourth quarter of 2014, the Company performed an assessment of the qualitative factors affecting the fair value of its IPR&D and concluded that it was not more likely than not that the fair value of its IPR&D was less than carrying value.
	Goodwill
	Goodwill represents the excess of the consideration transferred over the estimated fair values of assets acquired and liabilities assumed in a business combination and is considered to be indefinite-lived. Goodwill is not amortized but is tested for impairment on an annual basis and between annual tests if the Company becomes aware of any events occurring or changes in circumstances that would indicate an impairment of goodwill has occurred. During the fourth quarter of 2014, the Company performed an assessment of the qualitative factors affecting the fair value of its reporting unit and concluded that it was not more likely than not that the fair value of its reporting unit was less than carrying value and that, as a result, it is not more likely than not that goodwill is impaired..
	Contingent Consideration Liability
	Under the merger agreement with Ceregene, the Company may be required to make contingent earn-out payments if the Company grants a third-party license to develop and commercialize certain product candidates acquired from Ceregene, or if the Company commercializes any of these product candidates itself. These earn-out payments will become payable in the period they are earned. In accordance with ASC Topic 805, the Company determined the fair value of this liability for contingent consideration on the acquisition date using a probability-weighted discounted cash flow analysis. Future changes to the fair value of the contingent consideration will be determined each period and charged to expense in the “Changes in fair value of contingent liability” expense line item in the Consolidated Statements of Operations under operating expenses.
	Income Taxes
	Income tax expense has been provided using the liability method. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities as measured by the enacted tax rates that will be in effect when these differences reverse. The Company provides a valuation allowance against net deferred tax assets if, based upon the available evidence, it is not more likely than not that the deferred tax assets will be realized.
	Net Loss Per Share
	Basic net loss per share has been computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is calculated by dividing net loss by the weighted average number of shares of common stock and potential dilutive securities outstanding during the period.
	Because Sangamo is in a net loss position, diluted net loss per share excludes the effects of common stock equivalents consisting of options, which are all anti-dilutive. All stock options outstanding were excluded from the calculation of diluted net loss per share. Stock option outstanding at the end of 2014, 2013 and 2012 were 8,006,380, 8,405,864 and 9,184,346, respectively.
	Segments
	The Company operates in one segment. Management uses one measurement of profitability and does not segregate its business for internal reporting. As of December 31, 2014 and 2013, all of the Company’s assets were maintained in the U.S. For the years ended December 31, 2014, 2013 and 2012, substantially all of revenues and operating expenses were generated and incurred in the U.S.
	Recent Accounting Pronouncements
	In August 2014, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (ASU 2014-15). ASU 2014-15 requires management to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. In doing so, companies will have reduced diversity in the timing and content of footnote disclosures than under the current guidance. ASU 2014-15 is effective for the Company in the first quarter of 2016 with early adoption permitted. The Company does not believe the impact of adopting ASU 2014-15 on its consolidated financial statements will be material.
	In May 2014, the Financial Accounting Standards Board issued ASU 2014-09, Revenue from Contracts with Customers (ASU 2014-09). This standard outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The main principle of ASU 2014-09 is to recognize revenues when promised goods or services are transferred to customers in an amount that reflects the consideration that is expected to be received for those goods or services. ASU 2014-09 provides companies with two implementation methods: (i) apply the standard retrospectively to each prior reporting period presented (full retrospective application); or (ii) apply the standard retrospectively with the cumulative effect of initially applying the standard as an adjustment to the opening balance of retained earnings of the annual reporting period that includes the date of initial application (modified retrospective application). This guidance is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period, and early application is not permitted. The Company is currently in the process of evaluating the impact of the pending adoption of ASU 2014-09 on its consolidated financial statements.

Fair_Value_Measurement

Fair Value Measurement	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurement	NOTE 2 –FAIR VALUE MEASUREMENT
	The Company measures certain assets and liabilities at fair value on a recurring basis, including cash equivalents, available-for-sale securities and the contingent consideration liability. The fair value is determined based on a three-tier hierarchy under the authoritative guidance for fair value measurements and disclosures that prioritizes the inputs used in measuring fair value as follows:
	Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;
	Level 2: Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability;
	Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).
	The fair value measurements of cash equivalents, available-for-sale securities and the contingent consideration liabilities are identified at the following levels within the fair value hierarchy (in thousands):
		31-Dec-14
		Fair Value Measurements
		Total		Level 1		Level 2		Level 3
	Assets:
	Cash equivalents:
	Money market funds	$	3,182	$	3,182	$	—	$	—
	Total		3,182		3,182		—		—
	Marketable securities:
	Commercial paper securities		33,748		—		33,748		—
	Corporate debt securities		22,813		—		22,813		—
	U.S. government sponsored entity debt securities		163,631		—		163,631		—
	Total		220,192		—		220,192		—
	Total cash equivalents and marketable securities	$	223,374	$	3,182	$	220,192	$	—
	Liabilities:
	Contingent consideration liability	$	1,800	$	—	$	—	$	1,800
	Total	$	1,800	$	—	$	—	$	1,800
		31-Dec-13
		Fair Value Measurements
		Total		Level 1		Level 2		Level 3
	Assets:
	Cash equivalents:
	Money market funds	$	6,934	$	6,934	$	—	$	—
	Total		6,934		6,934		—		—
	Marketable securities:
	U.S. government sponsored entity debt securities		121,290		—		121,290		—
	Total cash equivalents and marketable securities	$	128,224	$	6,934	$	121,290	$	—
	Liabilities:
	Contingent consideration liability	$	1,570	$	—	$	—	$	1,570
	Total	$	1,570	$	—	$	—	$	1,570
	Investments
	The Company generally classifies its debt instruments as Level 2. Instruments can be classified as Level 2 when observable market prices for identical securities that are traded in less active markets are used. When observable market prices for identical securities are not available, such instruments are priced using benchmark curves, benchmarking of like securities, sector groupings, matrix pricing and valuation models. These valuation models are proprietary to the pricing providers or brokers and incorporate a number of inputs, including, listed in approximate order of priority: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data including market research publications. For certain security types, additional inputs may be used, or some of the standard inputs may not be applicable. Evaluators may prioritize inputs differently on any given day for any security based on market conditions, and not all inputs listed are available for use in the evaluation process for each security evaluation on any given day.
	Contingent Consideration Liability
	In October 2013, the Company acquired Ceregene and recorded a liability for the estimated fair value of contingent consideration payments to former Ceregene stockholders, as outlined under the terms of the merger agreement with Ceregene. These contingent payments are owed if the Company grants a third-party license to develop and commercialize certain product candidates acquired from Ceregene, or if the Company commercializes any of such product candidates itself. The fair value of this liability is estimated using a probability-weighted discounted cash flow analysis. Such valuations require significant estimates and assumptions including but not limited to: determining the timing and estimated costs to complete the in-process projects, projecting regulatory approvals, estimating future cash flows and developing appropriate discount rates. The Company has classified this liability as Level 3.
	Subsequent changes in the fair value of this contingent consideration liability is recorded to the “Change in fair value of contingent liability” expense line item in the consolidated statements of operations as operating expenses. During the twelve months ended December 31, 2014, the recognized amount of the liability for contingent consideration increased by $0.2 million primarily as the result of the passage of time.
	The following sets forth the changes in the estimated fair value for our contingent consideration liability classified as Level 3 (in thousands):
	Fair value as of December 31, 2013	$	1,570
	Change in fair value		230
	Fair value as of December 31, 2014	$	1,800

Marketable_Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2014
Investments Debt And Equity Securities [Abstract]
Marketable Securities	NOTE 3 – MARKETABLE SECURITIES
	The table below summarizes the Company’s cash equivalents and available-for-sale securities (in thousands):
				Gross		Gross
		Amortized		Unrealized		Unrealized			Estimated
		Cost		Gains		(Losses)			Fair Value
	31-Dec-14
	Cash equivalents:
	Money market funds	$	3,182	$	—	$	—		$	3,182
	Total		3,182		—		—			3,182
	Available-for-sale securities:
	Commercial paper securities	$	33,715	$	33	$	—		$	33,748
	Corporate debt securities		22,831		—		(18	)		22,813
	U.S. government sponsored entity debt securities		163,671		—		(40	)		163,631
	Total		220,217		33		(58	)		220,192
	Total cash equivalents and available-for-sale securities	$	223,399	$	33	$	(58	)	$	223,374
	31-Dec-13
	Cash equivalents:
	Money market funds	$	6,934	$	—	$	—		$	6,934
	Total		6,934		—		—			6,934
	Available-for-sale securities:
	U.S. government sponsored entity debt securities		121,278		12		—			121,290
	Total cash equivalents and available-for-sale securities	$	128,212	$	12	$	—		$	128,224
	As of December 31, 2014, all of the Company’s investments had maturity dates within two years. Approximately 79% of the Company’s available-for-sale securities mature within the next twelve months of the date of the balance sheet and approximately 21% of the Company’s available-for-sale securities have maturities between twelve and twenty-four months from the date of the balance sheet. The Company had no material realized losses or other-than-temporary impairments of available-for-sale securities for the years ended December 31, 2014, 2013 and 2012.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	NOTE 4 – STOCK-BASED COMPENSATION
	The following table shows total stock-based compensation expense recognized in the consolidated statements of operations (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Research and development	$	5,064		$	3,204		$	2,892
	General and administrative		4,136			2,942			2,446
	Total stock-based compensation expense	$	9,200		$	6,146		$	5,338
	As of December 31, 2014, total stock-based compensation expense related to unvested stock options to be recognized in future periods was $17.2 million, which is expected to be expensed over a weighted-average period of 3.04 years. As of December 31, 2014, total stock-based compensation expense related to unvested RSUs to be recognized in future periods was $8.5 million, which is expected to be expensed over a weighted-average period of 2.30 years. There was no capitalized stock-based employee compensation expense as of December 31, 2014.
	Valuation Assumptions
	The employee stock-based compensation expense was determined using the Black-Scholes option valuation model. Option valuation models require the input of subjective assumptions and these assumptions can vary over time.
	The Company primarily bases its determination of expected volatility through its assessment of the historical volatility of its common stock. The Company relied on its historical exercise and post-vested termination activity for estimating its expected term for use in determining the fair value of these options.
	The weighted-average estimated fair value per share of options granted during 2014, 2013 and 2012 was $8.16, $8.29 and $3.76, respectively, based upon the assumption in the Black-Scholes valuation model. The assumptions used for estimating the fair value of the employee stock options are as follows:
		Year Ended December 31,
		2014			2013			2012
	Risk-free interest rate	1.60-1.70%			1.50-1.88%			0.74-1.34%
	Expected life of option (in years)	5.28-5.33			5.36-5.38			5.40-5.58
	Expected dividend yield of stock		0	%		0	%		0	%
	Expected volatility	0.66-0.69				0.88		0.87-0.88
	Employees purchased approximately 107,203, 180,551 and 175,375 shares of common stock through the 2010 Purchase Plan at an average exercise price of $7.92, $2.75 and $2.61 per share during 2014, 2013 and 2012, respectively.
	The weighted-average estimated fair value of shares purchased under the Company’s ESPP during 2014, 2013 and 2012 were $3.25, $1.47 and $2.51, respectively, based upon the assumptions in the Black-Scholes valuation model. The weighted–average assumptions used for estimating the fair value of the ESPP purchase rights are as follows:
		Year Ended December 31,
		2014			2013			2012
	Risk-free interest rate	0.05-0.30%			0.05-0.61%			0.05-0.30%
	Expected life of option (in years)	0.5-2.0			0.5-2.0			0.5-2.0
	Expected dividend yield of stock		0	%		0	%		0	%
	Expected volatility	0.52-0.75			0.51-0.85			0.93-1.37

Major_Customers_Partnerships_a

Major Customers, Partnerships and Strategic Alliances	12 Months Ended
	Dec. 31, 2014
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Major Customers, Partnerships and Strategic Alliances	NOTE 5 – MAJOR CUSTOMERS, PARTNERSHIPS AND STRATEGIC ALLIANCES
	Collaboration Agreements
	Collaboration and License Agreement with Biogen Idec, Inc. in Human Therapeutics
	In January 2014, we entered into an exclusive worldwide collaboration and license agreement with Biogen to develop therapeutics for hemoglobinopathies, focused on beta-thalassemia and SCD. Under the agreement, the two companies will jointly conduct two research programs: the beta-thalassemia program and the SCD program. In the beta-thalassemia program, we are responsible for all discovery, research and development activities through the first human clinical trial. In the SCD program, both parties are responsible for research and development activities through the submission of an IND application for ZFP therapeutics intended to treat SCD. Biogen reimburses us for agreed upon internal and external program-related costs.
	Under the Biogen Agreement, Sangamo and Biogen will jointly conduct two research programs: the beta-thalassemia program and the SCD program. For the beta-thalassemia program, Sangamo is responsible for all discovery, research and development activities through the first human clinical trial for the first ZFP Therapeutic developed under the Biogen Agreement for the treatment of beta-thalassemia. For the SCD program, both parties are responsible for research and development activities through the submission of an Investigational New Drug (IND) application for ZFP Therapeutics intended to treat SCD. For both programs, Biogen is responsible for subsequent world-wide clinical development, manufacturing and commercialization of licensed products developed under the Biogen Agreement. At the end of specified research terms for each program or under certain specified circumstances, Biogen retains the right to step in and take over any remaining activities of Sangamo. Furthermore, Sangamo has an option to co-promote in the United States any licensed product to treat beta-thalassemia and SCD developed under the Biogen Agreement, and Biogen agrees to compensate Sangamo for such co-promotion activities.
	Sangamo received an upfront license fee of $20.0 million upon entering into the Biogen Agreement. In addition, the Company will also be eligible to receive $126.3 million in payments upon the achievement of specified research, regulatory, clinical development milestones, as well as $167.5 million in payments upon the achievement of specified commercialization and sales milestones. Biogen also reimburses Sangamo for agreed upon costs incurred in connection with research and development activities conducted by Sangamo. In addition, Sangamo is eligible to receive contingent payments upon the achievement of specified regulatory, clinical development, commercialization and sales milestones. The total amount of potential regulatory, clinical development, commercialization and sales contingent payments, assuming the achievement of all specified milestone events in the Biogen Agreement, is $293.8 million, including Phase 1 contingent payments of $7.5 million for each of the beta-thalassemia and SCD programs. In addition, if products are commercialized under this agreement, Biogen will pay Sangamo incremental royalties for each licensed product that are a tiered double-digit percentage of annual net sales of such product. There have been no licensed products approved under the Biogen Agreement as of December 31, 2014.
	All contingent payments under the Biogen Agreement, when earned, will be non-refundable and non-creditable. The Company has evaluated the contingent payments under the agreement with Biogen based on the authoritative guidance for research and development milestones and determined that certain of these payments meet the definition of a milestone and that all such milestones are evaluated to determine if they are considered substantive. Milestones are considered substantive if they are related to events (i) that can be achieved based in whole or in part on either the Company’s performance or on the occurrence of a specific outcome resulting from the Company’s performance, (ii) for which there was substantive uncertainty at the date the Biogen Agreement was entered into that the event would be achieved and (iii) that would result in additional payments being due to the Company. Accordingly, consideration received for the achievement of milestones that are determined to be substantive will be recognized as revenue in their entirety in the period when the milestones are achieved and collectability is reasonably assured. Revenue for the achievement of milestones that are not substantive will be recognized over the remaining period of the Biogen Agreement, assuming all other applicable revenue recognition criteria have been met.
	Subject to the terms of the Biogen Agreement, Sangamo grants Biogen an exclusive, royalty-bearing license, with the right to grant sublicenses, to use certain ZFP and other technology controlled by Sangamo for the purpose of researching, developing, manufacturing and commercializing licensed products developed under the Biogen Agreement. Sangamo also grants Biogen a non-exclusive, world-wide, royalty free, fully paid license, with the right to grant sublicenses, of Sangamo’s interest in certain other intellectual property developed pursuant to the Biogen Agreement.
	The Company has identified the deliverables within the arrangement as a license to the technology and on-going research services activities. The Company has concluded that the license is not a separate unit of accounting as it does not have stand-alone value to Biogen apart from the research services to be performed pursuant to the Biogen Agreement. As a result, the Company is recognizing revenue from the upfront payment on a straight-line basis over a forty-month estimated initial research term during which the Company performs research services. As of December 31, 2014, the Company has deferred revenue of $14.9 million related to this Biogen Agreement.
	Revenues recognized under the Biogen Agreement for the twelve months ended December 31, 2014 are as follows (in thousands):
		Year ended
		December 31,
		2014
	Revenue related to Biogen Collaboration:
	Recognition of upfront fee	$	5,313
	Research services		7,751
	Total	$	13,064
	Related costs and expenses incurred under the Biogen agreement related to the beta-thalassemia project, which is co-funded with California Institute for Regenerative Medicine (CIRM), were $5.2 million during the twelve months ended December 31, 2014. Related costs and expenses for other projects including SCD under the Biogen agreement were $3.5 million during the twelve months ended December 31, 2014.
	Collaboration and License Agreement with Shire International GmbH, formerly Shire AG, in Human Therapeutics and Diagnostics
	In January 2012, the Company entered into a collaboration and license agreement (Shire Agreement) with Shire pursuant to which the Company and Shire collaborate to research, develop and commercialize human therapeutics and diagnostics for monogenic diseases based on Sangamo’s ZFP technology. Under the Shire Agreement, the Company and Shire may develop potential human therapeutic or diagnostic products for seven gene targets. The initial four gene targets selected were blood clotting Factors VII, VIII, IX and X, and products developed for such initial gene targets will be used for treating or diagnosing hemophilia. In June 2012, Shire selected a fifth gene target for the development of a ZFP therapeutic for Huntington’s disease (HD), an inherited neurodegenerative disease for which there are currently no therapies available to slow the disease progression. Shire has the right, subject to certain limitations, to designate two additional gene targets. Pursuant to the Shire Agreement, the Company granted Shire an exclusive, world-wide, royalty-bearing license, with the right to grant sublicenses, to use Sangamo’s ZFP technology for the purpose of developing and commercializing human therapeutic and diagnostic products for the gene targets. The initial research term of the Shire Agreement is six years and is subject to extensions upon mutual agreement and under other specified circumstances.
	Under the terms of the Shire Agreement, the Company is responsible for all research activities through the submission of an IND or European Clinical Trial Application (CTA), while Shire is responsible for clinical development and commercialization of products generated from the research program from and after the acceptance of an IND or CTA for the product. Shire reimburses Sangamo for its internal and external research program-related costs.
	Under the Shire Agreement, the Company received an upfront license fee of $13.0 million. In addition, the Company will also be eligible to receive $33.5 million in payments upon the achievement of specified research, regulatory, clinical development milestones, including payments for each gene target through the acceptance of an IND or CTA submission totaling $8.5 million, as well as $180 million in payments upon the achievement of specified commercialization and sales milestones. The total amount of potential milestone payments for each of the seven gene targets, assuming the achievement of all specified milestones in the Shire Agreement, is $213.5 million. The Company will also be eligible to receive royalty payments that are a tiered double-digit percentage of net sales of licensed product sold by Shire or its sublicensees developed under the collaboration, if any. In the third quarter of 2014 we received a $1.0 million milestone payment from Shire related to toxicology studies for our hemophilia B program. To date, no products have been approved and therefore no royalty fees have been earned under the Shire Agreement.
	All contingent payments under the Shire Agreement, when earned, will be non-refundable and non-creditable. The Company has evaluated the contingent payments under the agreement with Shire based on the authoritative guidance for research and development milestones and determined that certain of these payments meet the definition of a milestone and that all such milestones are evaluated to determine if they are considered substantive. Milestones are considered substantive if they are related to events (i) that can be achieved based in whole or in part on either the Company’s performance or on the occurrence of a specific outcome resulting from the Company’s performance, (ii) for which there was substantive uncertainty at the date the Shire Agreement was entered into that the event would be achieved and (iii) that would result in additional payments being due to the Company. Accordingly, revenue for the achievement of milestones that are determined to be substantive will be recognized in its entirety in the period when the milestone is achieved and collectability is reasonably assured. Revenue for the achievement of milestones that are not substantive will be recognized over the remaining period of the Shire Agreement.
	The Company has identified the deliverables within the arrangement as a license to the technology and on-going research services activities. The Company has concluded that the license is not a separate unit of accounting as it does not have stand-alone value to Shire apart from the research services to be performed pursuant to the Shire Agreement. As a result, the Company is  recognizing revenue from the upfront payment on a straight-line basis over a six-year initial research term during which the Company performs research services. As of December 31, 2014, the Company has deferred revenue of $6.8 million related to the Shire Agreement.
	Revenues recognized under the Shire Agreement for the years ended December 31, 2014, 2013 and 2012, were as follows (in thousands):
		Year ended December 31,
		2014		2013		2012
	Revenue related to Shire Collaboration:
	Recognition of upfront fee	$	2,167	$	2,167	$	1,986
	Recognition of milestone		1,000		—		—
	Research services		22,765		14,286		9,026
	Total	$	25,932	$	16,453	$	11,012
	Related costs and expenses incurred under the Shire agreement were $21.1 million, $14.2 million and $7.7 million during the twelve months ended December 31, 2014, 2013 and 2012, respectively.
	Agreement with Sigma-Aldrich Corporation in Laboratory Research Reagents, Transgenic Animal and Commercial Protein Production Cell-line Engineering
	In July 2007, Sangamo entered into a license agreement with Sigma. Under the license agreement, Sangamo agreed to provide Sigma with access to Sangamo’s proprietary ZFP technology and the exclusive right to use the technology to develop and commercialize research reagent products and services in the research field, excluding certain agricultural research uses that Sangamo previously licensed to DAS. Under the agreement, Sangamo and Sigma agreed to conduct a three-year research program to develop laboratory research reagents using Sangamo’s ZFP technology during which time Sangamo agreed to assist Sigma in connection with its efforts to market and sell services employing the Company’s ZFP technology in the research field. Sangamo has transferred the ZFP manufacturing technology to Sigma.
	In October 2009, Sangamo expanded its license agreement with Sigma. In addition to the original terms of the license agreement, Sigma received exclusive rights to develop and distribute ZFP-modified cell lines for commercial production of protein pharmaceuticals and certain ZFP-engineered transgenic animals for commercial applications. Under the terms of the agreement, Sigma made an upfront cash payment of $20.0 million consisting of a $4.9 million purchase of 636,133 shares of Sangamo common stock, valued at $4.9 million, and a $15.1 million upfront license fee. Sangamo is also eligible to receive commercial license fees of $5.0 million based upon a percentage of net sales and sublicensing revenue and thereafter a reduced royalty rate of 10.5% of net sales and sublicensing revenue. In addition, upon the achievement of certain cumulative commercial milestones Sigma will make milestone payments to Sangamo up to an aggregate of $25.0 million.
	Revenues recognized under the agreement with Sigma for the years ended December 31, 2014, 2013 and 2012, were as follows (in thousands):
		Year ended December 31,
		2014		2013		2012
	Revenue related to Sigma Collaboration:
	Royalty revenues	$	344	$	824	$	1,288
	License fee and milestone revenues		448		1,351		1,000
	Total	$	792	$	2,175	$	2,288
	Related costs and expenses incurred under the Sigma agreement were $0.1 million, $0.2 million and $0.3 million during 2014, 2013 and 2012, respectively.
	Agreement with Dow AgroSciences in Plant Agriculture
	In October 2005, Sangamo entered into an exclusive commercial license with DAS. Under this agreement, Sangamo is providing DAS with access to its proprietary ZFP technology and the exclusive right to use the technology to modify the genomes or alter the nucleic acid or protein expression of plant cells, plants, or plant cell cultures. Sangamo has retained rights to use plants or plant-derived products to deliver ZFP transcription factors (ZFP TFs) or ZFP nucleases (ZFNs) into humans or animals for diagnostic, therapeutic or prophylactic purposes. The Company’s agreement with DAS provided for an initial three year research term. In June 2008, DAS exercised its option under the agreement to obtain a commercial license to sell products incorporating or derived from plant cells generated using the Company’s ZFP technology, including agricultural crops, industrial products and plant-derived biopharmaceuticals. The exercise of the option triggered a one-time commercial license fee of $6.0 million, payment of the remaining $2.3 million of the previously agreed upon $4.0 million in research milestones, development and commercialization milestone payments for each product, and royalties on sales of products. Furthermore, DAS has the right to sublicense Sangamo’s ZFP technology to third parties for use in plant cells, plants, or plant cell cultures, and Sangamo will be entitled to 25% of any cash consideration received by DAS under such sublicenses. In December 2010, the Company amended its agreement with DAS to extend the period of reagent manufacturing services and research services through December 31, 2012.
	The agreement with DAS also provides for minimum sublicense fees each year due to Sangamo every October, provided the agreement is not terminated by DAS. Annual fees range from $250,000 to $3.0 million and total $25.3 million over 11 years. The Company does not have any performance obligations with respect to the sublicensing activities to be conducted by DAS. DAS has the right to terminate the agreement at any time; accordingly, the Company’s actual sublicense fees over the term of the agreement could be lower than $25.3 million. In addition, each party may terminate the agreement upon an uncured material breach of the agreement by the other party. In the event of any termination of the agreement, all rights to use the Company’s ZFP technology will revert to Sangamo, and DAS will no longer be permitted to practice Sangamo’s ZFP technology or to develop or, except in limited circumstances, commercialize any products derived from the Company’s ZFP technology.
	Revenues under the agreement with DAS were $3.0 million, $3.0 million and $4.7 million during 2014, 2013 and 2012, respectively. Related costs and expenses incurred under the agreement with DAS were $0.0 million, $0.4 million and $0.6 million during 2014, 2013 and 2012, respectively.
	Funding from Research Foundations
	California Institute for Regenerative Medicine - HIV
	In October 2009, CIRM, a State of California entity, granted a $14.5 million Disease Team Research Award to develop an HIV/AIDS therapy based on the application of ZFN genome editing technology in hematopoietic stem cells (HSCs). The four year grant supports an innovative research project conducted by a multidisciplinary team of investigators, including investigators from the University of Southern California, City of Hope National Medical Center and Sangamo BioSciences. Sangamo received funds totaling $5.2 million from the total amount awarded based on expenses incurred for research and development efforts by Sangamo as prescribed in the grant agreement, and subject to its terms and conditions. The award is intended to substantially fund Sangamo’s research and development efforts related to the grant agreement. The State of California has the right to receive, subject to the terms and conditions of the agreement between Sangamo and CIRM, payments from Sangamo resulting from sales of a commercial product resulting from research and development efforts supported by the grant, not to exceed two times the amount Sangamo receives in funding under the agreement with CIRM. As of December 31, 2013, all revenues under the award have been recognized and all funds have been received.
	In May 2014, CIRM agreed to fund a $5.6 million Strategic Partnership Award to fund clinical studies of a potentially curative ZFP Therapeutic for HIV/AIDS based on the application of its ZFN genome editing technology in hematopoietic stem progenitor cells (HSPCs). The four year grant provides matching funds to support evaluation of the Company’s stem cell-based ZFP Therapeutic in a clinical trial in HIV-infected individuals conducted at City of Hope. The Company expects funding for this grant to commence in 2015.
	Revenues attributable to research and development performed under the CIRM grant agreements for HIV/AIDS were $0.0 million, $1.2 million and $1.2 million during 2014, 2013 and 2012, respectively. Related costs during 2014, 2013 and 2012 were $1.8 million, $1.8 million and $1.2 million, respectively.
	California Institute for Regenerative Medicine - Beta-Thalassemia
	In May 2013, CIRM granted the Company a $6.4 million Strategic Partnership Award to develop a potentially curative ZFP Therapeutic for beta-thalassemia based on the application of its ZFN genome editing technology in HSCs. The four year grant provides matching funds for preclinical work that will support an IND application and a Phase 1 clinical trial in transfusion-dependent beta-thalassemia patients. The State of California has the right to receive, subject to the terms and conditions of the agreement between Sangamo and CIRM, payments from Sangamo, or its collaborators, from sales of a commercial product resulting from research and development efforts supported by the grant, in accordance with Title 17, California Code of Regulations, Section 100600.
	Revenue attributable to research and development performed under the CIRM grant agreement for beta-thalassemia were $1.4 million and $0.1 million in 2014 and 2013, respectively. Related costs during 2014 and 2013 were $1.1 million and $0.4 million, respectively.
	CHDI Foundation, Inc.
	In April 2011, Sangamo entered into an agreement with the CHDI to develop a novel therapeutic for HD based on Sangamo’s proprietary ZFP technology. The ZFP therapeutic approach targets the gene that causes HD, an inherited neurodegenerative disease, to slow the disease progression. Under the agreement with CHDI, and subject to its terms and conditions, CHDI paid the Company $1.3 million, the total funds due under the agreement, over a period of one year which is intended to substantially fund the Company’s research efforts related to the agreement. During 2012, the agreement with CHDI was amended to extend the project through August 2012 and to increase total potential funding from $1.3 million to $2.1 million, plus reimbursement for certain direct expenses related to the project. The agreement with CHDI terminated on August 31, 2012.
	Revenues attributable to research and development performed under the CHDI collaboration agreement were $1.1 million during 2012. Related costs during 2012 were $1.1 million. There were no such revenues or related costs in 2014 and 2013.
	The Juvenile Diabetes Research Foundation International
	In October 2006, Sangamo entered into an agreement with the Juvenile Diabetes Research Foundation International (JDRF) to provide financial support for one of Sangamo’s Phase 2 human clinical studies of the Company’s product candidate SB-509, a ZFP Therapeutic that was in development for the treatment of diabetic neuropathy. In January 2010, JDRF and Sangamo amended this agreement and, subject to its terms and conditions, JDRF agreed to provide additional funding of up to $3.0 million for a Phase 2b trial in diabetic neuropathy.
	In October 2011, the Company announced that it would not pursue additional clinical development of the SB-509 program. In March 2012, the Company received a final payment of $0.8 million for work performed under the agreement with JDRF. The Company does not expect to receive additional funding under this agreement.
	Revenues attributable to research and development activities performed under the JDRF agreements were $0.8 million during 2012. There were no such revenues in 2014 and 2013.

Acquisition_of_Ceregene

Acquisition of Ceregene	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Acquisition of Ceregene	NOTE 6 – ACQUISITION OF CEREGENE
	In August 2013, Sangamo and its wholly-owned subsidiary CG Acquisition Sub, Inc., a Delaware corporation, entered into an Agreement and Plan of Merger (the Merger Agreement) with Ceregene, and a stockholders’ representative. Pursuant to the Merger Agreement, the Company acquired all outstanding shares of Ceregene, a privately held biotechnology company focused on the development of AAV gene therapies. The acquired assets include all of Ceregene’s therapeutic programs, including CERE-110 for the treatment of AD, which is currently in a Phase 2 clinical trial. In addition to the clinical assets acquired, the Company acquired certain intellectual property rights relating to the manufacturing of AAV, and certain toxicology data and safety and efficacy data from Ceregene’s human clinical trials, which will be used in the preparation and filing of IND applications for Sangamo’s in vivo ZFP Therapeutics, particularly those that target the brain. The acquisition closed in October 2013 (the Closing Date).
	Under the Merger Agreement, the aggregate consideration transferred or transferable by Sangamo to former Ceregene stockholders at closing consisted of 100,000 shares of Sangamo common stock, with an approximate fair value of $1.2 million on the Closing Date. In addition, Sangamo may be required to make contingent earn-out payments (the Earn-Out Payments) to the stockholders of Ceregene if Sangamo develops and commercializes Ceregene’s AAV gene therapies.
	Also on the Closing Date, Sangamo, Ceregene and certain of Ceregene’s stockholders entered into an indemnity escrow agreement, pursuant to which $0.3 million of Ceregene remaining cash was deposited in an escrow account to be held until April 1, 2015 for the benefit of Sangamo to satisfy indemnity obligations of the stockholders under the Merger Agreement.
	Consideration Transferred
	The following table summarizes the estimated fair value of the consideration transferred by Sangamo to the Ceregene stockholders on the Closing Date (in thousands):
	Sangamo shares of common stock	$	1,200
	Contingent earn-out		1,510
	Total purchase consideration	$	2,710
	Fair Value Estimate of Assets Acquired and Liabilities Assumed
	The following table summarizes the estimated fair value of the net assets acquired as of the Closing Date (in thousands):
	Cash and equivalents	$	79
	Accounts receivable		22
	Identifiable intangible assets		1,870
	Goodwill		1,585
	Total assets acquired		3,556
	Deferred tax liability		(748	)
	Accounts payable and accrued liabilities		(98	)
	Total liabilities assumed		(846	)
	Net assets acquired	$	2,710
	In-Process Research and Development
	Intangible assets include IPR&D, which consists of Ceregene’s two clinical product candidates, CERE-110 for the treatment of AD and CERE-120 for the treatment of Parkinson’s disease. The Company determined that the combined Closing Date estimated fair values of CERE-110 and CERE-120 was $1.9 million. The Company used an income approach, which is a measurement of the present value of the net economic benefit or cost expected to be derived from an asset or liability, to measure the fair value of these two product candidates. Under the income approach, an intangible asset’s fair value is equal to the present value of the incremental after-tax cash flows (excess earnings) attributable solely to the intangible asset over its remaining useful life.
	A summary of these assets and estimated fair values at the Closing Date is as follows (in thousands):
		Value of Intangible
		Assets Acquired
	CERE-110 for the treatment of Alzheimer's disease	$	1,640
	CERE-120 for the treatment of Parkinson's disease		230
	Total identifiable intangible assets	$	1,870
	IPR&D is an intangible asset classified as indefinite-lived until the completion or abandonment of the associated research and development effort, and will be amortized over an estimated useful life to be determined at the date the project is completed. IPR&D is not amortized until the project is completed or abandoned, but rather tested for impairment.
	Goodwill
	The excess of the consideration transferred over the fair values assigned to the assets acquired and liabilities assumed was $1.6 million, which represents the goodwill resulting from the acquisition. Goodwill represents benefits that Sangamo believes will result from combining its operations with the operations of Ceregene and any intangible assets that do not qualify for separate recognition, as well as any future, yet unidentified products.
	None of the goodwill is expected to be deductible for income tax purposes. The Company tests goodwill for impairment on an annual basis or sooner, if deemed necessary. There have been no changes to the assets acquired or liabilities assumed, including goodwill, since the Closing Date.
	Liability for Contingent Consideration
	In addition to the transfer of shares of Sangamo common stock on the Closing Date, the Company may be required to make contingent Earn-Out Payments in the future if the Company grants a third-party license to develop and commercialize products based on the technology acquired from Ceregene (the “Earn-out Products”) or if the Company commercializes any Earn-Out Products itself. These payments are a percentage of any upfront or milestone payments received in the case Sangamo grants a third-party license to develop and commercialize the Earn-Out Products, or are a percentage of net sales in the case Sangamo develops and commercialized the Earn-Out Products itself. The total maximum payment is not limited, other than due to size of any potential upfront or milestone payments received or by future net sales of Earn Out Products, if any.
	The fair value of the liability for the contingent consideration recognized on the Close Date was $1.5 million. The Company determined the fair value of the liability for the contingent consideration based on a probability-weighted discounted cash flow analysis. The fair value of the liability for the contingent consideration recognized as of December 31, 2014 is $1.8 million based on a probability-weighted discounted cash flow analysis with the increase in fair value due to the passage of time.

Intangible_Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	NOTE 7 – INTANGIBLE ASSETS
	Intangible assets for IPR&D consist of two clinical product candidates from our acquisition of Ceregene. IPR&D is an intangible asset classified as indefinite-lived until the completion or abandonment of the associated research and development effort, and will be amortized over an estimated useful life to be determined at the date the project is completed. If the project is abandoned, the IPR&D will be expensed at the time such determination is made.
	The carrying values of these intangibles assets are as follows (in thousands):
		Year ended December 31,
		2014		2013
	CERE-110 for the treatment of Alzheimer's disease	$	1,640	$	1,640
	CERE-120 for the treatment of Parkinson's disease		230		230
	Total identifiable intangible assets	$	1,870	$	1,870

Property_and_Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2014
Property Plant And Equipment [Abstract]
Property and Equipment	NOTE 8 – PROPERTY AND EQUIPMENT
	Property and equipment consist of the following (in thousands):
		December 31,
		2014			2013
	Laboratory equipment	$	3,665		$	3,208
	Furniture and fixtures		550			563
	Leasehold improvements		1,163			1,156
			5,378			4,927
	Less accumulated depreciation and amortization		(3,899	)		(3,521	)
		$	1,479		$	1,406
	Depreciation and amortization expense was $0.5 million in 2014 and $0.6 million for 2013 and 2012. In 2012, the Company disposed of $0.5 million in fixed assets with associated accumulated depreciation of $0.4 million. The Company recognized a $0.1 million loss on the write-off of these assets.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 9 – COMMITMENTS AND CONTINGENCIES
	Sangamo occupies office and laboratory space under operating leases in Richmond, California. In August 2013, Sangamo amended its lease agreement wherein the lease was extended through August 2019. The Company also entered into a lease for research space located at 1003 West Cutting Boulevard in Richmond, California in December 2014. The lease expires in January 2018. Rent expenses were $0.7 million in 2014, $0.7 million in 2013, and $0.6 million for 2012. Future minimum payments under contractual obligations at December 31, 2014 consist of the following (in thousands):
		Operating
	Fiscal Year:	Lease
	2015	$	865
	2016		901
	2017		928
	2018		748
	2019		496
	Thereafter		—
	Total minimum payments	$	3,938
	Contingencies
	Sangamo is not party to any material pending legal proceeding. From time to time, we may be involved in legal proceedings arising in the ordinary course of business

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Stockholders' Equity	NOTE 10 – STOCKHOLDERS’ EQUITY
	Preferred Stock
	The Company has 5,000,000 preferred shares authorized, which may be issued at the Board of director’s discretion.
	Common Stock
	On March 25, 2014, Sangamo completed an underwritten public offering of its common stock, in which the Company sold an aggregate of 4,444,444 shares of its common stock at a public offering price of $22.50 per share. The net proceeds to Sangamo from the sale of shares in this offering, after deducting underwriting discounts and commissions and other offering expenses, were approximately $93.8 million. On September 23, 2013, Sangamo completed an underwritten public offering of its common stock, in which the Company sold an aggregate of 7,015,000 shares of its common stock, including 915,000 shares issued to the Underwriters pursuant to a 30-day overallotment option, at a public offering price of $10.58 per share. The net proceeds to Sangamo from the sale of shares in this offering, after deducting underwriting discounts and commissions and other offering expenses, were approximately $69.5 million.
	Stock Incentive Plan
	In April 2013, Sangamo’s board of directors adopted, subject to stockholder approval, the Company’s 2013 Stock Incentive Plan (the 2013 Plan) as the successor to the Company’s 2004 Stock Incentive Plan (the 2004 Plan). At the Annual Meeting of Stockholders held on June 12, 2013, the 2013 Plan was approved by the Company’s stockholders and became effective. In connection with the approval by stockholders of the 2013 Plan, outstanding awards under the 2004 Plan were transferred to the 2013 Plan. The 2004 Plan was terminated and no further awards will be made pursuant to the 2004 Plan.
	Under the 2013 Plan, the exercise price per share of options granted will generally not be less than 100 percent of the fair value per share of common stock on the grant date, and the option term will not exceed ten years. If the person to whom the option is granted is a 10 percent stockholder, and the option granted qualifies as an Incentive Stock Option Grant, then the exercise price per share will not be less than 110 percent of the fair value per share of common stock on the grant date, and the option term will not exceed five years. Options granted under the 2013 Plan generally vest over four years at a rate of 25 percent one year from the grant date and one thirty-sixth per month thereafter and expire ten years after the grant, or earlier upon employment termination. Certain options previously granted under the 2004 Plan to the Company’s non-employee directors are structured so that they may be exercised prior to vesting, with the related shares subject to Sangamo’s right to repurchase any shares that have not vested pursuant to the vesting schedule in effect for such award at the exercise price paid if the option holder’s board service terminates. Approximately 14.1 million shares were initially reserved for issuance under the 2013 Plan, including 9.7 million shares of common stock subject to outstanding awards previously granted under the 2004 Plan that were transferred to the 2013 Plan, and an additional 4.4 million shares of common stock.
	The number of shares of common stock reserved for issuance under the 2013 Plan will be reduced: (i) on a 1-for-1 basis for each share of common stock subject to a stock option or stock appreciation right granted under the plan, (ii) on a 1-for-1 basis for each share of common stock issued pursuant to a full value award granted under the plan prior to the plan effective date, and (iii) by a fixed ratio of 1.33 shares of common stock for each share of common stock issued pursuant to a full-value award granted under the plan on or after the plan effective date.
	Shares subject to any outstanding options or other awards under the 2013 Plan that expire or otherwise terminate prior to the issuance of the shares subject to those options or awards will be available for subsequent issuance under the 2013 Plan. Any unvested shares issued under the 2013 Plan that the Company subsequently purchases, pursuant to repurchase rights under the 2013 Plan, will be added back to the number of shares reserved for issuance under the 2013 Plan on a 1-for-1 basis or a 1.33-for-1 basis (depending on the ratio at which the share reserve was debited for the original award) and will accordingly be available for subsequent issuance in accordance with the terms of the plan. There are no net counting provisions in effect under the 2013 Plan.
	Employee Stock Purchase Plan
	Sangamo’s 2010 Employee Stock Purchase Plan (Purchase Plan), which supersedes the 2000 Employee Stock Purchase Plan, provides a total reserve of 2,100,000 shares of common stock for issuance under the Purchase Plan. Eligible employees may purchase common stock at 85 percent of the lesser of the fair market value of Sangamo’s common stock on the first day of the applicable two-year offering period or the last day of the applicable six-month purchase period.
	Stock Option Activity
	A summary of Sangamo’s stock option activity is as follows:
					Weighted-
					Average		Weighted Average		Aggregate
		Number of			Exercise per		Remaining		Intrinsic
		Shares			Share Price		Contractual Term		Value
							(In years)		(In thousands)
	Options outstanding at December 31, 2013		8,405,864		$	7.2
	Options granted		1,694,400		$	14.19
	Options exercised		(1,959,201	)	$	6.17
	Options canceled		(134,683	)	$	8.77
	Options outstanding at December 31, 2014		8,006,380		$	8.9		6.62	$	50,766
	Options vested and expected to vest at December 31, 2014		7,526,430		$	8.67		6.44	$	49,437
	Options exercisable at December 31, 2014		4,929,932		$	7.21		5.07	$	39,475
	Newly created shares are issued upon exercise of options. There were no shares subject to Sangamo’s right of repurchase as of December 31, 2014. The intrinsic value of options exercised was $20.4 million, $8.9 million and $0.6 million during 2014, 2013 and 2012, respectively.
	At December 31, 2014, the aggregate intrinsic values of the outstanding and exercisable options were $50.8 million and $39.5 million, respectively. The aggregate intrinsic value of options vested and expected to vest during 2014, 2013 and 2012 was $49.4 million, $54.9 million and $8.5 million, respectively.
	The following table summarizes information with respect to stock options outstanding at December 31, 2014:
		Options Outstanding and Exercisable					Options Exercisable
		Number of					Number of
		Shares of					Shares of
		common stock			Weighted Average		common stock
		subject to			Remaining		subject to		Weighted Average
	Range of Exercise Price	options			Contractual Life		options		Exercise Price
					(In years)
	$2.55 – $3.45		950,512			4.41		880,721	$	3.37
	$3.80 – $5.35		898,399			5.01		874,189	$	5.27
	$5.41 – $5.41		985,758			7.9		436,290	$	5.41
	$5.42 – $5.42		50,000			5.24		50,000	$	5.42
	$5.70 – $5.70		804,771			5.94		804,771	$	5.7
	$5.94 – $11.03		809,679			5.12		713,466	$	6.7
	$11.35 – $11.88		59,250			2.38		38,750	$	11.76
	$12.12 – $12.12		942,287			8.95		234,592	$	12.12
	$12.23 – $13.99		750,324			4.66		548,824	$	13.97
	$14.07 – $23.02		1,755,400			8.67		348,329	$	14.32
			8,006,380			6.62		4,929,932	$	7.21
	Restricted Stock Units
	During 2014 and 2013, the Company awarded 488,000 and 392,500 Restricted Stock Units (RSUs), respectively. The RSUs awarded in 2014 and 2013 had an average grant date fair value of $14.05 and $12.12, respectively. These awards will vest as follows: one-third of the award will vest in a series of three successive equal annual installments. The aggregate value of shares vested during 2014, 2013 and 2012 was $9.1 million, $4.1 million and $0.1 million, respectively.
	A summary of Sangamo’s RSU activity is as follows:
		Number			Weighted Average
		of			Remaining		Aggregate Intrinsic
		Shares			Contractual Term		Value
					(In years)		(In thousands)
	RSUs outstanding at December 31, 2013		1,063,657
	RSUs awarded		488,000
	RSUs released		(616,756	)
	RSUs forfeited		(35,499	)
	RSUs outstanding at December 31, 2014		899,402			1.61	$	13,680
	RSUs vested and expected to vest at December 31, 2014		754,931			1.55	$	11,482
	RSUs that vested in 2014, 2013 and 2012 were net-share settled such that the Company withheld shares with value equivalent to the employees’ minimum statutory obligation for the applicable income and other employment taxes, and remitted the cash to the appropriate taxing authorities. The total shares withheld were approximately 309,102 and 167,138 for 2014 and 2013, respectively, and were based on the value of the RSUs on their respective issuance dates as determined by the Company’s closing stock price. There were no such shares withheld in 2012. Total payments for the employees’ tax obligations to taxing authorities were $4.6 million and $2.0 million in 2014 and 2013, respectively, and are reflected as a financing activity within the consolidated statements of cash flows. These net-share settlements had the effect of share repurchases by the Company as they reduced and retired the number of shares that would have otherwise been issued as a result of the vesting and did not represent an expense to the Company.
	As of December 31, 2014, there were 768,044 shares reserved for future awards under the Company’s 2013 Plan and 1,420,560 shares of common stock reserved for future issuance under the Purchase Plan.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 11 – INCOME TAXES
	The Company recorded no income tax expense. The principal difference between the statutory tax rate of 34% and the Company’s effective tax rate is due to the Company permanent differences related to stock-based compensation and its change in valuation allowance.
	Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets are as follows (in thousands):
		December 31,
		2014			2013
	Assets:
	Deferred tax assets:
	Net operating loss carryforwards	$	90,921		$	81,944
	Research and development tax credit carryforwards		8,646			7,996
	Stock-based compensation		8,171			7,927
	Deferred revenue		2,690			3,563
	Other		2,471			1,677
	Total deferred tax asset		112,899			103,107
	Valuation allowance		(112,899	)		(103,107	)
	Net deferred tax assets	$	—		$	—
	Liabilities:
	Net deferred tax liability related to intangible assets		(748	)		(748	)
	Total deferred tax liability	$	(748	)	$	(748	)
	As part of accounting for the acquisition of Ceregene, the Company recorded goodwill and intangible assets. The intangible assets acquired are for the use in a particular research and development project IPR&D and are considered indefinite-lived assets. They will remain indefinite lived until the completion or abandonment of the associated research and development efforts. Since the intangible assets acquired have no tax basis, a deferred tax liability was established due to the difference between the book and tax bases for those assets. The indefinite-lived asset is not treated as a future source of income and, therefore, no valuation allowance is released until the assets are amortized or abandoned,
	Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. The valuation allowance increased by $9.8 million, $14.9 million and $5.4 million for the years ended December 31, 2014, 2013 and 2012, respectively. As of December 31, 2014, Sangamo had net operating loss carryforwards for federal and state income tax purposes of approximately $330.9 million and $278.1 million, respectively. If not utilized, the net federal and state operating loss carryforwards will start to expire in 2018 and 2015 respectively. The Company also has federal and state research tax credit carryforwards of $6.7 million and $7.0 million, respectively. The federal research credits will begin to expire in 2018 while the state research credits have no expiration date. Utilization of the Company’s net operating loss carryforwards and research tax credit carryforwards may be subject to substantial annual limitations due to the ownership change limitations provided by the Internal Revenue Code and similar state provisions. The annual limitation could result in the expiration of the net operating loss carryforwards and research tax credit carryforwards before utilization.
	The Company files federal and state income tax returns with varying statutes of limitations. The tax years from 2000 forward remain open to examination due to the carryover of net operating losses or tax credits. The Company also files a UK income tax return, and the tax years from 2008 and thereafter remain open to examination.
	The Company’s practice is to recognize interest and/or penalties related to income tax matters in income tax expense. As of December 31, 2014, the Company had no accrued interest and/or penalties. The unrecognized tax benefits may change during the next year for items that arise in the ordinary course of business. In the event that any unrecognized tax benefits are recognized, the effective tax rate will not be affected.
	The following table summarizes the activity related to the Company’s unrecognized tax benefits (in thousands):
		December 31,
		2014			2013			2012
	Beginning balance	$	3,182		$	2,735		$	2,750
	Additions based on tax positions related to the current year		228			294			153
	Additions for tax positions of prior years		28			153			59
	Reductions for tax positions of prior years		—			—			(227	)
	Ending balance	$	3,438		$	3,182		$	2,735

Accounts_Payable_and_Accrued_L

Accounts Payable and Accrued Liabilities	12 Months Ended
	Dec. 31, 2014
Payables And Accruals [Abstract]
Accounts Payable and Accrued Liabilities	NOTE 12 – ACCOUNTS PAYABLE AND ACCRUED LIABILITIES
	Accounts payable and accrued liabilities consist of the following (in thousands):
		December 31,
		2014		2013
	Accounts payable	$	5,525	$	3,022
	Accrued research and development expenses		2,435		727
	Accrued professional fees		531		510
	Deferred rent		129		121
	Other		84		—
	Total accounts payable and accrued liabilities	$	8,704	$	4,380

Employee_Benefit_Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2014
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plan	NOTE 13 – EMPLOYEE BENEFIT PLAN
	The Company sponsors a defined-contribution savings plan under Section 401(k) of the Internal Revenue Code covering all full-time employees (Sangamo 401(k) Plan). The Sangamo 401(k) Plan is intended to qualify under Section 401 of the Internal Revenue Code.
	The Company matched contributions by employees equal to 50% of the first 6% of employee contributions up to a limit of $2,000 in 2014 and $1,500 in 2013. Matching funds are fully vested when contributed. Contributions to the Sangamo 401(k) Plan by the Company were $0.2 million for the year ended December 31, 2014 and $0.1 million for years ended December 31, 2013 and 2012.

Quarterly_Financial_Data_Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	NOTE 14 – QUARTERLY FINANCIAL DATA (UNAUDITED)
	The following table sets forth certain unaudited quarterly financial data for the eight quarters ended December 31, 2014. The unaudited information set forth below has been prepared on the same basis as the audited information and includes all adjustments necessary to present fairly the information set forth herein. The operating results for any quarter are not indicative of results for any future period. All data is in thousands except per common share data.
		2014												2013
		Q1			Q2			Q3			Q4			Q1			Q2			Q3			Q4
	Revenues	$	8,116		$	10,385		$	12,417		$	14,952		$	4,623		$	6,934		$	5,707		$	6,869
	Expenses	$	15,727		$	17,432		$	20,071		$	19,421		$	11,528		$	12,402		$	11,866		$	15,043
	Net loss	$	(7,572	)	$	(6,981	)	$	(7,545	)	$	(4,319	)	$	(6,885	)	$	(5,450	)	$	(6,145	)	$	(8,144	)
	Net loss per share	$	(0.12	)	$	(0.10	)	$	(0.11	)	$	(0.06	)	$	(0.13	)	$	(0.10	)	$	(0.11	)	$	(0.13	)

Organization_and_Summary_of_Si1

Organization and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and the accompanying notes. Actual results could differ from those estimates. The consolidated financial statements include the accounts of Sangamo and its wholly owned subsidiaries, Ceregene and Gendaq Limited, after elimination of all intercompany balances and transactions.
Business Combinations	Business Combinations
	The Company accounted for the acquisition of Ceregene in accordance with Accounting Standards Codification (ASC) Topic 805, Business Combinations (ASC Topic 805). ASC Topic 805 establishes principles and requirements for recognizing and measuring the total consideration transferred to and the assets acquired, liabilities assumed and any non-controlling interests in the acquired target in a business combination. ASC Topic 805 also provides guidance for recognizing and measuring goodwill acquired in a business combination; requires purchased in-process research and development to be capitalized at fair value as intangible assets at the time of acquisition; requires acquisition-related expenses and restructuring costs to be recognized separately from the business combination; expands the definition of what constitutes a business; and requires the acquirer to disclose information that users may need to evaluate and understand the financial effect of the business combination.
Cash and Cash Equivalents	Cash and Cash Equivalents
	Sangamo considers all highly liquid investments purchased with original maturities of three months or less at the purchase date to be cash equivalents. Cash and cash equivalents consist of deposits in money market investment accounts, government sponsored entity debt securities, US Treasury debt securities and corporate bank accounts.
	As part of the acquisition of Ceregene, Sangamo was required to set aside $0.3 million in an escrow account until April 1, 2015. The cash held in escrow is recorded as restricted cash.
Marketable Securities	Marketable Securities
	Sangamo classifies its marketable securities as available-for-sale and records its investments at estimated fair value based on quoted market prices or observable market inputs of almost identical assets, with the unrealized holding gains and losses included in accumulated other comprehensive income.
	The Company’s investments are subject to a periodic impairment review. The Company recognizes an impairment charge when a decline in the fair value of its investments below the cost basis is judged to be other-than-temporary. The Company considers various factors in determining whether to recognize an impairment charge, including the length of time and extent to which the fair value has been less than the Company’s cost basis, the financial condition and near-term prospects of the investee, and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in the market value. Realized gains and losses on available-for-sale securities are included in other (expense)/income, which is determined using the specific identification method.
Fair Value Measurements	Fair Value Measurements
	The carrying amounts for financial instruments consisting of cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate fair value due to their short maturities. Marketable securities and contingent consideration liabilities are stated at their estimated fair values. The counterparties to the agreements relating to the Company’s investment securities consist of the US Treasury, governmental agencies, various major corporations and financial institutions with high credit standing.
Property and Equipment	Property and Equipment
	Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation is calculated using the straight-line method based on the estimated useful lives of the related assets (generally three to five years). For leasehold improvements, amortization is calculated using the straight-line method based on the shorter of the useful life or the lease term. The Company reviews its property and equipment for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable.
Revenue Recognition	Revenue Recognition
	Revenues from research activities made under strategic partnering agreements and collaborations are recognized as the services are provided when there is persuasive evidence that an arrangement exists, delivery has occurred, the price is fixed or determinable, and collectability is reasonably assured. Revenue generated from research and licensing agreements typically includes upfront signing or license fees, cost reimbursements, research services, minimum sublicense fees, milestone payments and royalties on future licensee’s product sales.
	Multiple Element Arrangements prior to the adoption of ASU No. 2009-13, Revenue Recognition—Multiple Deliverable Revenue Arrangements (ASU 2009-13). For revenue arrangements entered into before January 1, 2011, that include multiple deliverables, the elements of such agreement were divided into separate units of accounting if the deliverables met certain criteria, including whether the fair value of the delivered items could be determined and whether there was evidence of fair value of the undelivered items. In addition, the consideration was allocated among the separate units of accounting based on their fair values, and the applicable revenue recognition criteria are considered separately for each of the separate units of accounting. Prior to the adoption of ASU 2009-13, the Company recognized nonrefundable signing, license or non-exclusive option fees as revenue when rights to use the intellectual property related to the license were delivered and over the period of performance obligations if the Company had continuing performance obligations. The Company estimated the performance period at the inception of the arrangement and reevaluated it each reporting period. Changes to these estimates were recorded on a prospective basis.
	Multiple Element Arrangements after the adoption of ASU 2009-13. ASU 2009-13 amended the accounting standards for certain multiple element revenue arrangements to:
	o	provide updated guidance on whether multiple elements exist, how the elements in an arrangement should be separated, and how the arrangement consideration should be allocated to the separate elements;
	o	require an entity to allocate arrangement consideration to each element based on a selling price hierarchy where the selling price for an element is based on vendor-specific objective evidence (VSOE), if available; third-party evidence (TPE), if available and VSOE is not available; or the best estimate of selling price (ESP), if neither VSOE nor TPE is available; and
	o	eliminate the use of the residual method and require an entity to allocate arrangement consideration using the relative selling price method.
	For revenue agreements with multiple element arrangements, such as license and development agreements, entered into on or after January 1, 2011, the Company allocates revenue to each non-contingent element based on the relative selling price of each element. When applying the relative selling price method, the Company determines the selling price for each deliverable using VSOE of selling price or TPE of selling price. If neither exists the Company uses ESP for that deliverable. Revenue allocated is then recognized when the basic four revenue recognition criteria are met for each element. The collaboration and license agreements entered into with Shire International GmbH, formerly Shire AG, (Shire) in January 2012 and Biogen Idec Inc. (Biogen) in January 2014 were evaluated under these amended accounting standards.
	Additionally, the Company may be entitled to receive certain milestone payments which are contingent upon reaching specified objectives. These milestone payments are recognized as revenue in full upon achievement of the milestone if there is substantive uncertainty at the date the arrangement is entered into that objectives will be achieved and if the achievement is based on the Company’s performance.
	Minimum annual sublicense fees are also recognized as revenue in the period in which such fees are due. Royalty revenues are generally recognized when earned and collectability of the related royalty payment is reasonably assured. The Company recognizes cost reimbursement revenue under collaborative agreements as the related research and development costs for services are rendered. Deferred revenue represents the portion of research or license payments received which have not been earned.
	Sangamo’s research grants are typically multi-year agreements and provide for the reimbursement of qualified expenses for research and development as defined under the terms of the grant agreement. Revenue under grant agreements is recognized when the related qualified research expenses are incurred.
	During 2014, revenues related to Shire and Biogen represented 57% and 28%, respectively, of total revenues. During 2013, revenues related to Shire, Sigma-Aldrich Corporation (Sigma) and Dow AgroSciences LLC (DAS) represented 68%, 9% and 12%, respectively, of total revenues. During 2012, revenues related Shire, Sigma and DAS represented 51%, 11% and 22% of total revenues, respectively.
Research and Development Expenses	Research and Development Expenses
	Research and development costs are expensed as incurred. Research and development expenses consist of direct and research-related allocated overhead costs such as facilities costs, salaries and related personnel costs, and material and supply costs. In addition, research and development expenses include costs related to clinical trials, validation of the Company’s testing processes and procedures and as well as related overhead expenses. Research and development costs incurred in connection with collaborator-funded activities are expensed as incurred. Costs to acquire technologies that are utilized in research and development that have no alternative future use are expensed as incurred.
Stock-Based Compensation	Stock-Based Compensation
	The Company measures and recognizes compensation expense for all stock-based payment awards made to Sangamo employees and directors, including employee share options, restricted stuck units (RSUs) and employee share purchases related to the Employee Share Purchase Plan (ESPP), based on estimated fair values at grant date. The fair value of stock-based awards is amortized over the vesting period of the award using a straight-line method.
	To estimate the value of an award, the Company uses the Black-Scholes option pricing model. This model requires inputs such as expected life, expected volatility and risk-free interest rate. These inputs are subjective and generally require significant analysis and judgment to develop. While estimates of expected life and volatility are derived primarily from the Company’s historical data, the risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant commensurate with the expected life assumption. Further, the Company is required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses historical data to estimate pre-vesting option forfeitures and record stock-based compensation expense only for those awards that are expected to vest.
Indefinite-Lived Intangible Assets	Indefinite-Lived Intangible Assets
	As part of the Ceregene acquisition the Company recognized indefinite-lived intangible assets for in-process research and development and goodwill as further discussed below. ASC 350 and related updates require companies to test indefinite-lived intangible assets for impairment annually, and more frequently if indicators of impairment exist. ASC 350 includes an optional qualitative assessment for testing indefinite-lived intangible assets for impairment that permits companies to assess whether it is more likely than not (i.e., a likelihood of greater than 50%) that an indefinite-lived intangible asset is impaired. If a company concludes based on the qualitative assessment that it is not more likely than not that the fair value of an indefinite-lived intangible asset or, in the case of goodwill, that the fair value of the related reporting unit, is less than carrying value, it would not have to determine the asset’s or reporting unit’s fair value, as applicable.
In-Process Research and Development	In-Process Research and Development
	Intangible assets related to in-process research and development costs, or IPR&D, are considered to be indefinite-lived until the completion or abandonment of the associated research and development efforts. If and when development is complete, which generally occurs if and when regulatory approval to market a product is obtained, the associated assets would be deemed finite-lived and would then be amortized based on their respective estimated useful lives at that point in time. Prior to completion of the research and development efforts, the assets are considered indefinite-lived. During this period, the assets will not be amortized but will be tested for impairment on an annual basis and between annual tests if the Company becomes aware of any events occurring or changes in circumstances that would indicate a reduction in the fair value of the IPR&D projects below their respective carrying amounts. During the fourth quarter of 2014, the Company performed an assessment of the qualitative factors affecting the fair value of its IPR&D and concluded that it was not more likely than not that the fair value of its IPR&D was less than carrying value.
Goodwill	Goodwill
	Goodwill represents the excess of the consideration transferred over the estimated fair values of assets acquired and liabilities assumed in a business combination and is considered to be indefinite-lived. Goodwill is not amortized but is tested for impairment on an annual basis and between annual tests if the Company becomes aware of any events occurring or changes in circumstances that would indicate an impairment of goodwill has occurred. During the fourth quarter of 2014, the Company performed an assessment of the qualitative factors affecting the fair value of its reporting unit and concluded that it was not more likely than not that the fair value of its reporting unit was less than carrying value and that, as a result, it is not more likely than not that goodwill is impaired..
Contingent Consideration Liability	Contingent Consideration Liability
	Under the merger agreement with Ceregene, the Company may be required to make contingent earn-out payments if the Company grants a third-party license to develop and commercialize certain product candidates acquired from Ceregene, or if the Company commercializes any of these product candidates itself. These earn-out payments will become payable in the period they are earned. In accordance with ASC Topic 805, the Company determined the fair value of this liability for contingent consideration on the acquisition date using a probability-weighted discounted cash flow analysis. Future changes to the fair value of the contingent consideration will be determined each period and charged to expense in the “Changes in fair value of contingent liability” expense line item in the Consolidated Statements of Operations under operating expenses.
Income Taxes	Income Taxes
	Income tax expense has been provided using the liability method. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities as measured by the enacted tax rates that will be in effect when these differences reverse. The Company provides a valuation allowance against net deferred tax assets if, based upon the available evidence, it is not more likely than not that the deferred tax assets will be realized.
Net Loss Per Share	Net Loss Per Share
	Basic net loss per share has been computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is calculated by dividing net loss by the weighted average number of shares of common stock and potential dilutive securities outstanding during the period.
	Because Sangamo is in a net loss position, diluted net loss per share excludes the effects of common stock equivalents consisting of options, which are all anti-dilutive. All stock options outstanding were excluded from the calculation of diluted net loss per share. Stock option outstanding at the end of 2014, 2013 and 2012 were 8,006,380, 8,405,864 and 9,184,346, respectively.
Segments	Segments
	The Company operates in one segment. Management uses one measurement of profitability and does not segregate its business for internal reporting. As of December 31, 2014 and 2013, all of the Company’s assets were maintained in the U.S. For the years ended December 31, 2014, 2013 and 2012, substantially all of revenues and operating expenses were generated and incurred in the U.S.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In August 2014, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (ASU 2014-15). ASU 2014-15 requires management to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. In doing so, companies will have reduced diversity in the timing and content of footnote disclosures than under the current guidance. ASU 2014-15 is effective for the Company in the first quarter of 2016 with early adoption permitted. The Company does not believe the impact of adopting ASU 2014-15 on its consolidated financial statements will be material.
	In May 2014, the Financial Accounting Standards Board issued ASU 2014-09, Revenue from Contracts with Customers (ASU 2014-09). This standard outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The main principle of ASU 2014-09 is to recognize revenues when promised goods or services are transferred to customers in an amount that reflects the consideration that is expected to be received for those goods or services. ASU 2014-09 provides companies with two implementation methods: (i) apply the standard retrospectively to each prior reporting period presented (full retrospective application); or (ii) apply the standard retrospectively with the cumulative effect of initially applying the standard as an adjustment to the opening balance of retained earnings of the annual reporting period that includes the date of initial application (modified retrospective application). This guidance is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period, and early application is not permitted. The Company is currently in the process of evaluating the impact of the pending adoption of ASU 2014-09 on its consolidated financial statements.

Fair_Value_Measurement_Tables

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Summary of Fair Value Measurements of Cash Equivalents, Available-for-Sale Securities and Contingent Consideration Liability	The fair value measurements of cash equivalents, available-for-sale securities and the contingent consideration liabilities are identified at the following levels within the fair value hierarchy (in thousands):
		31-Dec-14
		Fair Value Measurements
		Total		Level 1		Level 2		Level 3
	Assets:
	Cash equivalents:
	Money market funds	$	3,182	$	3,182	$	—	$	—
	Total		3,182		3,182		—		—
	Marketable securities:
	Commercial paper securities		33,748		—		33,748		—
	Corporate debt securities		22,813		—		22,813		—
	U.S. government sponsored entity debt securities		163,631		—		163,631		—
	Total		220,192		—		220,192		—
	Total cash equivalents and marketable securities	$	223,374	$	3,182	$	220,192	$	—
	Liabilities:
	Contingent consideration liability	$	1,800	$	—	$	—	$	1,800
	Total	$	1,800	$	—	$	—	$	1,800
		31-Dec-13
		Fair Value Measurements
		Total		Level 1		Level 2		Level 3
	Assets:
	Cash equivalents:
	Money market funds	$	6,934	$	6,934	$	—	$	—
	Total		6,934		6,934		—		—
	Marketable securities:
	U.S. government sponsored entity debt securities		121,290		—		121,290		—
	Total cash equivalents and marketable securities	$	128,224	$	6,934	$	121,290	$	—
	Liabilities:
	Contingent consideration liability	$	1,570	$	—	$	—	$	1,570
	Total	$	1,570	$	—	$	—	$	1,570
Schedule of Changes in Estimated Fair Value of Contingent Consideration Liability	The following sets forth the changes in the estimated fair value for our contingent consideration liability classified as Level 3 (in thousands):
	Fair value as of December 31, 2013	$	1,570
	Change in fair value		230
	Fair value as of December 31, 2014	$	1,800

Marketable_Securities_Tables

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2014
Investments Debt And Equity Securities [Abstract]
Summary of Cash Equivalents and Available-for-Sale Securities	The table below summarizes the Company’s cash equivalents and available-for-sale securities (in thousands):
				Gross		Gross
		Amortized		Unrealized		Unrealized			Estimated
		Cost		Gains		(Losses)			Fair Value
	31-Dec-14
	Cash equivalents:
	Money market funds	$	3,182	$	—	$	—		$	3,182
	Total		3,182		—		—			3,182
	Available-for-sale securities:
	Commercial paper securities	$	33,715	$	33	$	—		$	33,748
	Corporate debt securities		22,831		—		(18	)		22,813
	U.S. government sponsored entity debt securities		163,671		—		(40	)		163,631
	Total		220,217		33		(58	)		220,192
	Total cash equivalents and available-for-sale securities	$	223,399	$	33	$	(58	)	$	223,374
	31-Dec-13
	Cash equivalents:
	Money market funds	$	6,934	$	—	$	—		$	6,934
	Total		6,934		—		—			6,934
	Available-for-sale securities:
	U.S. government sponsored entity debt securities		121,278		12		—			121,290
	Total cash equivalents and available-for-sale securities	$	128,212	$	12	$	—		$	128,224

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation Expense	The following table shows total stock-based compensation expense recognized in the consolidated statements of operations (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Research and development	$	5,064		$	3,204		$	2,892
	General and administrative		4,136			2,942			2,446
	Total stock-based compensation expense	$	9,200		$	6,146		$	5,338
Assumptions Used for Estimating Fair Value of Employee Stock Options	The assumptions used for estimating the fair value of the employee stock options are as follows:
		Year Ended December 31,
		2014			2013			2012
	Risk-free interest rate	1.60-1.70%			1.50-1.88%			0.74-1.34%
	Expected life of option (in years)	5.28-5.33			5.36-5.38			5.40-5.58
	Expected dividend yield of stock		0	%		0	%		0	%
	Expected volatility	0.66-0.69				0.88		0.87-0.88
Weighted-Average Assumptions Used for Estimating Fair Value of ESPP Purchase Rights	The weighted–average assumptions used for estimating the fair value of the ESPP purchase rights are as follows:
		Year Ended December 31,
		2014			2013			2012
	Risk-free interest rate	0.05-0.30%			0.05-0.61%			0.05-0.30%
	Expected life of option (in years)	0.5-2.0			0.5-2.0			0.5-2.0
	Expected dividend yield of stock		0	%		0	%		0	%
	Expected volatility	0.52-0.75			0.51-0.85			0.93-1.37

Major_Customers_Partnerships_a1

Major Customers, Partnerships and Strategic Alliances (Tables)	12 Months Ended
	Dec. 31, 2014
Biogen [Member]
Revenues Recognized under Agreement	Revenues recognized under the Biogen Agreement for the twelve months ended December 31, 2014 are as follows (in thousands):
		Year ended
		December 31,
		2014
	Revenue related to Biogen Collaboration:
	Recognition of upfront fee	$	5,313
	Research services		7,751
	Total	$	13,064
Shire AG [Member]
Revenues Recognized under Agreement	Revenues recognized under the Shire Agreement for the years ended December 31, 2014, 2013 and 2012, were as follows (in thousands):
		Year ended December 31,
		2014		2013		2012
	Revenue related to Shire Collaboration:
	Recognition of upfront fee	$	2,167	$	2,167	$	1,986
	Recognition of milestone		1,000		—		—
	Research services		22,765		14,286		9,026
	Total	$	25,932	$	16,453	$	11,012
Sigma-Aldrich Corporation [Member]
Revenues Recognized under Agreement	Revenues recognized under the agreement with Sigma for the years ended December 31, 2014, 2013 and 2012, were as follows (in thousands):
		Year ended December 31,
		2014		2013		2012
	Revenue related to Sigma Collaboration:
	Royalty revenues	$	344	$	824	$	1,288
	License fee and milestone revenues		448		1,351		1,000
	Total	$	792	$	2,175	$	2,288

Acquisition_of_Ceregene_Tables

Acquisition of Ceregene (Tables)	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Summary of Estimated Fair Value of Consideration Transferred	The following table summarizes the estimated fair value of the consideration transferred by Sangamo to the Ceregene stockholders on the Closing Date (in thousands):
	Sangamo shares of common stock	$	1,200
	Contingent earn-out		1,510
	Total purchase consideration	$	2,710
Summary of Estimated Fair Value of Net Assets Acquired	The following table summarizes the estimated fair value of the net assets acquired as of the Closing Date (in thousands):
	Cash and equivalents	$	79
	Accounts receivable		22
	Identifiable intangible assets		1,870
	Goodwill		1,585
	Total assets acquired		3,556
	Deferred tax liability		(748	)
	Accounts payable and accrued liabilities		(98	)
	Total liabilities assumed		(846	)
	Net assets acquired	$	2,710
Summary of Assets, Estimated Fair Values	A summary of these assets and estimated fair values at the Closing Date is as follows (in thousands):
		Value of Intangible
		Assets Acquired
	CERE-110 for the treatment of Alzheimer's disease	$	1,640
	CERE-120 for the treatment of Parkinson's disease		230
	Total identifiable intangible assets	$	1,870

Intangible_Assets_Tables

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Carrying Values of Intangibles Assets	The carrying values of these intangibles assets are as follows (in thousands):
		Year ended December 31,
		2014		2013
	CERE-110 for the treatment of Alzheimer's disease	$	1,640	$	1,640
	CERE-120 for the treatment of Parkinson's disease		230		230
	Total identifiable intangible assets	$	1,870	$	1,870

Property_and_Equipment_Tables

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property Plant And Equipment [Abstract]
Summary of Property and Equipment	Property and equipment consist of the following (in thousands):
		December 31,
		2014			2013
	Laboratory equipment	$	3,665		$	3,208
	Furniture and fixtures		550			563
	Leasehold improvements		1,163			1,156
			5,378			4,927
	Less accumulated depreciation and amortization		(3,899	)		(3,521	)
		$	1,479		$	1,406

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments And Contingencies Disclosure [Abstract]
Summary of Future Minimum Payments under Contractual Obligations	Future minimum payments under contractual obligations at December 31, 2014 consist of the following (in thousands):
		Operating
	Fiscal Year:	Lease
	2015	$	865
	2016		901
	2017		928
	2018		748
	2019		496
	Thereafter		—
	Total minimum payments	$	3,938

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Summary of Stock Option Activity	A summary of Sangamo’s stock option activity is as follows:
					Weighted-
					Average		Weighted Average		Aggregate
		Number of			Exercise per		Remaining		Intrinsic
		Shares			Share Price		Contractual Term		Value
							(In years)		(In thousands)
	Options outstanding at December 31, 2013		8,405,864		$	7.2
	Options granted		1,694,400		$	14.19
	Options exercised		(1,959,201	)	$	6.17
	Options canceled		(134,683	)	$	8.77
	Options outstanding at December 31, 2014		8,006,380		$	8.9		6.62	$	50,766
	Options vested and expected to vest at December 31, 2014		7,526,430		$	8.67		6.44	$	49,437
	Options exercisable at December 31, 2014		4,929,932		$	7.21		5.07	$	39,475
Summary of Stock Options Outstanding	The following table summarizes information with respect to stock options outstanding at December 31, 2014:
		Options Outstanding and Exercisable					Options Exercisable
		Number of					Number of
		Shares of					Shares of
		common stock			Weighted Average		common stock
		subject to			Remaining		subject to		Weighted Average
	Range of Exercise Price	options			Contractual Life		options		Exercise Price
					(In years)
	$2.55 – $3.45		950,512			4.41		880,721	$	3.37
	$3.80 – $5.35		898,399			5.01		874,189	$	5.27
	$5.41 – $5.41		985,758			7.9		436,290	$	5.41
	$5.42 – $5.42		50,000			5.24		50,000	$	5.42
	$5.70 – $5.70		804,771			5.94		804,771	$	5.7
	$5.94 – $11.03		809,679			5.12		713,466	$	6.7
	$11.35 – $11.88		59,250			2.38		38,750	$	11.76
	$12.12 – $12.12		942,287			8.95		234,592	$	12.12
	$12.23 – $13.99		750,324			4.66		548,824	$	13.97
	$14.07 – $23.02		1,755,400			8.67		348,329	$	14.32
			8,006,380			6.62		4,929,932	$	7.21
Summary of Restricted Stock Unit Activity	A summary of Sangamo’s RSU activity is as follows:
		Number			Weighted Average
		of			Remaining		Aggregate Intrinsic
		Shares			Contractual Term		Value
					(In years)		(In thousands)
	RSUs outstanding at December 31, 2013		1,063,657
	RSUs awarded		488,000
	RSUs released		(616,756	)
	RSUs forfeited		(35,499	)
	RSUs outstanding at December 31, 2014		899,402			1.61	$	13,680
	RSUs vested and expected to vest at December 31, 2014		754,931			1.55	$	11,482

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Company's Deferred Tax Assets	Significant components of the Company’s deferred tax assets are as follows (in thousands):
		December 31,
		2014			2013
	Assets:
	Deferred tax assets:
	Net operating loss carryforwards	$	90,921		$	81,944
	Research and development tax credit carryforwards		8,646			7,996
	Stock-based compensation		8,171			7,927
	Deferred revenue		2,690			3,563
	Other		2,471			1,677
	Total deferred tax asset		112,899			103,107
	Valuation allowance		(112,899	)		(103,107	)
	Net deferred tax assets	$	—		$	—
	Liabilities:
	Net deferred tax liability related to intangible assets		(748	)		(748	)
	Total deferred tax liability	$	(748	)	$	(748	)
Summary of Activity Related to Company's Unrecognized Tax Benefits	The following table summarizes the activity related to the Company’s unrecognized tax benefits (in thousands):
		December 31,
		2014			2013			2012
	Beginning balance	$	3,182		$	2,735		$	2,750
	Additions based on tax positions related to the current year		228			294			153
	Additions for tax positions of prior years		28			153			59
	Reductions for tax positions of prior years		—			—			(227	)
	Ending balance	$	3,438		$	3,182		$	2,735

Accounts_Payable_and_Accrued_L1

Accounts Payable and Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Payables And Accruals [Abstract]
Summary of Accounts Payable and Accrued Liabilities	Accounts payable and accrued liabilities consist of the following (in thousands):
		December 31,
		2014		2013
	Accounts payable	$	5,525	$	3,022
	Accrued research and development expenses		2,435		727
	Accrued professional fees		531		510
	Deferred rent		129		121
	Other		84		—
	Total accounts payable and accrued liabilities	$	8,704	$	4,380

Quarterly_Financial_Data_Unaud1

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Summary of Quarterly Financial Data	The following table sets forth certain unaudited quarterly financial data for the eight quarters ended December 31, 2014.
		2014												2013
		Q1			Q2			Q3			Q4			Q1			Q2			Q3			Q4
	Revenues	$	8,116		$	10,385		$	12,417		$	14,952		$	4,623		$	6,934		$	5,707		$	6,869
	Expenses	$	15,727		$	17,432		$	20,071		$	19,421		$	11,528		$	12,402		$	11,866		$	15,043
	Net loss	$	(7,572	)	$	(6,981	)	$	(7,545	)	$	(4,319	)	$	(6,885	)	$	(5,450	)	$	(6,145	)	$	(8,144	)
	Net loss per share	$	(0.12	)	$	(0.10	)	$	(0.11	)	$	(0.06	)	$	(0.13	)	$	(0.10	)	$	(0.11	)	$	(0.13	)

Organization_and_Summary_of_Si2

Organization and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Organization and Summary of Significant Accounting Policies [Line Items]
Liquid investments purchased with original maturities	three months or less
Restricted cash	320	320
Percentage of likelihood of indefinite lived intangible assets being impaired	50.00%
Stock options outstanding	8,006,380	8,405,864	9,184,346
Number of operating segments	1
Shire AG [Member] | Customer Concentration Risk [Member] | Total revenues [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Percentage of revenues	57.00%	68.00%	51.00%
Biogen [Member] | Customer Concentration Risk [Member] | Total revenues [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Percentage of revenues	28.00%
Sigma-Aldrich Corporation [Member] | Customer Concentration Risk [Member] | Total revenues [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Percentage of revenues		9.00%	11.00%
Dow AgroSciences LLC [Member] | Customer Concentration Risk [Member] | Total revenues [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Percentage of revenues		12.00%	22.00%
Minimum [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Estimated useful lives of related assets	3 years
Maximum [Member]
Organization and Summary of Significant Accounting Policies [Line Items]
Estimated useful lives of related assets	5 years

Fair_Value_Measurement_Summary

Fair Value Measurement - Summary of Fair Value Measurements of Cash Equivalents, Available-for-Sale Securities and Contingent Consideration Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	$3,182	$6,934
Total marketable securities	220,192
Total cash equivalents and marketable securities	223,374	128,224
Total contingent consideration liabilities	1,800	1,570
Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	3,182	6,934
Commercial paper securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	33,748
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	3,182	6,934
Total cash equivalents and marketable securities	3,182	6,934
Level 1 [Member] | Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	3,182	6,934
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	220,192
Total cash equivalents and marketable securities	220,192	121,290
Level 2 [Member] | Commercial paper securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	33,748
Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total contingent consideration liabilities	1,800	1,570
Corporate debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	22,813
Corporate debt securities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	22,813
U.S. government sponsored entity debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	163,631	121,290
U.S. government sponsored entity debt securities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	163,631	121,290
Contingent consideration liability [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total contingent consideration liabilities	1,800	1,570
Contingent consideration liability [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total contingent consideration liabilities	$1,800	$1,570

Fair_Value_Measurement_Additio

Fair Value Measurement - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]
Change in fair value of contingent liability	$230	$60

Fair_Value_Measurement_Schedul

Fair Value Measurement - Schedule of Changes in Estimated Fair Value of Contingent Consideration Liability (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair value as of December 31, 2013	$1,570
Change in fair value	230
Fair value as of December 31, 2014	$1,800

Marketable_Securities_Summary_

Marketable Securities - Summary of Cash Equivalents and Available-for-Sale Securities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	$6,030	$10,186	$21,679	$16,766
Total cash equivalents	3,182	6,934
Amortized Cost	223,399	128,212
Gross Unrealized Gains	33	12
Gross Unrealized (Losses)	-58
Estimated Fair Value	223,374	128,224
Cash equivalents [Member]
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	3,182	6,934
Total cash equivalents	3,182	6,934
Available-for-sale securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	220,217
Gross Unrealized Gains	33
Gross Unrealized (Losses)	-58
Estimated Fair Value	220,192
Money market funds [Member] | Cash equivalents [Member]
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	3,182	6,934
Total cash equivalents	3,182	6,934
Commercial paper securities [Member] | Available-for-sale securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	33,715
Gross Unrealized Gains	33
Estimated Fair Value	33,748
Corporate debt securities [Member] | Available-for-sale securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	22,831
Gross Unrealized (Losses)	-18
Estimated Fair Value	22,813
U.S. government sponsored entity debt securities [Member] | Available-for-sale securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	163,671	121,278
Gross Unrealized Gains		12
Gross Unrealized (Losses)	-40
Estimated Fair Value	$163,631	$121,290

Marketable_Securities_Addition

Marketable Securities - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Investments Debt And Equity Securities [Abstract]
Investments maturity period	2 years
Available for sale securities maturity percentage next twelve months	79.00%
Available for sale securities maturity percentage in twelve and twenty four months	21.00%
Realized losses	$0	$0	$0
Other-than-temporary impairments of available-for-sale securities	$0	$0	$0

StockBased_Compensation_StockB

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Costs and expenses:
Total stock-based compensation expense	$9,200	$6,146	$5,338
Research and development [Member]
Costs and expenses:
Total stock-based compensation expense	5,064	3,204	2,892
General and administrative [Member]
Costs and expenses:
Total stock-based compensation expense	$4,136	$2,942	$2,446

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost related to unvested stock options and RSU	$17,200,000
Weighted-average period of unvested stock options and RSU	3 years 15 days
Capitalized stock-based employee compensation expense	0
Weighted-average estimated fair value per share of options granted	$8.16	$8.29	$3.76
Issuance of common stock under employee stock purchase plan, shares	107,203	180,551	175,375
Stock issued under employee stock purchase plans, average exercise price	$7.92	$2.75	$2.61
Weighted-average estimated fair value of shares purchased under ESPP plan	$3.25	$1.47	$2.51
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost related to unvested stock options and RSU	$8,500,000
Weighted-average period of unvested stock options and RSU	2 years 3 months 18 days

StockBased_Compensation_Assump

Stock-Based Compensation - Assumptions Used for Estimating Fair Value of Employee Stock Options (Detail) (Employee Stock Option [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield of stock	0.00%	0.00%	0.00%
Expected volatility		0.88%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.60%	1.50%	0.74%
Expected life of option (in years)	5 years 3 months 11 days	5 years 4 months 10 days	5 years 4 months 24 days
Expected volatility	0.66%		0.87%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.70%	1.88%	1.34%
Expected life of option (in years)	5 years 3 months 29 days	5 years 4 months 17 days	5 years 6 months 29 days
Expected volatility	0.69%		0.88%

StockBased_Compensation_Weight

Stock-Based Compensation - Weighted-Average Assumptions Used for Estimating Fair Value of ESPP Purchased Rights (Detail) (2010 Employee Stock Purchase Plan [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield of stock	0.00%	0.00%	0.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.05%	0.05%	0.05%
Expected life of option (in years)	6 months	6 months	6 months
Expected volatility	0.52%	0.51%	0.93%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.30%	0.61%	0.30%
Expected life of option (in years)	2 years	2 years	2 years
Expected volatility	0.75%	0.85%	1.37%

Major_Customers_Partnerships_a2

Major Customers, Partnerships and Strategic Alliances - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended			0 Months Ended	1 Months Ended		3 Months Ended
	Jan. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Jun. 30, 2012	Jan. 31, 2012	Sep. 30, 2014
	Program				Product	Targets	Targets
	Company
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Number of companies jointly conducting research program	2
Number of research programs	2
Research and development		$56,744,000	$36,979,000	$31,709,000
Biogen [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenues under agreement	20,000,000
Potential amount eligible to receive for certain milestones	126,300,000
Potential amount to be funded for achievement of specified commercialized and sales milestones	167,500,000
Milestone revenue receivable	293,800,000
Number of licensed products approved under agreement					0
Research program to develop laboratory research reagents		40 months
Deferred revenue		14,900,000			14,900,000
Biogen [Member] | Beta-thalassemia [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone revenue receivable	7,500,000
Research and development		5,200,000
Biogen [Member] | Sickle cell disease [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone revenue receivable	7,500,000
Biogen [Member] | Other Projects
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development		3,500,000
Shire AG [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenues under agreement							13,000,000
Potential amount to be funded for achievement of specified commercialized and sales milestones							180,000,000
Milestone revenue receivable							33,500,000
Research program to develop laboratory research reagents		6 years
Deferred revenue		6,800,000			6,800,000
Research and development		21,100,000	14,200,000	7,700,000
Aggregate number of gene targets							7
Number of initial gene targets							4
Number of gene targets						5
Number of additional gene targets						2
IND or CTA submission amount							8,500,000
Potential amount to be funded for certain Shire milestones							213,500,000
Milestone payment		1,000,000						1,000,000
Number of products approved		0
Royalty revenues		$0

Major_Customers_Partnerships_a3

Major Customers, Partnerships and Strategic Alliances - Revenues Recognized under Agreement (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Biogen [Member]
Revenue related to Biogen Collaboration:
Recognition of upfront fee		$5,313
Research services		7,751
Total		13,064
Shire AG [Member]
Revenue related to Biogen Collaboration:
Recognition of milestone	1,000	1,000
Royalty revenues		0
Research services		22,765	14,286	9,026
Total		25,932	16,453	11,012
Shire AG [Member] | Upfront Fee And Milestone Revenue
Revenue related to Biogen Collaboration:
Recognition of upfront fee		2,167	2,167	1,986
Sigma-Aldrich Corporation [Member]
Revenue related to Biogen Collaboration:
Royalty revenues		344	824	1,288
License fee and milestone revenues		448	1,351	1,000
Total		$792	$2,175	$2,288

Major_Customers_Partnerships_a4

Major Customers, Partnerships and Strategic Alliances - Agreement with Sigma-Aldrich Corporation - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 31, 2009	Jul. 31, 2007
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Common stock issued under license agreement	$93,796,000	$69,492,000
Research and development	56,744,000	36,979,000	31,709,000
Sigma-Aldrich Corporation [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research program to develop laboratory research reagents					3 years
Upfront license fee				20,000,000
Public offering, common stock shares issued				636,133
Reduced royalty rate				10.50%
Funding available under the amended agreement				25,000,000
Sigma-Aldrich Corporation [Member] | Upfront license fee [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Upfront license fee				15,100,000
Common stock issued under license agreement				4,900,000
Sigma-Aldrich Corporation [Member] | License agreement terms [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty revenues expected to be received				5,000,000
Research and development	$100,000	$200,000	$300,000

Major_Customers_Partnerships_a5

Major Customers, Partnerships and Strategic Alliances - Agreement with Dow AgroSciences in Plant Agriculture - Additional Information (Detail) (Dow Agro Sciences [Member], License agreement terms [Member], USD $)	1 Months Ended	12 Months Ended
	Oct. 31, 2005	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research program to develop laboratory research reagents	3 years
One-time license fee earned on exercise of option	$6,000,000
Royalty revenues	2,300,000
Percentage of royalties to be received from sublicensing	25.00%
Previously agreed research, development and commercialization milestone payments, and royalties on sales of products	4,000,000
Fee due	25,300,000
Minimum license annual fees specific reckoning period	11 years
Collaboration agreement related costs and expenses		0	400,000	600,000
Revenue attributable to research and development		3,000,000	3,000,000	4,700,000
Minimum [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Annual fees	250,000
Maximum [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Annual fees	$3,000,000

Major_Customers_Partnerships_a6

Major Customers, Partnerships and Strategic Alliances - California Institute for Regenerative Medicine - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	31-May-14	Oct. 31, 2009	31-May-13
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Receivables from sale against the grant funded to entity from sale of product	Two times the amount Sangamo receives in funding under the agreement.
Research grants	$1,990,000	$2,455,000	$3,469,000
California Institute for Regenerative Medicine [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Funds due under the agreement				5,600,000	14,500,000
Expected amount to be received for research and development					5,200,000
Agreement to receive				4 years	4 years
Agreement date	31-Oct-09
Collaboration agreement related costs and expenses	1,800,000	1,800,000	1,200,000
California Institute for Regenerative Medicine [Member] | License agreement terms [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research grants	0	1,200,000	1,200,000
California Institute for Regenerative Medicine [Member] | Beta-thalassemia [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Funds due under the agreement						6,400,000
Research grants	1,400,000	100,000
Collaboration agreement related costs and expenses	$1,100,000	$400,000
Agreement to receive						4 years

Major_Customers_Partnerships_a7

Major Customers, Partnerships and Strategic Alliances - CHDI Foundation, Inc. - Additional Information (Detail) (CHDI Foundation, Inc. [Member], USD $)	1 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Apr. 30, 2011	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
CHDI Foundation, Inc. [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Funds due under agreement	$1.30
Agreement date		30-Apr-11
Agreement to receive	1 year
Contractual agreement termination date		31-Aug-12
Funds due under agreement as per amendment			1.3	2.1
Collaboration agreement related costs and expenses		0	0	1.1
Revenues under the agreement		$0	$0	$1.10

Major_Customers_Partnerships_a8

Major Customers, Partnerships and Strategic Alliances - Juvenile Diabetes Research Foundation International - Additional Information (Detail) (Juvenile Diabetes Research Foundation International [Member], USD $)	1 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2012	Jan. 31, 2010	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Juvenile Diabetes Research Foundation International [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Agreement date			31-Oct-06
Grant funding amount maximum under amended agreement		$3
Received for work performed under agreement	0.8
Revenues under the agreement			$0	$0	$0.80

Acquisition_of_Ceregene_Additi

Acquisition of Ceregene - Additional Information (Detail) (USD $)	1 Months Ended	15 Months Ended
	Oct. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill		$1,585,000	$1,585,000
Ceregene, Inc. [Member]
Business Acquisition [Line Items]
Common stock, transferred, shares	100,000
Sangamo shares of common stock	1,200,000
Purchase price deposited in escrow account	300,000
Estimated fair values of in-process research and development	1,900,000
Goodwill	1,585,000
Changes to the assets acquired or liabilities assumed, including goodwill		0
Fair value liability for contingent consideration recognized	$1,500,000	$1,800,000

Acquisition_of_Ceregene_Summar

Acquisition of Ceregene - Summary of Estimated Fair Value of Consideration Transferred (Detail) (Ceregene, Inc. [Member], USD $)	1 Months Ended
In Thousands, unless otherwise specified	Oct. 31, 2013
Ceregene, Inc. [Member]
Business Acquisition [Line Items]
Sangamo shares of common stock	$1,200
Contingent earn-out	1,510
Total purchase consideration	$2,710

Acquisition_of_Ceregene_Summar1

Acquisition of Ceregene - Summary of Estimated Fair Value of Net Assets Acquired (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Oct. 31, 2013
In Thousands, unless otherwise specified
Business Acquisition [Line Items]
Goodwill	$1,585	$1,585
Ceregene, Inc. [Member]
Business Acquisition [Line Items]
Cash and equivalents			79
Accounts receivable			22
Identifiable intangible assets			1,870
Goodwill			1,585
Total assets acquired			3,556
Deferred tax liability			-748
Accounts payable and accrued liabilities			-98
Total liabilities assumed			-846
Net assets acquired			$2,710

Acquisition_of_Ceregene_Summar2

Acquisition of Ceregene - Summary of Assets, Estimated Fair Values (Detail) (Ceregene, Inc. [Member], USD $)	Oct. 31, 2013
In Thousands, unless otherwise specified
Business Acquisition [Line Items]
Identifiable intangible assets	$1,870
CERE-110 for the treatment of Alzheimer's disease ("IPR&D") [Member]
Business Acquisition [Line Items]
Identifiable intangible assets	1,640
CERE-120 for the treatment of Parkinson's disease ("IPR&D") [Member]
Business Acquisition [Line Items]
Identifiable intangible assets	$230

Intangible_Assets_Carrying_Val

Intangible Assets - Carrying Value of Intangibles Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets	$1,870	$1,870
CERE-110 for the treatment of Alzheimer's disease ("IPR&D") [Member]
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets	1,640	1,640
CERE-120 for the treatment of Parkinson's disease ("IPR&D") [Member]
Finite-Lived Intangible Assets [Line Items]
Total identifiable intangible assets	$230	$230

Property_and_Equipment_Summary

Property and Equipment - Summary of Property and Equipment (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$5,378	$4,927
Less accumulated depreciation and amortization	-3,899	-3,521
Property and equipment, Net	1,479	1,406
Laboratory equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	3,665	3,208
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	550	563
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$1,163	$1,156

Property_and_Equipment_Additio

Property and Equipment - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property Plant And Equipment [Abstract]
Depreciation and amortization	$549,000	$569,000	$660,000
Disposition of fixed assets			500,000
Accumulated depreciation			400,000
Write-off of assets	$100,000

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments And Contingencies Disclosure [Abstract]
Rent expenses	$0.70	$0.70	$0.60
Lease expiration date	31-Jan-18

Commitments_and_Contingencies_2

Commitments and Contingencies - Summary of Future Minimum Payments under Contractual Obligations (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Commitments And Contingencies Disclosure [Abstract]
2015	$865
2016	901
2017	928
2018	748
2019	496
Total minimum payments	$3,938

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 25, 2014	Sep. 23, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred shares authorized	5,000,000
Proceeds from public offering of common stock, net of issuance costs	$93,796,000	$69,492,000
Stock option maximum term	5 years 26 days
Specified stockholder ownership percentage	10.00%
Purchase price of common stock percent under stock incentive plans for specified stockholder	110.00%
Stock option maximum term for specified stockholder	5 years
Share of common stock subject to a stock option or stock appreciation right	1
Fixed ratio shares of common stock	1.33
Intrinsic value of options exercised	20,400,000	8,900,000	600,000
Options outstanding, Aggregate Intrinsic Value	50,766,000
Options exercisable, Aggregate Intrinsic Value	39,475,000
Options vested and expected to vest, aggregate intrinsic value	49,400,000	54,900,000	8,500,000
Restricted stock units awarded	488,000
Aggregate value of shares vested in period	9,100,000	4,100,000	100,000
Total payments for the employees' tax obligations to taxing authorities	4,556,000	2,015,000
2013 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of fair value per share of common stock on option grant date	100.00%
Stock options vesting period	4 years
Stock options expiration term	10 years
Stock reserved for issuance under plan	14,100,000
Additional shares authorized under 2013 stock incentive plan	4,400,000
Shares reserved for issuance of future awards	768,044
2004 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock reserved for issuance under plan	9,700,000
2010 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of fair value per share of common stock on option grant date	85.00%
Stock reserved for issuance under plan	2,100,000
Purchase plan offering period	2 years
Purchase plan purchase period	6 months
Shares reserved for issuance of future awards	1,420,560
Maximum [Member] | 2013 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option maximum term	10 years
Stock Option Activity [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares subject to repurchase rights	0
Stock Option Activity [Member] | 2013 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based vesting rights	Options granted under the 2013 Plan generally vest over four years at a rate of 25 percent one year from the grant date and one thirty-sixth per month thereafter and expire ten years after the grant, or earlier upon employment termination.
Stock options granted vesting percentage	25.00%
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based vesting rights	These awards will vest as follows: one-third of the award will vest in a series of three successive equal annual installments.
Restricted stock units awarded	488,000	392,500
Grant date fair value of restricted stock units awarded	$14.05	$12.12
Share-based compensation arrangement by share-based payment award, number of vesting installment	3
Share-based compensation arrangement by share-based payment award, vesting portion	0.33%
Shares withheld from issuance in order to pay employee taxes	309,102	167,138	0
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Public offering, common stock shares issued	4,444,444	7,015,000		4,444,444	7,015,000
Public offering price of common stock issued				$22.50	$10.58
Proceeds from public offering of common stock, net of issuance costs				$93,800,000	$69,500,000
Underwriters | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of stock, number of shares issued in transaction					915,000

Stockholders_Equity_Summary_of

Stockholders' Equity - Summary of Stock Option Activity (Detail) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding at December 31, 2013	8,405,864	9,184,346
Options granted	1,694,400
Options exercised	-1,959,201
Options canceled	-134,683
Options outstanding at December 31, 2014	8,006,380	9,184,346
Options vested and expected to vest at December 31, 2014	7,526,430
Options exercisable at December 31, 2014	4,929,932
Options outstanding, Weighted-Average Exercise per Share Price, Beginning Balance	$7.20
Options granted, Weighted-Average Exercise per Share Price	$14.19
Options exercised, Weighted-Average Exercise per Share Price	$6.17
Options canceled, Weighted-Average Exercise per Share Price	$8.77
Options outstanding, Weighted-Average Exercise per Share Price, Ending Balance	$8.90
Options vested and expected to vest at December 31, 2013, Weighted-Average Exercise Per Share Price	$8.67
Options exercisable at December 31, 2013, Weighted-Average Exercise per Share Price	$7.21
Options outstanding, Weighted Average Remaining Contractual Term, Beginning	6 years 7 months 13 days
Options outstanding, Weighted Average Remaining Contractual Term, Ending	6 years 7 months 13 days
Options vested and expected to vest at December, 31, 2014, Weighted Average Remaining Contractual Term	6 years 5 months 9 days
Options exercisable at December, 31, 2014, Weighted Average Remaining Contractual Term	5 years 26 days
Options outstanding, Aggregate Intrinsic Value	$50,766
Options vested and expected to vest at December 31, 2014, Aggregate Intrinsic Value	49,437
Options exercisable at December 31, 2014, Aggregate Intrinsic Value	$39,475

Stockholders_Equity_Summary_of1

Stockholders' Equity - Summary of Stock Options Outstanding (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Options Outstanding and Exercisable Number of Shares of common stock subject to options	8,006,380
Options Outstanding and Exercisable Weighted Average Remaining Contractual Life (In years)	6 years 7 months 13 days
Options Exercisable Number of Shares of common stock subject to options	4,929,932
Options Exercisable Weighted Average Exercise Price	$7.21
Range 1 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Lower Range of Exercise Price	$2.55
Upper Range of Exercise Price	$3.45
Options Outstanding and Exercisable Number of Shares of common stock subject to options	950,512
Options Outstanding and Exercisable Weighted Average Remaining Contractual Life (In years)	4 years 4 months 28 days
Options Exercisable Number of Shares of common stock subject to options	880,721
Options Exercisable Weighted Average Exercise Price	$3.37
Range 2 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Lower Range of Exercise Price	$3.80
Upper Range of Exercise Price	$5.35
Options Outstanding and Exercisable Number of Shares of common stock subject to options	898,399
Options Outstanding and Exercisable Weighted Average Remaining Contractual Life (In years)	5 years 4 days
Options Exercisable Number of Shares of common stock subject to options	874,189
Options Exercisable Weighted Average Exercise Price	$5.27
Range 3 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Lower Range of Exercise Price	$5.41
Upper Range of Exercise Price	$5.41
Options Outstanding and Exercisable Number of Shares of common stock subject to options	985,758
Options Outstanding and Exercisable Weighted Average Remaining Contractual Life (In years)	7 years 10 months 24 days
Options Exercisable Number of Shares of common stock subject to options	436,290
Options Exercisable Weighted Average Exercise Price	$5.41
Range 4 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Lower Range of Exercise Price	$5.42
Upper Range of Exercise Price	$5.42
Options Outstanding and Exercisable Number of Shares of common stock subject to options	50,000
Options Outstanding and Exercisable Weighted Average Remaining Contractual Life (In years)	5 years 2 months 27 days
Options Exercisable Number of Shares of common stock subject to options	50,000
Options Exercisable Weighted Average Exercise Price	$5.42
Range 5 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Lower Range of Exercise Price	$5.70
Upper Range of Exercise Price	$5.70
Options Outstanding and Exercisable Number of Shares of common stock subject to options	804,771
Options Outstanding and Exercisable Weighted Average Remaining Contractual Life (In years)	5 years 11 months 9 days
Options Exercisable Number of Shares of common stock subject to options	804,771
Options Exercisable Weighted Average Exercise Price	$5.70
Range 6 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Lower Range of Exercise Price	$5.94
Upper Range of Exercise Price	$11.03
Options Outstanding and Exercisable Number of Shares of common stock subject to options	809,679
Options Outstanding and Exercisable Weighted Average Remaining Contractual Life (In years)	5 years 1 month 13 days
Options Exercisable Number of Shares of common stock subject to options	713,466
Options Exercisable Weighted Average Exercise Price	$6.70
Range 7 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Lower Range of Exercise Price	$11.35
Upper Range of Exercise Price	$11.88
Options Outstanding and Exercisable Number of Shares of common stock subject to options	59,250
Options Outstanding and Exercisable Weighted Average Remaining Contractual Life (In years)	2 years 4 months 17 days
Options Exercisable Number of Shares of common stock subject to options	38,750
Options Exercisable Weighted Average Exercise Price	$11.76
Range 8 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Lower Range of Exercise Price	$12.12
Upper Range of Exercise Price	$12.12
Options Outstanding and Exercisable Number of Shares of common stock subject to options	942,287
Options Outstanding and Exercisable Weighted Average Remaining Contractual Life (In years)	8 years 11 months 12 days
Options Exercisable Number of Shares of common stock subject to options	234,592
Options Exercisable Weighted Average Exercise Price	$12.12
Range 9 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Lower Range of Exercise Price	$12.23
Upper Range of Exercise Price	$13.99
Options Outstanding and Exercisable Number of Shares of common stock subject to options	750,324
Options Outstanding and Exercisable Weighted Average Remaining Contractual Life (In years)	4 years 7 months 28 days
Options Exercisable Number of Shares of common stock subject to options	548,824
Options Exercisable Weighted Average Exercise Price	$13.97
Range 10 [Member]
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Lower Range of Exercise Price	$14.07
Upper Range of Exercise Price	$23.02
Options Outstanding and Exercisable Number of Shares of common stock subject to options	1,755,400
Options Outstanding and Exercisable Weighted Average Remaining Contractual Life (In years)	8 years 8 months 1 day
Options Exercisable Number of Shares of common stock subject to options	348,329
Options Exercisable Weighted Average Exercise Price	$14.32

Stockholders_Equity_Summary_of2

Stockholders' Equity - Summary of Restricted Stock Unit Activity (Detail) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
RSUs outstanding at December 31, 2013	1,063,657
RSUs awarded	488,000
RSUs released	-616,756
RSUs forfeited	-35,499
RSUs outstanding at December 31, 2014	899,402
RSUs vested and expected to vest at December 31, 2013	754,931
RSUs outstanding at December, 31, 2014, Weighted-Average Remaining Contractual Term	1 year 7 months 10 days
RSUs vested and expected to vest at December 31, 2014, Weighted-Average Remaining Contractual Term	1 year 6 months 18 days
RSUs outstanding at December 31, 2014, Aggregate Intrinsic Value	$13,680
RSUs vested and expected to vest at December 31, 2014, Aggregate Intrinsic Value	$11,482

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes [Line Items]
Income tax expense	$0
Statutory tax rate	34.00%
Valuation allowance	112,899,000	103,107,000
Increase in deferred tax assets valuation allowance	9,800,000	14,900,000	5,400,000
Deferred tax assets, net operating loss carryforwards for federal	330,900,000
Deferred tax assets, net operating loss carryforwards for state	278,100,000
Federal research tax credit carryforwards	6,700,000
State research tax credit carryforwards	7,000,000
Tax credit carryforward, expiration year	2018
Accrued interest and/or penalties	0
State
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2015
Federal
Income Taxes [Line Items]
Operating loss carryforwards, expiration year	2018
Indefinite-lived assets [Member]
Income Taxes [Line Items]
Valuation allowance	$0

Income_Taxes_Schedule_of_Compa

Income Taxes - Schedule of Company's Deferred Tax Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred tax assets:
Net operating loss carryforwards	$90,921	$81,944
Research and development tax credit carryforwards	8,646	7,996
Stock-based compensation	8,171	7,927
Deferred revenue	2,690	3,563
Other	2,471	1,677
Total deferred tax asset	112,899	103,107
Valuation allowance	-112,899	-103,107
Liabilities:
Net deferred tax liability related to intangible assets	-748	-748
Total deferred tax liability	($748)	($748)

Income_Taxes_Summary_of_Activi

Income Taxes - Summary of Activity Related to Company's Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Beginning balance	$3,182	$2,735	$2,750
Additions based on tax positions related to the current year	228	294	153
Additions for tax positions of prior years	28	153	59
Reductions for tax positions of prior years			-227
Ending balance	$3,438	$3,182	$2,735

Accounts_Payable_and_Accrued_L2

Accounts Payable and Accrued Liabilities - Summary of Accounts Payable and Accrued Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Payables And Accruals [Abstract]
Accounts payable	$5,525	$3,022
Accrued research and development expenses	2,435	727
Accrued professional fees	531	510
Deferred rent	129	121
Other	84
Total accounts payable and accrued liabilities	$8,704	$4,380

Employee_Benefit_Plan_Addition

Employee Benefit Plan - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Compensation And Retirement Disclosure [Abstract]
Defined contribution plan, employer's matching contribution percent	50.00%
Employers matching contribution percentage towards employees contribution	6.00%
Defined contribution plan, maximum employer's contribution per employee	$2,000	$1,500
Aggregate employers contributions to defined contribution plan	$200,000	$100,000	$100,000

Quarterly_Financial_Data_Unaud2

Quarterly Financial Data (Unaudited) - Summary of Quarterly Financial Data (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Selected Quarterly Financial Information [Abstract]
Revenues	$14,952	$12,417	$10,385	$8,116	$6,869	$5,707	$6,934	$4,623	$45,870	$24,133	$21,655
Expenses	19,421	20,071	17,432	15,727	15,043	11,866	12,402	11,528	72,651	50,839	43,853
Net loss	($4,319)	($7,545)	($6,981)	($7,572)	($8,144)	($6,145)	($5,450)	($6,885)	($26,417)	($26,624)	($22,264)
Net loss per share	($0.06)	($0.11)	($0.10)	($0.12)	($0.13)	($0.11)	($0.10)	($0.13)	($0.39)	($0.48)	($0.42)