0001193125-23-214708 | 10-Q | XBRL Viewer

Leases (Tables)

6 Months Ended

Jun. 30, 2023

For the three and six months ended June 30, 2023 and 2022, the components of lease costs were as follows (in thousands):


	Three Months Ended June 30,					Six Months Ended June 30,
	2023			2022		2023			2022
Operating lease cost	$	696		$	505	$	1,392		$	1,011
Variable lease cost		270			205		412			425
Short-term lease cost		2			2		5			5
Less: Sublease income		(251	)		—		(506	)		—

Total lease cost	$	717		$	712	$	1,303		$	1,441

The following summarizes additional information related to operating leases:


	June 30,
	2023			2022
Weighted-average remaining lease term		4.9 years			5.9 years
Weighted-average discount rate		9.7	%		8.9	%

Schedule of Lessee, Operating Lease, Liability, Maturity

The maturity of the Company’s operating lease liabilities as of June 30, 2023 were as follows (in thousands):


	June 30,
	2023
2023 (remainder)	$	1,349
2024		2,740
2025		2,818
2026		2,902
2027		2,990
Thereafter		946

Total future minimum lease payments		13,745
Less: Imputed interest		2,853

Total operating lease liabilities	$	10,892

Schedule of Operating Lease, Lease Income

The supplemental disclosure for the statement of cash flows related to operating leases was as follows (in thousands):


	Six Months Ended June 30,
	2023		2022
Cash paid for amounts included in the measurement of lease liabilities:	$	1,319	$	924

Leases

6 Months Ended

Jun. 30, 2023

Leases [Abstract]

Leases

8. Leases

65 Grove Street Lease

In July 2019, the Company entered into a lease with

BRE-BMR

Grove LLC for 25,078 square feet of laboratory and office space located at

Grove Street, Watertown, Massachusetts, or the Headquarters Lease. On September 1, 2022, the Company entered into an amendment, or the Lease Agreement Amendment, to the Headquarters Lease, to expand the Company’s corporate headquarters located at 65 Grove Street, Watertown, Massachusetts by approximately 7,216 square feet. In connection with the Lease Agreement Amendment, the Company secured a letter of credit for the Headquarters Lease from SVB for $1.6 million as of December 31, 2022.

In May 2023, the Company received notice from

BRE-BMR

Grove LLC that the requirements to reduce the amount of the letter of credit for the Headquarters Lease had been met. In connection therewith, in June 2023, the Company secured a letter of credit from JPMorgan Chase Bank, N.A. for $1.4 million, which is recognized as long-term restricted cash as of June 30, 2023, and renews automatically each year. As of June 30, 2023, the existing letter of credit from SVB for $1.6 million has been classified as current based on the anticipated release date of the restrictions of this cash.

For the three and six months ended June 30, 2023 and 2022, the components of lease costs were as follows (in thousands):


	Three Months Ended June 30,					Six Months Ended June 30,
	2023			2022		2023			2022
Operating lease cost	$	696		$	505	$	1,392		$	1,011
Variable lease cost		270			205		412			425
Short-term lease cost		2			2		5			5
Less: Sublease income		(251	)		—		(506	)		—

Total lease cost	$	717		$	712	$	1,303		$	1,441

The maturity of the Company’s operating lease liabilities as of June 30, 2023 were as follows (in thousands):


	June 30,
	2023
2023 (remainder)	$	1,349
2024		2,740
2025		2,818
2026		2,902
2027		2,990
Thereafter		946

Total future minimum lease payments		13,745
Less: Imputed interest		2,853

Total operating lease liabilities	$	10,892

The supplemental disclosure for the statement of cash flows related to operating leases was as follows (in thousands):


	Six Months Ended June 30,
	2023		2022
Cash paid for amounts included in the measurement of lease liabilities:	$	1,319	$	924

The changes in the Company’s

right-of-use

assets and lease liabilities for the six months ended June 30, 2023 and 2022 are reflected in the

non-cash

lease expense and accrued expenses and other liabilities, respectively, in the consolidated statements of cash flows.

The following summarizes additional information related to operating leases:


	June 30,
	2023			2022
Weighted-average remaining lease term		4.9 years			5.9 years
Weighted-average discount rate		9.7	%		8.9	%

Collaboration and License Agreements - Genovis (Details) $ in Millions	1 Months Ended
	Feb. 28, 2023 USD ($)
Genovis AB
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payment	$ 4.0

Revenue Arrangements - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended		6 Months Ended
	Jan. 31, 2023	Oct. 31, 2021	Jun. 30, 2020	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Short-term contract liability				$ 4,234		$ 4,234		$ 593
Long-term contract liability				4,863		4,863		0
Revenue recognized						(1,996)
Accounts receivable				5,385		5,385		6,596
Collaboration and license revenue				5,249	$ 39,273	11,187	$ 73,272
Remaining performance obligation				9,100		9,100
SOBI Purchase Agreement
Disaggregation of Revenue [Line Items]
Revenue recognized				4,300	29,200
Accounts receivable				5,100		5,100		5,000
Collaboration and license revenue						8,700	52,900
SOBI Purchase Agreement \| Unbilled Revenues
Disaggregation of Revenue [Line Items]
Accounts receivable				1,100		1,100		3,200
Takeda Agreement
Disaggregation of Revenue [Line Items]
Upfront cash payment		$ 3,000
Short-term contract liability				0		0		100
Asset, reclassified to receivable				500
Revenue recognized					0		1,000
Future additional payments, expected		$ 1,124,000
Collaboration and license revenue				100		$ 600
Collaborative Arrangement
Disaggregation of Revenue [Line Items]
Upfront cash payment			$ 75,000
Sales milestone payments			$ 630,000
Astellas Gene Therapies
Disaggregation of Revenue [Line Items]
Upfront payment	$ 10,000
Development and commercial milestones plus royalties	340,000
Reimbursement percentage, budgeted costs incurred to complete the development						25.00%
Upfront cash payment	10,000
Development cost reimbursements	$ 5,500
Short-term contract liability				4,200		$ 4,200
Long-term contract liability				4,900		4,900
Asset, reclassified to receivable						300
Revenue recognized				800		1,400
Sarepta Therapeutics, Inc.
Disaggregation of Revenue [Line Items]
Short-term contract liability								$ 500
Revenue recognized				$ 0	10,100	500	$ 10,200
Option term			24 months
Spark License Agreement
Disaggregation of Revenue [Line Items]
Short-term contract liability									$ 9,200
Revenue recognized					$ 0	$ 9,200

Description of the Business	6 Months Ended
Description of the Business	Jun. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business	1. Description of the Business Selecta Biosciences, Inc., or the Company, was incorporated in Delaware on December 10, 2007, and is based in Watertown, Massachusetts. T he Company is a clinical-stage biotechnology company leveraging the Company’s ImmTOR ® platform to develop tolerogenic therapies that selectively mitigate unwanted immune responses. With a proven ability to induce tolerance to highly immunogenic proteins, the Company believes ImmTOR has the potential to amplify the efficacy of biologic therapies, including redosing of life-saving gene therapies, as well as restore the body’s natural self-tolerance in autoimmune diseases. The Company has several proprietary and partnered programs in its pipeline focused on enzyme therapies, gene therapies, and autoimmune diseases. In April 2023, in light of current market conditions, the Company’s Board of Directors, or the Board, took steps to extend cash runway by pausing further development of SEL-302 for the treatment of methylmalonic acidemia, or MMA, and conducting a targeted headcount reduction of approximately 25%. On August 1 7 , 2023, the Company announced additional steps to extend cash runway and maximize value for stockholders by continuing to prioritize development of SEL-212 and support of its collaboration with Astellas Gene Therapies, or Astellas, for Xork, and pausing further development of all of the Company’s other clinical and preclinical product candidates that it is no longer actively advancing. The Company intends to seek collaboration partners for the assets in the development programs that it is no longer actively advancing. Since inception, the Company has devoted its efforts principally to research and development of its technology and product candidates, recruiting management and technical staff, acquiring operating assets, and raising capital. The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance-reporting capabilities. The Company’s product candidates are in development. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, or maintained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees and consultants. Unaudited Interim Financial Information The accompanying unaudited consolidated financial statements for the three and six months ended June 30, 2023 and 2022 have been prepared by the Company, pursuant to the rules and regulations of the Securities and Exchange Commission, or the SEC, for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP, have been condensed or omitted pursuant to such rules and regulations. These consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2022 included in the Company’s Annual Report on Form 10-K that was filed with the SEC on March 2, 2023. The unaudited interim financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of management, the accompanying unaudited interim consolidated financial statements contain all adjustments that are necessary for a fair statement of the Company’s financial position as of June 30, 2023, the consolidated results of operations for the three and six months ended June 30, 2023, and cash flows for the six months ended June 30, 2023. Such adjustments are of a normal and recurring nature. The results of operations for the three and six months ended June 30, 2023 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2023. Liquidity and Management’s Plan The future success of the Company is dependent on its ability to develop its product candidates and ultimately upon its ability to attain and sustain profitable operations. The Company is subject to a number of risks similar to other early-stage life science companies, including, but not limited to, successful development of its product candidates, raising additional capital with favorable terms, protection of proprietary technology and market acceptance of any approved future products. The successful development of product candidates requires substantial working capital, which may not be available to the Company on favorable terms or at all. To date, the Company has financed its operations primarily through public offerings and private placements of its securities, funding received from research grants, collaboration and license arrangements and its credit facility. The Company currently has no source of product revenue, and it does not expect to generate product revenue for the foreseeable future. To date, the Company’s revenue has primarily been from collaboration and license agreements. The Company has devoted substantially all of its financial resources and efforts to developing its ImmTOR platform, identifying potential product candidates and conducting preclinical studies and clinical trials. The Company is in the early stages of development of its product candidates, and it has not completed development of any ImmTOR-enabled therapies. As of June 30, 2023, the Company’s cash, cash equivalents and restricted cash were $115.0 million, of which $3.0 million was restricted cash related to lease commitments and $0.2 million was held by its Russian subsidiary designated solely for use in its operations. In April 2023, in light of current market conditions, the Board took steps to extend cash runway by pausing further development of SEL-302 for the treatment of MMA and conducting a targeted headcount reduction of approximately 25%. On August 1 7 , 2023, the Company announced additional steps to extend cash runway and maximize value for stockholders by continuing to prioritize development of SEL-212 and support of its collaboration with Astellas for Xork, and pausing further development of all of the Company’s other clinical and preclinical product candidates that it is no longer actively advancing. The Company intends to seek collaboration partners for the assets in the development programs that it is no longer actively advancing. The Company believes the cash, cash equivalents and restricted cash as of June 30, 2023 will enable it to fund its current planned operations for at least the next twelve months from the date of issuance of these financial statements, though it may realize additional cash resources upon the achievement of certain contingent collaboration milestones or it may pursue additional cash resources through public or private equity or debt financings or by establishing collaborations with other companies. Management’s expectations with respect to its ability to fund current and long-term planned operations are based on estimates that are subject to risks and uncertainties. If actual results are different from management’s estimates, the Company may need to seek additional strategic or financing opportunities sooner than would otherwise be expected. However, there is no guarantee that any collaboration milestones will be achieved or that any of these strategic or financing opportunities will be executed on favorable terms, and some could be dilutive to existing stockholders. If the Company is unable to obtain additional funding on a timely basis, it may be forced to significantly curtail, delay, or discontinue one or more of its planned research or development programs or be unable to expand or maintain its operations or otherwise capitalize on its commercialization of its product candidates. The Company anticipates continuing to generate operating losses for the foreseeable future due to, among other things, costs related to research and development of its product candidates and its administrative organization. Guarantees and Indemnifications As permitted under Delaware law, the Company indemnifies its officers, directors, consultants and employees for certain events or occurrences that happen by reason of the relationship with, or position held at the Company. Through June 30, 2023, the Company had not experienced any losses related to these indemnification obligations, and no claims were outstanding. The Company does not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible, and no related reserves were established.

Debt - Term Loans (Narrative) (Details) - 2020 Term Loans - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Line of Credit Facility [Line Items]
Loan and security agreement, percentage of consolidated cash	100.00%
Loan and security agreement, percentage of then-outstanding obligations	150.00%
Term loan facility	$ 22.4	$ 25.0

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References + Details

Fair Value Measurements - Schedule of Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Assets:
Marketable securities:		$ 28,164
Liabilities:
Warrant liabilities	$ 16,878	19,140
U.S. government agency securities and treasuries
Assets:
Marketable securities:		13,557
Corporate bonds
Assets:
Marketable securities:		1,951
Commercial paper
Assets:
Marketable securities:		12,656
Recurring
Assets:
Total assets	73,384	81,716
Liabilities:
Warrant liabilities	16,878	19,140
Total liabilities	16,878	19,140
Recurring \| U.S. government agency securities and treasuries
Assets:
Marketable securities:		13,557
Recurring \| Corporate bonds
Assets:
Marketable securities:		1,951
Recurring \| Commercial paper
Assets:
Marketable securities:		12,656
Recurring \| Money market funds (included in cash equivalents)
Assets:
Money market funds (included in cash equivalents)	73,384	53,552
Recurring \| Level 1
Assets:
Total assets	73,384	53,552
Liabilities:
Warrant liabilities	0	0
Total liabilities	0	0
Recurring \| Level 1 \| U.S. government agency securities and treasuries
Assets:
Marketable securities:		0
Recurring \| Level 1 \| Corporate bonds
Assets:
Marketable securities:		0
Recurring \| Level 1 \| Commercial paper
Assets:
Marketable securities:		0
Recurring \| Level 1 \| Money market funds (included in cash equivalents)
Assets:
Money market funds (included in cash equivalents)	73,384	53,552
Recurring \| Level 2
Assets:
Total assets	0	28,164
Liabilities:
Warrant liabilities	0	0
Total liabilities	0	0
Recurring \| Level 2 \| U.S. government agency securities and treasuries
Assets:
Marketable securities:		13,557
Recurring \| Level 2 \| Corporate bonds
Assets:
Marketable securities:		1,951
Recurring \| Level 2 \| Commercial paper
Assets:
Marketable securities:		12,656
Recurring \| Level 2 \| Money market funds (included in cash equivalents)
Assets:
Money market funds (included in cash equivalents)	0	0
Recurring \| Level 3
Assets:
Total assets	0	0
Liabilities:
Warrant liabilities	16,878	19,140
Total liabilities	16,878	19,140
Recurring \| Level 3 \| U.S. government agency securities and treasuries
Assets:
Marketable securities:		0
Recurring \| Level 3 \| Corporate bonds
Assets:
Marketable securities:		0
Recurring \| Level 3 \| Commercial paper
Assets:
Marketable securities:		0
Recurring \| Level 3 \| Money market funds (included in cash equivalents)
Assets:
Money market funds (included in cash equivalents)	$ 0	$ 0

Stock Incentive Plans - Employee Stock Purchase Plan (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized and reserved for future issuance (in shares)		63,167,349		63,167,349
Share-based payment arrangement, expense		$ 3,783	$ 3,564	$ 6,059	$ 6,317
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized and reserved for future issuance (in shares)		5,060,074		5,060,074		173,076
Number of shares authorized, increase (in shares)	1,530,424
Shares of common stock issued to employees under the ESPP (in shares)				108,068
Share-based payment arrangement, expense				$ 100	$ 100

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(v)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

Equity - Warranty Activity (Details)	Jun. 30, 2023 $ / shares shares
Class of Warrant or Right [Line Items]
Class of warrant or right, outstanding (in shares)	31,228,279
Exercise price (in dollars per share) \| $ / shares	$ 1.53
Warrants to purchase common stock
Class of Warrant or Right [Line Items]
Class of warrant or right, outstanding (in shares)	28,991,953
Warrants to purchase common stock
Class of Warrant or Right [Line Items]
Class of warrant or right, outstanding (in shares)	2,236,326

Debt (Tables)

6 Months Ended

Jun. 30, 2023

Debt Disclosure [Abstract]

Schedule of Term Loan And Unamortized Debt Discount Balances

Total 2020 Term Loan and unamortized debt discount balances as of June 30, 2023 are as follows (in thousands):


Outstanding principal	$	22,414
Venture debt termination fee		2,250
Less: Debt discount		(642	)
Less: Current portion of loan payable		(10,235	)

Loan payable, net of current portion	$	13,787

Schedule of Future Minimum Payments on the Term Loans

Future minimum principal payments on the 2020 Term Loan as of June 30, 2023 are as follows (in thousands):


Year ended:
2023 (remainder)	$	5,173
2024		10,345
2025		6,896

Total minimum principal payments	$	22,414

Related-party Transactions - Number of Shares of Common Stock Purchased (Details) - TAS Partners, LLC (affiliate of Timothy A. Springer, Ph.D.) - Affiliated Entity $ in Thousands	3 Months Ended
	Jun. 30, 2022 USD ($) shares
Related Party Transaction [Line Items]
Shares issued, value \| $	$ 9,421,056
Common stock
Related Party Transaction [Line Items]
Stock issued (in shares)	6,681,600
Warrant
Related Party Transaction [Line Items]
Stock issued (in shares)	5,011,200

Description of the Business (Details) - USD ($) $ in Millions	1 Months Ended
	Apr. 30, 2023	Jun. 30, 2023
Cash and Cash Equivalents [Line Items]
Number of positions eliminated, period percent	25.00%
Cash, cash equivalents, restricted cash and marketable securities		$ 115.0
Restricted cash and cash equivalents		3.0
Russian subsidiary
Cash and Cash Equivalents [Line Items]
Cash maintained in Russian bank accounts		$ 0.2

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References + Details

Collaboration and License Agreements - Ginkgo Agreement (Details) - USD ($) $ in Thousands				1 Months Ended	12 Months Ended
	Jul. 19, 2023	Jan. 03, 2023	Jun. 13, 2022	Oct. 31, 2021	Dec. 31, 2022	Jun. 30, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accrued collaboration and licensing					$ 0	$ 2,523
Ginkgo Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Clinical and commercial milestone payment, expected		$ 207,000		$ 85,000
Milestone payment			$ 500
Sale of stock, number of shares issued in transaction (in shares)			892,857
Sale common stock					$ 1,000
Second Ginkgo Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payment	$ 1,000
Sale of stock, number of shares issued in transaction (in shares)	1,339,285
Sale common stock	$ 1,500
Accrued collaboration and licensing						$ 2,500

Equity

6 Months Ended

Jun. 30, 2023

Equity [Abstract]

Equity

10. Equity

Equity Financings

“At-the-Market”

Offerings

On October 25, 2021, the Company entered into a Sales Agreement, or the 2021 Sales Agreement, with SVB Leerink LLC (now known as Leerink Partners LLC), or Leerink Partners, pursuant to which the Company may sell shares of the Company’s common stock, from time to time, through an “at the market” equity offering program under which Leerink Partners will act as sales agent. The shares of common stock sold pursuant to the 2021 Sales Agreement will be issued pursuant to the Company’s shelf registration statement on Form

S-3

(File

No. 333-241692),

for aggregate gross sales proceeds of up to $75.0 million.

During the year ended December 31, 2022, the Company sold 774,544 shares of its common stock pursuant to the 2021 Sales Agreement for aggregate net proceeds of $2.1 million, after deducting commissions and other transaction costs.

During the six months ended June 30, 2023, the Company sold no shares of its common stock pursuant to the 2021 Sales Agreement.

Warrants

During the three and six months ended June 30, 2023, there were no warrants issued, exercised, or canceled. See Note 10 to the consolidated financial statements in our Annual Report on Form

10-K

for the year ended December 31, 2022 for further discussion of the terms related to the Company’s warrants.


	Number of Warrants
	Equity classified		Liability classified		Total		Weighted average exercise price
Outstanding at June 30, 2023		2,236,326		28,991,953		31,228,279	$	1.53

Reserved Shares

The Company has authorized shares of common stock for future issuance as of June 30, 2023 as follows:


Exercise of warrants			31,228,279
Shares available for future stock incentive awards			8,073,729
RSUs reserved for issuance			125
Unvested restricted stock units			2,411,792
Outstanding common stock options			20,114,139
Accrued Ginkgo Bioworks Holdings, Inc. milestone award			1,339,285

Total			63,167,349

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481004/946-505-50-6

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480237/815-40-50-6

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480008/505-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//505/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (g)
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-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Section 50
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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Reference 16: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Section 50
-Paragraph 18
-Subparagraph (b)
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-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

+ Details

Debt - Schedule of Future Minimum Payments on the Term Loans (Details) - 2020 Term Loans $ in Thousands	Jun. 30, 2023 USD ($)
Long-term Debt, Fiscal Year Maturity [Abstract]
2023 (remainder)	$ 5,173
2024	10,345
2025	6,896
Total minimum principal payments	$ 22,414

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References + Details

Defined Contribution Plan	6 Months Ended
Defined Contribution Plan	Jun. 30, 2023
Retirement Benefits [Abstract]
Defined Contribution Plan	16. Defined Contribution Plan The Company maintains a defined contribution plan, or the 401(k) Plan, under Section 401(k) of the Internal Revenue Code. The 401(k) Plan covers all employees who meet defined minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pretax basis. The 401(k) Plan provides for matching contributions on a portion of participant contributions pursuant to the 401(k) Plan’s matching formula. Commencing in January 2022, all matching contributions vest ratably over two years and participant contributions vest immediately. Contributions by the Company totaled $0.1 million during each of the three months ended June 30, 2023 and 2022, and $0.2 million during each of the six months ended June 30, 2023 and 2022.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480794/715-70-50-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
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-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480482/715-20-55-17

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
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-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Paragraph 1
-Subparagraph (d)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 1
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-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Paragraph 1
-Subparagraph (l)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-Name Accounting Standards Codification
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-URI https://asc.fasb.org//715/tableOfContent

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(iii)
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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-Name Accounting Standards Codification
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-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480126/715-20-S99-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 60
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480266/715-60-50-3

+ Details

Fair Value Measurements

6 Months Ended

Jun. 30, 2023

Fair Value Disclosures [Abstract]

Fair Value Measurements

5. Fair Value Measurements

The following tables present the Company’s assets and liabilities that are measured at fair value on a recurring basis as of June 30, 2023 and December 31, 2022 (in thousands):


	June 30, 2023
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds (included in cash equivalents)	$	73,384	$	73,384	$	—	$	—

Total assets	$	73,384	$	73,384	$	—	$	—

Liabilities:
Warrant liabilities	$	16,878	$	—	$	—	$	16,878

Total liabilities	$	16,878	$	—	$	—	$	16,878


	December 31, 2022
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds (included in cash equivalents)	$	53,552	$	53,552	$	—	$	—
Marketable securities:
U.S. government agency securities and treasuries		13,557		—		13,557		—
Corporate bonds		1,951		—		1,951		—
Commercial paper		12,656		—		12,656		—

Total assets	$	81,716	$	53,552	$	28,164	$	—

Liabilities:
Warrant liabilities	$	19,140	$	—	$	—	$	19,140

Total liabilities	$	19,140	$	—	$	—	$	19,140

There were no transfers within the fair value hierarchy during the six months ended June 30, 2023 or year ended December 31, 2022.

Cash, Cash Equivalents, and Restricted Cash

As of June 30, 2023 and December 31, 2022, money market funds were classified as cash and cash equivalents on the accompanying consolidated balance sheets as they mature within 90 days from the date of purchase.

As of June 30, 2023, the Company had restricted cash balances relating to secured letters of credit in connection with its lease for the Company’s headquarters. Short-term restricted cash is included within prepaid expenses and other current assets in the consolidated balance sheets. The Company’s consolidated statements of cash flows include the following as of June 30, 2023 and 2022 (in thousands):


	June 30,
	2023		2022
Cash and cash equivalents	$	112,027	$	138,057
Short-term restricted cash		1,600		—
Long-term restricted cash		1,377		1,379

Total cash, cash equivalents, and restricted cash	$	115,004	$	139,436

Marketable Securities

No marketable securities were held as of June 30, 2023. As of December 31, 2022, marketable securities classified as Level 2 within the valuation hierarchy consist of U.S. government agency securities and treasuries, corporate bonds and commercial paper which are

available-for-sale

securities in accordance with the Company’s investment policy. The Company estimates the fair value of these marketable securities by taking into consideration valuations that include market pricing based on real-time trade data for the same or similar securities, and other observable inputs. The amortized cost of

available-for-sale

debt securities is adjusted for amortization of premiums and accretion of discounts to the earliest call date for premiums or to maturity for discounts.

Loans Payable

At June 30, 2023, in light of the issuance of the first tranche under the Company’s term loan pursuant the Loan and Security Agreement, dated August 31, 2020, as amended, among the Company, Oxford Finance LLC, or Oxford, as Collateral Agent and a Lender, and Silicon Valley Bank, a division of First-Citizens Bank & Trust Company (successor by purchase to the Federal Deposit Insurance Corporation as Receiver for Silicon Valley Bridge Bank, N.A. (as successor to Silicon Valley Bank)), or SVB, as a Lender, or the Loan and Security Agreement, the Company believes the carrying value approximates the fair value of the loan.

Warrants

In December 2019, the Company issued warrants to purchase common stock in connection with a private placement of shares of common stock, or the 2019 Warrants. Pursuant to the terms of the 2019 Warrants, the Company could be required to settle the 2019 Warrants in cash in the event of certain acquisitions of the Company and, as a result, the 2019 Warrants were required to be measured at fair value and reported as a liability on the balance sheet. On December 20, 2022, the Company amended the terms of the outstanding 2019 Warrants held by certain members of the Board, or the Amended 2019 Warrants, to remove the cash settlement provision. As a result, the Amended 2019 Warrants were remeasured at fair value on December 20, 2022 and reclassified from a liability to equity on the balance sheet. See Note 10 to the consolidated financial statements included in our Annual Report on Form

10-K

for the year ended December 31, 2022 for further discussion on the equity-classified Amended 2019 Warrants.

In April 2022, the Company issued warrants in connection with an underwritten offering of shares of common stock and warrants to purchase shares of common stock, or the 2022 Warrants. Pursuant to the terms of the 2022 Warrants, the Company could be required to settle the 2022 Warrants in cash in the event of an acquisition of the Company under certain circumstances and, as a result, the 2022 Warrants are required to be measured at fair value and reported as a liability on the balance sheet.

The Company recorded the fair value of the 2019 Warrants and the 2022 Warrants upon issuance using the Black-Scholes valuation model and is required to revalue the 2019 Warrants and the 2022 Warrants at each reporting date, with any changes in fair value recorded in the statement of operations and comprehensive income (loss). The valuations of the 2019 Warrants and the 2022 Warrants are classified as Level 3 of the fair value hierarchy due to the need to use assumptions in the valuations that are both significant to the fair value measurement and unobservable, including the stock price volatility and the expected life of the 2019 Warrants and the 2022 Warrants. Generally, increases (decreases) in the fair value of the underlying stock and estimated term would result in a directionally similar impact to the fair value measurement.

The estimated fair values of the 2019 Warrants and the 2022 Warrants were determined using the following inputs to the Black-Scholes simulation valuation:

Estimated fair value of the underlying stock

The Company estimates the fair value of the common stock based on the closing stock price at the end of each reporting period.

Risk-free interest rate

. The risk-free interest rate is based on the U.S. Treasury at the valuation date commensurate with the expected remaining life assumption.

Dividend rate

. The dividend rate is based on the historical rate, which the Company anticipates will remain at zero.

Expected life

. The expected life of the 2019 Warrants and the 2022 Warrants is assumed to be equivalent to their remaining contractual terms which expire on December 23, 2024 and April 11, 2027, respectively.

Volatility

. The Company estimates stock price volatility based on the Company’s historical volatility for a period of time commensurate with the expected remaining life of the warrants.

A summary of the Black-Scholes pricing model assumptions used to record the fair value of the 2019 Warrants liability is as follows:


	June 30,			December 31,
	2023			2022
Risk-free interest rate		5.40	%		4.74	%
Dividend yield		—			—
Expected life (in years)		1.48			1.98
Expected volatility		82.80	%		79.92	%

A summary of the Black-Scholes pricing model assumptions used to record the fair value of the 2022 Warrants liability is as follows:


	June 30,			December 31,
	2023			2022
Risk-free interest rate		4.49	%		4.22	%
Dividend yield		—			—
Expected life (in years)		3.78			4.28
Expected volatility		91.59	%		98.05	%

Changes in Level 3 Liabilities Measured at Fair Value on a Recurring Basis

The following table reflects a roll-forward of fair value for the Company’s Level 3 warrant liabilities (see Note 10 to these unaudited consolidated financial statements), for the six months ended June 30, 2023 (in thousands):


	Warrant liabilities
Fair value as of December 31, 2022	$	19,140
Change in fair value		(2,262	)

Fair value as of June 30, 2023	$	16,878

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Payroll and employee related expenses	$ 2,978	$ 4,242
Collaboration and licensing	2,523	0
Accrued patent fees	471	696
Accrued external research and development costs	5,094	7,274
Accrued professional and consulting services	1,257	985
Accrued interest	187	222
Other	392	665
Accrued expenses	$ 12,902	$ 14,084

Stock Incentive Plans - Schedule of Assumptions (Details) - Shares available for future stock incentive awards - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	3.38%	3.26%	3.95%	1.63%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Expected term	6 years	6 years 18 days	5 years 11 months 8 days	6 years 10 days
Expected volatility	94.40%	92.03%	94.64%	91.85%
Weighted-average fair value of common stock (in dollars per share)	$ 1.31	$ 1.29	$ 1.15	$ 3.1

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Fair Value Measurements - Change in the Warrant Liabilities (Details) - Warrant liabilities $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value as of December 31, 2022	$ 19,140
Change in fair value	(2,262)
Fair value as of June 30, 2023	$ 16,878

Net (Loss) Income Per Share

6 Months Ended

Jun. 30, 2023

Earnings Per Share [Abstract]

Net (Loss) Income Per Share

4. Net (Loss) Income Per Share

The following table sets forth the computation of basic and diluted net (loss) income per share for the three and six months ended June 30, 2023 and 2022 (in thousands, except share and

per-share

data):


	Three Months Ended June 30,					Six Months Ended June 30,
	2023			2022		2023			2022
Numerator:
Net (loss) income	$	(11,387	)	$	8,601	$	(33,050	)	$	37,379
Less: Change in fair value of liability warrants		—			—		—			(13,868	)

Adjusted net (loss) income	$	(11,387	)	$	8,601	$	(33,050	)	$	23,511

Denominator:
Weighted-average common shares outstanding - basic		153,442,413			148,505,729		153,396,380			136,436,316
Dilutive effect of employee equity incentive plans and outstanding warrants		—			—		—			529,996

Weighted-average common shares used in per share calculations - diluted		153,442,413			148,505,729		153,396,380			136,966,312

Net (loss) income per share:
Basic	$	(0.07	)	$	0.06	$	(0.22	)	$	0.27

Diluted	$	(0.07	)	$	0.06	$	(0.22	)	$	0.17

The following table represents the potential dilutive shares of common stock excluded from the computation of the diluted net (loss) income per share for all periods presented, as the effect would have been anti-dilutive:


	Three Months Ended June 30,				Six Months Ended June 30,
	2023		2022		2023		2022
Options, RSUs and ESPP shares		22,607,689		16,422,488		22,607,689		16,660,700
Warrants to purchase common stock		31,228,279		31,307,409		31,228,279		20,863,898

Total		53,835,968		47,729,897		53,835,968		37,524,598

Leases - Other Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Leases [Abstract]
Cash paid for amounts included in the measurement of lease liabilities:	$ 1,319	$ 924

Property and Equipment (Tables)

6 Months Ended

Jun. 30, 2023

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment

Property and equipment consists of the following (in thousands):


	June 30,			December 31,
	2023			2022
Laboratory equipment	$	6,263		$	6,001
Computer equipment and software		702			697
Leasehold improvements		61			57
Furniture and fixtures		453			453
Office equipment		196			192
Construction in process		492			599

Total property and equipment		8,167			7,999
Less: Accumulated depreciation		(5,574	)		(5,205	)

Property and equipment, net	$	2,593		$	2,794

Equity - Schedule of Authorized Shares of Common Stock for Future Issuance (Details)	Jun. 30, 2023 shares
Class of Stock [Line Items]
Total (in shares)	63,167,349
Shares available for future stock incentive awards
Class of Stock [Line Items]
Total (in shares)	8,073,729
RSUs reserved for issuance
Class of Stock [Line Items]
Total (in shares)	125
Unvested restricted stock units
Class of Stock [Line Items]
Total (in shares)	2,411,792
Outstanding common stock options
Class of Stock [Line Items]
Total (in shares)	20,114,139
Exercise of warrants
Class of Stock [Line Items]
Total (in shares)	31,228,279
Accrued Ginkgo Bioworks Holdings, Inc. milestone award
Class of Stock [Line Items]
Total (in shares)	1,339,285

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 272
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-Paragraph 3
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-URI https://asc.fasb.org//1943274/2147483014/272-10-45-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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Reference 18: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Summary of Significant Accounting Policies	6 Months Ended
Summary of Significant Accounting Policies	Jun. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The Company disclosed its significant accounting policies in Note 2 – Summary of Significant Accounting Policies included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. There have been no material changes to the Company’s significant accounting policies during the three or six months ended June 30, 2023, with the exception of the matters discussed in recent accounting pronouncements. Recent Accounting Pronouncements Recently Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments . Subsequently, in November 2018, the FASB issued ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments-Credit Losses . ASU 2016-13 requires entities to measure all expected credit losses for most financial assets held at the reporting date based on an expected loss model which includes historical experience, current conditions, and reasonable and supportable forecasts. ASU 2016-13 also requires enhanced disclosures to help financial statement users better understand significant estimates and judgments used in estimating credit losses. This ASU is effective for smaller reporting companies for fiscal years beginning after December 15, 2022, with early adoption permitted. The Company adopted the new standard effective January 1, 2023, using a modified retrospective transition method, and there was no impact on its consolidated financial statements or results of operations upon adoption.

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities
Net (loss) income	$ (33,050)	$ 37,379
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Depreciation and amortization	382	696
Amortization of premiums and discounts on marketable securities	(79)	0
Non-cash lease expense	842	591
Gain on disposal of property and equipment	0	(147)
Stock-based compensation expense	6,059	6,317
Non-cash interest expense	533	579
Warrant liabilities revaluation	(2,262)	(13,868)
Changes in operating assets and liabilities:
Accounts receivable	1,211	(14,080)
Unbilled receivable	2,107	0
Prepaid expenses, deposits and other assets	815	(374)
Accounts payable	(49)	300
Income taxes payable	0	(280)
Deferred revenue	8,504	(42,213)
Accrued expenses and other liabilities	(3,673)	965
Net cash used in operating activities	(18,660)	(24,135)
Cash flows from investing activities
Proceeds from maturities of marketable securities	28,254	10,000
Purchases of property and equipment	(142)	(554)
Net cash provided by investing activities	28,112	9,446
Cash flows from financing activities
Repayments of principal on outstanding debt	(2,586)	0
Debt amendment fee included in debt discount	0	(110)
Net proceeds from issuance of common stock and common warrants	0	36,890
Proceeds from exercise of stock options	0	21
Proceeds from issuance of common stock under Employee Stock Purchase Plan	149	127
Net cash (used in) provided by financing activities	(2,437)	38,603
Effect of exchange rate changes on cash	(49)	86
Net change in cash, cash equivalents, and restricted cash	6,966	24,000
Cash, cash equivalents, and restricted cash at beginning of period	108,038	115,436
Cash, cash equivalents, and restricted cash at end of period	115,004	139,436
Supplemental cash flow information
Cash paid for interest	1,242	1,014
Noncash investing and financing activities
Issuance of common stock, license agreement in stock-based compensation expense	0	1,000
Stock-based compensation expense in accrued liabilities	1,500	0
Purchase of property and equipment not yet paid	48	320
Equity offering costs in accrued liabilities	0	31
At-The-Market Offering
Cash flows from financing activities
Net proceeds from issuance of common stock- at-the-market offering	$ 0	$ 1,675

Leases - Operating Lease, Liability, Maturity (Details) $ in Thousands	Jun. 30, 2023 USD ($)
Leases [Abstract]
2023 (remainder)	$ 1,349
2024	2,740
2025	2,818
2026	2,902
2027	2,990
Thereafter	946
Total future minimum lease payments	13,745
Less: Imputed interest	2,853
Total operating lease liabilities	$ 10,892

Revenue Arrangements

6 Months Ended

Jun. 30, 2023

Revenue from Contract with Customer [Abstract]

Revenue Arrangements

12. Revenue Arrangements

Astellas Gene Therapies

In January 2023, the Company entered into a License and Development Agreement, or the Astellas Agreement, with Audentes Therapeutics, Inc., doing business as Astellas. Under the Astellas Agreement, the Company granted Astellas an exclusive license to the Company’s IdeXork technology arising from Xork (defined below), to develop and commercialize Xork for use in Pompe disease in combination with an Astellas gene therapy investigational or authorized product. Xork, Genovis’ IgG Protease, is licensed by the Genovis Agreement, as described in Note 14 to these consolidated financial statements, Astellas paid a $10.0 million upfront payment to the Company upon signing of the Astellas Agreement, and the Company is entitled to receive up to $340.0 million in future additional payments over the course of the partnership that are contingent on the achievement of various development and regulatory milestones and, if commercialized, sales thresholds for annual net sales where Xork is used as a

pre-treatment

for an Astellas investigational or authorized product, and tiered royalty payments ranging from low to high single digits.

Pursuant to the Astellas Agreement, the Company will have the exclusive right and responsibility to complete research and development of Xork products and to conduct all preclinical studies and clinical trials for Xork for use in Pompe disease with an Astellas gene therapy investigational or authorized product, or the Xork Development Services. Astellas will reimburse the Company for 25% of all budgeted costs incurred to complete the development of Xork for use in Pompe disease with an Astellas gene therapy investigational or authorized product. The Company will have control and responsibility over regulatory filings, including any investigational drug applications, biologics license applications, and marketing authorization applications relating to the licensed product. Astellas will have the exclusive right and responsibility to research, develop, and commercialize Astellas products used in combination with Xork and will have control and responsibility over all regulatory filings, including any investigational drug applications, biologics license applications, and marketing authorization applications, relating to Astellas products and Astellas products used in combination with Xork.

The Company determined the Astellas Agreement represents a service arrangement under the scope of ASC 606. The Company determined that the sublicense of Xork to Astellas, the licensed

know-how,

and the Xork Development Services represent a single promise and performance obligation to be transferred to Astellas over time due to the nature of the promises in the contract. As such, the Company will recognize the transaction price as revenue utilizing the input method to measure the progress of satisfying the single performance obligation to Astellas.

In determining the transaction price, the Company concluded the upfront payment of $10.0 million and development cost reimbursements of $5.5 million will be included in the initial transaction price. All other development milestones will be fully constrained and will only be included in the transaction price when the applicable milestone is deemed probable of achievement. Each of these variable consideration items were evaluated under the most likely amount method to determine whether such amounts were probable of occurrence, or whether such amounts should be constrained until they become probable. As part of its evaluation of the constraint, the Company considered numerous factors, including that receipt and timing of such development milestones is outside the control of the Company and probability of success criteria is estimated. The Company will

re-evaluate

the transaction price in each reporting period, as uncertain events are resolved, or as other changes in circumstances occur. In accordance with ASC 606, the Company will only recognize revenue associated with sales-based milestones and royalties when the subsequent sales thresholds are reached and underlying sales occur, respectively. The Company determined that a significant financing component does not exist in its arrangement with Astellas. The Company also determined the options to negotiate additional fields, enter into a clinical supply agreement, and enter into a commercial supply agreement do not represent material rights under the Astellas Agreement. Astellas has the right to terminate the Astellas Agreement in its entirety or on a

field-by-field

basis, upon 90 days’ written notice to the Company.

As of June 30, 2023, the Company recorded $4.2 million as a short-term contract liability and $4.9 million as a long-term contract liability, representing deferred revenue associated with the Astellas Agreement. As of June 30, 2023, the Company recorded a receivable of $0.3 million, representing billings for the Xork Development Services that are subject to reimbursement by Astellas. Revenue of $0.8 million and $1.4 million related to the Astellas Agreement was recognized during the three and six months ended June 30, 2023, respectively.

Takeda Pharmaceuticals USA, Inc.

License and Development Agreement

In October 2021, the Company entered into a License Agreement, or the Takeda Agreement, with Takeda Pharmaceuticals USA, Inc., or Takeda. Under the Takeda Agreement, the Company granted Takeda an exclusive license to the Company’s ImmTOR technology initially for two specified disease indications within the field of lysosomal storage disorders. Takeda paid a $3.0 million upfront payment to the Company upon signing of the Takeda Agreement, and the Company is entitled to receive up to $1.124 billion in future additional payments over the course of the partnership that are contingent on the achievement of development or commercial milestones or Takeda’s election to continue its activities at specified development stages. The Company is also eligible for tiered royalties on future commercial sales of any licensed products. A more detailed description of the Takeda Agreement and the Company’s evaluation of this agreement under ASC 606 can be found in Note 12 to the consolidated financial statements in our Annual Report on Form

10-K

for the year ended December 31, 2022.

On March 9, 2023, the Company was notified by Takeda of the achievement of the milestone event related to the completion of a

non-clinical

milestone for one of the specified disease indications within the field of lysosomal storage disorders under the Takeda Agreement. Accordingly, the Company received a milestone payment of $0.5 million during the three months ended June 30, 2023.

In April 2023, the Company was notified by Takeda of its intention to terminate the Takeda Agreement effective July 25, 2023.

As of June 30, 2023 and December 31, 2022, the Company recorded no short-term contract liability and $0.1 million as a short-term contract liability, respectively, representing deferred revenue associated with the Takeda Agreement. Revenue of $0.1 million and $0.6 million related to the Takeda Agreement was recognized during the three and six months ended June 30, 2023, respectively. No revenue was recognized during the three months ended June 30, 2022, and revenue of $1.0 million related to the Takeda Agreement was recognized during the six months ended June 30, 2022.

Swedish Orphan Biovitrum AB (publ.)

License and Development Agreement

In June 2020, the Company and Sobi entered into a License and Development Agreement, or the Sobi License. Pursuant to the Sobi License, the Company agreed to grant Sobi an exclusive, worldwide (except as to Greater China) license to develop, manufacture and commercialize the Company’s

SEL-212

drug candidate, which is currently in development for the treatment of chronic refractory gout. The

SEL-212

drug candidate is a pharmaceutical composition containing a combination of pegadricase, or the Compound, and ImmTOR. Pursuant to the Sobi License, in consideration of the license, Sobi agreed to pay the Company a

one-time,

upfront payment of $75.0 million. Sobi has also agreed to make milestone payments totaling up to $630.0 million to the Company upon the achievement of various development and regulatory milestones and, if commercialized, sales thresholds for annual net sales of

SEL-212,

and tiered royalty payments ranging from the low double digits on the lowest sales tier to the high teens on the highest sales tier. A more detailed description of the Sobi License and the Company’s evaluation of this agreement under ASC 606 can be found in Note 12 to the consolidated financial statements in our Annual Report on Form

10-K

for the year ended December 31, 2022.

As of June 30, 2023 and December 31, 2022, the Company recorded a total outstanding receivable of $5.1 million and $5.0 million, respectively, representing billings for the Phase 3 DISSOLVE program that are subject to reimbursement by Sobi. Additionally, as of June 30, 2023 and December 31, 2022, the Company recorded a total unbilled receivable of $1.1 million and $3.2 million, respectively, representing revenue earned but not yet billed for the Phase 3 DISSOLVE program. Revenue of $4.3 million and $8.7 million related to the Sobi License was recognized during the three and six months ended June 30, 2023, respectively. Revenue of $29.2 million and $52.9 million related to the Sobi License was recognized during the three and six months ended June 30, 2022, respectively.

Sarepta Therapeutics, Inc.

Research License and Option Agreement

In June 2020, the Company and Sarepta Therapeutics, Inc., or Sarepta, entered into a Research License and Option Agreement, or the Sarepta Agreement. Pursuant to the Sarepta Agreement, the Company agreed to grant Sarepta a license under the Company’s intellectual property rights covering the Company’s antigen-specific biodegradable nanoparticle encapsulating ImmTOR to research and evaluate ImmTOR in combination with Sarepta’s adeno-associated virus gene therapy technology, or gene editing technology, using viral or

non-viral

delivery, to treat Duchenne Muscular Dystrophy and certain Limb-Girdle

Muscular Dystrophy subtypes, or the Indications. Sarepta initially had an option term of 24 months during which it could

opt-in

to obtain an exclusive license to further develop and commercialize the product to treat at least one indication, with a potential to extend the option term for an additional fee. The Company agreed to supply ImmTOR to Sarepta for clinical supply on a cost-plus basis under the Sarepta Agreement. A more detailed description of the Sarepta Agreement and the Company’s evaluation of this agreement under ASC 606 can be found in Note 12 to the consolidated financial statements in our Annual Report on Form

10-K

for the year ended December 31, 2022.

On March 13, 2023, the Company was notified by Sarepta that Sarepta would not be exercising its exclusive option under the Sarepta Agreement. Therefore, the remaining deferred revenue balance as of December 31, 2022 of $0.5 million was recognized as revenue during the six months ended June 30, 2023. No revenue was recognized during the three months ended June 30, 2023. Revenue of $10.1 million and $10.2 million was recognized during the three and six months ended June 30, 2022, respectively.

Spark Therapeutics, Inc.

Spark License Agreement

In December 2016, the Company entered into a License and Option Agreement, or the Spark License Agreement, with Spark Therapeutics, Inc., or Spark, pursuant to which the Company and Spark agreed to collaborate on the development of gene therapies for certain targets utilizing the ImmTOR platform. The Spark License Agreement provides Spark with certain exclusive, worldwide, royalty bearing licenses to the Company’s intellectual property, allowing Spark to develop and commercialize gene therapies in combination with ImmTOR for Factor VIII, an essential blood clotting protein relevant to the treatment of hemophilia A, the initial target.

On January 18, 2022, both parties agreed to mutually terminate the Spark License Agreement. Therefore, the short-term contract liability of $9.2 million as of December 31, 2021 was recognized as revenue during the six months ended June 30, 2022. No revenue was recognized during the three months ended June 30, 2022.

Transaction Price Allocated to Future Performance Obligations

Remaining performance obligations represent the transaction price of contracts for which work has not been performed, or has been partially performed. As of June 30, 2023, the aggregate amount of the transaction price allocated to remaining performance obligations was $9.1 million.

Contract Balances from Contracts with Customers

The following table presents changes in the Company’s contract liabilities during the six months ended June 30, 2023 (in thousands):


	Balance at							Balance at
	beginning of period		Additions		Deductions			end of period
Six Months Ended June 30, 2023
Contract liabilities:
Deferred revenue	$	593	$	10,500	$	(1,996	)	$	9,097

Total contract liabilities	$	593	$	10,500	$	(1,996	)	$	9,097

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-13

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

+ Details

Leases - Additional Information (Details) - A65 Grove Street Watertown M A [Member] $ in Millions	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 01, 2022 ft²	Jul. 31, 2019 ft²
Lessee, Lease, Description [Line Items]
Area of a real estate property \| ft²			7,216	25,078
Letters of credit outstanding, amount	$ 1.6	$ 1.6
Letter of Credit [Member]
Lessee, Lease, Description [Line Items]
Restricted cash, noncurrent	$ 1.4

Collaboration and License Agreements - AskBio (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration expense	$ 23,887	$ 25,413	$ 48,206	$ 48,639
AskBio License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration expense	$ 100	$ 200	$ 100	$ 600
Cost share percentage			50.00%

Equity - Narrative (Details) - At-The-Market Offering - USD ($) $ in Thousands		6 Months Ended		12 Months Ended
	Oct. 25, 2021	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Subsidiary, Sale of Stock [Line Items]
Sale common stock	$ 75,000
Sale of stock, number of shares issued in transaction (in shares)		0		774,544
Net proceeds from issuance of common stock		$ 0	$ 1,675	$ 2,100

Net (Loss) Income Per Share - Computation of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Numerator:
Net (loss) income	$ (11,387)	$ (21,663)	$ 8,601	$ 28,778	$ (33,050)	$ 37,379
Less: Change in fair value of liability warrants	0		0		0	(13,868)
Adjusted net (loss) income	(11,387)		8,601		(33,050)	23,511
Adjusted net (loss) income	$ (11,387)		$ 8,601		$ (33,050)	$ 23,511
Denominator:
Weighted-average common shares outstanding - basic (in shares)	153,442,413		148,505,729		153,396,380	136,436,316
Dilutive effect of employee equity incentive plans and outstanding warrants (in shares)	0		0		0	529,996
Weighted-average common shares used in per share calculations - diluted (in shares)	153,442,413		148,505,729		153,396,380	136,966,312
Net (loss) income per share:
Basic (in dollars per share)	$ (0.07)		$ 0.06		$ (0.22)	$ 0.27
Diluted (in dollars per share)	$ (0.07)		$ 0.06		$ (0.22)	$ 0.17

Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	17. Commitments and Contingencies As of June 30, 2023, the Company was not a party to any litigation that could have a material adverse effect on the Company’s business, financial position, results of operations or cash flows. Other As permitted under Delaware law, the Company has agreed to indemnify its directors and officers for certain events or occurrences while the director or officer is, or was, serving at the Company’s request in such capacity. The term of the indemnification is for the director’s or officer’s lifetime. The maximum potential amount of future payments the Company could be required to make is unlimited; however, the Company has directors’ and officers’ insurance coverage that limits its exposure and enables it to recover a portion of any future amounts paid. The Company also has indemnification arrangements under certain of its facility leases that require it to indemnify the landlord against certain costs, expenses, fines, suits, claims, demands, liabilities, and actions directly resulting from certain breaches, violations, or non-performance of any covenant or condition of the Company’s lease. The term of the indemnification is for the term of the related lease agreement. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is unlimited. To date, the Company had not experienced any material losses related to any of its indemnification obligations, and no material claims with respect thereto were outstanding. The Company is a party in various other contractual disputes and potential claims arising in the ordinary course of business. The Company does not believe that the resolution of these matters will have a material adverse effect the Company’s business, financial position, results of operations or cash flows.

Property and Equipment

6 Months Ended

Jun. 30, 2023

Property, Plant and Equipment [Abstract]

Property and Equipment

6. Property and Equipment

Property and equipment consists of the following (in thousands):


	June 30,			December 31,
	2023			2022
Laboratory equipment	$	6,263		$	6,001
Computer equipment and software		702			697
Leasehold improvements		61			57
Furniture and fixtures		453			453
Office equipment		196			192
Construction in process		492			599

Total property and equipment		8,167			7,999
Less: Accumulated depreciation		(5,574	)		(5,205	)

Property and equipment, net	$	2,593		$	2,794

Depreciation expense was $0.2 million for each of the three months ended June 30, 2023 and 2022 and $0.4 million and $0.3 million for the six months ended June 30, 2023 and 2022, respectively.

Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Collaboration and license revenue	$ 5,249	$ 39,273	$ 11,187	$ 73,272
Operating expenses:
Research and development	17,782	19,182	36,406	36,871
General and administrative	6,105	6,231	11,800	11,768
Total operating expenses	23,887	25,413	48,206	48,639
Operating (loss) income	(18,638)	13,860	(37,019)	24,633
Investment income	1,394	207	2,725	222
Foreign currency transaction, net	23	(104)	42	(76)
Interest expense	(752)	(715)	(1,560)	(1,422)
Change in fair value of warrant liabilities	6,341	(4,647)	2,262	13,868
Other income, net	245	0	500	154
Net (loss) income	(11,387)	8,601	(33,050)	37,379
Other comprehensive income (loss):
Foreign currency translation adjustment	(27)	118	(49)	86
Unrealized gain on marketable securities	0	0	11	0
Total comprehensive income (loss)	$ (11,414)	$ 8,719	$ (33,088)	$ 37,465
Net (loss) income per share:
Basic (in dollars per share)	$ (0.07)	$ 0.06	$ (0.22)	$ 0.27
Diluted (in dollars per share)	$ (0.07)	$ 0.06	$ (0.22)	$ 0.17
Weighted average common shares outstanding:
Basic (in shares)	153,442,413	148,505,729	153,396,380	136,436,316
Diluted (in shares)	153,442,413	148,505,729	153,396,380	136,966,312

Net (Loss) Income Per Share - Schedule of Potential Common Shares Issuable Upon Conversion of Warrants (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Potential common shares
Total (in shares)	53,835,968	47,729,897	53,835,968	37,524,598
Employees
Potential common shares
Total (in shares)	22,607,689	16,422,488	22,607,689	16,660,700
Warrants to purchase common stock
Potential common shares
Total (in shares)	31,228,279	31,307,409	31,228,279	20,863,898

Defined Contribution Plan (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Defined Contribution Plan (Details) - USD ($) $ in Millions	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Retirement Benefits [Abstract]
Vesting period			2 years
Employer contribution made, net	$ 0.1	$ 0.1	$ 0.2	$ 0.2

Subsequent Events	6 Months Ended
Subsequent Events	Jun. 30, 2023
Subsequent Events [Abstract]
Subsequent Events	18. Subsequent Events The Company has evaluated subsequent events through the date on which the consolidated financial statements were issued. The Company has concluded that no subsequent events have occurred that require disclosure, except as disclosed within these consolidated financial statements.

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 8,167	$ 7,999
Less: Accumulated depreciation	(5,574)	(5,205)
Property and equipment, net	2,593	2,794
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	6,263	6,001
Computer equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	702	697
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	61	57
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	453	453
Office equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	196	192
Construction in process
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 492	$ 599

Marketable Securities and Investments - Summary of Available-for-Sale Marketable Securities (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Debt Securities, Available-for-sale [Line Items]
Amortized cost	$ 28,175
Unrealized losses	(11)
Fair value	28,164
U.S. government agency securities and treasuries
Debt Securities, Available-for-sale [Line Items]
Amortized cost	13,566
Unrealized losses	(9)
Fair value	13,557
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized cost	1,953
Unrealized losses	(2)
Fair value	1,951
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized cost	12,656
Unrealized losses	0
Fair value	$ 12,656

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

+ Details

Marketable Securities and Investments - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Sep. 07, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Investments	$ 2,000	$ 2,000
Cyrus Biotechnology, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Investments	$ 2,000	$ 2,000	$ 2,000

Accrued Expenses (Tables)

6 Months Ended

Jun. 30, 2023

Payables and Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses consist of the following (in thousands):


	June 30,		December 31,
	2023		2022
Payroll and employee related expenses	$	2,978	$	4,242
Collaboration and licensing		2,523		—
Accrued patent fees		471		696
Accrued external research and development costs		5,094		7,274
Accrued professional and consulting services		1,257		985
Accrued interest		187		222
Other		392		665

Accrued expenses	$	12,902	$	14,084

Stock Incentive Plans - Schedule of Stock-Based Compensation Expense Related to Stock Options and Restricted Common Stock (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 3,783	$ 3,564	$ 6,059	$ 6,317
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	2,677	2,021	3,869	3,039
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 1,106	$ 1,543	$ 2,190	$ 3,278

Net (Loss) Income Per Share (Tables)

6 Months Ended

Jun. 30, 2023

Earnings Per Share [Abstract]

Schedule of Computation of Basic and Diluted Net Loss Per Share

The following table sets forth the computation of basic and diluted net (loss) income per share for the three and six months ended June 30, 2023 and 2022 (in thousands, except share and

per-share

data):


	Three Months Ended June 30,					Six Months Ended June 30,
	2023			2022		2023			2022
Numerator:
Net (loss) income	$	(11,387	)	$	8,601	$	(33,050	)	$	37,379
Less: Change in fair value of liability warrants		—			—		—			(13,868	)

Adjusted net (loss) income	$	(11,387	)	$	8,601	$	(33,050	)	$	23,511

Denominator:
Weighted-average common shares outstanding - basic		153,442,413			148,505,729		153,396,380			136,436,316
Dilutive effect of employee equity incentive plans and outstanding warrants		—			—		—			529,996

Weighted-average common shares used in per share calculations - diluted		153,442,413			148,505,729		153,396,380			136,966,312

Net (loss) income per share:
Basic	$	(0.07	)	$	0.06	$	(0.22	)	$	0.27

Diluted	$	(0.07	)	$	0.06	$	(0.22	)	$	0.17

Schedule of Potential Common Shares Issuable Upon Conversion of Warrants


	Three Months Ended June 30,				Six Months Ended June 30,
	2023		2022		2023		2022
Options, RSUs and ESPP shares		22,607,689		16,422,488		22,607,689		16,660,700
Warrants to purchase common stock		31,228,279		31,307,409		31,228,279		20,863,898

Total		53,835,968		47,729,897		53,835,968		37,524,598

Stock Incentive Plans (Tables)

6 Months Ended

Jun. 30, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation

Stock-based compensation expense by classification included within the consolidated statements of operations and comprehensive income (loss), including $1.5 million recognized as stock-based compensation expense upon the achievement of a technical milestone by Ginkgo Bioworks Holdings, Inc., or Ginkgo, during the three and six months ended June 30, 2023 and $1.0 million recognized as stock-based compensation expense upon the issuance of common stock to Ginkgo during the three and six months ended June 30, 2022 as described in Note 14, was as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2023		2022		2023		2022
Research and development	$	2,677	$	2,021	$	3,869	$	3,039
General and administrative		1,106		1,543		2,190		3,278

Total stock-based compensation expense	$	3,783	$	3,564	$	6,059	$	6,317

Schedule of Weighted Average Assumptions Used

The estimated grant date fair values of employee stock option awards granted under the 2016 Plan and the 2018 Inducement Incentive Award Plan were calculated using the Black-Scholes option pricing model, based on the following weighted-average assumptions:


	Three Months Ended June 30,						Six Months Ended June 30,
	2023			2022			2023			2022
Risk-free interest rate		3.38	%		3.26	%		3.95	%		1.63	%
Dividend yield		—			—			—			—
Expected term		6.00			6.05			5.94			6.03
Expected volatility		94.40	%		92.03	%		94.64	%		91.85	%
Weighted-average fair value of common stock	$	1.31		$	1.29		$	1.15		$	3.10

Schedule of Options Activity

The following table summarizes the stock option activity under the 2008 Plan, the 2016 Plan, and the 2018 Inducement Incentive Award Plan:


	Number of options			Weighted-average exercise price ($)		Weighted-average remaining contractual term (in years)		Aggregate intrinsic value (in thousands)
Employees
Outstanding at December 31, 2022		15,578,412		$	3.44		7.57	$	4
Granted		5,477,200		$	1.15
Forfeited		(1,207,712	)	$	2.84

Outstanding at June 30, 2023		19,847,900		$	2.85		7.93	$	1

Vested at June 30, 2023		8,956,975		$	3.92		6.68	$	1
Vested and expected to vest at June 30, 2023		18,564,837		$	2.93		7.84	$	1
Non-employee consultants
Outstanding at December 31, 2022		266,239		$	8.05		5.08	$	—

Outstanding at June 30, 2023		266,239		$	8.05		4.58	$	—

Vested at June 30, 2023		266,239		$	8.05		4.58	$	—
Vested and expected to vest at June 30, 2023		266,239		$	8.05		4.58	$	—

Schedule of Disclosure of Share-based Compensation Arrangements by Share-based Payment Award

The following table summarizes the Company’s restricted stock units under the 2016 Plan and 2018 Inducement Incentive Award Plan:


	Number of shares			Weighted average grant date fair value ($)
Unvested at December 31, 2022		1,705,558		$	2.62
Granted		1,054,600			1.13
Vested		(277,193	)		3.22
Forfeited		(71,173	)		1.99

Unvested at June 30, 2023		2,411,792		$	1.92

Collaboration and License Agreements - MIT (Narrative) (Details) - Spark License Agreement - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contractual payments defined in the Exclusive Patent License agreement	$ 0	$ 0
MIT
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contractual payments defined in the Exclusive Patent License agreement		2,200,000
License and option agreement, payments made relative to calculated premium paid for initial equity investment made under the purchase agreement		$ 400,000

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 112,027	$ 106,438
Marketable securities	0	28,164
Accounts receivable	5,385	6,596
Unbilled receivables	1,055	3,162
Prepaid expenses and other current assets	4,258	3,778
Total current assets	122,725	148,138
Property and equipment, net	2,593	2,794
Right-of-use asset, net	10,775	11,617
Long-term restricted cash	1,377	1,311
Investments	2,000	2,000
Other assets	36	26
Total assets	139,506	165,886
Current liabilities:
Accounts payable	267	316
Accrued expenses	12,902	14,084
Loan payable	10,235	8,476
Lease liability	1,729	1,608
Deferred revenue	4,234	593
Total current liabilities	29,367	25,077
Non-current liabilities:
Loan payable, net of current portion	13,787	17,786
Lease liability	9,163	10,055
Deferred revenue	4,863	0
Warrant liabilities	16,878	19,140
Total liabilities	74,058	72,058
Commitments and contingencies (Note 17)
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized; no shares issued and outstanding as of June 30, 2023 and December 31, 2022	0	0
Common stock, $0.0001 par value; 350,000,000 shares authorized; 153,427,571 and 153,042,435 shares issued and outstanding as of June 30, 2023 and December 31, 2022, respectively	15	15
Additional paid-in capital	498,016	493,308
Accumulated deficit	(427,987)	(394,937)
Accumulated other comprehensive loss	(4,596)	(4,558)
Total stockholders' equity	65,448	93,828
Total liabilities and stockholders' equity	$ 139,506	$ 165,886

Accrued Expenses

6 Months Ended

Jun. 30, 2023

Payables and Accruals [Abstract]

Accrued Expenses

7. Accrued Expenses

Accrued expenses consist of the following (in thousands):


	June 30,		December 31,
	2023		2022
Payroll and employee related expenses	$	2,978	$	4,242
Collaboration and licensing		2,523		—
Accrued patent fees		471		696
Accrued external research and development costs		5,094		7,274
Accrued professional and consulting services		1,257		985
Accrued interest		187		222
Other		392		665

Accrued expenses	$	12,902	$	14,084

Leases - Components of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Leases [Abstract]
Operating lease cost	$ 696	$ 505	$ 1,392	$ 1,011
Variable lease cost	270	205	412	425
Short-term lease cost	2	2	5	5
Less: Sublease income	(251)	0	(506)	0
Total lease cost	$ 717	$ 712	$ 1,303	$ 1,441

Debt - Term Loan And Unamortized Debt Discount Balances (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Loan payable, net of current portion	$ 13,787	$ 17,786
2020 Term Loans
Debt Instrument [Line Items]
Outstanding principal	22,414
Venture debt termination fee	2,250
Less: Debt discount	(642)
Less: Current portion of loan payable	(10,235)
Loan payable, net of current portion	$ 13,787

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
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+ Details

Stock Incentive Plans - Restricted Stock Units (Details) - Restricted Stock Units (RSUs)	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested at beginning of period (in shares) \| shares	1,705,558
Grants in period (in shares) \| shares	1,054,600
Vested in period (in shares) \| shares	(277,193)
Forfeited in period (in shares) \| shares	(71,173)
Unvested at end of period (in shares) \| shares	2,411,792
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested at beginning of period (in dollars per share) \| $ / shares	$ 2.62
Grants in period (in dollars per share) \| $ / shares	1.13
Vested in period (in dollars per share) \| $ / shares	3.22
Forfeited in period (in dollars per share) \| $ / shares	1.99
Unvested at end of period (in dollars per share) \| $ / shares	$ 1.92

Collaboration and License Agreements	6 Months Ended
Collaboration and License Agreements	Jun. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Collaboration and License Agreements	14. Collaboration and License Agreements Ginkgo Bioworks Holdings, Inc. Collaboration and License Agreements On January 3, 2022, the Company entered into a Collaboration and License Agreement, or the Second Ginkgo Agreement, with Ginkgo Bioworks Holdings, Inc., or Ginkgo. Under this agreement, the Company will engage with Ginkgo to develop adeno-associated virus, or AAV, capsids designed to enhance transduction efficiency and transgene expression. In return, Ginkgo is eligible to earn both upfront research and development fees and milestone payments, including certain milestone payments in the form of shares of the Company’s common stock, clinical and commercial milestone payments of up to $207 million in cash. The Second Ginkgo Agreement was assessed for collaboration components and was determined not to be within the scope of ASC 808 as the risk and rewards are not shared by both parties. The Company will expense costs related to the Second Ginkgo Agreement as incurred until regulatory approval is received in accordance with ASC 730. The Company is accounting for the contingently issuable shares of common stock to be issued in exchange for the license obtained from Ginkgo as a liability-classified, stock-based compensation arrangement with a non-employee which will be recognized when achievement of the milestones is probable. The Company will assess the capitalization of costs incurred after the receipt of regulatory approval and, if applicable, will amortize these payments based on the expected useful life of each asset, typically based on the expected commercial exclusivity period. The Company is also obligated to pay Ginkgo tiered royalties ranging from low-single digit to high-single digit percentages of annual net sales of collaboration products which will be expensed as the commercial sales occur. In October 2021, the Company entered into a Collaboration and License Agreement, or the First Ginkgo Agreement, with Ginkgo. Under the First Ginkgo Agreement, Ginkgo will design next generation IgA proteases with potentially transformative therapeutic potential. In return, Ginkgo is eligible to earn research and development fees, clinical and commercial milestone payments of up to $85.0 million in cash, as well as certain milestone payments for fixed fair values in the form of shares of the Company’s common stock. The First Ginkgo Agreement was assessed for collaboration components and was determined not to be within the scope of ASC 808 as the risk and rewards are not shared by both parties. The Company will expense costs related to the First Ginkgo Agreement as incurred until regulatory approval is received in accordance with ASC 730. The Company is accounting for the contingently issuable shares of common stock to be issued in exchange for the license obtained from Ginkgo as a liability-classified, stock-based compensation arrangement with a non-employee which will be recognized when achievement of the milestones is probable. The Company will assess the capitalization of costs incurred after the receipt of regulatory approval and, if applicable, will amortize these payments based on the expected useful life of each asset, typically based on the expected commercial exclusivity period. The Company is also obligated to pay Ginkgo tiered royalties ranging from low-single digit to high-single digit percentages of annual net sales of collaboration products which will be expensed as the commercial sales occur. On June 13, 2022, the Company was notified of the achievement of the midpoint of the technical development plan under the First Ginkgo Agreement by Ginkgo. This milestone resulted in the payment of $0.5 million and issuance of 892,857 shares of the Company’s common stock then-valued at $1.0 million to Ginkgo during the year ended December 31, 2022. On July 19, 2023, the Company and Ginkgo mutually agreed that the completion of the technical development plan’s midpoint task under the Second Ginkgo Agreement had been achieved as of June 30, 2023. This milestone resulted in the accrual of $2.5 million as of June 30, 2023 expected to be settled through a payment of $1.0 million and future issuance of 1,339,285 shares of the Company’s common stock then-valued at $1.5 million to Ginkgo. Genovis AB (publ.) License Agreement In October 2021, the Company entered into an Exclusive License Agreement, or the Genovis Agreement, with Genovis AB (publ.), or Genovis. Under the Genovis Agreement, the Company paid to Genovis an upfront payment in exchange for an exclusive license to Genovis’ IgG Protease, or Xork, enzyme technology across all therapeutic uses in humans, excluding research, preclinical, diagnostic and other potential non-therapeutic applications of the enzyme. Genovis is eligible to earn from the Company development and sales-based milestones and sublicensing fees. The Genovis Agreement was assessed for collaboration components and was determined not to be within the scope of ASC 808 as the risk and rewards are not shared by both parties. The Company will expense costs related to the Genovis Agreement as incurred until regulatory approval is received in accordance with ASC 730. The Company will assess the capitalization of costs incurred after the receipt of regulatory approval and, if applicable, will amortize these payments based on the expected useful life of each asset, typically based on the expected commercial exclusivity period. The Company is also obligated to pay Genovis tiered royalties of low double digit percentages of worldwide annual net sales of collaboration products which will be expensed as the commercial sales occur. In February 2023, the Company made a $4.0 million payment to Genovis as a result of the sublicense of Xork to Astellas. See Note 12 to these unaudited consolidated financial statements for further discussion on the Astellas Agreement. Cyrus Biotechnology, Inc. Collaboration and License Agreement In September 2021, the Company and Cyrus entered into a collaboration and license agreement, or the Cyrus Agreement. Pursuant to the Cyrus Agreement, Cyrus agreed to grant the Company an exclusive, worldwide license to certain intellectual property to form a protein engineering collaboration combining the Company’s ImmTOR platform with Cyrus’ ability to redesign protein therapeutics. The lead program is a proprietary interleukin-2, or IL-2, protein agonist designed to selectively promote expansion of regulatory T cells for treatment of patients with autoimmune diseases and other deleterious immune conditions. In return for the licensed intellectual property, the Company made an upfront payment and is obligated to pay certain discovery, development, and sales-based milestones which could total up to approximately $1.5 billion across multiple programs. The Cyrus Agreement was assessed for collaboration components and was determined not to be within the scope of ASC 808 as the risk and rewards are not shared by both parties. The Company will expense costs related to the Cyrus Agreement as incurred until regulatory approval is received in accordance with ASC 730. The Company will assess the capitalization of costs incurred after the receipt of regulatory approval and, if applicable, will amortize these payments based on the expected useful life of each asset, typically based on the expected commercial exclusivity period. The Company is also obligated to pay Cyrus tiered royalties ranging from mid-single digit to low-double digit percentages of annual net sales of collaboration products which will be expensed as the commercial sales occur. Additionally, on September 7, 2021, the Company entered into a stock purchase agreement, or the Series B Preferred Stock Purchase Agreement, in connection with the Cyrus Agreement. Pursuant to the Series B Preferred Stock Purchase Agreement, the Company purchased 2,326,934 shares of Cyrus’ Series B Preferred Stock, par value $0.0001 per share, at a purchase price of $0.8595 per share, for $2.0 million. In accordance with ASC 810, the Company has a variable interest in Cyrus resulting from its equity investment. The Company will share in Cyrus’ expected losses or receive a portion of its expected returns and absorb the variability associated with changes in the entity’s net assets. However, the Company is not the primary beneficiary as it does not have the power to direct the activities most significant to Cyrus, and therefore it is not required to consolidate Cyrus. The Company has recognized the $2.0 million investment of Cyrus’ Series B Preferred Stock at cost on the purchase date. On June 13, 2022, the Company and Cyrus mutually agreed that the preclinical key in-vitro success milestone had been achieved. As of June 30, 2023, no impairment indicators are present and therefore the carrying value of the investment in Cyrus is $2.0 million on the accompanying consolidated balance sheet. The Company’s maximum exposure to loss related to this variable interest entity is limited to the carrying value of the investment. The Company has not provided financing to Cyrus other than the amount contractually required by the Series B Preferred Stock Purchase Agreement. Asklepios Biopharmaceutical, Inc. Feasibility Study and License Agreement In August 2019, the Company entered into a feasibility study and license agreement, or the AskBio Collaboration Agreement, with Asklepios Biopharmaceutical, Inc., or AskBio. Pursuant to the AskBio Collaboration Agreement, the Company and AskBio agreed to license intellectual property rights to each other as part of a collaboration to research, develop, and commercialize certain AAV gene therapy products utilizing the Company’s ImmTOR platform to enable re-dosing of such AAV gene therapy products to treat serious rare and orphan genetic diseases for which there is a significant unmet medical need. Pursuant to the AskBio Collaboration Agreement, the Company and AskBio agreed to conduct proof of concept studies to potentially validate the use of ImmTOR in conjunction with AskBio’s AAV gene therapy, or SEL-302 (previously disclosed as MMA-101, in combination with ImmTOR), for the treatment of MMA to mitigate the formation of neutralizing anti-AAV capsid antibodies, or the POC Studies. On April 29, 2021, the Company was notified by AskBio that AskBio intended to opt-out of development of the MMA indication. The AskBio Collaboration Agreement otherwise remains in effect. Consequently, the Company has assumed all rights to the MMA program. The Company filed an investigational new drug application, or IND, to conduct a Phase 1/2 clinical trial of its SEL-302 product candidate in pediatric patients with MMA in the third quarter of 2021. In December 2022, the Company initiated ReiMMAgine, the Phase 1/2 clinical trial of SEL-302, however, the Company has since paused further development of SEL-302 for the treatment of MMA. The SEL-399 program combined an empty AAV capsid (EMC-101), which is an AAV capsid containing no transgene, with ImmTOR and is being conducted in partnership with AskBio. Building on the preclinical data the Company has generated showing ImmTOR’s effect on mitigating or reducing the formation of neutralizing antibodies to AAV gene therapies, the Company completed a clinical trial of SEL-399 in healthy adult volunteers in Belgium. The goal of the SEL-399 clinical trial was to demonstrate the appropriate dose of ImmTOR in humans to mitigate the formation of antibodies to AAV capsids used in gene therapies. The Company believes this promising study in healthy volunteers provides support for the potential use of ImmTOR for the inhibition of neutralizing antibodies to AAV8 in gene therapy clinical trials. The Company and AskBio will share responsibility for the research, development and commercialization of products developed under the SEL-399 program collaboration. The parties will also share research, development, and commercialization costs equally for all collaboration products, but with a right of either party to opt out of certain products, and thereby no longer be required to share costs for such products. Each party will receive a percentage of net profits under the collaboration equal to the percentage of shared costs borne by such party in the development of such product. Pursuant to the AskBio Collaboration Agreement, AskBio is responsible for manufacturing the AAV capsids and AAV vectors and the Company is responsible for manufacturing ImmTOR. The AskBio Collaboration Agreement is considered to be within the scope of ASC 808, as both parties are active participants and exposed to the risks and rewards of the collaborative activity. The Company evaluated the terms of the AskBio Collaboration Agreement and has identified the following promises in the arrangement (1) conducting research and development activities to develop and commercialize products under the collaboration, or the R&D Services, (2) granting a non-exclusive, non-transferable, royalty-free, fully paid up, worldwide license to certain intellectual property of the Company, or the IP Rights, for the purpose of performing the POC Studies, or the Research License, (3) granting an exclusive, nontransferable, worldwide license to the IP Rights for use in certain indications, or the Collaboration License, (4) providing manufactured supply of preclinical and clinical ImmTOR, or the Manufactured Supply, (5) participation on identified steering committees responsible for the oversight of the collaboration, or the JSC Participation, and (6) granting an exclusive option to obtain a license under the IP Rights to research, develop and commercialize licensed products. The Company determined that the R&D Services, Research License, Collaboration License, Manufactured Supply, and JSC Participation were not capable of being distinct, and therefore must be combined into a single performance obligation. Therefore, promises (1) through (5) identified above were combined into a single performance obligation. Furthermore, the Company evaluated the related option agreement and determined that it does not provide AskBio with a material right under ASC 606 as the option was not priced at a discount. The Company noted that AskBio did not meet the definition of a customer within the scope of ASC 606 for any distinct performance obligations as the Company concluded that such items were not an output of the Company’s ordinary activities. As such, the Company determined that the entire arrangement would be accounted for within the scope of ASC 808. In accordance with ASC 808, collaboration expenses are recognized within research and development expense and selling, general and administrative expense on the Company’s condensed consolidated statements of operations and comprehensive income (loss). Under certain collaborative arrangements, the Company is entitled to reimbursement of certain research and development expense. Activities under collaborative arrangements for which the Company is entitled to reimbursement are considered to be collaborative activities under the scope of ASC 808. For these units of account, the Company does not analogize to ASC 606 or recognize revenue. Rather, the Company analogizes to the guidance in ASC 730, which requires that reimbursements from counterparties be recognized as an offset to the related costs. In accordance with ASC 730, the Company records reimbursement payments received from collaborators as reductions to research and development expense. During the three and six months ended June 30, 2023, the Company recognized less than $0.1 million and $0.1 million, respectively, of collaboration expense under the AskBio Collaboration Agreement in which actual costs incurred by both parties approximate a 50% cost share. During the three and six months ended June 30, 2022, the Company recognized $0.2 million and $0.6 million, respectively, of collaboration expense under the AskBio Collaboration Agreement. Massachusetts Institute of Technology In November 2008, the Company entered into an Exclusive Patent License Agreement, or the MIT License, with the Massachusetts Institute of Technology, or MIT, under which the Company received an exclusive royalty-bearing license to utilize patents held by MIT in exchange for upfront consideration and annual license maintenance fees. Such fees are expensed as incurred and have not been material to any period presented. In June 2020, the Company entered into a Fifth Amendment, or the MIT Amendment, to the MIT License, which is effective as of May 15, 2020. Pursuant to the MIT Amendment, certain of the Company’s diligence obligations were extended. The extension included the obligation to commence a Phase 3 trial for a licensed product by the second quarter of 2021 or to file an IND (or equivalent) with the FDA or comparable European regulatory agency for a licensed product by the second quarter of 2023. Additionally, certain of the Company’s development and regulatory milestones and payments upon achievement of such milestones were adjusted. As of June 30, 2023, and in connection with the execution of the Spark License Agreement, the Company has made contractual payments pursuant to the MIT License totaling $2.2 million. In connection with the Spark Purchase Agreement and the calculated premium paid by Spark for the equity investments made as described in Note 12 to the consolidated financial statements within the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, the Company has made additional contractual payments pursuant to the MIT License which totaled $0.4 million as of June 30, 2023. The Company made no additional payments during the three and six months ended June 30, 2023. Shenyang Sunshine Pharmaceutical Co., Ltd In May 2014, the Company entered into a license agreement, or the 3SBio License, with Shenyang Sunshine Pharmaceutical Co., Ltd., or 3SBio. The Company has paid to 3SBio an aggregate of $7.0 million in upfront and milestone-based payments under the 3SBio License as of June 30, 2023. The Company is required to make future payments to 3SBio contingent upon the occurrence of events related to the achievement of clinical and regulatory approval milestones of up to an aggregate of $15.0 million for products containing the Company’s ImmTOR platform.

Stock Incentive Plans - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized and reserved for future issuance (in shares)	63,167,349		63,167,349
Share-based payment arrangement, expense	$ 3,783	$ 3,564	$ 6,059	$ 6,317
Employee stock option grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized and reserved for future issuance (in shares)	8,073,729		8,073,729
Weighted average grant date fair value of stock options (in dollars per share)	$ 1.02	$ 0.99	$ 0.9	$ 2.33
Unrecognized compensation expense related to unvested employee stock options	$ 13,200		$ 13,200
Weighted average period for recognition			2 years 8 months 12 days
Estimated forfeitures rate			10.00%
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)			1,054,600
Grants in period (in dollars per share)			$ 1.13
2016 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for grants (in shares)							1,210,256
Number of shares authorized, increase (in shares)			6,121,697
Common stock authorized and reserved for future issuance (in shares)	2,587,797		2,587,797
2016 Plan \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)			1,054,600
Grants in period (in dollars per share)			$ 1.13
Award vesting term			4 years
Employment Inducement Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for grants (in shares)	425,858		425,858
Common stock authorized and reserved for future issuance (in shares)					2,000,000	1,175,000
Employment Inducement Incentive Award Plan \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period for recognition			2 years 6 months
Unrecognized compensation expense	$ 3,100		$ 3,100
Accrued Ginkgo Bioworks Holdings, Inc. milestone award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based payment arrangement, expense	$ 1,500	$ 1,000	$ 1,500	$ 1,000

Fair Value Measurements - Assumptions Used to Record the Fair Value of the Warrants (Details) - Valuation technique, option pricing model	Jun. 30, 2023	Dec. 31, 2022
Risk-free interest rate \| 2019 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and rights outstanding, measurement input	0.054	0.0474
Risk-free interest rate \| 2022 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and rights outstanding, measurement input	0.0449	0.0422
Dividend yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and rights outstanding, measurement input	0
Dividend yield \| 2019 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and rights outstanding, measurement input	0	0
Dividend yield \| 2022 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and rights outstanding, measurement input	0	0
Expected life (in years) \| 2019 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and rights outstanding, term	1 year 5 months 23 days	1 year 11 months 23 days
Expected life (in years) \| 2022 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and rights outstanding, term	3 years 9 months 10 days	4 years 3 months 10 days
Expected volatility \| 2019 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and rights outstanding, measurement input	0.828	0.7992
Expected volatility \| 2022 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and rights outstanding, measurement input	0.9159	0.9805

Income Taxes - Narrative (Details) $ in Millions	12 Months Ended
Income Taxes - Narrative (Details) $ in Millions	Dec. 31, 2022 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Federal operating loss carryforwards	$ 62.4
Net operating losses percentage eligible to be carried forward	80.00%
Research tax credits amount eligible to be carried forward	75.00%
Domestic Tax Authority
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development credits	$ 2.3
Research and experimental expenditure amortization period	5 years
Foreign Tax Authority
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and experimental expenditure amortization period	15 years

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2023

Fair Value Disclosures [Abstract]

Schedule of Assets Measured at Fair Value on a Recurring Basis

The following tables present the Company’s assets and liabilities that are measured at fair value on a recurring basis as of June 30, 2023 and December 31, 2022 (in thousands):


	June 30, 2023
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds (included in cash equivalents)	$	73,384	$	73,384	$	—	$	—

Total assets	$	73,384	$	73,384	$	—	$	—

Liabilities:
Warrant liabilities	$	16,878	$	—	$	—	$	16,878

Total liabilities	$	16,878	$	—	$	—	$	16,878


	December 31, 2022
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds (included in cash equivalents)	$	53,552	$	53,552	$	—	$	—
Marketable securities:
U.S. government agency securities and treasuries		13,557		—		13,557		—
Corporate bonds		1,951		—		1,951		—
Commercial paper		12,656		—		12,656		—

Total assets	$	81,716	$	53,552	$	28,164	$	—

Liabilities:
Warrant liabilities	$	19,140	$	—	$	—	$	19,140

Total liabilities	$	19,140	$	—	$	—	$	19,140

Schedule of Cash and Cash Equivalents

The Company’s consolidated statements of cash flows include the following as of June 30, 2023 and 2022 (in thousands):


	June 30,
	2023		2022
Cash and cash equivalents	$	112,027	$	138,057
Short-term restricted cash		1,600		—
Long-term restricted cash		1,377		1,379

Total cash, cash equivalents, and restricted cash	$	115,004	$	139,436

Schedule of Restricted Cash and Cash Equivalents

The Company’s consolidated statements of cash flows include the following as of June 30, 2023 and 2022 (in thousands):


	June 30,
	2023		2022
Cash and cash equivalents	$	112,027	$	138,057
Short-term restricted cash		1,600		—
Long-term restricted cash		1,377		1,379

Total cash, cash equivalents, and restricted cash	$	115,004	$	139,436

Schedule of Fair Value Measurement Inputs and Valuation Techniques

A summary of the Black-Scholes pricing model assumptions used to record the fair value of the 2019 Warrants liability is as follows:


	June 30,			December 31,
	2023			2022
Risk-free interest rate		5.40	%		4.74	%
Dividend yield		—			—
Expected life (in years)		1.48			1.98
Expected volatility		82.80	%		79.92	%

A summary of the Black-Scholes pricing model assumptions used to record the fair value of the 2022 Warrants liability is as follows:


	June 30,			December 31,
	2023			2022
Risk-free interest rate		4.49	%		4.22	%
Dividend yield		—			—
Expected life (in years)		3.78			4.28
Expected volatility		91.59	%		98.05	%

Schedule Of Changes In The Warrant Liabilities


	Warrant liabilities
Fair value as of December 31, 2022	$	19,140
Change in fair value		(2,262	)

Fair value as of June 30, 2023	$	16,878

Fair Value Measurements - Narrative (Details)	6 Months Ended	12 Months Ended
Fair Value Measurements - Narrative (Details)	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, measurement with unobservable inputs reconciliation, recurring basis, asset, transfers, net	$ 0	$ 0
Fair value, measurement with unobservable inputs reconciliation, recurring basis, liability, transfers, net	$ 0	$ 0
Dividend yield \| Valuation technique, option pricing model
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrants and rights outstanding, measurement input	0

Debt

6 Months Ended

Jun. 30, 2023

Debt Disclosure [Abstract]

Debt

9. Debt

2020 Term Loan

On August 31, 2020, the Company entered into the Loan and Security Agreement with Oxford and Silicon Valley Bank. On March 10, 2023, Silicon Valley Bank was closed by the California Department of Financial Protection and Innovation, and the Federal Deposit Insurance Corporation, or the FDIC, was appointed as receiver. On March 13, 2023, the FDIC announced that all of Silicon Valley Bank’s deposits and substantially all of its assets had been transferred to a newly created, full-service, FDIC-operated bridge bank, Silicon Valley Bridge Bank, N.A., or SVBB. SVBB assumed all loans that were previously held by Silicon Valley Bank. On March 27, 2023, First-Citizens Bank & Trust Company assumed all of SVBB’s customer deposits and certain other liabilities and acquired substantially all of SVBB’s loans and certain other assets from the FDIC, including the Loan and Security Agreement.

On March 31, 2023, the Company entered into a Fourth Amendment to Loan and Security Agreement or the Fourth Amendment, with Oxford as Collateral Agent and a Lender and SVB. The Fourth Amendment relieved the Company of the requirement to maintain all Collateral Accounts (as such term is defined in the Loan and Security Agreement) with SVB and instead requires the Company to hold an amount equal to the lesser of (i) 100% of our consolidated cash and (ii) 150% of the then-outstanding Obligations (as such term is defined in the Loan and Security Agreement) in Collateral Accounts with SVB that are subject to a Control Agreement (as such term is defined in the Loan and Security Agreement) in favor of SVB.

As of June 30, 2023 and December 31, 2022, the outstanding principal balance under the 2020 Term Loan was $22.4 million and $25.0 million, respectively.

Total 2020 Term Loan and unamortized debt discount balances as of June 30, 2023 are as follows (in thousands):


Outstanding principal	$	22,414
Venture debt termination fee		2,250
Less: Debt discount		(642	)
Less: Current portion of loan payable		(10,235	)

Loan payable, net of current portion	$	13,787

Future minimum principal payments on the 2020 Term Loan as of June 30, 2023 are as follows (in thousands):


Year ended:
2023 (remainder)	$	5,173
2024		10,345
2025		6,896

Total minimum principal payments	$	22,414

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
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-URI https://asc.fasb.org//470/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-Paragraph 1I
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

+ Details

Fair Value Measurements - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Cash and cash equivalents	$ 112,027	$ 106,438	$ 138,057
Short-term restricted cash	1,600		0
Long-term restricted cash	1,377	1,311	1,379
Total cash, cash equivalents, and restricted cash	$ 115,004	$ 108,038	$ 139,436	$ 115,436

Related-party Transactions (Tables)

6 Months Ended

Jun. 30, 2023

Schedule of Related Party Transactions

The following table sets forth the number of shares of common stock and 2022 Warrants purchased in such offering by directors and executive officers, as of the time of such offering, and related parties thereto:


Name	Shares of common stock purchased		2022 Warrants purchased		Total aggregate purchase price
TAS Partners, LLC (affiliate of Timothy A. Springer, Ph.D.)		6,681,600		5,011,200	$	9,421,056

Marketable Securities and Investments

6 Months Ended

Jun. 30, 2023

Investments, Debt and Equity Securities [Abstract]

Marketable Securities and Investments

3. Marketable Securities and Investments

No marketable securities were held as of June 30, 2023. The following table summarizes the marketable securities held as of December 31, 2022 (in thousands):


	Amortized cost		Unrealized losses			Fair value
December 31, 2022
U.S. government agency securities and treasuries	$	13,566	$	(9	)	$	13,557
Corporate bonds	$	1,953	$	(2	)	$	1,951
Commercial paper		12,656		—			12,656

Total	$	28,175	$	(11	)	$	28,164

Investments

As of June 30, 2023 and December 31, 2022, the Company has a $2.0 million investment in Cyrus Biotechnology, Inc., or Cyrus, pursuant to an investment agreement entered into in connection with the Collaboration and License Agreement with Cyrus. The Company’s maximum exposure to loss related to this variable interest entity is limited to the carrying value of the investment.

Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	15. Income Taxes The Company provides for income taxes under ASC 740. Under ASC 740, the Company provides deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the Company’s financial statement carrying amounts and the tax bases of assets and liabilities using enacted tax rates expected to be in effect in the years in which the differences are expected to reverse. The Company has provided a full valuation allowance against its net deferred tax assets, as the Company believes that it is more likely than not that the deferred tax assets will not be realized. Effective for tax years beginning on or after January 1, 2022, research and experimental expenditures under IRC Section 174 must be capitalized over five years when performed in the U.S. and 15 years for research and experimental expenditures performed outside of the U.S. As of June 30, 2023, the Company has performed a high-level analysis of the impact of this legislation enactment and determined the projected taxable loss position for 2023 does not result in income tax due. As of December 31, 2022, the Company has $62.4 million of federal net operating losses available, subject to an 80% limitation. The Company also has $2.3 million of federal tax credits, subject to a 75% limitation. The Company maintains its full valuation allowance. Utilization of the net operating loss and research and development credit carryforwards may be subject to a substantial annual limitation under Section 382 and 383 of the Internal Revenue Code due to ownership change limitations that have occurred previously, or that could occur in the future. These ownership changes may limit the amount of net operating loss and research and development credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. As of December 31, 2021, the Company completed both a Section 382 and research and development tax credit study through December 31, 2020. The Company generated research credits for the years ended December 31, 2022 and 2021, but has not conducted a formal study to document its qualified activities. The statute of limitations for assessment by the Internal Revenue Service and Massachusetts tax authorities is open for tax years since inception as the Company claimed research tax credits on its 2020 tax return which remains open for examination for the 2020 year as well as for any year in which a credit has been claimed. The Company files income tax returns in the United States and Massachusetts. There are currently no federal, state or foreign audits in progress.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Revenue Arrangements (Tables)

6 Months Ended

Jun. 30, 2023

Revenue from Contract with Customer [Abstract]

Schedule of Changes in Contract Liabilities

The following table presents changes in the Company’s contract liabilities during the six months ended June 30, 2023 (in thousands):


	Balance at							Balance at
	beginning of period		Additions		Deductions			end of period
Six Months Ended June 30, 2023
Contract liabilities:
Deferred revenue	$	593	$	10,500	$	(1,996	)	$	9,097

Total contract liabilities	$	593	$	10,500	$	(1,996	)	$	9,097

Stock Incentive Plans - Schedule of Options Activity (Details) - 2008 Plan, 2016 Plan, and 2018 Inducement Incentive Award Plan - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Employees
Number of Options
Beginning balance (in shares)	15,578,412
Granted (in shares)	5,477,200
Forfeited (in shares)	(1,207,712)
Ending balance (in shares)	19,847,900	15,578,412
Vested (in shares)	8,956,975
Vested and expected to vest (in shares)	18,564,837
Weighted-average exercise price
Beginning balance (in dollars per share)	$ 3.44
Granted (in dollars per share)	1.15
Forfeited (in dollars per share)	2.84
Ending balance (in dollars per share)	2.85	$ 3.44
Vested (in dollars per share)	3.92
Vested and expected to vest (in dollars per share)	$ 2.93
Weighted-average remaining contractual term
Outstanding, term	7 years 11 months 4 days	7 years 6 months 25 days
Vested, term	6 years 8 months 4 days
Vested and expected to vest, term	7 years 10 months 2 days
Aggregate intrinsic value
Outstanding	$ 1	$ 4
Vested	1
Vested and expected to vest	$ 1
Non-employee consultants
Number of Options
Beginning balance (in shares)	266,239
Ending balance (in shares)	266,239	266,239
Vested (in shares)	266,239
Vested and expected to vest (in shares)	266,239
Weighted-average exercise price
Beginning balance (in dollars per share)	$ 8.05
Ending balance (in dollars per share)	8.05	$ 8.05
Vested (in dollars per share)	8.05
Vested and expected to vest (in dollars per share)	$ 8.05
Weighted-average remaining contractual term
Outstanding, term	4 years 6 months 29 days	5 years 29 days
Vested, term	4 years 6 months 29 days
Vested and expected to vest, term	4 years 6 months 29 days
Aggregate intrinsic value
Outstanding	$ 0	$ 0
Vested	0
Vested and expected to vest	$ 0

Related-party Transactions

6 Months Ended

Jun. 30, 2023

Related-party Transactions

13. Related-Party Transactions

April 2022 Offering

During the three and six months ended June 30, 2022, the Company completed the underwritten offering as described in Note 10 to the consolidated financial statements within the Company’s Annual Report on Form

10-K

for the year ended December 31, 2022. The following table sets forth the number of shares of common stock and 2022 Warrants purchased in such offering by directors and executive officers, as of the time of such offering, and related parties thereto:


Name	Shares of common stock purchased		2022 Warrants purchased		Total aggregate purchase price
TAS Partners, LLC (affiliate of Timothy A. Springer, Ph.D.)		6,681,600		5,011,200	$	9,421,056

During the three and six months ended June 30, 2023, there were no related party transactions.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

+ Details

Marketable Securities and Investments (Tables)

6 Months Ended

Jun. 30, 2023

Investments, Debt and Equity Securities [Abstract]

Schedule of Available-for-Sale Marketable Securities

The following table summarizes the marketable securities held as of December 31, 2022 (in thousands):


	Amortized cost		Unrealized losses			Fair value
December 31, 2022
U.S. government agency securities and treasuries	$	13,566	$	(9	)	$	13,557
Corporate bonds	$	1,953	$	(2	)	$	1,951
Commercial paper		12,656		—			12,656

Total	$	28,175	$	(11	)	$	28,164

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
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-Section 50
-Paragraph 9
-Subparagraph (a)
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Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

Consolidated Statements of Changes in Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated deficit	Accumulated other comprehensive loss
Beginning balance (in shares) at Dec. 31, 2021		123,622,965
Beginning balance at Dec. 31, 2021	$ 22,521	$ 12	$ 457,391	$ (430,316)	$ (4,566)
Increase (Decrease) in Stockholders' Equity
Issuance of common stock under Employee Stock Purchase Plan (in shares)		81,057
Issuance of common stock under Employee Stock Purchase Plan	127		127
Issuance of common stock upon exercise of options (in shares)		11,262
Issuance of common stock upon exercise of options	21		21
Issuance of vested restricted stock units (in shares)		89,142
Issuance of vested restricted stock units	0
Issuance of common stock through at-the-market offering, net (in shares)		576,418
Issuance of common stock through at-the-market offering, net	1,675		1,675
Other financing fees	(79)		(79)
Stock-based compensation expense	2,753		2,753
Currency translation adjustment	(32)				(32)
Net (loss) income	28,778			28,778
Ending balance (in shares) at Mar. 31, 2022		124,380,844
Ending balance at Mar. 31, 2022	55,764	$ 12	461,888	(401,538)	(4,598)
Beginning balance (in shares) at Dec. 31, 2021		123,622,965
Beginning balance at Dec. 31, 2021	22,521	$ 12	457,391	(430,316)	(4,566)
Increase (Decrease) in Stockholders' Equity
Currency translation adjustment	86
Unrealized gain on marketable securities	0
Net (loss) income	37,379
Ending balance (in shares) at Jun. 30, 2022		152,713,211
Ending balance at Jun. 30, 2022	89,606	$ 15	487,008	(392,937)	(4,480)
Beginning balance (in shares) at Mar. 31, 2022		124,380,844
Beginning balance at Mar. 31, 2022	55,764	$ 12	461,888	(401,538)	(4,598)
Increase (Decrease) in Stockholders' Equity
Issuance of vested restricted stock units (in shares)		10,938
Issuance of common stock and common warrants (in shares)		27,428,572
Issuance of common stock and common warrants	21,480	$ 3	21,477
Issuance of common stock, license agreement(in shares)		892,857
Issuance of common stock, license agreement	1,000		1,000
Other financing fees	79		79
Stock-based compensation expense	2,564		2,564
Currency translation adjustment	118				118
Unrealized gain on marketable securities	0
Net (loss) income	8,601			8,601
Ending balance (in shares) at Jun. 30, 2022		152,713,211
Ending balance at Jun. 30, 2022	$ 89,606	$ 15	487,008	(392,937)	(4,480)
Beginning balance (in shares) at Dec. 31, 2022	153,042,435	153,042,435
Beginning balance at Dec. 31, 2022	$ 93,828	$ 15	493,308	(394,937)	(4,558)
Increase (Decrease) in Stockholders' Equity
Issuance of common stock under Employee Stock Purchase Plan (in shares)		108,068
Issuance of common stock under Employee Stock Purchase Plan	149		149
Issuance of vested restricted stock units (in shares)		276,480
Issuance of vested restricted stock units	0
Stock-based compensation expense	2,276		2,276
Currency translation adjustment	(22)				(22)
Unrealized gain on marketable securities	11				11
Net (loss) income	(21,663)			(21,663)
Ending balance (in shares) at Mar. 31, 2023		153,426,983
Ending balance at Mar. 31, 2023	$ 74,579	$ 15	495,733	(416,600)	(4,569)
Beginning balance (in shares) at Dec. 31, 2022	153,042,435	153,042,435
Beginning balance at Dec. 31, 2022	$ 93,828	$ 15	493,308	(394,937)	(4,558)
Increase (Decrease) in Stockholders' Equity
Currency translation adjustment	(49)
Unrealized gain on marketable securities	11
Net (loss) income	$ (33,050)
Ending balance (in shares) at Jun. 30, 2023	153,427,571	153,427,571
Ending balance at Jun. 30, 2023	$ 65,448	$ 15	498,016	(427,987)	(4,596)
Beginning balance (in shares) at Mar. 31, 2023		153,426,983
Beginning balance at Mar. 31, 2023	74,579	$ 15	495,733	(416,600)	(4,569)
Increase (Decrease) in Stockholders' Equity
Issuance of vested restricted stock units (in shares)		588
Issuance of vested restricted stock units	0
Stock-based compensation expense	2,283		2,283
Currency translation adjustment	(27)				(27)
Unrealized gain on marketable securities	0
Net (loss) income	$ (11,387)			(11,387)
Ending balance (in shares) at Jun. 30, 2023	153,427,571	153,427,571
Ending balance at Jun. 30, 2023	$ 65,448	$ 15	$ 498,016	$ (427,987)	$ (4,596)

Revenue Arrangements - Schedule of Changes in Contract Liabilities (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($)
Contract liabilities:
Deferred revenue, beginning of period	$ 593
Deferred revenue, additions	10,500
Deferred revenue, deductions	(1,996)
Deferred revenue, end of period	9,097
Contract liabilities, beginning of period	593
Contract liabilities, additions	10,500
Contract liabilities, deductions	(1,996)
Contract liabilities, end of period	$ 9,097

Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 30, 2023
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments . Subsequently, in November 2018, the FASB issued ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments-Credit Losses . ASU 2016-13 requires entities to measure all expected credit losses for most financial assets held at the reporting date based on an expected loss model which includes historical experience, current conditions, and reasonable and supportable forecasts. ASU 2016-13 also requires enhanced disclosures to help financial statement users better understand significant estimates and judgments used in estimating credit losses. This ASU is effective for smaller reporting companies for fiscal years beginning after December 15, 2022, with early adoption permitted. The Company adopted the new standard effective January 1, 2023, using a modified retrospective transition method, and there was no impact on its consolidated financial statements or results of operations upon adoption.

Collaboration and License Agreements - Cyrus Biotechnology, Inc. (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 07, 2021	Jun. 30, 2023	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Equity securities without readily determinable fair value, amount		$ 2,000	$ 2,000
Cyrus Biotechnology, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payment	$ 1,500,000
Equity securities, stock purchase agreement, shares purchased (in shares)	2,326,934
Equity securities without readily determinable fair value, amount	$ 2,000	$ 2,000	$ 2,000
Cyrus Biotechnology, Inc. \| Series B Preferred Stock Purchase Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Equity securities, stock purchase agreement, par value per share (in dollars per share)	$ 0.0001
Equity securities, stock purchase agreement, purchase price per share (in dollars per share)	$ 0.8595

Cover Page - shares	6 Months Ended
Cover Page - shares	Jun. 30, 2023	Aug. 04, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2023
Document Transition Report	false
Entity File Number	001-37798
Entity Registrant Name	Selecta Biosciences, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-1622110
Entity Address, Address Line One	65 Grove Street
Entity Address, City or Town	Watertown
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02472
City Area Code	617
Local Phone Number	923-1400
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	SELB
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Smaller Reporting Company	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		153,427,571
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001453687
Current Fiscal Year End Date	--12-31

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	350,000,000	350,000,000
Common stock, shares issued (in shares)	153,427,571	153,042,435
Common stock, shares outstanding (in shares)	153,427,571	153,042,435

Equity (Tables)

6 Months Ended

Jun. 30, 2023

Equity [Abstract]

Schedule of Stockholders' Equity Note, Warrants or Rights

During the three and six months ended June 30, 2023, there were no warrants issued, exercised, or canceled. See Note 10 to the consolidated financial statements in our Annual Report on Form

10-K

for the year ended December 31, 2022 for further discussion of the terms related to the Company’s warrants.


	Number of Warrants
	Equity classified		Liability classified		Total		Weighted average exercise price
Outstanding at June 30, 2023		2,236,326		28,991,953		31,228,279	$	1.53

Schedule of Authorized Shares of Common Stock for Future Issuance

The Company has authorized shares of common stock for future issuance as of June 30, 2023 as follows:


Exercise of warrants			31,228,279
Shares available for future stock incentive awards			8,073,729
RSUs reserved for issuance			125
Unvested restricted stock units			2,411,792
Outstanding common stock options			20,114,139
Accrued Ginkgo Bioworks Holdings, Inc. milestone award			1,339,285

Total			63,167,349

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

Collaboration and License Agreements - Shenyang Sunshine Pharmaceutical Co., Ltd (Narrative) (Details) - 3SBio License $ in Millions	6 Months Ended
	Jun. 30, 2023 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Aggregate amount of upfront and milestone-based payments	$ 7.0
Aggregate amount for future payments upon achievement of clinical and regulatory approval milestones for products containing ImmTOR platform	$ 15.0

Property and Equipment - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 0.2	$ 0.2	$ 0.4	$ 0.3

Leases - Lease Term and Discount Rate (Details)	Jun. 30, 2023	Jun. 30, 2022
Leases [Abstract]
Operating lease, weighted average remaining lease term	4 years 10 months 24 days	5 years 10 months 24 days
Operating lease, weighted average discount rate, percent	9.70%	8.90%

Stock Incentive Plans

6 Months Ended

Jun. 30, 2023

Share-Based Payment Arrangement [Abstract]

Stock Incentive Plans

11. Stock Incentive Plans

The Company maintains the 2008 Stock Incentive Plan, or the 2008 Plan, for employees, consultants, advisors, and directors. The 2008 Plan provided for the granting of incentive and

non-qualified

stock option and restricted stock awards as determined by the Board.

In June 2016, the Company’s stockholders approved the 2016 Incentive Award Plan, or the 2016 Plan, which authorized 1,210,256 shares of common stock for future issuance under the 2016 Plan and the Company ceased granting awards under the 2008 Plan. Upon the effective date of the 2016 Plan, awards issued under the 2008 Plan remain subject to the terms of the 2008 Plan. Awards granted under the 2008 Plan that expire, lapse or terminate become available under the 2016 Plan as shares available for future grants.

Additionally, pursuant to the terms of the 2016 Plan, the Board is authorized to grant awards with respect to common stock, and may delegate to a committee of one or more members of the Board or executive officers of the Company the authority to grant options and restricted stock units. On December 9, 2020, the Board established a Stock Option Committee authorized to grant awards to certain employees and consultants subject to conditions and limitations within the 2016 Plan. In January 2023, the number of shares of common stock that may be issued under the 2016 Plan was increased by 6,121,697 shares. As of June 30, 2023, 2,587,797 shares remain available for future issuance under the 2016 Plan.

In September 2018, the Company’s 2018 Employment Inducement Incentive Award Plan, or the 2018 Inducement Incentive Award Plan was adopted by the Board without stockholder approval pursuant to Rule 5635(c)(4) of the Nasdaq Stock Market LLC listing rules, which authorized 1,175,000 shares of its common stock for issuance. In March 2019, the Board approved the amendment and restatement of the 2018 Inducement Incentive Award Plan to reserve an additional 2,000,000 shares of the Company’s common stock for issuance thereunder. As of June 30, 2023, there are 425,858 shares available for future grant under the 2018 Inducement Incentive Award Plan.

Stock-Based Compensation Expense


	Three Months Ended June 30,				Six Months Ended June 30,
	2023		2022		2023		2022
Research and development	$	2,677	$	2,021	$	3,869	$	3,039
General and administrative		1,106		1,543		2,190		3,278

Total stock-based compensation expense	$	3,783	$	3,564	$	6,059	$	6,317

Stock Options


	Three Months Ended June 30,						Six Months Ended June 30,
	2023			2022			2023			2022
Risk-free interest rate		3.38	%		3.26	%		3.95	%		1.63	%
Dividend yield		—			—			—			—
Expected term		6.00			6.05			5.94			6.03
Expected volatility		94.40	%		92.03	%		94.64	%		91.85	%
Weighted-average fair value of common stock	$	1.31		$	1.29		$	1.15		$	3.10

The expected term of the Company’s stock options granted to employees has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. Under the simplified method, the expected term is presumed to be the midpoint between the vesting date and the end of the contractual term. The Company utilizes this method due to lack of historical exercise data and the plain nature of its stock-based awards.

The weighted average grant date fair value of stock options granted to employees was $1.02 and $0.99 during the three months ended June 30, 2023 and 2022, respectively, and $0.90 and $2.33 during the six months ended June 30, 2023 and 2022, respectively.

As of June 30, 2023, total unrecognized compensation expense related to unvested employee stock options was $13.2 million, which is expected to be recognized over a weighted average period of 2.7 years.

The following table summarizes the stock option activity under the 2008 Plan, the 2016 Plan, and the 2018 Inducement Incentive Award Plan:


	Number of options			Weighted-average exercise price ($)		Weighted-average remaining contractual term (in years)		Aggregate intrinsic value (in thousands)
Employees
Outstanding at December 31, 2022		15,578,412		$	3.44		7.57	$	4
Granted		5,477,200		$	1.15
Forfeited		(1,207,712	)	$	2.84

Outstanding at June 30, 2023		19,847,900		$	2.85		7.93	$	1

Vested at June 30, 2023		8,956,975		$	3.92		6.68	$	1
Vested and expected to vest at June 30, 2023		18,564,837		$	2.93		7.84	$	1
Non-employee consultants
Outstanding at December 31, 2022		266,239		$	8.05		5.08	$	—

Outstanding at June 30, 2023		266,239		$	8.05		4.58	$	—

Vested at June 30, 2023		266,239		$	8.05		4.58	$	—
Vested and expected to vest at June 30, 2023		266,239		$	8.05		4.58	$	—

Restricted Stock Units

During the six months ended June 30, 2023, the Company granted 1,054,600 restricted stock awards with a weighted average fair value of $1.13 per share based on the closing price of the Company’s common stock on the date of grant to employees under the 2016 Plan, which will vest over a four-year term. Forfeitures are estimated at the time of grant and are adjusted, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company has estimated a forfeiture rate of 10% for restricted stock awards to employees based on historical experience.

Unrecognized compensation expense for all restricted stock units was $3.1 million as of June 30, 2023, which is expected to be recognized over a weighted average period of 2.5 years.

The following table summarizes the Company’s restricted stock units under the 2016 Plan and 2018 Inducement Incentive Award Plan:


	Number of shares			Weighted average grant date fair value ($)
Unvested at December 31, 2022		1,705,558		$	2.62
Granted		1,054,600			1.13
Vested		(277,193	)		3.22
Forfeited		(71,173	)		1.99

Unvested at June 30, 2023		2,411,792		$	1.92

Employee Stock Purchase Plan

In June 2016, the Company approved the 2016 Employee Stock Purchase Plan, or the ESPP, which authorized 173,076 shares of common stock for future issuance under the ESPP to participating employees. In January 2023, the number of shares of common stock authorized for issuance under the ESPP was increased by 1,530,424 shares. During the six months ended June 30, 2023, the Company issued 108,068 shares of common stock under the ESPP. As of June 30, 2023, 5,060,074 shares remain available for future issuance under the ESPP.

For each of the three and six months ended June 30, 2023 and 2022, the Company recognized less than $0.1 million of stock-based compensation expense under the ESPP.