Sangamo Therapeutics (SGMO) 10-Q 27 Oct 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 24, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Trading Symbol	SGMO
Entity Registrant Name	SANGAMO BIOSCIENCES INC
Entity Central Index Key	1,001,233
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		70,623,858

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 27,986	$ 69,482
Marketable securities	117,595	139,518
Interest receivable	310	307
Accounts receivable	1,482	2,521
Prepaid expenses	1,472	754
Total current assets	148,845	212,582
Marketable securities, non-current	9,507
Property and equipment, net	4,882	2,916
Goodwill	1,585	1,585
Other assets	159	152
Total assets	164,978	217,235
Current liabilities:
Accounts payable and accrued liabilities	6,317	8,229
Accrued compensation and employee benefits	2,837	2,748
Deferred revenues	4,714	9,120
Total current liabilities	13,868	20,097
Deferred revenues, non-current	5,018	4,699
Build-to-suit lease obligation	2,256
Total liabilities	21,142	24,796
Commitments and contingencies
Stockholders' equity:
Common stock, $0.01 par value; 160,000,000 shares authorized, 70,621,837 and 70,354,608 shares issued and outstanding at September 30, 2016 and December 31, 2015, respectively	706	703
Additional paid-in capital	574,340	560,989
Accumulated deficit	(431,287)	(369,253)
Accumulated other comprehensive income	77
Total stockholders' equity	143,836	192,439
Total liabilities and stockholders' equity	$ 164,978	$ 217,235

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	160,000,000	160,000,000
Common stock, shares issued	70,621,837	70,354,608
Common stock, shares outstanding	70,621,837	70,354,608

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues:
Collaboration agreements	$ 2,728	$ 8,406	$ 10,031	$ 28,878
Research grants	95	163	436	1,540
Total revenues	2,823	8,569	10,467	30,418
Operating expenses:
Research and development	17,008	16,694	51,728	47,292
General and administrative	5,021	4,560	21,468	14,309
Total operating expenses	22,029	21,254	73,196	61,601
Loss from operations	(19,206)	(12,685)	(62,729)	(31,183)
Interest and other income, net	238	101	668	406
Loss before income taxes	(18,968)	(12,584)	(62,061)	(30,777)
Benefit from income taxes	3	3,339	27	4,087
Net loss	$ (18,965)	$ (9,245)	$ (62,034)	$ (26,690)
Basic and diluted net loss per share	$ (0.27)	$ (0.13)	$ (0.88)	$ (0.38)
Shares used in computing basic and diluted net loss per share	70,618	69,892	70,493	69,622

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (18,965)	$ (9,245)	$ (62,034)	$ (26,690)
Change in unrealized gain (loss) on available-for-sale securities, net	(14)	57	77	79
Comprehensive loss	$ (18,979)	$ (9,188)	$ (61,957)	$ (26,611)

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating Activities:
Net loss	$ (62,034)	$ (26,690)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	745	745
Amortization of premium on marketable securities	159	681
Stock-based compensation	13,128	8,664
Change in fair value of contingent consideration liability		(1,800)
Intangible impairment		1,870
Other	54
Benefit from income taxes	(27)	(4,087)
Net changes in operating assets and liabilities:
Interest receivable	(3)	24
Accounts receivable	1,039	3,364
Prepaid expenses and other assets	(725)	129
Accounts payable and accrued liabilities	(1,919)	(2,534)
Accrued compensation and employee benefits	89	(74)
Deferred revenues	(4,087)	(4,908)
Net cash used in operating activities	(53,581)	(24,616)
Investing Activities:
Purchases of marketable securities	(188,129)	(168,627)
Maturities of marketable securities	200,497	203,175
Purchases of property and equipment	(509)	(2,327)
Net cash provided by investing activities	11,859	32,221
Financing Activities:
Taxes paid related to net share settlement of equity awards	(534)	(48)
Proceeds from issuance of common stock	760	6,248
Claims settlement under Section 16(b)		14,452
Net cash provided by financing activities	226	20,652
Net increase / (decrease) in cash and cash equivalents	(41,496)	28,257
Cash and cash equivalents, beginning of period	69,482	6,030
Cash and cash equivalents, end of period	27,986	$ 34,287
Supplemental disclosure of noncash investing activities:
Property and equipment included in accrued liabilities	$ 2,202

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	NOTE 1—BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying unaudited condensed consolidated financial statements of Sangamo BioSciences, Inc. (“Sangamo” or the “Company”) have been prepared in accordance with U.S. generally accepted accounting principles for interim financial information and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included. Operating results for the three and nine months ended September 30, 2016 are not necessarily indicative of the results that may be expected for the year ending December 31, 2016. The condensed consolidated balance sheet data at December 31, 2015 were derived from the audited consolidated financial statements included in Sangamo’s Form 10-K for the year ended December 31, 2015, as filed with the SEC. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited financial statements and footnotes thereto for the year ended December 31, 2015, included in Sangamo’s Form 10-K, as filed with the SEC. Use of Estimates 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. On an ongoing basis, management evaluates its estimates, including critical accounting policies or estimates related to revenue recognition, clinical trial accruals, and stock-based compensation. Estimates are based on historical experience and on various other market specific and other relevant assumptions that the Company believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates. During the first quarter of 2016, we revised the estimated performance period of the upfront Biogen license through June 2019. This change increased net loss by $0.9 million and $2.7 million for the three and nine months ended September 30, 2016, respectively. The change in the performance period also increased our basic net loss per share by $0.02 and $0.04 for the three and nine months ended September 30, 2016, respectively. 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. 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 Vendor Specific Objective Evidence (“VSOE”) of selling price or Third Party Evidence (“TPE”) of selling price. If neither exists, the Company uses Estimated Selling Price (“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 Inc., formerly Biogen Idec Inc. (Biogen) in January 2014, as amended, 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 the 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. Recent Accounting Standards In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-09, Improvements to Employee Share-Based Payment Accounting In February 2016, the FASB issued ASU 2016-02, Leases In August 2014, the FASB issued ASU 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern In May 2014 the FASB issued ASU 2014-09, Revenue from Contracts with Customers

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurement	NOTE 2—FAIR VALUE MEASUREMENT The Company measures certain financial assets and liabilities at fair value on a recurring basis, including cash equivalents, and available-for sale-securities. The fair values of these assets were 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; and 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 the Company’s cash equivalents, and available-for-sale marketable securities are identified at the following levels within the fair value hierarchy (in thousands): September 30, 2016 Fair Value Measurements Total Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 24,113 $ 24,113 $ — $ — U.S. government sponsored entity debt securities 3,002 — 3,002 — Total 27,115 24,113 3,002 — Marketable securities: Commercial paper securities 25,729 — 25,729 — Corporate debt securities 10,009 — 10,009 — U.S. government sponsored entity debt securities 91,364 — 91,364 — Total 127,102 — 127,102 — Total cash equivalents and marketable securities $ 154,217 $ 24,113 $ 130,104 $ — December 31, 2015 Fair Value Measurements Total Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 25,070 $ 25,070 $ — $ — Commercial paper securities 2,000 2,000 — — U.S. government sponsored entity debt securities 38,867 38,867 — — Total 65,937 65,937 — — Marketable securities: Commercial paper securities 30,717 — 30,717 — Corporate debt securities 17,263 — 17,263 — U.S. government sponsored entity debt securities 91,538 — 91,538 — Total 139,518 — 139,518 — Total cash equivalents and marketable securities $ 205,455 $ 65,937 $ 139,518 $ — The Company generally classifies its marketable securities 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.

Marketable Securities

Marketable Securities	9 Months Ended
	Sep. 30, 2016
Investments Debt And Equity Securities [Abstract]
Marketable Securities	NOTE 3—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 substantially identical assets. Unrealized holding gains and losses are included in accumulated other comprehensive income (loss). Investments that have maturities beyond one year as of the end of the reporting period are classified as non-current. 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 income, which is determined using the specific identification method The table below summarizes the Company’s investments (in thousands): Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains (Losses) Fair Value September 30, 2016 Cash equivalents: Money market funds $ 24,113 $ — $ — $ 24,113 U.S. government sponsored entity debt securities 3,002 — — 3,002 Total 27,115 — — 27,115 Available-for-sale securities: Commercial paper securities 25,655 74 — 25,729 Corporate debt securities 10,010 — (1 ) 10,009 U.S. government sponsored entity debt securities 91,309 55 — 91,364 Total 126,974 129 (1 ) 127,102 Total cash equivalents and available-for-sale securities $ 154,089 $ 129 $ (1 ) $ 154,217 December 31, 2015 Cash equivalents: Money market funds $ 25,070 $ — $ — $ 25,070 Commercial paper securities 2,000 — — 2,000 U.S. government sponsored entity debt securities 38,866 1 — 38,867 Total 65,936 1 — 65,937 Available-for-sale securities: Commercial paper securities 30,667 50 — 30,717 Corporate debt securities 17,275 — (12 ) 17,263 U.S. government sponsored entity debt securities 91,562 — (24 ) 91,538 Total 139,504 50 (36 ) 139,518 Total cash equivalents and available-for-sale securities $ 205,440 $ 51 $ (36 ) $ 205,455 The Company had no other-than-temporary impairments of its investments for the nine months ended September 30, 2016 or the twelve months ended December 31, 2015. As of September 30, 2016 and December 31, 2015, all of the Company’s investments had maturity dates within two years. The Company had no material realized losses or other-than-temporary impairments of available-for-sale securities as of the nine months ended September 30, 2016. Sangamo has the intent and ability to hold its investments for a period of time sufficient to allow for any anticipated recovery in market value.

Basic and Diluted Net Loss Per

Basic and Diluted Net Loss Per Share	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Basic and Diluted Net Loss Per Share	NOTE 4—BASIC AND DILUTED 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 stock options and restricted stock units, which are all anti-dilutive. The total number of shares subject to stock options and restricted stock units outstanding were excluded from consideration in the calculation of diluted net loss per share. Stock options and restricted stock units outstanding for the nine months ended September 30, 2016 and 2015 were 9,559,727 and 7,868,033, respectively.

Major Customers, Partnerships a

Major Customers, Partnerships and Strategic Alliances	9 Months Ended
	Sep. 30, 2016
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 Inc. in Human Therapeutics In January 2014 the Company entered into a Global Research, Development and Commercialization Collaboration and License Agreement (the “Biogen Agreement”) with Biogen, pursuant to which Sangamo and Biogen collaborate to discover, develop, seek regulatory approval for and commercialize therapeutics based on Sangamo’s zinc finger DNA-binding protein (ZFP) technology for hemoglobinopathies, including beta-thalassemia and sickle cell disease (SCD). Under the Biogen Agreement, Sangamo and Biogen 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. In January 2016 Sangamo and Biogen agreed on an updated beta-thalassemia Development Plan and budget using the BCL11A Enhancer target. As a result of this change, the Company updated the estimated performance period of the upfront license through June 2019. Sangamo also updated the milestones to be received based on the updated performance period of our deliverables under the Biogen Agreement. Sangamo received an upfront license fee of $20.0 million upon entering into the Biogen Agreement in January 2014. In addition, the Company will be eligible to receive up to $126.3 million in payments upon the achievement of specified research, regulatory, clinical development milestones, as well as up to $167.5 million in payments upon the achievement of specified commercialization and sales milestones. In addition, if products are commercialized under the Biogen 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. To date, no milestone payments have been received and no products have been approved and therefore no royalty fees have been earned under the Biogen Agreement. 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 Biogen Agreement 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. 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 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 will recognize revenue from the upfront payment on a straight-line basis through June 2019, which is the estimated term during which the Company will perform research services. The estimated period of performance is reviewed quarterly and adjusted, as needed, to reflect our current assumptions regarding the timing of our deliverables. As of September 30, 2016, the Company has deferred revenue of $6.7 million related to the Biogen Agreement. Revenues recognized under the agreement with Biogen for the three and nine months ended September 30, 2016 and 2015 were as follows (in thousands): Three months ended Nine months ended September 30, September 30, 2016 2015 2016 2015 Revenue related to Biogen Collaboration: Recognition of upfront fee $ 607 $ 1,556 $ 1,823 $ 4,619 Research services 1,238 2,594 5,163 5,827 Total $ 1,845 $ 4,150 $ 6,986 $ 10,446 Related costs and expenses incurred under the Biogen Agreement related to the beta-thalassemia project, which was co-funded with California Institute for Regenerative Medicine (CIRM), were $1.2 million and $2.3 million during the three months ended September 30, 2016 and 2015, respectively, and $5.3 million and $4.7 million during the nine months ended September 30, 2016 and, 2015, respectively. Related costs and expenses for other projects including sickle cell disease under the Biogen agreement were $0.1 million and $0.7 million during the three months ended September 30, 2016 and 2015, respectively, and $0.2 million and $2.7 million during the nine months ended September 30, 2016 and 2015, respectively. Amended Collaboration and License Agreement with Shire International GmbH in Human Therapeutics and Diagnostics In January 2012 the Company entered into a collaboration and license agreement (the “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 novel ZFP technology. This agreement was amended on September 1, 2015. Under the original Shire Agreement, the Company and Shire agreed to 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 A and B. In June 2012, Shire selected a fifth gene target for the development of a ZFP Therapeutic for Huntington’s disease. Shire had 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. Under the terms of the original Shire Agreement, the Company was responsible for all research activities through the submission of an IND or European Clinical Trial Application (CTA), while Shire was 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 reimbursed Sangamo for agreed upon internal and external program-related research costs. The Company received an upfront license fee of $13.0 million upon entering into the Shire Agreement in 2012. In 2014 Sangamo recognized a $1.0 million milestone payment related to the hemophilia program. On September 1, 2015, the Shire Agreement was amended such that Shire agreed to return to Sangamo the exclusive, world-wide rights to gene targets for the development and commercialization of ZFP Therapeutics for hemophilia A and B. Shire retains the rights and will continue to develop a ZFP Therapeutic for Huntington’s disease and a ZFP Therapeutic for one additional gene target yet to be named. Sangamo will provide certain target feasibility services, and upon Shire’s request, certain research activities according to a research plan as agreed upon by both companies. Such research activities performed by Sangamo will be reimbursed by Shire. Shire’s rights with respect to other targets contemplated in the original agreement revert to Sangamo. Under the revised agreement, each company is responsible for expenses associated with its own programs and will reimburse the other for any ongoing services provided. Shire reimbursed Sangamo $3.4 million related to obligations prior to the amendment date which was recognized in revenue and expensed as incurred. During the three and nine months ended September 30, 2016, there were no expenses incurred and no revenue recognized related to prior obligations. Sangamo has granted Shire a right of first negotiation to license the hemophilia A and B programs. Under the amended agreement, Shire does not have any milestone payment obligations to Sangamo with respect to the retained programs, but it is required to pay single digit percentage royalties to us, up to a specified maximum cap, on the commercial sales of ZFP therapeutic products from such programs. Under the Agreement, Sangamo has full control over, and full responsibility for the costs of, the hemophilia programs returned to us, subject to certain diligence obligations and Shire’s right of first negotiation to obtain a license to such programs under certain circumstances. The Company is required to pay single digit percentage royalties to Shire, up to a specified maximum cap, on commercial sales of ZFP therapeutic products from such returned programs. The Company has identified the deliverables within the amended 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 amendment. Sangamo continues to be responsible for research activities related to our licensed technology with Shire under the amendment. As a result, the Company will continue to recognize revenue from the upfront payment received upon entering into the original Shire agreement in 2012 on a straight-line basis over the six-year initial research term during which the Company expects to perform research services. As of September 30, 2016, the Company has deferred revenue of $2.9 million related to the Shire Agreement. Revenues recognized under the agreement with Shire for the three and nine months ended September 30, 2016 and 2015 were as follows (in thousands): Three months ended Nine months ended September 30, September 30, 2016 2015 2016 2015 Revenue related to Shire Collaboration: Recognition of upfront fee $ 542 $ 542 $ 1,625 $ 1,625 Research services 165 3,313 957 11,729 Total $ 707 $ 3,855 $ 2,582 $ 13,354 Related costs and expenses incurred under the Shire agreement were $0.2 million and $3.2 million during the three months ended September 30, 2016 and 2015, respectively, and $0.9 million and $11.9 million during the nine months ended September 30, 2016 and 2015, respectively. Agreement with Sigma-Aldrich Corporation in Laboratory Research Reagents, Transgenic Animal and Commercial Protein Production Cell-line Engineering In July 2007 the Company entered into a license agreement (the “Sigma Agreement”) with Sigma-Aldrich Corporation (“Sigma”). Under the Sigma 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 Dow AgroSciences LLC (DAS). Under the Sigma 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 its ZFP manufacturing technology to Sigma. In October 2009 the Company expanded the Sigma Agreement. In addition to the original terms of the Sigma 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 has received 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 three and nine months ended September 30, 2016 and 2015 were as follows (in thousands): Three months ended Nine months ended September 30, September 30, 2016 2015 2016 2015 Revenue related to Sigma Collaboration: Royalty revenues $ 42 $ 97 $ 103 $ 390 License fee revenues 7 172 77 4,449 Total $ 49 $ 269 $ 180 $ 4,839 Related costs and expenses incurred under the Sigma agreement were $0.1 million and $0.0 million during the three months ended September 30, 2016 and 2015, respectively, and $0.1 million and $0.3 million during the nine months ended September 30, 2016 and 2015, respectively. Agreement with Dow AgroSciences in Plant Agriculture In October 2005 the Company entered into an exclusive commercial license agreement with Dow AgroSciences, LLC (DAS). Under this agreement, Sangamo provides DAS with access to 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 $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 ongoing 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 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. There were no revenues or related costs and expenses incurred under the agreement during the three and nine months ended September 30, 2016 and 2015, respectively. Funding from Research Foundations California Institute for Regenerative Medicine - HIV In May 2014 CIRM agreed to fund a $5.6 million Strategic Partnership Award to fund the clinical studies of a potentially curative ZFP Therapeutic for HIV/AIDS based on the application of Sangamo’s ZFN genome editing technology in hematopoietic stem and 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. There were no revenues attributable to research and development performed under the Strategic Partnership Award during the three and nine months ended September 30, 2016 and 2015, respectively. Related costs and expenses incurred under the CIRM Strategic Partnership Award were $0.6 million and $0.6 million during the three months ended September 30, 2016 and 2015, respectively, and $1.2 million and $1.3 million during the nine months ended September 30, 2016 and 2015, respectively.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 6—INCOME TAXES The Company maintains deferred tax assets that 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. These deferred tax assets include net operating loss carryforwards, research credits and capitalized research and development costs. Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain based on Sangamo’s history of losses. Accordingly, the Company’s net deferred tax assets have been fully offset by a valuation allowance. Utilization of operating losses and credits may be subject to substantial annual limitation due to ownership change provisions of the Internal Revenue Code of 1986, as amended and similar state provisions. The annual limitation may result in the expiration of net operating losses and credits before utilization.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	NOTE 7—STOCK-BASED COMPENSATION The following table shows total stock-based compensation expense included in the condensed consolidated statements of operations for the three and nine months ended September 30, 2016 and 2015 (in thousands): Three months ended Nine months ended September 30, September 30, 2016 2015 2016 2015 Research and development $ 1,790 $ 1,595 $ 5,368 $ 5,020 General and administrative 945 1,233 7,760 3,644 Total stock-based compensation expense $ 2,735 $ 2,828 $ 13,128 $ 8,664 For the nine months ended September 30, 2016 the Company recognized $4.1 million in stock-based compensation expense and $2.0 million in salaries and benefits associated with separation costs for the transition of the Company’s CEO in June 2016.

Build-to-Suit Lease

Build-to-Suit Lease	9 Months Ended
	Sep. 30, 2016
Leases Operating [Abstract]
Build-to-Suit Lease	NOTE 8—BUILD-TO-SUIT LEASE In December 2015 the Company entered into a long-term property lease which includes construction by the lessor of a building with approximately 41,400 square feet of space, in Richmond, California. The lease agreement expires five years after substantial completion of the building, which is estimated to occur in late 2016. The Company has two options to extend the lease term for up to a combined additional ten years. The Company is deemed, for accounting purposes only, to be the owner of the entire project including the building shell, even though it is not the legal owner. In connection with the Company’s accounting for this transaction, the Company will capitalize costs of construction as a build-to-suit property within property and equipment, net, and recognize a corresponding build-to-suit lease obligation for the same amount. As of September 30, 2016, $2.2 million of costs were capitalized in construction in progress with a corresponding build-to-suit lease obligation recognized related to this lease. Upon construction a portion of the monthly lease payment will be allocated to land rent and recorded as an operating lease expense, and the non-interest portion of the amortized lease payments to the landlord related to the rent of the building will be applied to reduce the build-to-suit lease obligation.

Basis of Presentation and Sum15

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements of Sangamo BioSciences, Inc. (“Sangamo” or the “Company”) have been prepared in accordance with U.S. generally accepted accounting principles for interim financial information and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included. Operating results for the three and nine months ended September 30, 2016 are not necessarily indicative of the results that may be expected for the year ending December 31, 2016. The condensed consolidated balance sheet data at December 31, 2015 were derived from the audited consolidated financial statements included in Sangamo’s Form 10-K for the year ended December 31, 2015, as filed with the SEC. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited financial statements and footnotes thereto for the year ended December 31, 2015, included in Sangamo’s Form 10-K, as filed with the SEC.
Use of Estimates	Use of Estimates 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. On an ongoing basis, management evaluates its estimates, including critical accounting policies or estimates related to revenue recognition, clinical trial accruals, and stock-based compensation. Estimates are based on historical experience and on various other market specific and other relevant assumptions that the Company believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates. During the first quarter of 2016, we revised the estimated performance period of the upfront Biogen license through June 2019. This change increased net loss by $0.9 million and $2.7 million for the three and nine months ended September 30, 2016, respectively. The change in the performance period also increased our basic net loss per share by $0.02 and $0.04 for the three and nine months ended September 30, 2016, respectively.
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. 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 Vendor Specific Objective Evidence (“VSOE”) of selling price or Third Party Evidence (“TPE”) of selling price. If neither exists, the Company uses Estimated Selling Price (“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 Inc., formerly Biogen Idec Inc. (Biogen) in January 2014, as amended, 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 the 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.
Recent Accounting Standards	Recent Accounting Standards In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-09, Improvements to Employee Share-Based Payment Accounting In February 2016, the FASB issued ASU 2016-02, Leases In August 2014, the FASB issued ASU 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern In May 2014 the FASB issued ASU 2014-09, Revenue from Contracts with Customers

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Summary of Fair Value Measurements of Cash Equivalents, and Available-for-Sale Marketable Securities	The fair value measurements of the Company’s cash equivalents, and available-for-sale marketable securities are identified at the following levels within the fair value hierarchy (in thousands): September 30, 2016 Fair Value Measurements Total Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 24,113 $ 24,113 $ — $ — U.S. government sponsored entity debt securities 3,002 — 3,002 — Total 27,115 24,113 3,002 — Marketable securities: Commercial paper securities 25,729 — 25,729 — Corporate debt securities 10,009 — 10,009 — U.S. government sponsored entity debt securities 91,364 — 91,364 — Total 127,102 — 127,102 — Total cash equivalents and marketable securities $ 154,217 $ 24,113 $ 130,104 $ — December 31, 2015 Fair Value Measurements Total Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 25,070 $ 25,070 $ — $ — Commercial paper securities 2,000 2,000 — — U.S. government sponsored entity debt securities 38,867 38,867 — — Total 65,937 65,937 — — Marketable securities: Commercial paper securities 30,717 — 30,717 — Corporate debt securities 17,263 — 17,263 — U.S. government sponsored entity debt securities 91,538 — 91,538 — Total 139,518 — 139,518 — Total cash equivalents and marketable securities $ 205,455 $ 65,937 $ 139,518 $ —

Marketable Securities (Tables)

Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2016
Investments Debt And Equity Securities [Abstract]
Schedule of Investments	The table below summarizes the Company’s investments (in thousands): Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains (Losses) Fair Value September 30, 2016 Cash equivalents: Money market funds $ 24,113 $ — $ — $ 24,113 U.S. government sponsored entity debt securities 3,002 — — 3,002 Total 27,115 — — 27,115 Available-for-sale securities: Commercial paper securities 25,655 74 — 25,729 Corporate debt securities 10,010 — (1 ) 10,009 U.S. government sponsored entity debt securities 91,309 55 — 91,364 Total 126,974 129 (1 ) 127,102 Total cash equivalents and available-for-sale securities $ 154,089 $ 129 $ (1 ) $ 154,217 December 31, 2015 Cash equivalents: Money market funds $ 25,070 $ — $ — $ 25,070 Commercial paper securities 2,000 — — 2,000 U.S. government sponsored entity debt securities 38,866 1 — 38,867 Total 65,936 1 — 65,937 Available-for-sale securities: Commercial paper securities 30,667 50 — 30,717 Corporate debt securities 17,275 — (12 ) 17,263 U.S. government sponsored entity debt securities 91,562 — (24 ) 91,538 Total 139,504 50 (36 ) 139,518 Total cash equivalents and available-for-sale securities $ 205,440 $ 51 $ (36 ) $ 205,455

Major Customers, Partnerships18

Major Customers, Partnerships and Strategic Alliances (Tables)	9 Months Ended
	Sep. 30, 2016
Biogen Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenues Recognized under Agreement	Revenues recognized under the agreement with Biogen for the three and nine months ended September 30, 2016 and 2015 were as follows (in thousands): Three months ended Nine months ended September 30, September 30, 2016 2015 2016 2015 Revenue related to Biogen Collaboration: Recognition of upfront fee $ 607 $ 1,556 $ 1,823 $ 4,619 Research services 1,238 2,594 5,163 5,827 Total $ 1,845 $ 4,150 $ 6,986 $ 10,446
Shire AG [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenues Recognized under Agreement	Revenues recognized under the agreement with Shire for the three and nine months ended September 30, 2016 and 2015 were as follows (in thousands): Three months ended Nine months ended September 30, September 30, 2016 2015 2016 2015 Revenue related to Shire Collaboration: Recognition of upfront fee $ 542 $ 542 $ 1,625 $ 1,625 Research services 165 3,313 957 11,729 Total $ 707 $ 3,855 $ 2,582 $ 13,354
Sigma-Aldrich Corporation [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenues Recognized under Agreement	Revenues recognized under the agreement with Sigma for the three and nine months ended September 30, 2016 and 2015 were as follows (in thousands): Three months ended Nine months ended September 30, September 30, 2016 2015 2016 2015 Revenue related to Sigma Collaboration: Royalty revenues $ 42 $ 97 $ 103 $ 390 License fee revenues 7 172 77 4,449 Total $ 49 $ 269 $ 180 $ 4,839

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation Expense	The following table shows total stock-based compensation expense included in the condensed consolidated statements of operations for the three and nine months ended September 30, 2016 and 2015 (in thousands): Three months ended Nine months ended September 30, September 30, 2016 2015 2016 2015 Research and development $ 1,790 $ 1,595 $ 5,368 $ 5,020 General and administrative 945 1,233 7,760 3,644 Total stock-based compensation expense $ 2,735 $ 2,828 $ 13,128 $ 8,664

Basis of Presentation and Sum20

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) - Biogen Inc [Member] - Change in estimated performance period [Member] - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Change In Accounting Estimate [Line Items]
Increase in net loss	$ 0.9	$ 2.7
Increase in basic net loss per share	$ 0.02	$ 0.04

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Fair Value Measurements of Cash Equivalents, and Available-for-Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	$ 27,115	$ 65,937
Total marketable securities	127,102	139,518
Total cash equivalents and marketable securities	154,217	205,455
Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	24,113	25,070
Commercial paper securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents		2,000
Total marketable securities	25,729	30,717
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	24,113	65,937
Total cash equivalents and marketable securities	24,113	65,937
Level 1 [Member] | Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	24,113	25,070
Level 1 [Member] | Commercial paper securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents		2,000
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	3,002
Total marketable securities	127,102	139,518
Total cash equivalents and marketable securities	130,104	139,518
Level 2 [Member] | Commercial paper securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	25,729	30,717
U.S. government sponsored entity debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	3,002	38,867
Total marketable securities	91,364	91,538
U.S. government sponsored entity debt securities [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents		38,867
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 cash equivalents	3,002
Total marketable securities	91,364	91,538
Corporate debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	10,009	17,263
Corporate debt securities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	$ 10,009	$ 17,263

Marketable Securities - Schedul

Marketable Securities - Schedule of Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	$ 27,986	$ 69,482	$ 34,287	$ 6,030
Total cash equivalents	27,115	65,937
Amortized Cost	154,089	205,440
Gross Unrealized Gains	129	51
Gross Unrealized (Losses)	(1)	(36)
Estimated Fair Value	154,217	205,455
Available-for-sale securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	126,974	139,504
Gross Unrealized Gains	129	50
Gross Unrealized (Losses)	(1)	(36)
Estimated Fair Value	127,102	139,518
Money market funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	24,113	25,070
Total cash equivalents	24,113	25,070
Cash equivalents [Member]
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	27,115	65,936
Gross Unrealized Gains		1
Total cash equivalents	27,115	65,937
Commercial paper securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents		2,000
Total cash equivalents		2,000
Commercial paper securities [Member] | Available-for-sale securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	25,655	30,667
Gross Unrealized Gains	74	50
Estimated Fair Value	25,729	30,717
U.S. government sponsored entity debt securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Cash and cash equivalents	3,002	38,866
Gross Unrealized Gains		1
Total cash equivalents	3,002	38,867
U.S. government sponsored entity debt securities [Member] | Available-for-sale securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	91,309	91,562
Gross Unrealized Gains	55
Gross Unrealized (Losses)		(24)
Estimated Fair Value	91,364	91,538
Corporate debt securities [Member] | Available-for-sale securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	10,010	17,275
Gross Unrealized (Losses)	(1)	(12)
Estimated Fair Value	$ 10,009	$ 17,263

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Investments Debt And Equity Securities [Abstract]
Investments other-than-temporarily impaired	$ 0	$ 0
Investments maturity period	2 years	2 years
Realized losses	$ 0
Other-than-temporary impairments of available-for-sale securities	$ 0

Basic and Diluted Net Loss Pe24

Basic and Diluted Net Loss Per Share - Additional Information (Detail) - shares	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Stock options and restricted stock units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Stock options and restricted stock units outstanding	9,559,727	7,868,033

Major Customers, Partnerships25

Major Customers, Partnerships and Strategic Alliances - Additional Information (Detail)	Sep. 01, 2015USD ($)	Jan. 31, 2016USD ($)	Jan. 31, 2014USD ($)Program	Jun. 30, 2012Targets	Jan. 31, 2012USD ($)Targets	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)ProductTargets	Sep. 30, 2015USD ($)	Dec. 31, 2014USD ($)
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Number of research programs | Program			2
Research and development						$ 17,008,000	$ 16,694,000	$ 51,728,000	$ 47,292,000
Biogen Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenues under agreement			$ 20,000,000
Milestone payments received								$ 0
Number of products approved | Product								0
Royalty revenues								$ 0
Deferred revenue						6,700,000		6,700,000
Biogen Inc [Member] | Beta-thalassemia Project [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development						1,200,000	2,300,000	5,300,000	4,700,000
Biogen Inc [Member] | Other Projects [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development						100,000	700,000	200,000	2,700,000
Biogen Inc [Member] | Maximum [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
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
Shire AG [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenues under agreement					$ 13,000,000
Deferred revenue						2,900,000		2,900,000
Research and development						200,000	$ 3,200,000	$ 900,000	$ 11,900,000
Aggregate number of gene targets | Targets					7
Number of initial gene targets | Targets					4
Number of gene targets | Targets				5
Number of additional gene targets | Targets				2				1
Recognition of milestone										$ 1,000,000
Amount reimbursed and recognized related to prior obligations	$ 3,400,000					$ 0		$ 0
Research program to develop laboratory research reagents								6 years

Major Customers, Partnerships26

Major Customers, Partnerships and Strategic Alliances - Revenues Recognized under Agreement (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Biogen Inc [Member]
Revenues:
Recognition of upfront fee	$ 607,000	$ 1,556,000	$ 1,823,000	$ 4,619,000
Royalty revenues			0
Research services	1,238,000	2,594,000	5,163,000	5,827,000
Total	1,845,000	4,150,000	6,986,000	10,446,000
Shire AG [Member]
Revenues:
Recognition of upfront fee	542,000	542,000	1,625,000	1,625,000
Research services	165,000	3,313,000	957,000	11,729,000
Total	707,000	3,855,000	2,582,000	13,354,000
Sigma-Aldrich Corporation [Member]
Revenues:
Royalty revenues	42,000	97,000	103,000	390,000
License fee revenues	7,000	172,000	77,000	4,449,000
Total	$ 49,000	$ 269,000	$ 180,000	$ 4,839,000

Major Customers, Partnerships27

Major Customers, Partnerships and Strategic Alliances - Agreement with Sigma-Aldrich Corporation - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Oct. 31, 2009	Jul. 31, 2007	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development			$ 17,008	$ 16,694	$ 51,728	$ 47,292
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
Public offering, common stock shares issued	636,133
Reduced royalty rate	10.50%
Funding available under the amended agreement	$ 25,000
Sigma-Aldrich Corporation [Member] | Upfront license fee [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Upfront license fee	15,100
Common stock issued under license agreement	$ 4,900
Sigma-Aldrich Corporation [Member] | License agreement terms [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenues under agreement					5,000
Research and development			$ 100	$ 0	$ 100	$ 300

Major Customers, Partnerships28

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	3 Months Ended		9 Months Ended
	Oct. 31, 2005	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
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	$ 0	$ 0	$ 0
Revenue attributable to research and development		$ 0	$ 0	$ 0	$ 0
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, Partnerships29

Major Customers, Partnerships and Strategic Alliances - California Institute for Regenerative Medicine - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	May 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research grants		$ 95,000	$ 163,000	$ 436,000	$ 1,540,000
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
Agreement to receive	4 years
Research grants		0	0	0	0
Collaboration agreement related costs and expenses		$ 600,000	$ 600,000	$ 1,200,000	$ 1,300,000

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 2,735	$ 2,828	$ 13,128	$ 8,664
Research and development [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	1,790	1,595	5,368	5,020
General and administrative [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 945	$ 1,233	$ 7,760	$ 3,644

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 13,128,000	$ 8,664,000
CEO [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	4,100
Stock-based compensation expense	$ 2,000,000

Build-to-Suit Lease - Additiona

Build-to-Suit Lease - Additional Information (Detail) $ in Millions	1 Months Ended
	Dec. 31, 2015ft²Option	Sep. 30, 2016USD ($)
Operating Leased Assets [Line Items]
Property leased | ft²	41,400
Operating lease expiration period	5 years
Number of lease term extension options | Option	2
Costs capitalized | $		$ 2.2
Maximum [Member]
Operating Leased Assets [Line Items]
Lease agreement, extendable lease term	10 years