sgmo-20240630

Any third-party trade names, trademarks and service marks appearing in this Quarterly Report are the property of their respective holders. Solely for convenience, trademarks and trade names referred to in this Quarterly Report may appear without the ® or TM symbols, but such references are not intended to indicate in any way that the Company will not assert, to the fullest extent under applicable law, its rights or the rights of the applicable licensor to these trademarks and trade names. The Company does not intend its use or display of other entities’ trade names, trademarks or service marks to imply a relationship with, or endorsement or sponsorship of the Company by, any other entity.

Some statements contained in this report are “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. These statements relate to our future events, including our anticipated operations, research, development, manufacturing and commercialization activities, clinical trials, operating results and financial condition. These forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performances or achievements expressed or implied by the forward-looking statements. Forward-looking statements may include, but are not limited to, statements about:

In some cases, you can identify forward-looking statements by use of future dates or by terms such as: “anticipates,” “believes,” “continues,” “could,” “estimates,” “expects,” “intends,” “may,” “plans,” “seeks,” “should,” “will” and similar expressions intended to identify forward-looking statements. These statements reflect our current views with respect to future events, are based on assumptions and involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. These risks and uncertainties include, without limitation:

•There is substantial doubt about our ability to continue to operate as a going concern. We need substantial additional funding to execute our operating plan and to continue to operate as a going concern. If adequate funds are not available to us on a timely basis, or at all, we will be required to take additional actions to address our liquidity needs, including additional cost reduction measures such as further reducing operating expenses and delaying, reducing the scope of, discontinuing or altering our research and development activities, which would have a material adverse effect on our business and prospects, or we may be required to cease operations entirely, liquidate all or a portion of our assets, and/or seek protection under the U.S. Bankruptcy Code, and you may lose all or part of your investment. Future sales and issuances of equity securities would also result in substantial dilution to our stockholders.

Additional discussion of the risks, uncertainties and other factors described above, as well as other risks and uncertainties material to our business, can be found under “Risk Factors” in Part I, Item 1A of our Annual Report on Form 10-K for the year ended December 31, 2023 as filed with the Securities and Exchange Commission on March 13, 2024, as supplemented by the risks described under “Risk Factors” in Part II, Item 1A of this Quarterly Report on Form 10-Q, and we encourage you to refer to that additional discussion. Given these risks, uncertainties and other factors, you should not place undue reliance on these forward-looking statements. Also, these forward-looking statements represent our plans, objectives, estimates, expectations and intentions only as of the date of this filing. You should read this report completely and with the understanding that our actual future results and the timing of events may be materially different from what we expect, and we cannot otherwise guarantee that any forward-looking statement will be realized. We hereby qualify all of our forward-looking statements by these cautionary statements.


	June 30, 2024		December 31, 2023
ASSETS
Current assets:
Cash and cash equivalents	$	27,786	$	45,204

Marketable securities	—		35,798
Accounts receivable	581		923
Prepaid expenses and other current assets	11,708		12,403

Total current assets	40,075		94,328

Property and equipment, net	20,619		26,874


Operating lease right-of-use assets	18,672		25,991
Refundable research income tax credits and other non-current assets	13,648		16,627
Restricted cash	—		1,500
Total assets	$	93,014	$	165,320
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities:
Accounts payable	$	17,590	$	15,259
Accrued compensation and employee benefits	5,655		8,918
Other accrued liabilities	15,760		23,554

Total current liabilities	39,005		47,731

Long-term portion of lease liabilities	29,097		33,515

Other non-current liabilities	1,222		1,187
Total liabilities	69,324		82,433
Commitments and contingencies
Stockholders’ equity:
Preferred stock	—		—
Common stock	2,082		1,781
Additional paid-in capital	1,519,084		1,492,077
Accumulated deficit	(1,491,593)		(1,406,376)
Accumulated other comprehensive loss	(5,883)		(4,595)
Total stockholders’ equity	23,690		82,887


Total liabilities and stockholders’ equity	$	93,014	$	165,320


	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Revenues	$	356	$	6,835	$	837	$	164,792
Operating expenses:
Research and development	24,223		63,046		60,114		126,262
General and administrative	12,045		16,014		23,812		34,150
Impairment of long-lived assets	1,172		—		5,521		20,433
Impairment of goodwill and indefinite-lived intangible assets	—		51,347		—		89,485


Total operating expenses	37,440		130,407		89,447		270,330
Loss from operations	(37,084)		(123,572)		(88,610)		(105,538)
Interest and other income, net	1,030		2,802		3,565		6,095
Loss before income taxes	(36,054)		(120,770)		(85,045)		(99,443)
Income tax expense (benefit)	74		(6,264)		172		(6,070)


Net loss	$	(36,128)	$	(114,506)	$	(85,217)	$	(93,373)

Basic and diluted net loss per share	$	(0.18)	$	(0.66)	$	(0.44)	$	(0.54)


Shares used in computing basic and diluted net loss per share	203,946		174,325		194,049		171,445


	Three Months Ended June 30, 2024
	Common Stock			Additional Paid-in Capital		Accumulated Deficit		Accumulated Other Comprehensive Loss		Total Stockholders’ Equity
	Shares	Amount
Balances at March 31, 2024	203,686,086	$	2,037	$	1,515,926	$	(1,455,465)	$	(5,801)	$	56,697


Issuance of common stock upon exercise of pre-funded warrants	3,809,523	38		33		—		—		71
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax	326,045	3		(82)		—		—		(79)
Issuance of common stock under employee stock purchase plan	379,486	4		142		—		—		146
Stock-based compensation	—	—		3,065		—		—		3,065
Foreign currency translation adjustment	—	—		—		—		(313)		(313)
Net pension gain	—	—		—		—		231		231

Net loss	—	—		—		(36,128)		—		(36,128)
Balances at June 30, 2024	208,201,140	$	2,082	$	1,519,084	$	(1,491,593)	$	(5,883)	$	23,690


	Six Months Ended June 30, 2024
	Common Stock			Additional Paid-in Capital		Accumulated Deficit		Accumulated Other Comprehensive Loss		Total Stockholders’ Equity
	Shares	Amount
Balances at December 31, 2023	178,133,548	$	1,781	$	1,492,077	$	(1,406,376)	$	(4,595)	$	82,887

Issuance of common stock, net of offering expenses	24,761,905	248		21,540		—		—		21,788
Issuance of common stock upon exercise of pre-funded warrants	3,809,523	38		33		—		—		71
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax	1,116,678	11		(492)		—		—		(481)
Issuance of common stock under employee stock purchase plan	379,486	4		142		—		—		146
Stock-based compensation	—	—		5,784		—		—		5,784
Foreign currency translation adjustment	—	—		—		—		(1,293)		(1,293)
Net pension gain	—	—		—		—		238		238
Net unrealized loss on marketable securities, net of tax	—	—		—		—		(233)		(233)
Net loss	—	—		—		(85,217)		—		(85,217)
Balances at June 30, 2024	208,201,140	$	2,082	$	1,519,084	$	(1,491,593)	$	(5,883)	$	23,690


	Three Months Ended June 30, 2023
	Common Stock			Additional Paid-in Capital		Accumulated Deficit		Accumulated Other Comprehensive Loss		Total Stockholders’ Equity
	Shares	Amount
Balances at March 31, 2023	171,771,568	$	1,718	$	1,467,062	$	(1,127,412)	$	(5,758)	$	335,610

Issuance of common stock in at-the-market offering, net of offering expenses	4,286,831	43		5,358		—		—		5,401
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax	260,561	3		(197)		—		—		(194)
Issuance of common stock under employee stock purchase plan	755,586	7		712		—		—		719
Stock-based compensation	—	—		6,790		—		—		6,790

Foreign currency translation adjustment	—	—		—		—		80		80

Net unrealized loss on marketable securities, net of tax	—	—		—		—		(258)		(258)

Net loss	—	—		—		(114,506)		—		(114,506)
Balances at June 30, 2023	177,074,546	$	1,771	$	1,479,725	$	(1,241,918)	$	(5,936)	$	233,642


	Six Months Ended June 30, 2023
	Common Stock			Additional Paid-in Capital		Accumulated Deficit		Accumulated Other Comprehensive Loss		Total Stockholders’ Equity
	Shares	Amount
Balances at December 31, 2022	166,793,320	$	1,668	$	1,450,239	$	(1,148,545)	$	(8,404)	$	294,958
Issuance of common stock in at-the-market offering, net of offering expenses	8,249,261	83		15,023		—		—		15,106
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax	1,276,379	13		(1,316)		—		—		(1,303)
Issuance of common stock under employee stock purchase plan	755,586	7		712		—		—		719
Stock-based compensation	—	—		15,067		—		—		15,067

Foreign currency translation adjustment	—	—		—		—		2,125		2,125
Net pension losses	—	—		—		—		(3)		(3)
Net unrealized gain on marketable securities, net of tax	—	—		—		—		346		346

Net loss	—	—		—		(93,373)		—		(93,373)
Balances at June 30, 2023	177,074,546	$	1,771	$	1,479,725	$	(1,241,918)	$	(5,936)	$	233,642


	Six Months Ended June 30,
	2024		2023
Operating Activities:
Net loss	$	(85,217)	$	(93,373)
Adjustments to reconcile net loss to net cash used in operating activities:
Impairment of long-lived assets	5,521		20,433
Depreciation and amortization	2,648		7,745
Accretion of discount on marketable securities	(273)		(1,865)
Amortization in operating lease right-of-use assets	2,451		4,018
Stock-based compensation	5,784		15,067
Other non-cash adjustments	(103)		—
Impairment of goodwill and indefinite-lived intangible assets	—		89,485
Deferred income tax benefit	—		(6,377)


Net changes in operating assets and liabilities:
Interest receivable	370		(425)
Accounts receivable	342		962
Prepaid expenses and other assets	3,565		5,548
Accounts payable and other accrued liabilities	(4,654)		(3,101)

Accrued compensation and employee benefits	(3,195)		(8,450)

Lease liabilities	(2,822)		(2,455)
Other non-current liabilities	36		61
Deferred revenues	—		(154,284)
Net cash used in operating activities	(75,547)		(127,011)
Investing Activities:
Purchases of marketable securities	—		(52,112)
Maturities of marketable securities	1,110		146,048
Sales of marketable securities	34,730		—
Sales of assets classified as held for sale	127		—
Purchases of property and equipment	—		(15,740)


Net cash provided by investing activities	35,967		78,196
Financing Activities:
Proceeds from issuance of common stock, net of offering expenses	21,924		—
Proceeds from at-the-market offering, net of offering expenses	—		15,105
Taxes paid related to net share settlement of equity awards	(481)		(1,303)

Proceeds from issuance of common stock under employee stock purchase plan	146		719
Net cash provided by financing activities	21,589		14,521
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(927)		680
Net (decrease) increase in cash, cash equivalents, and restricted cash	(18,918)		(33,614)
Cash, cash equivalents, and restricted cash, beginning of period	46,704		101,944
Cash, cash equivalents, and restricted cash, end of period	$	27,786	$	68,330
Supplemental cash flow disclosures:
Property and equipment included in unpaid liabilities	$	433	$	4,909

Warrants to purchase shares of common stock, with the exercise price of $1.00 per share, entitle holders to participate in dividends but are not required to absorb losses incurred and as a result were excluded from basic net loss per share calculations during the three and six ended June 30, 2024. The computation of diluted net loss per share for the three and six ended June 30, 2024 excluded 53.1 million shares subject to stock options, restricted stock units outstanding, warrants to purchase common stock, and the employee stock purchase plan shares reserved for issuance because their inclusion would have had an anti-dilutive effect on diluted net loss per share. The computation of diluted net loss per share for the three and six months ended June 30, 2023 excluded 24.3 million shares subject to stock options, restricted stock units outstanding, and the employee stock purchase plan shares reserved for issuance because their inclusion would have had an anti-dilutive effect on diluted net loss per share.

The discussion in “Management’s Discussion and Analysis of Financial Condition and Results of Operations” contains trend analysis, estimates and other forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act. These forward-looking statements include, without limitation, statements containing the words “anticipates,” “believes,” “continues,” “could,” “estimates,” “expects,” “intends,” “may,” “plans,” “seeks,” “should,” “will,” and other words of similar import or the negative of those terms or expressions. Such forward-looking statements are subject to known and unknown risks, uncertainties, estimates and other factors that may cause our actual results, performance or achievements, or industry results, to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Actual results could differ materially from those set forth in such forward-looking statements as a result of, but not limited to, the “Risk Factors” described in Part I, Item 1A our Annual Report on Form 10-K for the year ended December 31, 2023 as filed with the Securities and Exchange Commission on March 13, 2024, or the 2023 Annual Report, as supplemented by the risks described under “Risk Factors” in Part II, Item 1A of this Quarterly Report on Form 10-Q. You should also read the following discussion and analysis in conjunction with our Condensed Consolidated Financial Statements and accompanying notes included in this Quarterly Report and the Consolidated Financial Statements and accompanying notes thereto included in our 2023 Annual Report.

On August 2, 2024, we entered into a global epigenetic regulation and capsid delivery license agreement, or the Genentech Agreement, with Genentech, a member of the Roche Group, or Genentech, to develop intravenously administered genomic medicines to treat certain neurodegenerative diseases. We granted an exclusive license to Genentech for our proprietary zinc finger repressors, or ZFRs, that are directed to tau and our proprietary ZFRs that are directed to a second undisclosed neurology target. We also granted an exclusive license to Genentech to our proprietary, neurotropic adeno-associated virus capsid, STAC-BBB for use with therapies directed to tau or to the second neurology target. Under the terms of the Genentech Agreement, we are responsible for completing a technology transfer and certain preclinical activities, and Genentech is solely responsible for all clinical development, regulatory interactions, manufacturing and global commercialization of resulting products. Under the Genentech Agreement, Genentech is obligated to pay us a $40.0 million upfront license fee on or around the end of August 2024 and will become obligated to pay us a $10.0 million milestone payment after the completion of technology transfer activities, or the Genentech Payments. In addition, we are eligible to earn up to $1.9 billion in development and commercial milestones spread across multiple potential products under the Genentech Agreement and tiered mid-single digit to sub-teen double digit royalties on the net sales of such products subject to certain specified reductions.

Based on our current operating plan, our cash and cash equivalents as of June 30, 2024, taken together with the $50.0 million in upfront license fees and milestone payments that we expect to receive from the Genentech Payments, are expected to allow us to meet our liquidity requirements only into the first quarter of 2025. Our history of significant losses, negative cash flows from operations, limited liquidity resources currently on hand and dependence on our ability to obtain additional financing to fund our operations have resulted in management’s assessment that there is substantial doubt about our ability to continue as a going concern for at least the next 12 months from the date the financial statements included in this Quarterly Report are issued. Our ability to continue to operate as a going concern is dependent upon our ability to raise substantial additional capital to fund our operations and support our research and development endeavors, including to progress our preclinical and clinical programs as described in our 2023 Annual Report and in this Quarterly Report. Although we raised capital via a registered direct offering to institutional investors of common stock and accompanying warrants in March 2024, and we expect to receive the Genentech Payments, we will still need substantial additional capital in order to continue to operate as a going concern and fund our operations. We have been actively seeking, and continue to actively seek, substantial additional capital, including through public or private equity or debt financing, royalty financing or other sources, such as strategic collaborations and other direct investments in our programs. We may be unable to attract new investments as a result of the speculative nature of our newly reprioritized core neurology preclinical programs and additional capital may not be available on

acceptable terms or at all. If adequate funds are not available to us on a timely basis, or at all, we will be required to take additional actions to address our liquidity needs, including additional cost reduction measures such as further reducing operating expenses and delaying, reducing the scope of, discontinuing or altering our research and development activities, which would have a material adverse effect on our business and prospects, or we may be required to cease operations entirely, liquidate all or a portion of our assets, and/or seek protection under the U.S. Bankruptcy Code, and you may lose all or part of your investment. If we are unable to secure additional funding in the near term, we may seek protection under the U.S. Bankruptcy Code. We have explored, and will continue to explore, whether filing for bankruptcy protection is in the best interest of our Company and our stakeholders.

Our collaborations with biopharmaceutical companies bring us important financial and strategic benefits and reinforce the potential of our research and development efforts and our zinc finger, or ZF, technology platform. They leverage our collaborators’ therapeutic and clinical expertise and commercial resources with the goal of bringing our medicines more rapidly to patients. We believe these collaborations will potentially expand the addressable markets of our product candidates. To date, we have received approximately $817.0 million in upfront licensing fees, milestone payments and proceeds from sale of our common stock to collaborators and have the opportunity to earn up to $3.8 billion in potential future milestone payments from our ongoing collaborations, in addition to potential product royalties.

Our business and operations and those of our collaborators may be affected by financial instability and declining economic conditions in the United States and other countries caused by political instability and conflict, including the ongoing conflict between Russia and Ukraine and conflicts in the Middle East, or by general health crises, which have in the past led to market disruptions, including significant volatility in commodity prices, credit and capital markets instability, including disruptions in access to bank deposits and lending commitments, supply chain interruptions, rising interest rates and global inflationary pressures. These macroeconomic factors could materially and adversely affect our ability to continue to operate as a going concern and could otherwise have a material adverse effect on our business, operations, operating results and financial condition as well as the price of our common stock. In particular, our ability to raise the substantial additional capital we need in order to fund our business and to continue to operate as a going concern may be adversely impacted by these macroeconomic factors, and we cannot be certain that we will be able to obtain financing on terms acceptable to us, or at all.

Our revenues in the past have consisted primarily of revenues from collaboration agreements, which included upfront licensing fees, reimbursements for research services, and milestone achievements, and research grant funding. In 2023, our collaboration agreements with Biogen MA, Inc. and Biogen International GmbH, which we refer to together as Biogen, and Novartis Institutes for BioMedical Research, Inc., or Novartis, were terminated, and the collaboration agreement with Kite Pharma, Inc., a Gilead Sciences, Inc. subsidiary, or Kite, expired pursuant to its terms in April 2024. We expect revenues to continue to fluctuate from period to period and there can be no assurance that new collaborations or partner reimbursements will continue beyond their initial terms or that we are able to meet the milestones specified in these agreements. For additional information concerning the terms of our ongoing collaboration agreements, see Note 5 – Major Customers, Partnerships and Strategic Alliances in the accompanying notes to the Condensed Consolidated Financial Statements included in Part I, Item 1 of this Quarterly Report on Form 10-Q.

Although we expect research and development expenses to decrease in the near-term in connection with the restructuring of operations and reduction in workforce and significant reduction in our internal manufacturing and allogeneic research footprints in California announced in April 2023, or the April 2023 Restructuring, the further restructuring of operations and corresponding reduction in workforce announced in November 2023, or the November 2023 Restructuring, and the wind-down of operations in France and corresponding reduction in workforce, including closure of our cell therapy manufacturing facility and research labs in Valbonne, France, or the France Restructuring, we expect to continue to devote substantial resources to research and development in the future and expect research and development expenses to increase in the next several years if we are successful in advancing our product candidates from research stage through clinical trials.

General and administrative expenses consist primarily of salaries and personnel related expenses for executive, finance and administrative personnel, stock-based compensation expense, professional fees, allocated facilities and information technology expenses, patent prosecution expenses and other general corporate expenses. Although we expect general and administrative expenses to decrease in the near-term in connection with the April 2023 Restructuring, November 2023 Restructuring and France Restructuring, we expect the growth of our business to require increased general and administrative expenses as we continue to advance our product candidates into and through the clinic.

Our Condensed Consolidated Financial Statements and the related disclosures have been prepared in accordance with generally accepted accounting principles in the United States. The preparation of these Condensed Consolidated Financial Statements requires us to make estimates, assumptions and judgments that affect the reported amounts in our Condensed Consolidated Financial Statements and accompanying notes. We base our estimates on historical experience and on various other assumptions that we believe 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 may differ from these estimates under different assumptions or conditions. We believe the following policies to be the most critical to an understanding of our financial condition and results of operations because they require us to make estimates, assumptions and judgments about matters that are inherently uncertain.

Revenues during the three and six months ended June 30, 2024 primarily consisted of royalties from our license agreements with Sigma-Aldrich Corporation, or Sigma, and Open Monoclonal Technology, Inc. (now Ligand Pharmaceuticals Inc.), or Ligand. We anticipate revenues in the future will be derived primarily from our license agreements. The terminations of our collaboration agreements with Biogen and Novartis became effective in June 2023, following which we are not entitled to any further milestone payments or royalties from either Biogen or Novartis, nor does either Biogen or Novartis have any further obligations to develop or to reimburse us the costs of any of the programs previously subject to the Biogen and Novartis collaborations. Further, our collaboration agreement with Kite expired pursuant to its terms in April 2024.

Operating expenses


	Three Months Ended June 30,							Six Months Ended June 30,
	(in thousands, except percentage values)							(in thousands, except percentage values)
	2024		2023		Change		%	2024		2023		Change		%
Operating expenses:
Research and development	$	24,223	$	63,046	$	(38,823)	(62%)	$	60,114	$	126,262	$	(66,148)	(52%)
General and administrative	12,045		16,014		(3,969)		(25%)	23,812		34,150		(10,338)		(30%)
Impairment of long-lived assets	1,172		—		1,172		100%	5,521		20,433		(14,912)		(73%)
Impairment of goodwill and indefinite-lived intangible assets	—		51,347		(51,347)		(100%)	—		89,485		(89,485)		(100%)
Total operating expenses	$	37,440	$	130,407	$	(92,967)	(71%)	$	89,447	$	270,330	$	(180,883)	(67%)

The decrease of $38.8 million in research and development expenses for the three months ended June 30, 2024, compared to the same period in 2023, was primarily attributable to lower compensation and other personnel costs of $15.0 million due to lower headcount as a result of restructurings of operations and corresponding reductions in workforce announced during 2023 and restructuring expenses recorded during the three months ended June 30, 2023 relating to April restructuring, lower preclinical and clinical expenses of $15.1 million primarily related to the termination of collaboration agreements with Biogen and Novartis and deferral and reprioritization of certain programs, lower facilities and infrastructure related expenses of $3.9 million, and lower allocated overheads of $3.6 million. Stock-based compensation expense included in research and development expenses was $1.3 million and $3.9 million for the three months ended June 30, 2024 and 2023, respectively.

The decrease of $66.1 million in research and development expenses for the six months ended June 30, 2024, compared to the same period in 2023, was primarily attributable to lower compensation and other personnel costs of $27.3 million due to lower headcount as a result of restructurings of operations and corresponding reductions in workforce announced during 2023, a reduction in the bonus expense, and restructuring expenses recorded during the six months ended June 30, 2023 relating to April restructuring, lower preclinical and clinical expenses of $24.9 million primarily related to the termination of collaboration agreements with Biogen and Novartis and deferral and reprioritization of certain programs, lower facilities and infrastructure related expenses of $5.7 million mainly due to lower depreciation, and lower allocated overheads of $6.5 million. Stock-based compensation expense included in research and development expenses was $2.7 million and $8.8 million for the six months ended June 30, 2024 and 2023, respectively.

We expect to continue to devote substantial resources to research and development in the future. While we anticipate that our research and development expenses will decrease in the near-term in connection with the April 2023 Restructuring, November 2023 Restructuring and France Restructuring and the related reprioritization of certain programs and deferral of certain new investments, we ultimately expect research and development expenses to increase in the next several years if we are successful in advancing our clinical programs and if we are able to progress our preclinical product candidates into clinical trials and/or if we are successful in securing new collaborations or other capital necessary to advance our clinical programs.

The length of time required to complete our development programs and our development costs for those programs may be impacted by the results of preclinical testing, scope and timing of enrollment in clinical trials for our product candidates, our decisions to pursue development programs in other therapeutic areas, whether we pursue development of our product candidates with a partner or collaborator or independently and our ability to secure the necessary funding to progress the development of our programs. For example, our current focus is on our core neurology preclinical program, and we do not yet know whether and to what extent we will progress any resulting product candidates from our preclinical program into the clinic and in what therapeutic areas. In this regard, we are deferring new investments in registrational trial planning activities for our Fabry disease gene therapy program until we secure a collaboration partner or external investment in this program. We are actively seeking collaboration partners or a direct external investment, as applicable, to progress our Fabry disease, STAC-BBB and modular integrase programs. Furthermore, the scope and number of clinical trials required to obtain regulatory approval for each pursued therapeutic area is subject to the input of the applicable regulatory authorities, and we have not yet sought such input for all potential therapeutic areas that we may elect to pursue, and even after having given such input, applicable regulatory authorities may subsequently require additional clinical studies prior to granting regulatory approval based on new data generated by us or other

Our potential therapeutic products are subject to a lengthy and uncertain regulatory process that may not result in our receipt of any necessary regulatory approvals. Failure to receive the necessary regulatory approvals would prevent us from commercializing the product candidates affected. In addition, clinical trials of our product candidates may fail to demonstrate safety and efficacy, which could prevent or significantly delay regulatory approval. A discussion of the risks and uncertainties with respect to our research and development activities, including completing the development of our product candidates, and the consequences to our business, financial position and growth prospects can be found in “Risk Factors” in Part I, Item 1A of the 2023 Annual Report, as supplemented by the risks described under “Risk Factors” in Part II, Item 1A of this Quarterly Report on Form 10-Q.

The decrease of $4.0 million in general and administrative expenses for the three months ended June 30, 2024, compared to the same period in 2023, was primarily attributable to lower compensation and other personnel costs of $5.0 million due to lower headcount as a result of restructurings of operations and corresponding reductions in workforce announced during 2023 and restructuring expenses recorded during the three months ended June 30, 2023 relating to April restructuring, Biogen contract cost asset amortization of $2.8 million recorded during the three months ended June 30, 2023 due to the termination of the collaboration agreement, lower external professional services of $0.8 million, and lower facilities and infrastructure related costs of $1.5 million. These decreases were partially offset by higher allocated overheads of $3.6 million, and a $2.4 million expense relating to a terminated manufacturing-related supplier arrangement for costs that will be incurred without economic benefit to Sangamo. Stock-based compensation expense included in general and administrative expenses was $1.7 million and $2.9 million for the three months ended June 30, 2024 and 2023, respectively.

The decrease of $10.3 million in general and administrative expenses for the six months ended June 30, 2024, compared to the same period in 2023, was primarily attributable to lower compensation and other personnel costs of $9.4 million due to lower headcount as a result of restructurings of operations and corresponding reductions in workforce announced during 2023, a reduction in bonus expense, and restructuring expenses recorded during the three months ended June 30, 2023 relating to April restructuring, Biogen contract cost asset amortization of $2.8 million recorded during the three months ended June 30, 2023 due to the termination of the collaboration agreement, lower external professional services of $3.9 million, and lower facilities and infrastructure related costs of $3.2 million. These decreases were partially offset by higher allocated overheads of $6.6 million, and a $2.4 million expense relating to a terminated manufacturing-related supplier arrangement for costs that will be incurred without economic benefit to Sangamo. Stock-based compensation expense included in general and administrative expenses was $3.1 million and $6.3 million for the six months ended June 30, 2024 and 2023, respectively.

In 2023, we executed a series of restructurings of operations and corresponding reductions in workforce announced in April 2023 and November 2023. In 2024, we are executing a wind-down of our French operations and a corresponding workforce reduction announced in March 2024. These restructurings were designed to reduce overall costs and advance our strategic transformation into a neurology focused genomic medicine company focused on epigenetic regulation programs addressing serious neurological diseases and novel AAV capsid delivery technology. In connection with the November 2023 Restructuring and France Restructuring, the expenses incurred during the three and six months ended June 30, 2024 related to employee severance and notice period payments, benefits, and other employee-related costs were not material. During the three months ended June 30, 2024, we recognized $2.4 million as expense relating to a terminated manufacturing-related supplier arrangement for costs that will be incurred without economic benefit to Sangamo.

During the three and six months ended June 30, 2024, we recognized impairment charges of $1.2 million and $5.5 million, respectively. During the six months ended June 30, 2024, our Board of Directors approved the France Restructuring, we initiated several actions aimed at reducing costs, including activities related to the closure of our facility in Brisbane, California, and we faced a sustained decline in our stock price and related market capitalization. There was also a decline in the market rates for facility subleases, indicating the carrying values of right of use and leasehold improvement assets could be impaired. As a result of these factors, we concluded certain long-lived assets, primarily comprising right-of-use assets, related leasehold improvements, and certain manufacturing and laboratory equipment, were impaired.

In August 2020, we entered into an Open Market Sale Agreement℠, or the sales agreement, with Jefferies LLC, providing for the sale of up to $150.0 million of our common stock from time to time in “at-the-market” offerings under an existing shelf registration statement. In December 2022, we entered into Amendment No. 2 to the Open Market Sale Agreement℠, which increased the aggregate offering price under the sales agreement by an additional $175.0 million. Approximately $194.5 million remained available under the sales agreement as of June 30, 2024. No shares were sold during the three and six months ended June 30, 2024. During the three and six months ended June 30, 2023, we sold 4,286,831 and 8,249,261 shares of its common stock for net proceeds under the sales agreement of approximately $5.4 million and $15.1 million, respectively.

Under Accounting Standard Codification Topic 205-40, Presentation of Financial Statements—Going Concern, or ASC Topic 205-40, we have the responsibility to evaluate whether conditions and/or events raise substantial doubt about our ability to meet our future financial obligations as they become due within one year after the date that the Condensed Consolidated Financial Statements included in this Quarterly Report on Form 10-Q are issued. As required under ASC Topic 205-40, management’s evaluation should initially not take into consideration the potential mitigating effects of management’s plans that have not been fully implemented as of the date the Condensed Consolidated Financial Statements are issued. When substantial doubt exists, management evaluates whether the mitigating effects of its plans sufficiently alleviate the substantial doubt about the company’s ability to continue as a going concern. The mitigating effects of management’s plans, however, are only considered if both (i) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued, and (ii) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt

Based on our current operating plan, our cash and cash equivalents as of June 30, 2024, taken together with the Genentech Payments, are expected to allow us to meet our liquidity requirements only into the first quarter of 2025. Our history of significant losses, negative cash flows from operations, limited liquidity resources currently on hand and dependence on our ability to obtain additional financing to fund our operations have resulted in management’s assessment that there is substantial doubt about our ability to continue as a going concern for at least the next 12 months from the date the financial statements included in this Quarterly Report are issued. Our ability to continue to operate as a going concern is dependent upon our ability to raise substantial additional capital to fund our operations and support our research and development endeavors, including to progress our preclinical and clinical programs as described in our 2023 Annual Report and in this Quarterly Report. Although we raised capital via a registered direct offering to institutional investors of common stock and accompanying warrants in March 2024, and although we expect to receive the Genentech Payments, we will still need substantial additional capital in order to continue to operate as a going concern and fund our operations. We have been actively seeking, and continue to actively seek, substantial additional capital, including through public or private equity or debt financing, royalty financing or other sources, such as strategic collaborations and other direct investments in our programs. We may be unable to attract new investments as a result of the speculative nature of our newly reprioritized core neurology preclinical programs. Additional capital may not be available on acceptable terms or at all. If adequate funds are not available to us on a timely basis, or at all, we will be required to take additional actions to address our liquidity needs, including additional cost reduction measures such as further reducing operating expenses and delaying, reducing the scope of, discontinuing or altering our research and development activities, which would have a material adverse effect on our business and prospects, or we may be required to cease operations entirely, liquidate all or a portion of our assets, and/or seek protection under the U.S. Bankruptcy Code, and you may lose all or part of your investment. If we are unable to secure additional funding in the near term, we may seek protection under the U.S. Bankruptcy Code. We have explored, and will continue to explore, whether filing for bankruptcy protection is in the best interest of our Company and our stakeholders.

While we expect the April 2023 Restructuring, November 2023 Restructuring and France Restructuring to be substantially complete by the end of 2024, we may also incur other charges or cash expenditures not currently contemplated due to events that may occur as a result of, or associated with, each of the restructurings. In addition, we may not achieve the expected benefits of these cost reduction measures and other cost reduction plans on the anticipated timeline, or at all, or we may use our available capital more quickly than we expect, which could otherwise accelerate our liquidity needs and could force us to further curtail or suspend, or entirely cease, our operations. Moreover, we rely in part on our collaboration partners to provide funding for and otherwise advance our preclinical and clinical programs. However, in June 2023 our collaboration agreements with Biogen and Novartis terminated, and in April 2024, our collaboration agreement with Kite expired. While we may identify new collaboration partners who can progress some of the programs that were the subject of these collaborations as well as our Fabry disease, STAC-BBB and modular integrase programs, we have not yet been, and may never be, successful in doing so in a timely manner, on acceptable terms or at all, and we may otherwise fail to raise sufficient additional capital in order to progress these programs ourselves, in which case, we will not receive any return on our investments in these programs. In any event, we need substantial additional funding in order to progress the programs that were the subject of these collaborations as well as our Fabry disease, STAC-BBB and modular integrase programs, and to otherwise execute on our current operating plan. If we raise additional capital through public or private equity offerings, including sales pursuant to our at-the-market offering program with Jefferies LLC, the ownership interest of our existing stockholders will be diluted, and such dilution may be substantial given our current stock price decline, and the terms of any new equity securities may have a preference over, and include rights superior to, our common stock. If we raise additional capital through royalty financings or other collaborations, strategic alliances or licensing arrangements with third parties, we may need to relinquish certain valuable rights to our product candidates, technologies, future revenue streams or research programs or grant licenses on terms that may not be favorable. If we raise additional capital through debt financing, we may be subject to specified financial covenants or covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or pursuing certain transactions, any of which could restrict our ability to commercialize our product candidates or operate as a business.

In addition, as we focus our efforts on proprietary human therapeutics, we will need to seek regulatory approvals of our product candidates from the FDA or other comparable foreign regulatory authorities, a process that could cost in excess of hundreds of millions of dollars per product. We may experience difficulties in accessing the capital markets due to external factors beyond our control, such as volatility in the equity markets for emerging biotechnology companies and general economic and market conditions both in the United States and abroad. In particular, our ability to raise the substantial additional capital we need in order to fund our business may be adversely impacted by global economic conditions and disruptions to and volatility in the credit and financial markets in the United States and worldwide, such as has been experienced recently due in part to, among other things, the ongoing conflict between Russia and Ukraine and conflicts in the Middle East. We cannot be certain that we will be able to obtain financing on terms acceptable to us, or at all.

We anticipate continuing to incur operating losses for at least the next several years and need to raise substantial additional capital. The effects of the current macroeconomic environment, including the effects of war in Ukraine and conflicts in the Middle East, inflation, climate change, rising interest rates and other economic uncertainty and volatility, has resulted and may continue to result in significant disruption of global financial markets, which could impair our ability to access capital on terms that are acceptable or at all, and in turn could negatively affect our liquidity and our ability to continue to operate as a going concern. Future capital requirements beyond the first quarter of 2025, the period into which we expect our existing cash and cash equivalents, in combination with the Genentech Payments, will be sufficient to fund our planned operations, will be substantial, and we need to raise substantial additional capital to continue to operate as a going concern and to fund the development,

Our management, including the principal executive officer and principal financial officer, does not expect that our disclosure controls and procedures and our internal control over financial reporting will prevent all error and all fraud. A control system, no matter how well designed and operated, can only provide reasonable assurances that the objectives of the control system are met. The design of a control system reflects resource constraints; the benefits of controls must be considered relative to their costs. Because there are inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that all control issues and instances of fraud, if any, for our company have been or will be detected. As these inherent limitations are known features of the disclosure and financial reporting processes, it is possible to design into the processes safeguards to reduce, though not eliminate, these risks. These inherent limitations include the realities that judgments in decision-making can be

faulty and that breakdowns occur because of simple error or mistake. Controls can also be circumvented by the individual acts of some persons, by collusion of two or more people, or by management override of the control. The design of any system of controls is based in part upon certain assumptions about the likelihood of future events. While our disclosure controls and procedures and our internal control over financial reporting are designed to provide reasonable assurance of achieving their objectives, there can be no assurance that any design will succeed in achieving its stated goals under all future conditions. Over time, controls may become inadequate because of changes in conditions or deterioration in the degree of compliance with the policies or procedures. Because of the inherent limitations in a cost-effective control system, misstatements due to error or fraud may occur and not be detected.

We have a history of recurring net losses, including $85.2 million for the six months ended June 30, 2024 and $257.8 million and $192.3 million for the years ended December 31, 2023 and 2022, respectively, and we have otherwise generated operating losses since we began operations in 1995. The extent of our future losses and the timing of profitability are uncertain, and we expect to incur losses for the foreseeable future. We have been engaged in developing our zinc finger, or ZF, technology since inception, which has and will continue to require significant research and development expenditures. To date, we have generated our funding from issuance of equity securities, revenues derived from collaboration agreements, other strategic partnerships in non-therapeutic applications of our technology, federal government research grants and grants awarded by research foundations. We expect to continue to incur additional operating losses for the next several years as we continue to develop our preclinical core neurology therapeutic programs and capsid engineering platform. If the time required to generate significant product revenues and achieve profitability is longer than we currently anticipate or if we are unable to generate liquidity through equity financing or other sources of funding, we may be forced to further curtail or suspend, or entirely cease, our operations.

There is substantial doubt about our ability to continue to operate as a going concern. We need substantial additional funding to execute our operating plan and to continue to operate as a going concern. If adequate funds are not available to us on a timely basis, or at all, we will be required to take additional actions to address our liquidity needs, including additional cost reduction measures such as further reducing operating expenses and delaying, reducing the scope of, discontinuing or altering our research and development activities, which would have a material adverse effect on our business and prospects, or we may be required to cease operations entirely, liquidate all or a portion of our assets, and/or seek protection under the U.S. Bankruptcy Code, and you may lose all or part of your investment. Future sales and issuances of equity securities would also result in substantial dilution to our stockholders.

We have incurred significant operating losses and negative operating cash flows since inception and have not achieved profitability. Based on our current operating plan, we estimate that our available cash, cash equivalents and marketable securities as of June 30, 2024, taken together with the $50.0 million in upfront license fees and milestone payments that we expect to receive from Genentech in the near term (the “Genentech Payments”), will be sufficient to fund our planned operations only into the first quarter of 2025. Our financial position raises substantial doubt about our ability to continue to operate as a going concern. Our ability to continue to operate as a going concern is dependent upon our ability to raise substantial additional capital to fund our operations and support our research and development endeavors, including to progress our preclinical and clinical programs as described in our 2023 Annual Report and in this Quarterly Report. In this regard, we have been seeking, and continue to actively seek substantial additional capital, including through public or private equity or debt financing, royalty financing or other sources, such as strategic collaborations and other direct investments in our programs. Although we raised capital via a registered direct offering to institutional investors of common stock and accompanying warrants in March 2024, or the 2024 Registered Direct Offering, for net proceeds of approximately $21.8 million after deducting placement agents’ fees and estimated offering expenses payable by us, and although we expect to receive the Genentech Payments, we will still need substantial additional capital in order to continue to operate as a going concern and fund our operations. Additional capital may not be available on acceptable terms or at all. In particular, the perception of our ability to continue to operate as a going concern may make it more difficult to obtain financing for the continuation of our operations, particularly in light of currently challenging macroeconomic and market conditions. Further, we may be unable to attract new investments as a result of the speculative nature of our newly reprioritized core neurology preclinical programs. If adequate funds are not available to us on a timely basis, or at all, we will be required to take additional actions to address our liquidity needs, including additional cost reduction measures such as further reducing operating expenses and delaying, reducing the scope of, discontinuing or altering our research and development activities, which would have a material adverse effect on our business and prospects, or we may be required to cease operations entirely, liquidate all or a portion of our assets, and/or seek protection under the U.S. Bankruptcy Code, and you may lose all or

In April 2023, we announced a restructuring of operations and a reduction in force and a significant reduction in our internal manufacturing and allogeneic research footprints in California, or the April 2023 Restructuring, and in November 2023, we announced a further restructuring of operations and reduction in force, or the November 2023 Restructuring, including a strategic transformation to focus resources on our proprietary neurology-focused epigenetic regulation programs and AAV capsid delivery technology and move all U.S. operations, including our headquarters, to our Richmond, California facility. On March 1, 2024, our board of directors approved the wind-down of our operations in France and closure of our facility in Valbonne, France by the end of 2024, or the France Restructuring. While we expect the April 2023 Restructuring, November 2023 Restructuring and France Restructuring to be complete by the third quarter of 2024, the third quarter of 2024 and the fourth quarter of 2024, respectively, we may also incur other charges or cash expenditures not currently contemplated due to events that may occur as a result of, or associated with, each of the restructurings. In addition, we may not achieve the expected benefits of these cost reduction measures and other cost reduction plans on the anticipated timeline, or at all, or we may use our available capital more quickly than we expect, which could otherwise accelerate our liquidity needs and could force us to further curtail or suspend, or entirely cease, our operations. Moreover, we have historically relied in part on collaboration partners to provide funding for and otherwise advance our preclinical and clinical programs. However, in June 2023, our collaboration agreements with Biogen and Novartis terminated, and our collaboration agreement with Kite expired pursuant to its terms in April 2024. Although we have entered into the Genentech Agreement pursuant to which we are eligible to earn a $10.0 million milestone payment upon completion of technology transfer activities as well as additional development and commercial milestone payments, we may be unable to complete the requisite actions to earn the technology transfer milestone payment, in which case our financial position would be adversely affected, and we may never receive any future development or commercial milestone payments. Further, while we may identify new collaboration partners who can progress some of the programs that were the subject of these collaborations as well as our Fabry disease and modular integrase programs, we have not yet been, and may never be, successful in doing so in a timely manner, on acceptable terms or at all, and we may otherwise fail to raise sufficient additional capital in order to progress these and our other programs ourselves, in which case, we will not receive any return on our investments in these programs. In any event, we need substantial additional funding in order to advance our core neurology programs as well as our Fabry disease, STAC-BBB and modular integrase programs, and to otherwise execute on our current operating plan.

If we raise additional capital through public or private equity offerings, including sales pursuant to our at-the-market offering program with Jefferies LLC, the ownership interest of our existing stockholders will be diluted, and such dilution may be substantial given our current stock price decline. For example, in the 2024 Registered Direct Offering, we issued 24,761,905 shares of common stock, pre-funded warrants to purchase 3,809,523 shares of common stock and accompanying warrants to purchase an aggregate of 28,571,428 shares of common stock at a price per share of common stock (or pre-funded warrant in lieu thereof) and accompanying warrant of $0.84 per share. In addition, the terms of any new equity securities we may issue may have a preference over, and include rights superior to, our common stock. If we raise additional capital through royalty financings or other collaborations, strategic alliances or licensing arrangements with third parties, we may need to relinquish certain valuable rights to our product candidates, technologies, future revenue streams or research programs or grant licenses on terms that may not be favorable. If we raise additional capital through debt financing, we may be subject to specified financial covenants or covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or pursuing certain transactions, any of which could restrict our ability to commercialize our product candidates or operate as a business.

In addition, as we focus our efforts on proprietary human therapeutics, we will need to seek regulatory approvals of our product candidates from the FDA or other comparable foreign regulatory authorities, a process that could cost in excess of hundreds of millions of dollars per product. We may experience difficulties in accessing the capital markets due to external factors beyond our control, such as volatility in the equity markets for emerging biotechnology companies and general economic and market conditions both in the United States and abroad. In particular, our ability to raise the substantial additional capital we need in order to fund our business may be adversely impacted by global economic conditions and disruptions to and volatility in the credit and financial markets in the United States and worldwide, such as has been experienced recently. We cannot be certain that we will be able to obtain financing on terms acceptable to us, or at all. Our failure to obtain adequate and timely funding will adversely affect our ability to continue to operate as a going concern and our ability to develop our technology and products candidates.

continue to actively seek, substantial additional capital, including through public or private equity or debt financing, royalty financing or other sources, such as strategic collaborations and other direct investments in our programs, and we have been unsuccessful in securing any such additional capital to date. As a result, we have explored, and will continue to explore, whether filing for bankruptcy protection is in the best interest of our Company and our stakeholders. In the event we file for relief under the U.S. Bankruptcy Code, our operations, our ability to develop our product candidates and execute on our operating plan, and our ability to continue as a going concern will be subject to the risks and uncertainties associated with bankruptcy proceedings, including, among others: our ability to execute, confirm and consummate a plan of reorganization; the additional, significant costs of bankruptcy proceedings and related fees; our ability to obtain sufficient financing to allow us to emerge from bankruptcy and execute our business plan thereafter, and our ability to comply with terms and conditions of any such financing; our ability to continue our operations in the ordinary course; our ability to maintain our relationships with our collaborators, counterparties, employees and other third parties; our ability to obtain, maintain or renew contracts that are critical to our operations on reasonably acceptable terms and conditions or at all; our ability to attract, motivate and retain key employees; the ability of third parties to use certain provisions of the U.S. Bankruptcy Code to terminate contracts without first seeking Bankruptcy Court approval; the ability of third parties to seek and obtain court approval to terminate or shorten the exclusivity period for us to propose and confirm a plan of reorganization, to appoint a trustee, or to convert a proceeding under Chapter 11 of the U.S. Bankruptcy Code to a proceeding under Chapter 7 of the U.S. Bankruptcy Code; and the actions and decisions of our stakeholders and other third parties who have interests in our bankruptcy proceedings that may be inconsistent with our operational and strategic plans. Any delays in our bankruptcy proceedings would increase the risks that we may not be able to reorganize our business and emerge from bankruptcy proceedings and may increase our costs associated with the bankruptcy process or result in prolonged operational disruption. In addition, we would need the prior approval of the Bankruptcy Court for transactions outside the ordinary course of business during the course of any bankruptcy proceedings, which may limit our ability to respond timely to certain events or take advantage of certain opportunities. Because of the risks and uncertainties associated with any bankruptcy proceedings, we cannot accurately predict or quantify the ultimate impact of events that could occur during any such proceedings. There can be no guarantees that if we seek protection under the U.S. Bankruptcy Code, we will emerge from any such proceedings as a going concern or that holders of our common stock will receive any recovery from any bankruptcy proceedings.

In the event we are unable to pursue protection under Chapter 11 of the U.S. Bankruptcy Code, or, if pursued, successfully emerge from such proceedings, it may be necessary for us to pursue protection under Chapter 7 of the U.S. Bankruptcy Code for all or a part of our businesses. In such event, a Chapter 7 trustee would be appointed or elected to liquidate our assets for distribution in accordance with the priorities established by the U.S. Bankruptcy Code. We believe that liquidation under Chapter 7 would result in significantly smaller distributions being made to our stakeholders than those we might obtain under Chapter 11, or no distribution at all, primarily because of the likelihood that the assets would have to be sold or otherwise disposed of in a distressed fashion over a short period of time rather than in a controlled manner and as a going concern. In such event, you may lose part or all of your investment.

We were party to collaboration agreements with Novartis to develop product candidates to treat certain neurodevelopment disorders, including autism and intellectual disability and with Biogen to develop product candidates to treat tauopathies including Alzheimer’s disease, alpha-synuclein related diseases including Parkinson’s disease and other neurological diseases. In June 2023, our collaboration agreements with Novartis and Biogen terminated. We were also party to a collaboration agreement with Kite to develop engineered cell therapies for cancer, which expired by its terms in April 2024. As a result of these terminations and expirations, we are no longer entitled to any milestone payments or royalties from Novartis, Biogen or Kite, and such counterparties have no further obligations to develop or to reimburse the costs of any of the programs under the applicable agreement. In connection with the Restructurings, we made the strategic decision to pause further development of the programs that were the subject of these collaborations. In the future, we may identify alternative options to advance some of the programs that were subject to such agreements, including potential development internally or with a collaboration partner. However, we

If we are unable to secure additional collaborations or if our collaborators are unable or unwilling to diligently advance the development, regulatory approval and commercialization of our product candidates, our growth may slow and adversely affect our ability to generate funding for development of our technologies and product candidates as well as our ability to continue to operate as a going concern, and we may be required to cease operations. For example, although we have decided to defer new investments in our Fabry disease gene therapy program unless and until we are able to successfully secure a collaboration partner or external investment in this program, there can be no assurance that such efforts will be successful in a timely manner, or at all, in which case, we will not receive any return on our investments in these programs and our ability to continue to operate as a going concern may be materially and adversely affected. In addition, our ongoing collaborators may sublicense or abandon development programs with little advance notice, or we may have disagreements or disputes with our collaborators, which would cause associated product development to slow or cease. In addition, the business or operations of our collaborators may change significantly through restructurings, acquisitions, other strategic transactions that may negatively impact their ability to advance our programs.

Under typical collaborations, we expect to receive revenue for the research and development of our product candidates based on achievement of specific milestones, as well as royalties based on a percentage of sales of any commercialized products. Achieving these milestones will depend, in part, on the efforts of our collaborators, which we have no control over, as well as our own efforts. In addition, business combinations, changes in a collaborator’s business strategy and financial difficulties or other factors could result in that collaborator abandoning or delaying development of any product candidates covered by our collaboration agreement with that collaborator. For example, Novartis’s and Biogen’s decisions to terminate their respective collaboration agreements with us each related to a recent strategic review. Further, if we fail or any collaboration partner fails to meet specific milestones, then the collaboration agreement may be terminated, which would preclude our ability to earn any additional milestone payments under that collaboration agreement and would reduce our revenues. In addition, even if a collaboration product candidate is successfully developed and approved for marketing by relevant regulatory authorities, if sales of the commercialized product fails to meet expectations, we could receive lower royalties than expected. In any event, the milestone and royalty payment opportunities associated with our collaborations involve a substantial degree of risk to achieve and may never be received. Accordingly, investors should not assume that we will receive all of the potential milestone payments provided for under our ongoing collaborations, and it is possible that we may never receive any further significant milestone payments or any royalty payments under our collaborations.

We evaluate the carrying value of long-lived assets, which include property and equipment, leasehold improvements and right-of-use assets, for impairment whenever events or changes in circumstances indicate that the carrying amounts of the asset may not be fully recoverable. Factors that may indicate potential impairment and trigger an impairment test include, but are not limited to, general macroeconomic conditions, conditions specific to the industry and market, an adverse change in legal factors, business climate or operational performance of the business, and sustained decline in the stock price and market capitalization compared to the net book value. During the year ended December 31, 2023 and the six months ended June 30, 2024, we recognized impairment charges of $155.0 million and $5.5 million, respectively. We have fully impaired our goodwill and indefinite-lived intangible assets in 2023 and have significantly impaired our long-lived assets in both 2023 and 2024. We will continue to assess whether its long-lived assets are impaired in future periods. We are finalizing the wind-down of our France operations and corresponding reduction in force of all France employees, as well as the closure of our Brisbane facility, and we have recognized related impairments in the past twelve months. It is reasonably possible that additional impairment charges will be recognized, for example, if sublease rates of leased facilities or selling prices of the assets held for sale are less than those estimated. For additional information regarding these impairment charges, see Note 6 – Impairment and Write-Down of Assets Held For Sale in the accompanying notes to the Condensed Consolidated Financial Statements included in Part I, Item 1 of this Quarterly Report on Form 10-Q.

Our common stock is currently listed on the Nasdaq Global Select Market, which has minimum requirements that a company must meet in order to remain listed. These requirements include maintaining a minimum closing bid price of $1.00 per share, which closing bid price cannot fall below $1.00 per share for a period of more than 30 consecutive trading days, or the Bid Price Requirement. On April 24, 2024, we received a deficiency notice, or the Notice, from the Listing Qualifications Staff, or the Staff of Nasdaq notifying us that, for the last 30 consecutive business days, the bid price of our common stock had closed below $1.00 per share, thereby failing to satisfy the Bid Price Requirement set forth in the continued listing requirements of Nasdaq Listing Rule 5450(a)(1). The Notice has no immediate effect on the listing of our common stock on the Nasdaq Global Select Market. In accordance with Nasdaq Listing Rule 5810(c)(3)(A), we have 180 calendar days, or until October 21, 2024, to regain compliance with the Bid Price Requirement by having shares of our common stock maintain a minimum closing bid price of at least $1.00 per share for a minimum of 10 consecutive trading days. In the event we do not regain compliance with the Bid Price Requirement prior to the expiration of the compliance period, unless Nasdaq exercises its discretion to extend this period, our common stock may be subject to a delisting action by Nasdaq.

A reverse stock split may allow us to meet the Bid Price Requirement, but we cannot assure you that a reverse stock split will be approved by our stockholders or that any reverse stock split, if implemented, will be sufficient to enable us to maintain our Nasdaq listing. Additionally, if a reverse stock split is implemented, there can be no assurance that the market price per new share of our common stock following the reverse stock split will remain unchanged or will increase in proportion to the reduction in the number of old shares of our common stock outstanding before the reverse stock split. The liquidity of the shares of our common stock may be affected adversely by any reverse stock split given the reduced number of shares of our common stock that will be outstanding following such reverse stock split. Furthermore, following any reverse stock split, the resulting market price of our common stock may not attract new investors and may not satisfy the investing requirements of those investors.

In the event that our common stock is delisted from Nasdaq as a result of our failure to regain compliance with the Bid Price Requirement, as a result of Nasdaq not granting us an extension or the panel not granting us a favorable decision or due to our failure to continue to comply with any other requirement for continued listing on Nasdaq, trading of our common stock could be conducted in the over-the-counter market or on an electronic bulletin board established for unlisted securities such as the Pink Sheets or the OTC Bulletin Board, but there can be no assurance that our common stock will be eligible for trading on such alternative exchange or market.

Additionally, if our common stock is delisted from Nasdaq, the liquidity of our common stock would be adversely affected, the market price of our common stock could decrease, our ability to obtain sufficient additional capital to fund our operations and to continue to operate as a going concern would be substantially impaired and transactions in our common stock could lose federal preemption of state securities laws. Furthermore, there could also be a further reduction in our coverage by securities analysts and the news media and broker-dealers may be deterred from making a market in or otherwise seeking or generating interest in our common stock, which could cause the price of our common stock to decline further. Moreover, delisting may also negatively affect our collaborators’, vendors’, suppliers’ and employees’ confidence in us and employee morale.

On August 2, 2024, the Company entered into a global epigenetic regulation and capsid delivery license agreement, or the Genentech Agreement, with Genentech, a member of the Roche Group, or Genentech, to develop intravenously administered genomic medicines to treat certain neurodegenerative diseases. Under the Genentech Agreement, the Company granted an exclusive license to Genentech for the Company’s proprietary zinc finger repressors, or ZFRs, that are directed to tau and the Company’s proprietary ZFRs that are directed to a second undisclosed neurology target. The Company also granted an exclusive license to Genentech to the Company’s proprietary, neurotropic adeno-associated virus capsid, STAC-BBB for use with therapies directed to tau or to the second neurology target. The Company is prohibited from exploiting (itself or with or for a third party) products directed to tau or to the second neurology target during the applicable exclusivity periods set forth in the Genentech Agreement. Under the terms of the Genentech Agreement, the Company is responsible for completing a technology transfer and certain preclinical activities, and Genentech is solely responsible for all clinical development, regulatory interactions, manufacturing and global commercialization of resulting products. Under the Genentech Agreement, Genentech is obligated to pay the Company a $40.0 million upfront license fee on or around the end of August 2024 and will become obligated to pay the Company a $10.0 million milestone payment after the completion of technology transfer activities. In addition, the Company is eligible to earn up to $1.9 billion in development and commercial milestones spread across multiple potential products under the Genentech Agreement and tiered mid-single digit to sub-teen double digit royalties on the net sales of such products, subject to certain specified reductions.


PART I. FINANCIAL INFORMATION

Item 1.	Financial Statements	6
	Condensed Consolidated Balance Sheets at June 30 , 2024 and December 31, 2023	6
	Condensed Consolidated Statements of Operations for the Three and Six Months Ended June 30 , 2024 and 2023	7
	Condensed Consolidated Statements of Comprehensive Loss for the Three and Six Months Ended June 30 , 2024 and 2023	8
	Condensed Consolidated Statements of Stockholders’ Equity for the Three and Six Months Ended June 30 , 2024 and 2023	9
	Condensed Consolidated Statements of Cash Flows for the Six Months Ended June 30 , 2024 and 2023	11
	Notes to Condensed Consolidated Financial Statements	12
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	28
Item 3.	Quantitative and Qualitative Disclosures about Market Risk	38
Item 4.	Controls and Procedures	38

PART II. OTHER INFORMATION

Item 1.	Legal Proceedings	40
Item 1A.	Risk Factors	40
Item 2.	Unregistered Sales of Equity Securities, Use of Proceeds, and Issuer Purchases of Equity Securities	44
Item 3.	Defaults Upon Senior Securities	44
Item 4.	Mine Safety Disclosures	44
Item 5.	Other Information	45
Item 6.	Exhibits	46

SIGNATURES		47


	December 31, 2023
	Fair Value Measurements
	Total		Level 1		Level 2		Level 3
Assets:
Cash equivalents:
Money market funds	$	2,508	$	2,508	$	—	$	—
Total	2,508		2,508		—		—
Marketable securities:
U.S. government-sponsored entity debt securities	22,566		—		22,566		—
Commercial paper securities	2,826		—		2,826		—
Corporate debt securities	1,405		—		1,405		—
Asset-backed securities	2,377		—		2,377		—
U.S. treasury bills	5,593		—		5,593		—
Certificates of deposit	1,031		—		1,031		—

Total	35,798		—		35,798		—
Total cash equivalents and marketable securities	$	38,306	$	2,508	$	35,798	$	—


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value

















December 31, 2023
Assets
Cash equivalents:
Money market funds	$	2,508	$	—	$	—	$	2,508
Total	2,508		—		—		2,508
Marketable securities:
U.S. government-sponsored entity debt securities	22,347		219		—		22,566
Commercial paper securities	2,825		2		(1)		2,826
Corporate debt securities	1,399		6		—		1,405
Asset-backed securities	2,368		9		—		2,377
U.S. treasury bills	5,599		—		(6)		5,593
Certificates of deposit	1,026		5		—		1,031

Total	35,564		241		(7)		35,798
Total cash equivalents and marketable securities	$	38,072	$	241	$	(7)	$	38,306


	December 31, 2023
Maturing in one year or less	$	10,855
Maturing after one year through five years	24,943
Total	$	35,798


	Six Months Ended June 30, 2024
Balance at December 31, 2023	$	11,733
Restructuring charges	2,784
Cash payments	(9,472)

Balance at June 30, 2024	$	5,045


☒			QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934


☐			TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934


	June 30, 2024		December 31, 2023		June 30, 2023		December 31, 2022
Cash and cash equivalents	$	27,786	$	45,204	$	66,830	$	100,444

Non-current restricted cash	—		1,500		1,500		1,500
Cash, cash equivalents, and restricted cash as reported within the Condensed Consolidated Statements of Cash Flows	$	27,786	$	46,704	$	68,330	$	101,944


Exhibit number		Description of Document
3.1		Restated Certificate of Incorporation (incorporated by reference to Exhibit 3.3 to the Company’s Current Report on Form 8-K filed June 2, 2023).

3.2		Certificate of Amendment of the Certificate of Incorporation (incorporated by reference to Exhibit 3.1 to the Company’s Current Report on Form 8-K filed June 5, 2024).

3.3		Fifth Amended and Restated Bylaws (incorporated by reference to Exhibit 3.1 to the Company’s Current Report on Form 8-K filed December 19, 2022).





















31.1+		Rule 13a — 14(a) Certification of Principal Executive Officer.

31.2+		Rule 13a — 14(a) Certification of Principal Financial Officer.

32.1+	*	Certifications Pursuant to 18 U.S.C. Section 1350.

101.INS	**	Inline XBRL Instance Document - the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document.

101.SCH	**	Inline XBRL Taxonomy Extension Schema With Embedded Linkbase Documents.









104		The cover page from Sangamo’s Quarterly Report on Form 10-Q for the three months ended June 30, 2024 is formatted in Inline XBRL Taxonomy Extension and it is contained in Exhibit 101.


			SANGAMO THERAPEUTICS, INC.

			/s/ ALEXANDER D. MACRAE
			Alexander D. Macrae
			President and Chief Executive Officer
			(Principal Executive Officer)

			/s/ PRATHYUSHA DURAIBABU
			Prathyusha Duraibabu
			Senior Vice President and Chief Financial Officer
			(Principal Financial and Accounting Officer)


Date: August 6, 2024

/s/ ALEXANDER D. MACRAE
Alexander D. Macrae
President and Chief Executive Officer
(Principal Executive Officer)

Cover - shares	6 Months Ended
Cover - shares	Jun. 30, 2024	Aug. 02, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2024
Document Transition Report	false
Entity File Number	000-30171
Entity Registrant Name	SANGAMO THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	68-0359556
Entity Address, Address Line One	501 Canal Blvd.
Entity Address, City or Town	Richmond
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94804
City Area Code	510
Local Phone Number	970-6000
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	SGMO
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		208,220,670
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001001233
Current Fiscal Year End Date	--12-31

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 27,786	$ 45,204
Marketable securities	0	35,798
Accounts receivable	581	923
Prepaid expenses and other current assets	11,708	12,403
Total current assets	40,075	94,328
Property and equipment, net	20,619	26,874
Operating lease right-of-use assets	18,672	25,991
Refundable research income tax credits and other non-current assets	13,648	16,627
Restricted cash	0	1,500
Total assets	93,014	165,320
Current liabilities:
Accounts payable	17,590	15,259
Accrued compensation and employee benefits	5,655	8,918
Other accrued liabilities	15,760	23,554
Total current liabilities	39,005	47,731
Long-term portion of lease liabilities	29,097	33,515
Other non-current liabilities	1,222	1,187
Total liabilities	69,324	82,433
Commitments and contingencies
Stockholders’ equity:
Preferred stock	0	0
Common stock	2,082	1,781
Additional paid-in capital	1,519,084	1,492,077
Accumulated deficit	(1,491,593)	(1,406,376)
Accumulated other comprehensive loss	(5,883)	(4,595)
Total stockholders’ equity	23,690	82,887
Total liabilities and stockholders’ equity	$ 93,014	$ 165,320

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues:
Revenues	$ 356	$ 6,835	$ 837	$ 164,792
Operating expenses:
Research and development	24,223	63,046	60,114	126,262
General and administrative	12,045	16,014	23,812	34,150
Impairment of long-lived assets	1,172	0	5,521	20,433
Impairment of goodwill and indefinite-lived intangible assets	0	51,347	0	89,485
Total operating expenses	37,440	130,407	89,447	270,330
Loss from operations	(37,084)	(123,572)	(88,610)	(105,538)
Interest and other income, net	1,030	2,802	3,565	6,095
Loss before income taxes	(36,054)	(120,770)	(85,045)	(99,443)
Income tax expense (benefit)	74	(6,264)	172	(6,070)
Net loss	$ (36,128)	$ (114,506)	$ (85,217)	$ (93,373)
Basic net loss per share (in dollars per share)	$ (0.18)	$ (0.66)	$ (0.44)	$ (0.54)
Diluted net loss per share (in dollars per share)	$ (0.18)	$ (0.66)	$ (0.44)	$ (0.54)
Shares used in computing basic net loss per share (in shares)	203,946	174,325	194,049	171,445
Shares used in computing diluted net loss per share (in shares)	203,946	174,325	194,049	171,445

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2022		166,793,320
Beginning balance at Dec. 31, 2022	$ 294,958	$ 1,668	$ 1,450,239	$ (1,148,545)	$ (8,404)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net of offering expenses (in shares)		8,249,261
Issuance of common stock, net of offering expenses	15,106	$ 83	15,023
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax (in shares)		1,276,379
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax	(1,303)	$ 13	(1,316)
Issuance of common stock under employee stock purchase plan (in shares)		755,586
Issuance of common stock under employee stock purchase plan	719	$ 7	712
Stock-based compensation	15,067		15,067
Foreign currency translation adjustment	2,125				2,125
Net pension gain (loss)	(3)				(3)
Net unrealized (loss) gain on marketable securities, net of tax	346				346
Net loss	(93,373)			(93,373)
Ending balance (in shares) at Jun. 30, 2023		177,074,546
Ending balance at Jun. 30, 2023	233,642	$ 1,771	1,479,725	(1,241,918)	(5,936)
Beginning balance (in shares) at Mar. 31, 2023		171,771,568
Beginning balance at Mar. 31, 2023	335,610	$ 1,718	1,467,062	(1,127,412)	(5,758)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net of offering expenses (in shares)		4,286,831
Issuance of common stock, net of offering expenses	5,401	$ 43	5,358
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax (in shares)		260,561
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax	(194)	$ 3	(197)
Issuance of common stock under employee stock purchase plan (in shares)		755,586
Issuance of common stock under employee stock purchase plan	719	$ 7	712
Stock-based compensation	6,790		6,790
Foreign currency translation adjustment	80				80
Net pension gain (loss)	0
Net unrealized (loss) gain on marketable securities, net of tax	(258)				(258)
Net loss	(114,506)			(114,506)
Ending balance (in shares) at Jun. 30, 2023		177,074,546
Ending balance at Jun. 30, 2023	233,642	$ 1,771	1,479,725	(1,241,918)	(5,936)
Beginning balance (in shares) at Dec. 31, 2023		178,133,548
Beginning balance at Dec. 31, 2023	82,887	$ 1,781	1,492,077	(1,406,376)	(4,595)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net of offering expenses (in shares)		24,761,905
Issuance of common stock, net of offering expenses	21,788	$ 248	21,540
Issuance of common stock upon exercise of pre-funded warrants (in shares)		3,809,523
Issuance of common stock upon exercise of pre-funded warrants	71	$ 38	33
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax (in shares)		1,116,678
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax	(481)	$ 11	(492)
Issuance of common stock under employee stock purchase plan (in shares)		379,486
Issuance of common stock under employee stock purchase plan	146	$ 4	142
Stock-based compensation	5,784		5,784
Foreign currency translation adjustment	(1,293)				(1,293)
Net pension gain (loss)	238				238
Net unrealized (loss) gain on marketable securities, net of tax	(233)				(233)
Net loss	(85,217)			(85,217)
Ending balance (in shares) at Jun. 30, 2024		208,201,140
Ending balance at Jun. 30, 2024	23,690	$ 2,082	1,519,084	(1,491,593)	(5,883)
Beginning balance (in shares) at Mar. 31, 2024		203,686,086
Beginning balance at Mar. 31, 2024	56,697	$ 2,037	1,515,926	(1,455,465)	(5,801)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of pre-funded warrants (in shares)		3,809,523
Issuance of common stock upon exercise of pre-funded warrants	71	$ 38	33
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax (in shares)		326,045
Issuance of common stock upon exercise of stock options and vesting of restricted stock units, net of tax	(79)	$ 3	(82)
Issuance of common stock under employee stock purchase plan (in shares)		379,486
Issuance of common stock under employee stock purchase plan	146	$ 4	142
Stock-based compensation	3,065		3,065
Foreign currency translation adjustment	(313)				(313)
Net pension gain (loss)	231				231
Net unrealized (loss) gain on marketable securities, net of tax	0
Net loss	(36,128)			(36,128)
Ending balance (in shares) at Jun. 30, 2024		208,201,140
Ending balance at Jun. 30, 2024	$ 23,690	$ 2,082	$ 1,519,084	$ (1,491,593)	$ (5,883)

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Operating Activities:
Net loss	$ (85,217)	$ (93,373)
Adjustments to reconcile net loss to net cash used in operating activities:
Impairment of long-lived assets	5,521	20,433
Depreciation and amortization	2,648	7,745
Accretion of discount on marketable securities	(273)	(1,865)
Amortization in operating lease right-of-use assets	2,451	4,018
Stock-based compensation	5,784	15,067
Other non-cash adjustments	103	0
Impairment of goodwill and indefinite-lived intangible assets	0	89,485
Deferred income tax benefit	0	(6,377)
Net changes in operating assets and liabilities:
Interest receivable	370	(425)
Accounts receivable	342	962
Prepaid expenses and other assets	3,565	5,548
Accounts payable and other accrued liabilities	(4,654)	(3,101)
Accrued compensation and employee benefits	(3,195)	(8,450)
Lease liabilities	(2,822)	(2,455)
Other non-current liabilities	36	61
Deferred revenues	0	(154,284)
Net cash used in operating activities	(75,547)	(127,011)
Investing Activities:
Purchases of marketable securities	0	(52,112)
Maturities of marketable securities	1,110	146,048
Sales of marketable securities	34,730	0
Sales of assets classified as held for sale	127	0
Purchases of property and equipment	0	(15,740)
Net cash provided by investing activities	35,967	78,196
Financing Activities:
Proceeds from issuance of common stock, net of offering expenses	21,924	0
Proceeds from at-the-market offering, net of offering expenses	0	15,105
Taxes paid related to net share settlement of equity awards	(481)	(1,303)
Proceeds from issuance of common stock under employee stock purchase plan	146	719
Net cash provided by financing activities	21,589	14,521
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(927)	680
Net (decrease) increase in cash, cash equivalents, and restricted cash	(18,918)	(33,614)
Cash, cash equivalents, and restricted cash, beginning of period	46,704	101,944
Cash, cash equivalents, and restricted cash, end of period	27,786	68,330
Supplemental cash flow disclosures:
Property and equipment included in unpaid liabilities	$ 433	$ 4,909

BASIC AND DILUTED NET LOSS PER SHARE	6 Months Ended
BASIC AND DILUTED NET LOSS PER SHARE	Jun. 30, 2024
Earnings Per Share [Abstract]
BASIC AND DILUTED NET LOSS PER SHARE	BASIC AND DILUTED NET LOSS PER SHARE Basic net loss per share has been computed by dividing 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 plus potentially dilutive securities outstanding during the period. Potential shares of common stock exercisable for little or no consideration are included in both basic and diluted weighted-average number of shares of common stock outstanding. During the three and six months ended June 30, 2024, both basic and diluted weighted-average number of shares outstanding were 203.9 million and 194.0 million shares, respectively, and included pre-funded warrants to purchase 3,809,523 shares of common stock with an exercise price of $0.01 per share. These warrants were exercised during the three months ended June 30, 2024. Warrants to purchase shares of common stock, with the exercise price of $1.00 per share, entitle holders to participate in dividends but are not required to absorb losses incurred and as a result were excluded from basic net loss per share calculations during the three and six ended June 30, 2024. The computation of diluted net loss per share for the three and six ended June 30, 2024 excluded 53.1 million shares subject to stock options, restricted stock units outstanding, warrants to purchase common stock, and the employee stock purchase plan shares reserved for issuance because their inclusion would have had an anti-dilutive effect on diluted net loss per share. The computation of diluted net loss per share for the three and six months ended June 30, 2023 excluded 24.3 million shares subject to stock options, restricted stock units outstanding, and the employee stock purchase plan shares reserved for issuance because their inclusion would have had an anti-dilutive effect on diluted net loss per share.

IMPAIRMENT AND WRITE-DOWN OF ASSETS HELD FOR SALE	6 Months Ended
IMPAIRMENT AND WRITE-DOWN OF ASSETS HELD FOR SALE	Jun. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
IMPAIRMENT AND WRITE-DOWN OF ASSETS HELD FOR SALE	IMPAIRMENT AND WRITE-DOWN OF ASSETS HELD FOR SALE During the year ended December 31, 2023, the Company experienced a sustained decline in stock price and related market capitalization, the collaboration agreements with Biogen and Novartis were terminated, and actions were initiated including deferral and reprioritization of certain research and development programs, announcement and execution of restructuring of operations and reductions in force. As a result, throughout the year the Company tested various long-lived and indefinite-life intangible assets for impairment and recognized a pre-tax goodwill impairment charge of $38.1 million, a pre-tax indefinite-lived intangible asset impairment charge of $51.4 million along with the income tax benefit from the reduction of the associated deferred tax liability of $6.3 million, and a pre-tax long-lived assets impairment charge of $65.5 million during the year ended December 31, 2023. Six months ended June 30, 2024 During the three months ended March 31, 2024, the Company’s Board of Directors approved the wind-down of operations in France and corresponding reduction in workforce, including closure of the Company’s cell therapy manufacturing facility and research labs in Valbonne, France (the “France Restructuring”), and also initiated several actions aimed at reducing costs, including actions to commence the closure of its facility in Brisbane, California. As such, the Company reassessed its long-lived assets for impairment as of March 31, 2024. In connection with the France Restructuring, the Company concluded its equipment, furniture and fixtures located in France met the held for sale criteria as of March 31, 2024. The Company wrote down the carrying value of these assets to their estimated fair value of $1.0 million, net of the estimated costs to sell, recognizing a loss of $1.8 million. The fair value measurement represents a level 3 nonrecurring fair value measurement. The loss is included in impairment of long-lived assets in the accompanying Condensed Consolidated Statements of Operations. The Company also reassessed whether its remaining long-lived assets continued to represent a single asset group for purposes of impairment assessment. After considering changes in the manner in which the right-of-use assets and leasehold improvements related to the Company’s Brisbane and Valbonne, France, facilities are used, costs incurred to cease use of these assets, the France Restructuring, and the Company’s activities to market these facilities for sublease, the Company concluded the identifiable operations and cash flows of these assets are now largely independent of the operations and the cash flows of each other, as well as of the remainder of the Company. Accordingly, the Company assessed impairment of the resulting asset groups separately. Based on the changes in the use of assets related to the Brisbane and Valbonne facility leases, the Company concluded there were indicators of impairment for these asset groups, and further established that the carrying values of these asset groups were not recoverable. The Company proceeded to determine their fair values using a discounted cash flow method, which represents a level 3 nonrecurring fair value measurement. As a result, the Company recognized pre-tax long-lived asset impairment charges of $2.0 million on the right-of-use assets and $0.5 million on the related leasehold improvements during the three months ended March 31, 2024. No impairment was recognized on the remaining long-lived assets, as their carrying values were not in excess of their fair values. During the three months ended June 30, 2024, the Company faced a sustained decline in its stock price and related market capitalization, and continued the France Restructuring, and activities related to the closure of its facility in Brisbane, California. There was also a decline in the market rates for facility subleases in Brisbane, California, indicating the carrying values of right of use and leasehold improvement assets could be impaired. As such, the Company reassessed its long-lived assets for impairment as of June 30, 2024. The Company concluded there were indicators of impairment for the Brisbane and Valbonne facility lease asset groups, and further established that the carrying values of these asset groups were not recoverable. The Company proceeded to determine their fair values using a discounted cash flow method, which represents a level 3 nonrecurring fair value measurement. As a result, the Company recognized pre-tax long-lived asset impairment charges of $0.9 million on the right-of-use assets and $0.1 million on the related leasehold improvements during the three months ended June 30, 2024. The Company also reassessed the fair value of assets held for sale as of June 30, 2024 and recorded an additional charge to write-down the carrying value of these assets by $0.1 million. Assets held for sale are included within prepaid expenses and other current assets on the Company’s Condensed Consolidated Balance Sheet as of June 30, 2024. The fair value measurement represents a level 3 nonrecurring fair value measurement. The loss is included in impairment of long-lived assets in the accompanying Condensed Consolidated Statements of Operations. The sale of these assets is expected to occur within one year, either collectively or separately. The Company will continue to assess whether its long-lived assets are impaired in future periods. As the Company finalizes the wind-down of its France operations and corresponding reduction in force of all France employees, as well as the closure of its Brisbane facility, it is reasonably possible that additional impairment charges will be recognized, for example, if sublease rates of leased facilities or selling prices of the assets held for sale are less than those estimated. Six months ended June 30, 2023 During the three months ended March 31, 2023, as a result of the sustained decline in the Company’s stock price and related market capitalization, termination of the collaboration agreements with Biogen and Novartis, the Company performed an impairment assessment of goodwill, indefinite-lived intangible assets, and other long-lived assets. The Company operated as a single reporting unit based on its business and reporting structure. For goodwill, a quantitative impairment assessment was performed using a market approach, whereby the Company’s fair value of equity was compared to its carrying value. The fair value of equity was derived using both the market capitalization of the Company and an estimate of a reasonable range of values of a control premium applied to the Company’s implied business enterprise value. The control premium was estimated based upon control premiums observed in comparable market transactions. This represented a level 2 nonrecurring fair value measurement. Based on this analysis, the Company recognized a pre-tax goodwill impairment charge of $38.1 million during the three months ended March 31, 2023. As a result, the goodwill was fully impaired as of March 31, 2023. Before completing the goodwill impairment assessment, the Company also tested its indefinite-lived intangible assets and then its long-lived assets for impairment. Based on the qualitative assessment, the Company determined it was more likely than not that its indefinite-lived intangible assets were not impaired. The Company determined all of its long-lived assets represented one asset group for purposes of long-lived asset impairment assessment. The Company concluded that the carrying value of the asset group was not recoverable as it exceeded the future undiscounted cash flows the assets were expected to generate from the use and eventual disposition. To allocate and recognize the impairment loss, the Company determined individual fair values of its long-lived assets. The Company applied a discounted cash flow method to estimate fair values of its leasehold improvements and right-of-use assets, including leasehold improvements in the process of construction and a cost replacement method to estimate the fair value of its furniture, fixtures and laboratory and manufacturing equipment. These represented level 3 nonrecurring fair value measurements. Based on this analysis, the Company recognized pre-tax long-lived asset impairment charges of $11.2 million on the right-of-use assets, $5.0 million on the related leasehold improvements, and $4.2 million on construction-in-progress, during the three months ended March 31, 2023. No impairment was recognized on the remaining long-lived assets as their carrying values were not in excess of their fair values. During the three months ended June 30, 2023, the Company’s stock price and the related market capitalization continued to decline. In April 2023, the Company announced a restructuring of operations and a corresponding reduction in force. The Company also initiated discussions around several actions aimed at reducing costs, preserving liquidity and improving operational performance metrics, including deferral and reprioritization of certain research and development programs, further reduction in force, and closing or downsizing its facilities. The Company reassessed its indefinite-lived and long-lived assets for impairment as of June 30, 2023. Given the actions contemplated above, the Company determined that it was more likely than not that its indefinite-lived intangible assets were impaired. Accordingly, the Company developed an estimate of the fair value of its indefinite-lived intangible assets using the multi-period excess earnings model (income approach) and concluded the carrying value of its indefinite-lived intangible assets were fully impaired. This represents a level 3 nonrecurring fair value measurement. As a result, an indefinite-lived intangible assets impairment charge of $51.3 million, as well as the related income tax benefit of $6.3 million due to the reversal of a deferred tax liability associated with the indefinite-lived intangible assets was recognized during the three and six months ended June 30, 2023. The impairment charge was primarily driven by a higher discount rate applied to future cash flows based on market participants’ view of increased risk related to the asset. The Company determined that there were indicators of impairment in its long-lived asset group as of June 30, 2023, based on the same factors above as well as the impairment of its indefinite-lived intangible assets. As the estimated fair value of this asset group, based on a market approach, exceeded its carrying value, no impairment loss was recognized. This represents a level 3 nonrecurring fair value measurement.

COMMITMENTS AND CONTINGENCIES	6 Months Ended
COMMITMENTS AND CONTINGENCIES	Jun. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Leases On February 5, 2024, the Company entered into an amendment to the operating lease of office and research and development laboratory facilities in Brisbane, California. The amendment established early termination rights for the landlord upon thirty days notice to the Company, with the earliest date the landlord may terminate the lease being September 30, 2024. Additionally, the amendment authorizes the landlord to draw on the existing letter of credit to satisfy the majority of the Company’s February 2024 through April 2024 rent payments and obligates the Company to provide a cash security deposit or replenish the letter of credit back to $1.5 million by June 1, 2024. The Company concluded that the amendment represented a lease modification to be accounted for as a single contract with the existing lease under ASC Topic 842, Leases, and remeasured its lease liability using the current incremental borrowing rate of 9.6%, and recorded an adjustment to reduce both the lease liability and the corresponding right-of-use asset by $1.9 million as of the lease modification date. The Company and the landlord subsequently in May 2024 extended the deadline for replenishing the letter of credit to September 30, 2024, the effect of which had no material impact to the Company's financial statements.

STOCKHOLDERS' EQUITY	6 Months Ended
STOCKHOLDERS' EQUITY	Jun. 30, 2024
Equity [Abstract]
STOCKHOLDERS' EQUITY	STOCKHOLDERS’ EQUITY Common Stock The Company’s common stock authorized for issuance was 960,000,000 shares and 640,000,000 shares as of June 30, 2024 and December 31, 2023, respectively. At-the-Market Offering Agreement In August 2020, the Company entered into an Open Market Sale Agreement℠ with Jefferies LLC (“Jefferies”) with respect to an at-the-market offering program under which the Company may offer and sell, from time to time at its sole discretion, shares of the Company’s common stock having an aggregate offering price of up to $150.0 million through Jefferies as the Company’s sales agent or principal. In December 2022, the Company entered into Amendment No. 2 to the Open Market Sale Agreement℠ which increased the aggregate offering price under the at-the-market offering program by an additional $175.0 million. Approximately $194.5 million remained available under the sales agreement as of June 30, 2024. The Company is not obligated to sell any shares under the sales agreement. No shares were sold under the sales agreement during the three and six months ended June 30, 2024. During the three and six months ended June 30, 2023, the Company sold 4,286,831 and 8,249,261 shares of its common stock under the sales agreement for net proceeds of approximately $5.4 million and $15.1 million, respectively. Issuance and Sale of Common Stock and Warrants On March 21, 2024, the Company entered into a Securities Purchase Agreement (the “Purchase Agreement”) with certain institutional investors (collectively, the “Investors”). On March 26, 2024 the Company issued and sold in a registered direct offering (the “Registered Direct Offering”) an aggregate of 24,761,905 shares of common stock of the Company, par value $0.01 per share, and pre-funded warrants to purchase up to an aggregate of 3,809,523 shares of common stock, together with accompanying warrants (“Common Warrants”) to purchase up to an aggregate of 28,571,428 shares of common stock. The combined offering price of a unit consisting of one share of common stock and the accompanying Common Warrant to purchase one share of common stock was $0.84. The combined offering price of a unit consisting of a pre-funded warrant to purchase one share of common stock and the accompanying Common Warrant to purchase one share of common stock was $0.83. The pre-funded warrants are immediately exercisable at any time, until exercised in full, at a price of $0.01 per share of common stock. The Common Warrants are exercisable six months from issuance, expire five and a half years from the issuance date and have an exercise price of $1.00 per share. Both pre-funded warrants and Common Warrants can be exercised net in limited circumstances and entitle holders to dividends if and when paid by the Company. Barclays Capital Inc. and Cantor Fitzgerald & Co. (the “Placement Agents”) acted as the placement agents for the offering, pursuant to a Placement Agency Agreement, dated March 21, 2024 (the “Placement Agreement”). Pursuant to the Placement Agreement, the Company paid the Placement Agents a cash placement fee equal to 6.0% of the aggregate gross proceeds raised in the Registered Direct Offering. The Company received aggregate net proceeds from the Registered Direct Offering of $21.9 million, net of the Placement Agents’ fees of $1.4 million and other offering costs of $0.7 million. Common Warrants and pre-funded warrants were determined to be equity-classified and proceeds received from their issuance were recorded as a component of stockholders’ equity within additional paid-in capital. The Company determined that the warrants should be equity classified because they are freestanding financial instruments, do not embody an obligation for the Company to repurchase its shares, do not contain exercise contingencies tied to observable markets or indices, permit the holders to receive a fixed number of shares of common stock upon exercise in exchange for a fixed amount of consideration, subject only to adjustments that are inputs to the fair value of a fixed price/fixed consideration-option, and meet the equity classification criteria. The Common Warrants had not been exercised and remained outstanding as of June 30, 2024. The pre-funded warrants were exercised in full on April 8, 2024 and the Company issued an aggregate of 3,809,523 shares of common stock at an exercise price of $0.01.

SUBSEQUENT EVENTS	6 Months Ended
SUBSEQUENT EVENTS	Jun. 30, 2024
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS Epigenetic Regulation and Capsid Delivery License Agreement with Genentech On August 2, 2024, the Company entered into the Genentech Agreement to develop intravenously administered genomic medicines to treat certain neurodegenerative diseases. Under the Genentech Agreement, the Company granted an exclusive license to Genentech for the Company’s proprietary zinc finger repressors (“ZFRs”) that are directed to tau and the Company’s proprietary ZFRs that are directed to a second undisclosed neurology target. The Company also granted an exclusive license to Genentech to the Company’s proprietary, neurotropic adeno-associated virus capsid, STAC-BBB for use with therapies directed to tau or to the second neurology target. The Company is prohibited from exploiting (itself or with or for a third party) products directed to tau or to the second neurology target during the applicable exclusivity periods set forth in the Genentech Agreement. Under the terms of the Genentech Agreement, the Company is responsible for completing a technology transfer and certain preclinical activities, and Genentech is solely responsible for all clinical development, regulatory interactions, manufacturing and global commercialization of resulting products. Under the Genentech Agreement, Genentech is obligated to pay the Company a $40.0 million upfront license fee on or around the end of August 2024 and will become obligated to pay the Company a $10.0 million milestone payment after the completion of technology transfer activities. In addition, the Company is eligible to earn up to $1.9 billion in development and commercial milestones spread across multiple potential products under the Genentech Agreement and tiered mid-single digit to sub-teen double digit royalties on the net sales of such products, subject to certain specified reductions. The Genentech Agreement will continue, on a product-by-product and country-by-country basis, until the date when there is no remaining royalty payment obligation in such country with respect to such product, at which time the Genentech Agreement will expire with respect to such product in such country. Genentech has the right to terminate the Genentech Agreement for convenience. Each party has the right to terminate the Genentech Agreement on account of the other party’s uncured material breach.

ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	6 Months Ended
	Aug. 31, 2024	Jun. 30, 2023	Aug. 02, 2024	Jun. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Change in Accounting Estimate [Line Items]
Letter of credit established as a deposit				$ 1,500
Cash and cash equivalents		$ 66,830		$ 27,786	$ 45,204	$ 100,444
Forecast
Change in Accounting Estimate [Line Items]
Contract With Customer, Expected Consideration To Be Received	$ 50,000
Genentech, Roche Group \| License \| Forecast
Change in Accounting Estimate [Line Items]
Deferred revenues	$ 40,000
Genentech, Roche Group \| Subsequent Event \| License
Change in Accounting Estimate [Line Items]
Deferred revenues			$ 40,000
Variable consideration amount			$ 10,000
Kite Pharma, Inc.
Change in Accounting Estimate [Line Items]
Increase in revenue		8,900
Increase in net income		$ 8,900
Increased earnings per share, basic (in dollars per share)		$ 0.06
Increased earnings per share, diluted (in dollars per share)		$ 0.06

ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenues from Strategic Partnering Collaboration And Licensing Agreements (Details) - Revenue from contract with customer - Customer concentration risk	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023
Novartis Institutes for BioMedical Research, Inc.
Concentration Risk [Line Items]
Percentage of revenues	35.00%	7.00%
Biogen MA, Inc.
Concentration Risk [Line Items]
Percentage of revenues	32.00%	82.00%
Kite Pharma, Inc.
Concentration Risk [Line Items]
Percentage of revenues	18.00%	8.00%
Other license agreements
Concentration Risk [Line Items]
Percentage of revenues	15.00%	3.00%

ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Reconciliation of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 27,786	$ 45,204	$ 66,830	$ 100,444
Non-current restricted cash	0	1,500	1,500	1,500
Cash, cash equivalents, and restricted cash as reported within the Condensed Consolidated Statements of Cash Flows	$ 27,786	$ 46,704	$ 68,330	$ 101,944

FAIR VALUE MEASUREMENTS (Details) - USD ($)	Jun. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 0	$ 35,798,000
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		2,508,000
U.S. government-sponsored entity debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		22,566,000
Commercial paper securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		2,826,000
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		1,405,000
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		2,377,000
U.S. treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		5,593,000
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		1,031,000
Fair value on recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		2,508,000
Marketable securities		35,798,000
Total cash equivalents and marketable securities	$ 0	38,306,000
Fair value on recurring basis \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		2,508,000
Fair value on recurring basis \| U.S. government-sponsored entity debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		22,566,000
Fair value on recurring basis \| Commercial paper securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		2,826,000
Fair value on recurring basis \| Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		1,405,000
Fair value on recurring basis \| Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		2,377,000
Fair value on recurring basis \| U.S. treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		5,593,000
Fair value on recurring basis \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		1,031,000
Fair value on recurring basis \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		2,508,000
Marketable securities		0
Total cash equivalents and marketable securities		2,508,000
Fair value on recurring basis \| Level 1 \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		2,508,000
Fair value on recurring basis \| Level 1 \| U.S. government-sponsored entity debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		0
Fair value on recurring basis \| Level 1 \| Commercial paper securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		0
Fair value on recurring basis \| Level 1 \| Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		0
Fair value on recurring basis \| Level 1 \| Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		0
Fair value on recurring basis \| Level 1 \| U.S. treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		0
Fair value on recurring basis \| Level 1 \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		0
Fair value on recurring basis \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		0
Marketable securities		35,798,000
Total cash equivalents and marketable securities		35,798,000
Fair value on recurring basis \| Level 2 \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		0
Fair value on recurring basis \| Level 2 \| U.S. government-sponsored entity debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		22,566,000
Fair value on recurring basis \| Level 2 \| Commercial paper securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		2,826,000
Fair value on recurring basis \| Level 2 \| Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		1,405,000
Fair value on recurring basis \| Level 2 \| Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		2,377,000
Fair value on recurring basis \| Level 2 \| U.S. treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		5,593,000
Fair value on recurring basis \| Level 2 \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		1,031,000
Fair value on recurring basis \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		0
Marketable securities		0
Total cash equivalents and marketable securities		0
Fair value on recurring basis \| Level 3 \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		0
Fair value on recurring basis \| Level 3 \| U.S. government-sponsored entity debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		0
Fair value on recurring basis \| Level 3 \| Commercial paper securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		0
Fair value on recurring basis \| Level 3 \| Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		0
Fair value on recurring basis \| Level 3 \| Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		0
Fair value on recurring basis \| Level 3 \| U.S. treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		0
Fair value on recurring basis \| Level 3 \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities		$ 0

CASH EQUIVALENTS AND MARKETABLE SECURITIES - Summary of Cash Equivalents and Available-for-Sale Securities (Details) - USD ($)	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Cash equivalents:
Amortized Cost	$ 27,786,000	$ 45,204,000	$ 66,830,000	$ 100,444,000
Marketable securities:
Amortized Cost		35,564,000
Gross Unrealized Gains		241,000
Gross Unrealized Losses	0	(7,000)
Estimated Fair Value	0	35,798,000
Total cash equivalents and marketable securities, amortized cost	$ 0	38,072,000
Total cash equivalents and marketable securities, gross unrealized gains		241,000
Total cash equivalents and marketable securities, gross unrealized losses		(7,000)
Total cash equivalents and marketable securities, estimated fair value		38,306,000
U.S. government-sponsored entity debt securities
Marketable securities:
Amortized Cost		22,347,000
Gross Unrealized Gains		219,000
Gross Unrealized Losses		0
Estimated Fair Value		22,566,000
Commercial paper securities
Marketable securities:
Amortized Cost		2,825,000
Gross Unrealized Gains		2,000
Gross Unrealized Losses		(1,000)
Estimated Fair Value		2,826,000
Corporate debt securities
Marketable securities:
Amortized Cost		1,399,000
Gross Unrealized Gains		6,000
Gross Unrealized Losses		0
Estimated Fair Value		1,405,000
Asset-backed securities
Marketable securities:
Amortized Cost		2,368,000
Gross Unrealized Gains		9,000
Gross Unrealized Losses		0
Estimated Fair Value		2,377,000
U.S. treasury bills
Marketable securities:
Amortized Cost		5,599,000
Gross Unrealized Gains		0
Gross Unrealized Losses		(6,000)
Estimated Fair Value		5,593,000
Certificates of deposit
Marketable securities:
Amortized Cost		1,026,000
Gross Unrealized Gains		5,000
Gross Unrealized Losses		0
Estimated Fair Value		1,031,000
Cash equivalents:
Cash equivalents:
Amortized Cost		2,508,000
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Estimated Fair Value		2,508,000
Money market funds
Cash equivalents:
Amortized Cost		2,508,000
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Estimated Fair Value		$ 2,508,000

CASH EQUIVALENTS AND MARKETABLE SECURITIES - Summary of Available-for-Sale Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Maturing in one year or less		$ 10,855
Maturing after one year through five years		24,943
Marketable securities	$ 0	$ 35,798

MAJOR CUSTOMERS, PARTNERSHIPS AND STRATEGIC ALLIANCES - Pfizer Inc. (Details) $ in Millions	1 Months Ended		12 Months Ended	37 Months Ended	79 Months Ended	86 Months Ended
	Dec. 31, 2017 USD ($)	May 31, 2017 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2024 USD ($) product milestone	Jun. 30, 2024 USD ($) milestone
Pfizer Inc.
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Agreement termination, term		15 years
Pfizer Inc. \| S B Five Two Five And Other Products
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenues under agreement		$ 70.0
Potential amount to be funded for achievement of specified commercialized and sales milestones		266.5
Pfizer Inc. \| S B Five Two Five And Other Products \| Achievement of specified clinical development intellectual property and regulatory milestones
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Development and sales-based milestone payments to be received		208.5
Pfizer Inc. \| S B Five Two Five
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone revenue receivable		220.0
Pfizer Inc. \| Other products
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone revenue receivable		$ 175.0
Pfizer Inc. \| License \| Minimum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Percentage of net sales per developed licensed product which will trigger royalties by counterparty		14.00%
Pfizer Inc. \| License \| Maximum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Percentage of net sales per developed licensed product which will trigger royalties by counterparty		20.00%
Pfizer SB-525
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Collaborative arrangement transaction price			$ 134.0
Pfizer SB-525 \| S B Five Two Five And Other Products
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Collaborative arrangement, number of milestones achieved \| milestone						2
Milestone payments received						$ 55.0
Alexion Pharmaceuticals, Inc., AstraZeneca Rare Disease
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Agreement termination, term	15 years
Alexion Pharmaceuticals, Inc., AstraZeneca Rare Disease \| License \| Minimum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Percentage of net sales per developed licensed product which will trigger royalties by counterparty	14.00%
Alexion Pharmaceuticals, Inc., AstraZeneca Rare Disease \| License \| Maximum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Percentage of net sales per developed licensed product which will trigger royalties by counterparty	20.00%
Alexion Pharmaceuticals, Inc., AstraZeneca Rare Disease \| C9ORF72
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone payments received	$ 12.0				$ 5.0
Collaborative arrangement transaction price				$ 17.0
Number of products approved \| product					0
Number of milestones included in transaction price \| milestone					0
Alexion Pharmaceuticals, Inc., AstraZeneca Rare Disease \| C9ORF72 \| Achievement Of Specified Preclinical Development Clinical Development And First Commercial Sale Milestones \| Maximum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Development and sales-based milestone payments to be received	60.0
Alexion Pharmaceuticals, Inc., AstraZeneca Rare Disease \| C9ORF72 \| Achievement Of Commercial Milestones \| Maximum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Development and sales-based milestone payments to be received	$ 90.0

IMPAIRMENT AND WRITE-DOWN OF ASSETS HELD FOR SALE (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Impaired Long-Lived Assets Held and Used [Line Items]
Goodwill impairment				$ 38,100			$ 38,100
Impairment of intangible assets, indefinite-lived			$ 51,300			$ 51,300	51,400
Reduction in deferred tax liabilities			6,300			6,300	6,300
Impairment on right-of-use assets	$ 900	$ 2,000		11,200			$ 65,500
Estimated fair value of equipment, furniture and fixtures		1,000
Impairment of long-lived assets	1,172		$ 0		$ 5,521	$ 20,433
Impairment of leaseholdimprovements	$ 100	500		5,000
Impairment of assets held for sale					$ 100
Equipment, Furniture, And Fixtures
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets		$ 1,800
Construction in Progress
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets				$ 4,200

COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended		12 Months Ended
	Feb. 05, 2024	Jun. 30, 2024	Mar. 31, 2024	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Other Commitments [Line Items]
Impairment on right-of-use assets		$ 900	$ 2,000	$ 11,200			$ 65,500
Lease liabilities	$ 1,900				$ 2,822	$ 2,455
Lessee, Operating Lease, Discount Rate	9.60%
Lessee, Operating Lease, Required Notice Of Termination	30 days
Lessee, Required Letter Of Credit Outstanding, Amount	$ 1,500
Richmond, California
Other Commitments [Line Items]
Impairment on right-of-use assets	$ 1,900

STOCK-BASED COMPENSATION (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
STOCK-BASED COMPENSATION (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 3,065	$ 6,790	$ 5,784	$ 15,067
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	1,323	3,887	2,708	8,760
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,742	$ 2,903	$ 3,076	$ 6,307

STOCKHOLDERS' EQUITY (Details) - USD ($) $ / shares in Units, $ in Millions				1 Months Ended		3 Months Ended		6 Months Ended
	Apr. 08, 2024	Mar. 26, 2024	Mar. 21, 2024	Dec. 31, 2022	Aug. 31, 2020	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized (in shares)						960,000,000		960,000,000		640,000,000
Common stock par value (in dollars per share)		$ 0.01
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock (in shares)							4,286,831	24,761,905	8,249,261
Issuance of common stock upon exercise of pre-funded warrants (in shares)	3,809,523					3,809,523		3,809,523
Pre-funded warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of new stock issued during the period (in shares)						3,809,523		3,809,523
Stock price (USD) (in dollars per share)						$ 0.01		$ 0.01
Offering price of each common stock (in dollars per share)	$ 0.01					$ 1.00		$ 1.00
Direct offering
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Consideration received on transaction								$ 21.9
Sale of stock, number of shares issued in transaction (in shares)		24,761,905
Cash placement fees			6.00%
Net of placement fees								1.4
Proceeds from other offering expenses								0.7
Direct offering \| Pre-funded warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of new stock issued during the period (in shares)		3,809,523
Direct offering \| Common warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock for each Common warrant (in shares)		1
Sale of stock, number of shares issued in transaction, per unit (in shares)		1
Sale of stock, price per share (in dollars per share)		$ 0.84
Warrants exercisable, period after issuance			6 months
Term of warrants		5 years 6 months
Direct offering \| Pre-funded warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of stock, number of shares issued in transaction (in shares)		28,571,428
Number of shares of common stock for each Common warrant (in shares)		1
Sale of stock, number of shares issued in transaction, per unit (in shares)		1
Sale of stock, price per share (in dollars per share)		$ 0.83
Stock price (USD) (in dollars per share)		0.01
Offering price of each common stock (in dollars per share)		$ 1.00
Jefferies LLC \| At-The-Market Offering Agreement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock offering program, maximum value					$ 150.0
Stock offering program, increase to aggregate offering price				$ 175.0
Sale of stock agreement						$ 194.5		$ 194.5
Issuance of common stock (in shares)						0	4,286,831	0	8,249,261
Consideration received on transaction							$ 5.4		$ 15.1

RESTRUCTURING CHARGES - Narrative (Details)				3 Months Ended			6 Months Ended
RESTRUCTURING CHARGES - Narrative (Details)	Mar. 01, 2024 employee	Nov. 01, 2023 employee	Apr. 26, 2023 USD ($) employee	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2024 USD ($)	Sep. 30, 2024 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges							$ 2,784,000
April 2023 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Number of employees eliminated in restructuring \| employee			110
Percentage of positions eliminated in restructuring			23.00%
Restructuring expected cost			$ 5,000,000.0
Restructuring charges				$ 0		$ 5,000,000	0	$ 5,000,000
April 2023 Restructuring Plan \| Research and development
Restructuring Cost and Reserve [Line Items]
Restructuring charges						3,800,000		3,800,000
April 2023 Restructuring Plan \| General and administrative
Restructuring Cost and Reserve [Line Items]
Restructuring charges						$ 1,200,000		$ 1,200,000
April 2023 Restructuring Plan \| Full-Time Employees
Restructuring Cost and Reserve [Line Items]
Number of employees eliminated in restructuring \| employee			55
April 2023 Restructuring Plan \| Contracted Employees
Restructuring Cost and Reserve [Line Items]
Number of employees eliminated in restructuring \| employee			55
November 2023 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Number of employees eliminated in restructuring \| employee		162
Percentage of positions eliminated in restructuring		40.00%
Restructuring charges					$ 6,700,000
November 2023 Restructuring Plan \| Minimum
Restructuring Cost and Reserve [Line Items]
Restructuring expected cost				8,100,000			8,100,000
November 2023 Restructuring Plan \| Minimum \| Forecast
Restructuring Cost and Reserve [Line Items]
Expected cost remaining										$ 1,000,000.0
November 2023 Restructuring Plan \| Maximum
Restructuring Cost and Reserve [Line Items]
Restructuring expected cost				9,100,000			9,100,000
November 2023 Restructuring Plan \| Maximum \| Forecast
Restructuring Cost and Reserve [Line Items]
Expected cost remaining										$ 2,000,000.0
November 2023 Restructuring Plan \| Full-Time Employees
Restructuring Cost and Reserve [Line Items]
Number of employees eliminated in restructuring \| employee		108
November 2023 Restructuring Plan \| Contracted Employees
Restructuring Cost and Reserve [Line Items]
Number of employees eliminated in restructuring \| employee		54
France Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Number of employees eliminated in restructuring \| employee	93
Percentage of positions eliminated in restructuring	24.00%
Restructuring charges					$ 4,700,000
Restructuring costs incurred				2,400,000
France Restructuring Plan \| Minimum
Restructuring Cost and Reserve [Line Items]
Restructuring expected cost				7,300,000			7,300,000
France Restructuring Plan \| Minimum \| Forecast
Restructuring Cost and Reserve [Line Items]
Expected cost remaining									$ 200,000
France Restructuring Plan \| Maximum
Restructuring Cost and Reserve [Line Items]
Restructuring expected cost				$ 7,600,000			$ 7,600,000
France Restructuring Plan \| Maximum \| Forecast
Restructuring Cost and Reserve [Line Items]
Expected cost remaining									$ 500,000

RESTRUCTURING CHARGES - Accrued Restructuring Costs (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($)
Restructuring Reserve [Roll Forward]
Balance at December 31, 2023	$ 11,733
Restructuring charges	2,784
Cash payments	(9,472)
Balance at June 30, 2024	$ 5,045

SUBSEQUENT EVENTS (Details) - Subsequent Event - Genentech, Roche Group - License $ in Millions	Aug. 02, 2024 USD ($)
Subsequent Event [Line Items]
Variable consideration amount	$ 10.0
Deferred revenues	40.0
Remaining performance obligation amount	$ 1,900.0