0001558370-24-014632 | 10-Q | XBRL Viewer

Stock-Based Compensation

9 Months Ended

Sep. 30, 2024

9. Stock-Based Compensation

Stock incentive plans

Our 2017 Stock Incentive Plan, or the 2017 Plan, provided for us to grant incentive stock options or nonstatutory stock options, restricted stock, restricted stock units and other equity awards to employees, non-employees, and directors.

In May 2020, our board of directors adopted, and in June 2020, our stockholders approved, the 2020 Stock Incentive Plan, or the 2020 Plan, and together with the 2017 Plan, the Plans, which became effective on June 11, 2020. The 2020 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards. The number of shares of common stock reserved for issuance under the 2020 Plan is the sum of (1) 2,547,698 shares; plus (2) the number of shares (up to a maximum of 7,173,014 shares) as was equal to the sum of (x) the number of shares of common stock reserved for issuance under the 2017 Plan that remained available for grant under the 2017 Plan on June 11, 2020 and (y) the number of shares of common stock subject to outstanding awards granted under the 2017 Plan that expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased by us at their original issuance price pursuant to a contractual repurchase right; plus (3) an annual increase, to be added on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2021 and continuing until, and including, the fiscal year ending December 31, 2030, equal to the lesser of (i) 4% of the number of shares of common stock outstanding on such date, and (ii) an amount determined by the board of directors. In January 2024, the number of shares of common stock authorized for issuance under the 2020 Plan was increased from 16,813,962 shares to 19,462,688 shares. Upon the effectiveness of the 2020 Plan, we ceased granting additional awards under the 2017 Plan.

The Plans are administered by the board of directors or, at the discretion of the board of directors, by a committee of the board of directors. The exercise prices, vesting and other restrictions on any award under the Plans are determined at the discretion of the board of directors, or its committee if so delegated. Stock options granted under the Plans with service-

based vesting conditions generally vest over four years and expire after ten years. The exercise price for stock options granted is not less than the fair value of common stock as of the date of grant. Prior to our initial public offering, or IPO, in June 2020, the fair value of our common stock was determined by the board of directors. Subsequent to our IPO, fair value of common stock is based on quoted market prices.

As of September 30, 2024, 790,738 shares remained available for future issuance under the 2020 Plan. Shares subject to outstanding awards granted under the Plans that expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased by us at their original issuance price pursuant to a contractual repurchase right will be available for future awards under the 2020 Plan.

Grant of stock options

During the nine months ended September 30, 2024, we granted time-based options to certain employees for the purchase of an aggregate of 3,693,074 shares of common stock with a weighted average grant date fair value of $1.87 per share that vest over a weighted average period of approximately four years.

Employee stock purchase plan

In May 2020, our board of directors adopted, and in June 2020, our stockholders approved, the 2020 Employee Stock Purchase Plan, or the 2020 ESPP, which became effective June 11, 2020. The 2020 ESPP is administered by our board of directors or by a committee appointed by the board of directors. The number of shares of common stock authorized for issuance under the 2020 ESPP automatically increases on the first day of each fiscal year, beginning with the fiscal year that commenced on January 1, 2021 and continuing for each fiscal year until, and including the fiscal year commencing on, January 1, 2030, in an amount equal to the lowest of (1) 1,302,157 shares of common stock, (2) 1% of the number of shares of common stock outstanding on such date, and (3) an amount determined by the board of directors. In January 2024, the number of shares of common stock authorized for issuance under the 2020 ESPP was increased from 2,115,792 shares to 2,777,974 shares. As of September 30, 2024, 2,204,771 shares remained available for issuance under the 2020 ESPP.

Stock-based compensation

Stock-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
(in thousands)	2024		2023		2024		2023
Research and development expenses	$	1,520	$	2,874	$	4,452	$	8,608
General and administrative expenses		2,232		3,130		6,997		9,685
Total	$	3,752	$	6,004	$	11,449	$	18,293

As of September 30, 2024, total unrecognized compensation cost related to unvested time-based stock options and restricted stock units was $14.7 million, with $13.2 million expected to be recognized over a weighted average period of 2.1 years and $1.5 million expected to be recognized over a weighted average period of 2.2 years, respectively.

Accrued Expenses (Tables)

9 Months Ended

Sep. 30, 2024

Accrued Expenses

Summary of accrued expenses


	September 30,		December 31,
(in thousands)	2024		2023
Accrued employee compensation and benefits	$	4,505	$	13,208
Accrued external research and development expenses		600		1,169
Accrued professional fees		654		908
Property and equipment		33		838
Other		405		406
Total	$	6,197	$	16,529

Summary of accrued restructuring costs recorded and included in accrued expenses and other current liabilities


(in thousands)		Severance and Benefits Costs
Balance at December 31, 2023	$	5,291
Cash payments		(5,055)
Restructuring expenses		380
Adjustments		(402)
Balance at September 30, 2024	$	214

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities:
Net loss	$ (110,286)	$ (91,426)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss on lease termination	59,085	0
Stock-based compensation expense	11,449	18,293
Depreciation and amortization expense	3,755	3,938
Amortization (accretion) of premium (discount) on marketable securities, net	(6,312)	(6,699)
Other	84	24
Changes in operating assets and liabilities:
Collaboration receivable	(2,212)	0
Tenant receivable	0	(265)
Prepaid expenses and other current assets	694	1,408
Operating lease right-of-use assets	2,799	4,794
Other noncurrent assets	(2,840)	931
Accounts payable	(79)	1,386
Accrued expenses and other current liabilities	(9,526)	(2,633)
Deferred revenue	(12,154)	44,474
Operating lease liability	(7,236)	(1,992)
Net cash used in operating activities	(72,779)	(27,767)
Cash flows from investing activities:
Purchases of property and equipment	(2,023)	(2,817)
Proceeds from sale of property and equipment	149	0
Purchases of marketable securities	(115,881)	(295,967)
Maturities of marketable securities	142,000	291,000
Net cash provided by (used in) investing activities	24,245	(7,784)
Cash flows from financing activities:
Payment of share issuance costs	0	(179)
Proceeds from exercise of stock options and ESPP, net	278	367
Tax withholding payments related to net share settlements of restricted stock units	(172)	(448)
Net cash provided by financing activities	106	35,740
Net (decrease) increase in cash, cash equivalents and restricted cash	(48,428)	189
Cash, cash equivalents and restricted cash at beginning of period	72,237	98,863
Cash, cash equivalents and restricted cash at end of period	23,809	99,052
Supplemental disclosure of noncash investing and financing information:
Purchases of property and equipment included in accounts payable and accrued expenses	47	1,330
Unrealized gains on marketable securities	45	79
ModernaTX, Inc
Cash flows from financing activities:
Proceeds from issuance/sale of common stock	$ 0	$ 36,000

Marketable Securities and Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2024

Marketable Securities and Fair Value Measurements

Summary of marketable securities by security type

As of September 30, 2024

Gross

Amortized

Unrealized

Fair

(in thousands)

Cost

Gains

Losses

Value

U.S. treasury securities

177,836

319

—

178,155

As of December 31, 2023

Gross

Amortized

Unrealized

Fair

(in thousands)

Cost

Gains

Losses

Value

U.S. treasury securities

197,644

274

—

197,918

Schedule of marketable securities by contractual maturity


	As of September 30, 2024
	Amortized		Fair
(in thousands)	Cost		Value
Less than one year	$	162,932	$	163,113
Greater than one year but less than two years		14,904		15,042
Total	$	177,836	$	178,155

Summary of assets measured at fair value on a recurring basis

The following tables present our assets that are measured at fair value on a recurring basis and indicate the level within the fair value hierarchy of the valuation techniques that we utilized to determine such fair value:


	Fair Value Measurements at September 30, 2024 Using:
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	5,460	$	—	$	—	$	5,460
Marketable securities:
U.S. treasury securities		—		178,155		—		178,155
Totals	$	5,460	$	178,155	$	—	$	183,615


	Fair Value Measurements at December 31, 2023 Using:
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	38,210	$	—	$	—	$	38,210
Marketable securities:
U.S. treasury securities		—		197,918		—		197,918
Totals	$	38,210	$	197,918	$	—	$	236,128

Collaboration and License Agreement - Schedule of Allocated Transaction Price and Revenue Activity (Detail) - ModernaTX, Inc - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2024	Mar. 31, 2023
Collaboration and License Agreement
Collaboration and License Agreement
Standalone Selling Price			$ 96,050
Transaction Price Allocated	$ 73,931	$ 73,931	77,893
Revenue Recognized	7,554	15,704
Deferred Revenue	42,707	42,707
ctLNP technology and research license
Collaboration and License Agreement
Standalone Selling Price			52,500
Transaction Price Allocated	40,409	40,409	42,576
Revenue Recognized	7,554	15,704
Deferred Revenue	14,549	14,549
First liver program commercialization option license
Collaboration and License Agreement
Standalone Selling Price			7,000
Transaction Price Allocated	5,388	5,388	5,677
Revenue Recognized	0	0
Deferred Revenue	4,526	4,526
Second liver program commercialization option license
Collaboration and License Agreement
Standalone Selling Price			7,000
Transaction Price Allocated	5,388	5,388	5,677
Revenue Recognized	0	0
Deferred Revenue	4,526	4,526
First non-liver program commercialization option license
Collaboration and License Agreement
Standalone Selling Price			11,700
Transaction Price Allocated	9,006	9,006	9,488
Revenue Recognized	0	0
Deferred Revenue	7,565	7,565
Second non-liver program commercialization option license
Collaboration and License Agreement
Standalone Selling Price			11,700
Transaction Price Allocated	9,006	9,006	9,488
Revenue Recognized	0	0
Deferred Revenue	7,565	7,565
Third liver or non-liver program commercialization option license
Collaboration and License Agreement
Standalone Selling Price			6,150
Transaction Price Allocated	4,734	4,734	$ 4,987
Revenue Recognized	0	0
Deferred Revenue	$ 3,976	$ 3,976

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (15,313)	$ (28,266)	$ (110,286)	$ (91,426)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Leases - Future Lease Payments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Total undiscounted payments due under operating leases			$ 104,300
Current operating lease liability	$ 10,797	$ 8,120
Non-current operating lease liability	82,982	$ 89,774
Total	62,000
Active Lease
Lessee, Lease, Description [Line Items]
2024 (remaining 3 months)	1,935
2025	7,838
2026	8,059
2027	8,275
2028	8,535
Thereafter	2,834
Total undiscounted payments due under operating leases	37,476
Less imputed interest	(5,673)
Current operating lease liability	5,707
Non-current operating lease liability	26,096
Total	$ 31,803

Equity

9 Months Ended

Sep. 30, 2024

Equity

Equity

8. Equity

As of September 30, 2024, our amended and restated certificate of incorporation authorizes us to issue 150,000,000 shares of common stock, par value $0.0001 per share, and 5,000,000 shares of preferred stock, par value $0.0001 per share, all of which preferred stock is undesignated.

In August 2024, we entered into an “at-the-market” sales agreement pursuant to which we may, from time to time, sell shares of our common stock having an aggregate offering price of up to $237.0 million. Upon our entry into this sales agreement, we terminated our prior at-the-market program pursuant to a prior sales agreement that we entered into in August 2021. At the time of termination, approximately $237.3 million out of an aggregate of $250.0 million remained unsold under the prior sales agreement. As of November 6, 2024, the issuance date of these condensed consolidated financial statements, we have not issued and sold any shares of our common stock pursuant to the August 2024 sales agreement.

Each share of common stock entitles the holder to one vote on all matters submitted to a vote of our stockholders. Holders of common stock are not entitled to receive dividends, unless declared by the board of directors.

- Definition

The entire disclosure for equity.

+ References

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+ Details

Marketable Securities and Fair Value Measurements - Summary of marketable securities (Detail) - Fair Value, Recurring - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Marketable Securities [Line Items]
Amortized Cost	$ 177,836
Fair Value	178,155
U.S. treasury securities
Marketable Securities [Line Items]
Amortized Cost	177,836	$ 197,644
Gross Unrealized Gains	319	274
Gross Unrealized Losses	0	0
Fair Value	$ 178,155	$ 197,918

- Definition

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

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+ Details

Net Loss per Share (Tables)

9 Months Ended

Sep. 30, 2024

Net Loss per Share

Summary of potential dilutive securities, presented based on amounts outstanding


	September 30,
	2024	2023
Unvested restricted stock units	374,076	1,179,349
Stock options to purchase common stock	13,215,012	9,676,685
Total	13,589,088	10,856,034

Marketable Securities and Fair Value Measurements

9 Months Ended

Sep. 30, 2024

Marketable Securities and Fair Value Measurements

Marketable Securities and Fair Value Measurements

3. Marketable Securities and Fair Value Measurements

The following tables present our marketable securities by security type:

As of September 30, 2024

Gross

Amortized

Unrealized

Fair

(in thousands)

Cost

Gains

Losses

Value

U.S. treasury securities

177,836

319

—

178,155

As of December 31, 2023

Gross

Amortized

Unrealized

Fair

(in thousands)

Cost

Gains

Losses

Value

U.S. treasury securities

197,644

274

—

197,918

The following table summarizes our marketable securities by contractual maturity as of September 30, 2024:


	As of September 30, 2024
	Amortized		Fair
(in thousands)	Cost		Value
Less than one year	$	162,932	$	163,113
Greater than one year but less than two years		14,904		15,042
Total	$	177,836	$	178,155

Our marketable securities as of December 31, 2023 consisted of investments that mature within one year of their purchase date.

We assess our available-for-sale securities under the available-for-sale security impairment model in ASC 326, “Financial Instruments - Credit Losses”, or ASC 326, as of each reporting date in order to determine if a portion of any decline in fair value below carrying value recognized on our available-for-sale securities is the result of a credit loss. We also evaluate our available-for-sale securities for impairment using a variety of factors including our intent to sell the underlying securities prior to maturity and whether it is more likely than not that we would be required to sell the securities before the recovery of their amortized basis. During the nine months ended September 30, 2024 and 2023, we did not recognize any impairment or realized gains or losses on sales of available-for-sale securities, and we did not record an allowance for, or recognize, any expected credit losses.


	Fair Value Measurements at September 30, 2024 Using:
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	5,460	$	—	$	—	$	5,460
Marketable securities:
U.S. treasury securities		—		178,155		—		178,155
Totals	$	5,460	$	178,155	$	—	$	183,615


	Fair Value Measurements at December 31, 2023 Using:
(in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	38,210	$	—	$	—	$	38,210
Marketable securities:
U.S. treasury securities		—		197,918		—		197,918
Totals	$	38,210	$	197,918	$	—	$	236,128

- 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.

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+ Details

Stock-Based Compensation (Detail) - $ / shares			9 Months Ended
Stock-Based Compensation (Detail) - $ / shares	Nov. 06, 2024	Jun. 11, 2020	Sep. 30, 2024	Jan. 31, 2024	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued during the period	0
Service Based Options \| Certain Employees Directors And Consultants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued during the period			3,693,074
Weighted average grant date fair value			$ 1.87
Share based compensation by share based payment weighted average period			4 years
2020 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock reserved for future issuance		2,547,698	790,738
Share based compensation by share based payment arrangement number of shares authorized for issuance				19,462,688	16,813,962
Stock based compensation vesting period service based			4 years
Stock based compensation period of expiry			10 years
2020 Stock Incentive Plan \| Maximum \| Additional From 2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock reserved for future issuance		7,173,014
2020 Stock Incentive Plan \| Maximum \| Annual Increase 2021 To 2030
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of common stock shares additionally reserved for issuance		4.00%
Employee Stock Purchase Plan 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation by share based payment arrangement number of shares authorized for issuance				2,777,974	2,115,792
Shares issued			2,204,771
Employee Stock Purchase Plan 2020 \| Maximum \| Annual Increase 2021 To 2030
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of common stock shares additionally reserved for issuance		1.00%
Number of share instruments newly issued under a share-based compensation plan		1,302,157

Property and equipment, net - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 38,279	$ 45,494
Less: Accumulated depreciation and amortization	(22,269)	(19,695)
Property and equipment, net	16,010	25,799
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	14,543	14,859
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,422	1,447
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,293	1,293
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	20,909	20,865
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 112	$ 7,030

Leases - Costs included in operating expenses related to the operating lease (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Leases
Operating lease cost	$ 1,467	$ 3,280	$ 4,401	$ 9,842
Variable lease cost	528	832	1,575	2,542
Total	$ 1,995	$ 4,112	$ 5,976	$ 12,384

Nature of the Business and Basis of Presentation - Additional information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Summary of Significant Accounting Policies
Date of incorporation			Oct. 21, 2016
Net loss and net loss attributable to common stockholders	$ 15,313	$ 28,266	$ 110,286	$ 91,426
Accumulated deficit	$ 681,663		$ 681,663		$ 571,377

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References + Details

Accrued Expenses

9 Months Ended

Sep. 30, 2024

Accrued Expenses

Accrued Expenses

6. Accrued Expenses

Accrued expenses and other current liabilities consisted of the following:


	September 30,		December 31,
(in thousands)	2024		2023
Accrued employee compensation and benefits	$	4,505	$	13,208
Accrued external research and development expenses		600		1,169
Accrued professional fees		654		908
Property and equipment		33		838
Other		405		406
Total	$	6,197	$	16,529

In November 2023, following a review of strategic priorities and a determination by our management and board of directors to implement a strategic reorganization, to invest in our ctLNP delivery platform to develop wholly-owned programs for extrahepatic cell types and to develop our iqDNA platform for our lead program in hemophilia A and other programs, we announced a reduction in our workforce of approximately 40%, or RIF, and implemented reductions in operational expenditures including Good Manufacturing Practice readiness and manufacturing expenses. We completed the RIF during the second quarter of 2024.

In connection with the RIF, affected employees were eligible to receive one-time severance benefits, including cash severance, temporary healthcare coverage, to the extent they were eligible for and elected such coverage, and transition support services, subject to each such employee entering into an effective separation agreement, which included a general release of claims against us. We offered a retention bonus to certain affected employees if such employees remained in continuous employment with us through their respective separation dates and executed a general release of claims against us.

Below is a summary of accrued restructuring costs recorded and included in accrued expenses and other current liabilities during the year ended September 30, 2024:


(in thousands)		Severance and Benefits Costs
Balance at December 31, 2023	$	5,291
Cash payments		(5,055)
Restructuring expenses		380
Adjustments		(402)
Balance at September 30, 2024	$	214

During the nine months ended September 30, 2024, we recorded $0.4 million of restructuring expenses in our condensed consolidated statements of operation and comprehensive loss all of which was classified as general and administrative expense. We did not recognize any restructuring expense during the nine months ended September 30, 2023.

Marketable Securities and Fair Value Measurements - Summary of marketable securities by contractual maturity (Detail) - Fair Value, Recurring $ in Thousands	Sep. 30, 2024 USD ($)
Amortized Cost
Less than one year	$ 162,932
Greater than one year but less than two years	14,904
Debt Securities, Available-for-sale, Amortized Cost, Total	177,836
Fair Value
Less than one year	163,113
Greater than one year but less than two years	15,042
Debt Securities, Available-for-sale, Fair Value	$ 178,155

- Definition

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

+ References

+ Details

Net Loss per Share - Summary of Potential Dilutive Securities (Detail) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive net loss per share	13,589,088	10,856,034
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive net loss per share	374,076	1,179,349
Stock options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive net loss per share	13,215,012	9,676,685

Collaboration And License Agreement (Tables)

9 Months Ended

Sep. 30, 2024

Collaboration and License Agreement

Summary of allocation of transaction price to each unit of account


Performance Obligations (in thousands)	Standalone Selling Price		Transaction Price Allocated
ctLNP technology and research license	$	52,500	$	42,576
First liver program commercialization option license		7,000		5,677
Second liver program commercialization option license		7,000		5,677
First non-liver program commercialization option license		11,700		9,488
Second non-liver program commercialization option license		11,700		9,488
Third liver or non-liver program commercialization option license		6,150		4,987
Total	$	96,050	$	77,893

Summary of transaction price allocated with revenue activity

The following table provides a summary of the transaction price allocated to each unit of account, in addition to revenue activity during the period:


Performance Obligations	Transaction Price Allocated		Revenue Recognized During		Revenue Recognized During		Deferred Revenue
(in thousands)	As of September 30, 2024		Three Months Ended September 30, 2024		Nine Months Ended September 30, 2024		As of September 30, 2024
ctLNP technology and research license	$	40,409	$	7,554	$	15,704	$	14,549
First liver program commercialization option license		5,388		—		—		4,526
Second liver program commercialization option license		5,388		—		—		4,526
First non-liver program commercialization option license		9,006		—		—		7,565
Second non-liver program commercialization option license		9,006		—		—		7,565
Third liver or non-liver program commercialization option license		4,734		—		—		3,976
Total	$	73,931	$	7,554	$	15,704	$	42,707

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value per share	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	66,753,508	66,205,550
Common stock, shares outstanding	66,753,508	66,205,550

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues:
Collaboration revenue	$ 7,554	$ 2,146	$ 15,704	$ 3,026
Operating expenses:
Research and development	15,088	21,862	45,811	65,694
General and administrative	9,181	11,641	29,124	37,474
Loss on lease termination	1,169	0	59,596	0
Total operating expenses	25,438	33,503	134,531	103,168
Loss from operations	(17,884)	(31,357)	(118,827)	(100,142)
Other income:
Other income and interest income, net	2,571	3,091	8,541	8,716
Net loss	$ (15,313)	$ (28,266)	$ (110,286)	$ (91,426)
Net loss per share, basic (in dollars per share)	$ (0.23)	$ (0.43)	$ (1.66)	$ (1.43)
Net loss per share, diluted (in dollars per share)	$ (0.23)	$ (0.43)	$ (1.66)	$ (1.43)
Weighted average common shares outstanding, basic (in shares)	66,738,468	65,907,000	66,568,326	63,951,508
Weighted average common shares outstanding, diluted (in shares)	66,738,468	65,907,000	66,568,326	63,951,508
Comprehensive loss:
Net loss	$ (15,313)	$ (28,266)	$ (110,286)	$ (91,426)
Other comprehensive (loss) income:
Unrealized gains on marketable securities	599	19	45	79
Comprehensive loss	$ (14,714)	$ (28,247)	$ (110,241)	$ (91,347)

Commitments and Contingencies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies.
Defined contribution plan, percentage	4.00%

Marketable Securities and Fair Value Measurements - Summary of assets measured at FV on a recurring basis (Detail) - Fair Value, Recurring - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Marketable securities:
Marketable securities	$ 178,155
Total	183,615	$ 236,128
Level 1
Marketable securities:
Total	5,460	38,210
Level 2
Marketable securities:
Total	178,155	197,918
Level 3
Marketable securities:
Total	0	0
Money Market Funds
Cash equivalents:
Cash equivalents	5,460	38,210
Money Market Funds \| Level 1
Cash equivalents:
Cash equivalents	5,460	38,210
Money Market Funds \| Level 2
Cash equivalents:
Cash equivalents	0	0
Money Market Funds \| Level 3
Cash equivalents:
Cash equivalents	0	0
U.S. treasury securities
Marketable securities:
Marketable securities	178,155	197,918
U.S. treasury securities \| Level 1
Marketable securities:
Marketable securities	0	0
U.S. treasury securities \| Level 2
Marketable securities:
Marketable securities	178,155	197,918
U.S. treasury securities \| Level 3
Marketable securities:
Marketable securities	$ 0	$ 0

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Accrued Expenses
Accrued employee compensation and benefits	$ 4,505	$ 13,208
Accrued external research and development expenses	600	1,169
Accrued professional fees	654	908
Property and equipment	33	838
Other	405	406
Total	$ 6,197	$ 16,529

Cover Page - shares	9 Months Ended
Cover Page - shares	Sep. 30, 2024	Nov. 01, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Fiscal Year Focus	2024
Document Transition Report	false
Securities Act File Number	001-39319
Entity Registrant Name	GENERATION BIO CO.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-4301284
Entity Address, Address Line One	301 Binney Street
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	617
Local Phone Number	655-7500
Title of 12(b) Security	Common Stock, $0.0001 Par Value
Trading Symbol	GBIO
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		66,792,822
Entity Central Index Key	0001733294
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q3
Amendment Flag	false

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2024
Summary of Significant Accounting Policies
Use of estimates	Use of estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the measurement of proportional performance of the performance obligation of our collaboration agreements, accrual of research, and development expenses and stock-based compensation expense. We base our estimates on historical experience, known trends and other market-specific or other relevant factors that we believe to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, as there are changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results may differ from those estimates or assumptions.
Unaudited interim financial information	Unaudited interim financial information The condensed consolidated balance sheet as of December 31, 2023 was derived from audited financial statements but does not include all disclosures required by GAAP. The accompanying unaudited financial statements as of September 30, 2024 and for the three and nine months ended September 30, 2024 and 2023 have been prepared by us pursuant to the rules and regulations of the Securities and Exchange Commission, or SEC, for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These financial statements should be read in conjunction with our audited financial statements included in our Annual Report on Form 10-K that was most recently filed with the SEC. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair presentation of our financial position as of September 30, 2024, the results of operations for the three and nine months ended September 30, 2024 and 2023, and cash flows for the nine months ended September 30, 2024 and 2023 have been made. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2024 or any other period. Our significant accounting policies are described in Note 2 of the Notes to Consolidated Financial Statements included in our Annual Report on Form 10-K that was most recently filed with the SEC. Updates to our significant accounting policies are discussed below.
Employee Retention Credit	Employee Retention Credit Under the provisions of the extension of the Coronavirus Aid, Relief, and Economic Security Act, or the CARES Act, passed by the United States Congress and signed by the President, we are eligible for a refundable Employee Retention Credit, or ERC, subject to certain criteria. ASC 105, Generally Accepted Accounting Principles, describes the decision-making framework when no clear guidance exists in GAAP for a particular transaction. Specifically, ASC 105-10-05-2 instructs companies to look for guidance for a similar transaction within GAAP and apply that guidance by analogy. As such, forms of government assistance, such as the ERC, provided to business entities would not be within the scope of International Accounting Standards 20, or IAS 20, Accounting for Government Grants and Disclosure of Government Assistance, but it may be applied by analogy under ASC 105-10-05-2. We accounted for the ERC as a government grant in accordance with IAS 20 by analogy under ASC 105-10-05-2. We recognized a $2.3 million ERC upon completion of an analysis providing reasonable assurance that we met the conditions set forth in the CARES Act and it was reasonably assured that we will receive the employee retention credit. We recorded the ERC in other long-term assets on our condensed consolidated balance sheet as of September 30, 2024 related to labor costs recognized during 2020 and 2021. The ERC was recorded in research and development expenses and general and administrative expenses proportionately in the manner in which the qualified wages and related costs were classified. We have filed for refunds of the ERC and as of the date of this Quarterly Report, we have not received any refunds.

Commitments and Contingencies

9 Months Ended

Sep. 30, 2024

Commitments and Contingencies.

Commitments and Contingencies

10. Commitments and Contingencies

401(k) Plan

We have a defined-contribution plan under Section 401(k) of the Internal Revenue Code of 1986, as amended, or the 401(k) Plan. The 401(k) Plan covers all employees who meet defined minimum age and service requirements and allows participants to contribute a portion of their annual compensation on a pre-tax and/or after-tax basis. In September 2020, we adopted a match program, beginning on January 1, 2021, for employee contributions to the 401(k) Plan up to a maximum of four percent of the employee’s salary, subject to the maximums established under the U.S. Internal Revenue Code of 1986, as amended.

Indemnification agreements

In the ordinary course of business, we may provide indemnification of varying scope and terms to vendors, lessors, contract research organizations, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, we have entered into indemnification agreements with members of our board of directors and our officers that will require us, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments we could be required to make under these indemnification agreements is, in many cases, unlimited. We have not incurred any material costs as a result of such indemnifications and are not currently aware of any indemnification claims.

Legal proceedings

We, from time to time, may be party to litigation arising in the ordinary course of business. On February 20, 2024, our Landlord served us with a complaint, filed in the Court with respect to the Seyon Lease. The complaint sought declaratory judgment that we unlawfully terminated the Seyon Lease and also asserted a claim for breach of contract damages. Following receipt of the complaint, we filed a counterclaim against Landlord asserting breach of contract and violation of Massachusetts General Law Chapter 93A. On October 29, 2024, the Court determined that although we did not have the right to terminate the Seyon Lease, Landlord’s subsequent termination was effective, and that we had alleged sufficient facts to state a claim for breach of contract and violation of Massachusetts General Law Chapter 93A by Landlord. We will continue to vigorously defend the action and our rights with respect to this matter. As a result, we may continue to incur costs and expenses relating to this facility, and we may remain responsible for payments under the Seyon Lease, which may have a material adverse effect on our business, results of operations or financial condition.

Property and equipment, net (Tables)

9 Months Ended

Sep. 30, 2024

Property and equipment, net.

Summary of Property and equipment, net


	September 30,		December 31,
(in thousands)	2024		2023
Laboratory equipment	$	14,543	$	14,859
Computer equipment and software		1,422		1,447
Furniture and fixtures		1,293		1,293
Leasehold improvements		20,909		20,865
Construction in progress		112		7,030
		38,279		45,494
Less: Accumulated depreciation and amortization		(22,269)		(19,695)
Total	$	16,010	$	25,799

Nature of the Business and Basis of Presentation

9 Months Ended

Sep. 30, 2024

Nature of the Business and Basis of Presentation

Nature of the Business and Basis of Presentation

Generation Bio Co.

Notes to Condensed Consolidated Financial Statements

(Unaudited)

1. Nature of the Business and Basis of Presentation

Generation Bio Co., or Generation Bio, was incorporated on October 21, 2016 as Torus Therapeutics, Inc. and subsequently changed its name to Generation Bio Co. Generation Bio Co. and its consolidated subsidiary, or the company, we, our or us, are innovating non-viral genetic medicines to provide durable, redosable treatments for potentially hundreds of millions of patients living with rare and prevalent diseases. We are developing two distinct and complementary platforms that we believe will enable highly differentiated therapeutic applications. Our first platform is a potent, highly selective cell-targeted lipid nanoparticle, or ctLNP, delivery system for nucleic acids, which is designed to avoid off-target clearance by the liver and spleen, enabling ctLNPs to persist in systemic circulation and allowing for highly selective and potent ligand-driven targeting to specific tissues and cell types. The identification and optimization of new ligands to target new tissues and cell types is an efficient, flexible, and modular process, which we believe will allow us to rapidly expand our portfolio. Our second platform is our novel immune-quiet DNA, or iqDNA, a partially single-stranded DNA, which is a variant of our closed-ended DNA, or ceDNA, designed to enable long-lasting high levels of gene expression from non-integrating episomes, while avoiding innate immune sensors that have long prevented DNA from use in non-viral systems. Underpinning the iqDNA platform is our highly scalable capsid-free manufacturing process that uses our proprietary cell-free rapid enzymatic synthesis, or RES, to produce highly pure iqDNA at scale. We are headquartered in Cambridge, Massachusetts.

We are subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, the ability to establish clinical- and commercial-scale manufacturing processes and the ability to secure additional capital to fund operations. Programs currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization of a product. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if our development efforts are successful, it is uncertain when, if ever, we will realize significant revenue from product sales.

The accompanying condensed consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. Since inception, we have funded our operations with proceeds from the sale of instruments convertible into convertible preferred stock (which converted into convertible preferred stock in 2017), sales of convertible preferred stock (which converted into common stock in 2020), and sales of common stock in underwritten public offerings, “at-the-market” offerings, and in a private placement, as well as collaboration revenue under our collaboration with ModernaTX, Inc., or Moderna. We have incurred recurring losses, including net losses of $110.3 million for the nine months ended September 30, 2024 and $91.4 million for the nine months ended September 30, 2023. As of September 30, 2024, we had an accumulated deficit of $681.7 million. We expect to continue to generate operating losses in the foreseeable future. As of November 6, 2024, the issuance date of these condensed consolidated financial statements, we expect that our cash, cash equivalents, and marketable securities will be sufficient to fund our operating expenses and capital expenditure requirements for at least 12 months.

We will need to obtain additional funding through public or private equity offerings, debt financings, collaborations, strategic alliances and/or licensing arrangements. We may not be able to obtain financing on acceptable terms, or at all, and we may not be able to enter into additional collaborative or strategic alliances or licensing arrangements. The terms of any financing may adversely affect the holdings or the rights of our stockholders. Arrangements with collaborators or others may require us to relinquish rights to certain of our technologies or programs. If we are unable to obtain funding, we could be forced to delay, reduce or eliminate some or all of our research and development programs, pipeline expansion or commercialization efforts, which could adversely affect our business prospects. Although management will continue to pursue these plans, there is no assurance that we will be successful in obtaining sufficient funding on terms acceptable to us to fund continuing operations when needed or at all.

The accompanying condensed consolidated financial statements reflect the operations of Generation Bio and our wholly owned subsidiary, Generation Bio Securities Corporation. Intercompany balances and transactions have been eliminated in consolidation. The accompanying condensed consolidated financial statements have been prepared in conformity with generally accepted accounting principles in the United States of America, or GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB.

Stock-Based Compensation - Expense Classification (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 3,752	$ 6,004	$ 11,449	$ 18,293
Research and development expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	1,520	2,874	4,452	8,608
General and administrative expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 2,232	$ 3,130	$ 6,997	$ 9,685

Property and equipment, net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 1,200	$ 1,300	$ 3,755	$ 3,938
Construction in progress
Property, Plant and Equipment [Line Items]
Impairment charge			$ 6,200

Collaboration and License Agreement (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 06, 2024 shares	Mar. 31, 2023 USD ($) item product $ / shares shares	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($) $ / shares	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($) $ / shares	Apr. 30, 2023 USD ($)
Collaboration and License Agreement
Sale of common stock in connection with the Moderna Share Purchase Agreement, shares \| shares	0
Collaboration revenue			$ 7,554	$ 2,146	$ 15,704	$ 3,026
Deferred revenue					$ (12,154)	$ 44,474
Net loss per share, basic (in dollars per share) \| $ / shares			$ (0.23)	$ (0.43)	$ (1.66)	$ (1.43)
Net loss per share, diluted (in dollars per share) \| $ / shares			$ (0.23)	$ (0.43)	$ (1.66)	$ (1.43)
Collaboration and License Agreement \| ModernaTX, Inc
Collaboration and License Agreement
Upfront payments		$ 40,000					$ 40,000
Prepaid research services funding		$ 7,500					$ 7,500
Milestone payments receivable			$ 1,800,000		$ 1,800,000
Number of performance obligations \| item		1
Premium paid on common stock		$ 13,300
Variable consideration		0
Transaction Price Allocated		$ 77,893	73,931		73,931
Collaboration and License Agreement \| ModernaTX, Inc \| Minimum
Collaboration and License Agreement
Number of products to be commercialized \| product		1
Royalty payment term		10 years
Collaboration and License Agreement \| Share Purchase Agreement \| Beneficial Owner \| ModernaTX, Inc
Collaboration and License Agreement
Sale of common stock in connection with the Moderna Share Purchase Agreement, shares \| shares		5,859,375
Shares issue price (in dollars per share) \| $ / shares		$ 6.14
Proceeds from issuance/sale of common stock		$ 36,000
Percent of shares to be issued		3.06%
Equity financing		$ 25,000
Collaboration and License Agreement \| Contracts Accounted for under Percentage of Completion
Collaboration and License Agreement
Transaction Price Allocated			(6,800)		(6,800)
Collaboration revenue			3,800		3,800
Deferred revenue			$ (3,800)		$ (3,800)
Net loss per share, basic (in dollars per share) \| $ / shares			$ (0.06)		$ (0.06)
Net loss per share, diluted (in dollars per share) \| $ / shares			$ (0.06)		$ (0.06)

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 21,657	$ 66,446
Marketable securities	163,113	197,918
Collaboration receivable	2,212	0
Tenant receivable	0	3,960
Prepaid expenses and other current assets	4,272	4,294
Total current assets	191,254	272,618
Marketable securities, net of current portion	15,042	0
Property and equipment, net	16,010	25,799
Operating lease right-of-use assets	21,220	69,852
Restricted cash	2,152	5,791
Other long-term assets	3,106	698
Total assets	248,784	374,758
Current liabilities:
Accounts payable	1,659	2,346
Accrued expenses and other current liabilities	6,197	16,529
Deferred revenue	11,512	12,919
Operating lease liability	10,797	8,120
Total current liabilities	30,165	39,914
Deferred revenue, net of current portion	31,195	41,942
Operating lease liability, net of current portion	82,982	89,774
Total liabilities	144,342	171,630
Commitments and contingencies (Note 10)
Stockholders' equity:
Preferred stock, $0.0001 par value; 5,000,000 shares authorized and no shares issued or outstanding at September 30, 2024 and December 31, 2023	0	0
Common stock, $0.0001 par value; 150,000,000 shares authorized at September 30, 2024 and December 31, 2023; 66,753,508 and 66,205,550 shares issued and outstanding at September 30, 2024 and December 31, 2023, respectively	7	7
Additional paid-in capital	785,779	774,224
Accumulated other comprehensive income	319	274
Accumulated deficit	(681,663)	(571,377)
Total stockholders' equity	104,442	203,128
Total liabilities and stockholders' equity	$ 248,784	$ 374,758

Equity - Additional Information (Detail) $ / shares in Units, $ in Millions		1 Months Ended	9 Months Ended
	Nov. 06, 2024 shares	Aug. 31, 2024 USD ($)	Sep. 30, 2024 security $ / shares shares	Dec. 31, 2023 $ / shares shares
Capital Unit [Line Items]
Common stock, shares authorized \| shares			150,000,000	150,000,000
Common stock, par value per share \| $ / shares			$ 0.0001	$ 0.0001
Preferred stock, shares authorized \| shares			5,000,000	5,000,000
Preferred stock, par value per share \| $ / shares			$ 0.0001	$ 0.0001
Shares issued during the period \| shares	0
Number of vote per common share \| security			1
Maximum
Capital Unit [Line Items]
Aggregate gross offering price \| $		$ 237.0
At the Market Offering
Capital Unit [Line Items]
Termination of shares reserved for future issuances \| $		237.3
Aggregate gross offering price \| $		$ 250.0

Accrued Expenses - Narrative (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	Nov. 30, 2023	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Accrued Expenses
Reduction in workforce	40.00%
Restructuring expenses		$ 0.0	$ 0.4	$ 0.0
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]			General and Administrative Expense

Stock-Based Compensation - Unrecognized Expense (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2024 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Expense	$ 14.7
Share based compensation expected to recognize over a weighted average period one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Expense	$ 13.2
Unrecognized stock compensation on account of unvested options remaining period over which the compensation is to be recognized	2 years 1 month 6 days
Share based compensation expected to recognize over a weighted average period two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Expense	$ 1.5
Unrecognized stock compensation on account of unvested options remaining period over which the compensation is to be recognized	2 years 2 months 12 days

- 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
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Leases

9 Months Ended

Sep. 30, 2024

Leases

Leases

7. Leases

We lease our office and laboratory space under a noncancelable operating lease that expires in 2029, or the Office and Lab Lease. We have an option to extend the Office and Lab Lease term for one additional term of five years at the greater of the then-current base rent or the then-current fair market value. Exercise of this option was not determined to be reasonably certain and thus was not considered in determining the operating lease liability on the consolidated balance sheet as of September 30, 2024. We posted a letter of credit in the amount of approximately $2.1 million as a security deposit. The letter of credit is subject to increase if we were to sublease any portion of the leased premises. The Office and Lab Lease does not include any restrictions or covenants that had to be accounted for under the lease guidance.

Future lease payments for our noncancelable operating leases as of September 30, 2024 and a reconciliation to the carrying amount of the operating lease liabilities presented in the condensed consolidated balance sheet as of September 30, 2024 are as follows:


Three Months Ended September 30,	(in thousands)
2024 (remaining 3 months)	$	1,935
2025		7,838
2026		8,059
2027		8,275
2028		8,535
Thereafter		2,834
Total undiscounted payments due under operating leases		37,476
Less imputed interest		(5,673)
Total	$	31,803

Current operating lease liability	$	5,707
Non-current operating lease liability		26,096
Total	$	31,803

The following table presents our costs included in operating expenses related to our noncancelable operating leases:


	Three Months Ended September 30,				Nine Months Ended September 30,
(in thousands)	2024		2023		2024		2023
Operating lease cost	$	1,467	$	3,280	$	4,401	$	9,842
Variable lease cost		528		832		1,575		2,542
Total	$	1,995	$	4,112	$	5,976	$	12,384

Net cash paid for the amounts included in the measurement of the operating lease liability on the condensed consolidated balance sheet and operating activities in our consolidated statement of cash flows was $5.7 million and $9.6 million for the nine months ended September 30, 2024 and 2023, respectively. The weighted-average remaining lease term and weighted-average incremental borrowing rate for all leases as of September 30, 2024 was approximately 5 years and 7.1%, respectively.

The Seyon Lease commenced in December 2021, when we were granted access to the facility, and monthly rent payments began in September 2022; the total rent payment was expected to be approximately $104.3 million for the 12-year lease term. We had an option to extend the Seyon Lease term for two additional terms of five years each at the greater of the then-current base rent or the then-current fair market value. Exercise of this option was not determined to be reasonably certain and thus was not considered in determining the operating lease liability. In connection with the Seyon Lease, we provided a security deposit of $3.6 million in the form of a letter of credit. We paid an initial monthly base rent of approximately $0.4 million that increased annually, up to a monthly base rent of $0.6 million. We were obligated to pay operating costs, taxes and utilities applicable to the facility. We were responsible for costs of constructing interior improvements within the facility that exceed a construction allowance of $26.0 million provided by the landlord. As previously disclosed in our most recent Annual Report on Form 10-K and in this Quarterly Report, the termination of the Seyon Lease is the subject of pending litigation with the landlord. As of September 30, 2024, the landlord has collected $3.6 million from our security deposit in lieu of rent payments and has fully utilized such deposit.

In connection with the termination of the Seyon Lease, during the nine months ended September 30, 2024, we recorded a material impairment loss of non-cash charges of $45.8 million in an impairment of the Seyon Lease right-of-use asset, $6.2 million in an impairment of construction in progress, and the write-off of $3.9 million in tenant improvement allowance receivable from the landlord. In addition, during the nine months ended September 30, 2024, we recognized

$3.7 million in accretion and other lease related expenses, which resulted in a $59.6 million loss on termination of lease in our condensed consolidated statement of operations and comprehensive loss. Accretion and other lease related expenses related to the Seyon Lease will continue to be recognized in loss on lease termination on our condensed consolidated statement of operations and comprehensive loss. As of September 30, 2024, as we have not met the criteria to extinguish the lease liability pursuant to ASC 405 Liabilities, and we had $62.0 million in operating lease liability related to the Seyon Lease on our condensed consolidated balance sheet. Additionally, in accordance with ASC 450 Contingencies, we have assessed the probability of realizing a material loss contingency for the potential losses, including obligations to pay any future variable lease costs, under the Seyon Lease. Based on this assessment, we have determined that it is not probable that we will be obligated to pay any such amounts. As a result, we have not accrued for any amounts related to the potential losses, primarily variable lease costs, such as common area fees and other charges, as they relate to the Seyon Lease.

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2024

Stock-Based Compensation

Summary of stock-based compensation expense was classified in the statements of operations and comprehensive loss


	Three Months Ended September 30,				Nine Months Ended September 30,
(in thousands)	2024		2023		2024		2023
Research and development expenses	$	1,520	$	2,874	$	4,452	$	8,608
General and administrative expenses		2,232		3,130		6,997		9,685
Total	$	3,752	$	6,004	$	11,449	$	18,293

Accrued Expenses - Schedule of accrued restructuring costs (Detail) - Severance and Benefits Costs $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Restructuring costs
Beginning Balance	$ 5,291
Cash payments	(5,055)
Restructuring expenses	380
Adjustments	(402)
Ending Balance	$ 214

Leases - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
Leases - Narrative (Details) - USD ($) $ in Thousands	Jul. 31, 2021	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Lease existence of option to extend				true
Operating lease agreement option to renewal term	5 years	5 years		5 years
Letter of credit for security deposit		$ 2,100		$ 2,100
Operating lease term						12 years
Total rent payments						$ 104,300
Initial monthly base rent on operating lease	$ 400
Option to extend lease	two
Construction allowance in operating lease	$ 26,000
Operating lease payments				$ 5,700	$ 9,600
Weighted-average remaining lease term		5 years		5 years
Weighted-average incremental borrowing		7.10%		7.10%
Security deposit liability		$ 3,600		$ 3,600
Impairment of right-of-use asset				45,800
Tenant improvement allowance receivable write-off				3,900
Accretion and other lease related expenses				3,700
Loss on lease termination		(1,169)	$ 0	(59,596)	$ 0
Operating Lease, Liability		$ 62,000		62,000
Construction in progress
Lessee, Lease, Description [Line Items]
Impairment charge				$ 6,200
Maximum
Lessee, Lease, Description [Line Items]
Estimated monthly base rent on operating lease	600
Letter of Credit [Member]
Lessee, Lease, Description [Line Items]
Security deposit	$ 3,600

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2024

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Use of estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the measurement of proportional performance of the performance obligation of our collaboration agreements, accrual of research, and development expenses and stock-based compensation expense. We base our estimates on historical experience, known trends and other market-specific or other relevant factors that we believe to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, as there are changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results may differ from those estimates or assumptions.

Unaudited interim financial information

The condensed consolidated balance sheet as of December 31, 2023 was derived from audited financial statements but does not include all disclosures required by GAAP. The accompanying unaudited financial statements as of September 30, 2024 and for the three and nine months ended September 30, 2024 and 2023 have been prepared by us pursuant to the rules and regulations of the Securities and Exchange Commission, or SEC, for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These financial statements should be read in conjunction with our audited financial statements included in our Annual Report on Form 10-K that was most recently filed with the SEC. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair presentation of our financial position as of September 30, 2024, the results of operations for the three and nine months ended September 30, 2024 and 2023, and cash flows for the nine months ended September 30, 2024 and 2023 have been made. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2024 or any other period.

Our significant accounting policies are described in Note 2 of the Notes to Consolidated Financial Statements included in our Annual Report on Form 10-K that was most recently filed with the SEC. Updates to our significant accounting policies are discussed below.

Employee Retention Credit

Under the provisions of the extension of the Coronavirus Aid, Relief, and Economic Security Act, or the CARES Act, passed by the United States Congress and signed by the President, we are eligible for a refundable Employee Retention Credit, or ERC, subject to certain criteria. ASC 105, Generally Accepted Accounting Principles, describes the decision-making framework when no clear guidance exists in GAAP for a particular transaction. Specifically, ASC 105-10-05-2 instructs companies to look for guidance for a similar transaction within GAAP and apply that guidance by analogy. As such, forms of government assistance, such as the ERC, provided to business entities would not be within the scope of International Accounting Standards 20, or IAS 20, Accounting for Government Grants and Disclosure of Government Assistance, but it may be applied by analogy under ASC 105-10-05-2. We accounted for the ERC as a government grant in accordance with IAS 20 by analogy under ASC 105-10-05-2.

We recognized a $2.3 million ERC upon completion of an analysis providing reasonable assurance that we met the conditions set forth in the CARES Act and it was reasonably assured that we will receive the employee retention credit. We recorded the ERC in other long-term assets on our condensed consolidated balance sheet as of September 30, 2024 related to labor costs recognized during 2020 and 2021. The ERC was recorded in research and development expenses and general and administrative expenses proportionately in the manner in which the qualified wages and related costs were classified. We have filed for refunds of the ERC and as of the date of this Quarterly Report, we have not received any refunds.

Leases (Tables)

9 Months Ended

Sep. 30, 2024

Leases

Future lease payments for noncancelable operating lease


Three Months Ended September 30,	(in thousands)
2024 (remaining 3 months)	$	1,935
2025		7,838
2026		8,059
2027		8,275
2028		8,535
Thereafter		2,834
Total undiscounted payments due under operating leases		37,476
Less imputed interest		(5,673)
Total	$	31,803

Current operating lease liability	$	5,707
Non-current operating lease liability		26,096
Total	$	31,803

Costs included in operating expenses related to the operating lease

The following table presents our costs included in operating expenses related to our noncancelable operating leases:


	Three Months Ended September 30,				Nine Months Ended September 30,
(in thousands)	2024		2023		2024		2023
Operating lease cost	$	1,467	$	3,280	$	4,401	$	9,842
Variable lease cost		528		832		1,575		2,542
Total	$	1,995	$	4,112	$	5,976	$	12,384

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accounting Policies (Detail) $ in Millions	Sep. 30, 2024 USD ($)
Summary of Significant Accounting Policies
Employee retention credit recognized	$ 2.3

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total
Beginning balance at Dec. 31, 2022	$ 6	$ 727,335	$ (83)	$ (444,765)	$ 282,493
Beginning balance, shares at Dec. 31, 2022	59,505,437
Sale of common stock in connection with the Moderna Share Purchase Agreement	$ 1	22,555			22,556
Sale of common stock in connection with the Moderna Share Purchase Agreement, shares	5,859,375
Vesting of restricted common stock		(448)			(448)
Vesting of restricted common stock, shares	455,463
Issuance of common stock under ESPP		367			367
Issuance of common stock under ESPP, shares	107,681
Stock-based compensation expense		18,293			18,293
Unrealized gains on marketable securities			79		79
Net loss				(91,426)	(91,426)
Ending balance at Sep. 30, 2023	$ 7	768,102	(4)	(536,191)	231,914
Ending balance, shares at Sep. 30, 2023	65,927,956
Beginning balance at Jun. 30, 2023	$ 7	762,228	(23)	(507,925)	254,287
Beginning balance, shares at Jun. 30, 2023	65,784,250
Vesting of restricted common stock		(130)			(130)
Vesting of restricted common stock, shares	143,706
Stock-based compensation expense		6,004			6,004
Unrealized gains on marketable securities			19		19
Net loss				(28,266)	(28,266)
Ending balance at Sep. 30, 2023	$ 7	768,102	(4)	(536,191)	231,914
Ending balance, shares at Sep. 30, 2023	65,927,956
Beginning balance at Dec. 31, 2023	$ 7	774,224	274	(571,377)	203,128
Beginning balance, shares at Dec. 31, 2023	66,205,550
Issuance of common stock upon exercise of stock options		31			31
Issuance of common stock upon exercise of stock options, shares	22,517
Vesting of restricted common stock		(172)			(172)
Vesting of restricted common stock, shares	369,414
Issuance of common stock under ESPP		247			247
Issuance of common stock under ESPP, shares	156,027
Stock-based compensation expense		11,449			11,449
Unrealized gains on marketable securities			45		45
Net loss				(110,286)	(110,286)
Ending balance at Sep. 30, 2024	$ 7	785,779	319	(681,663)	104,442
Ending balance, shares at Sep. 30, 2024	66,753,508
Beginning balance at Jun. 30, 2024	$ 7	782,030	(280)	(666,350)	115,407
Beginning balance, shares at Jun. 30, 2024	66,702,734
Issuance of common stock upon exercise of stock options		13			13
Issuance of common stock upon exercise of stock options, shares	9,680
Vesting of restricted common stock		(16)			(16)
Vesting of restricted common stock, shares	41,094
Stock-based compensation expense		3,752			3,752
Unrealized gains on marketable securities			599		599
Net loss				(15,313)	(15,313)
Ending balance at Sep. 30, 2024	$ 7	$ 785,779	$ 319	$ (681,663)	$ 104,442
Ending balance, shares at Sep. 30, 2024	66,753,508

Collaboration and License Agreement

9 Months Ended

Sep. 30, 2024

Collaboration and License Agreement

Collaboration and License Agreement

4. Collaboration and License Agreement

Moderna Collaboration and License Agreement

In March 2023, we entered into a Collaboration and License Agreement, or the Collaboration Agreement, with Moderna to collaborate on developing treatments for certain diseases by targeting delivery of nucleic acids to liver cells and certain cells outside of the liver.

Under the Collaboration Agreement, the parties have agreed to collaborate on preclinical research programs relating to lipid nanoparticle, or LNP, delivery systems and nucleic acid payloads, with each party obtaining certain rights to intellectual property used in and arising out of such research programs. Each party will be solely responsible for its own clinical development and commercialization of products under the Collaboration Agreement. Moderna will reimburse us for the internal and external costs incurred by us in conducting the research programs, to the extent consistent with such research plans and budgets.

Moderna has exclusive options, upon payment of option exercise fees, to obtain worldwide, exclusive, sublicensable licenses under specified company intellectual property to develop, manufacture and commercialize (a) products comprising LNP delivery systems and nucleic acid payloads that are directed to (i) up to two liver targets, (ii) up to two non-liver targets and (iii) a third liver or non-liver target and (b) Exclusive Targets, which are Independent Program Products (as defined below) that include messenger RNA, or mRNA, that are directed to gene and protein targets in any of certain agreed-upon immune cell types, referred to as the Cell Target Types. Subject to the exclusivity obligations described below, each party has granted to the other a worldwide, non-exclusive, sublicensable license under certain LNP-related intellectual property arising out of the non-liver ctLNP program, or the Joint Collaboration ctLNP Intellectual Property, to develop, manufacture and commercialize products comprising LNP delivery systems and nucleic acid payloads directed to gene and protein targets in any of the Cell Target Types, or Independent Program Products.

Each party is obligated to use commercially reasonable efforts to complete the activities assigned to it under the research plans, and Moderna is further obligated to use commercially reasonable efforts to develop, seek regulatory approval for and commercialize at least one product directed to each target for which Moderna exercises its exclusive license option in at least one indication in the United States and in specified European countries.

We have agreed not to, directly or indirectly, alone or with, for or through any third party, develop, manufacture, commercialize or exploit (a) products containing mRNA that are directed to any of the Cell Target Types, during an agreed-upon exclusivity period, which may be extended by payment of extension fees, (b) products directed to any liver

target or non-liver target during the option periods for those targets, (c) products directed to any liver target or non-liver target for which Moderna has exercised its exclusive license option or (d) products containing mRNA that are directed to any Exclusive Target for which Moderna has exercised its exclusive license option.

Under the terms of the Collaboration Agreement, in April 2023, Moderna made an upfront payment to us of $40.0 million, and paid us $7.5 million in prepaid research funding. In addition, we are eligible to receive up to $1.8 billion in milestone payments upon the achievement of specified development, regulatory, commercial, and sales milestone events, research term extension fees and exclusivity extension fees. Subject to reductions in specified circumstances, we will also be entitled to receive tiered royalties: (i) ranging from high-single-digits to low-double-digits on sales of licensed products that are directed to any liver target or non-liver target with respect to which Moderna has exercised its exclusive license option, and (ii) in the single digits on sales of Independent Program Products, including the exclusively licensed Independent Program Products directed to the Exclusive Targets. In consideration for the non-exclusive license granted by Moderna to us under the Joint Collaboration ctLNP Intellectual Property, we have agreed to pay Moderna tiered royalties in the single digits on sales of Independent Program Products that include mRNA, subject to reductions in specified circumstances. Royalties will be paid by each party, on a licensed product-by-licensed product and country-by-country basis, until the latest to occur of: (i) expiration of the last-to-expire of specified licensed patent rights; (ii) expiration of regulatory exclusivity; or (iii) ten years after the first commercial sale of the applicable licensed product.

In addition, in connection with the execution of the Collaboration Agreement, we entered into a Share Purchase Agreement, or the Share Purchase Agreement, with Moderna, pursuant to which we issued and sold 5,859,375 shares of our common stock to Moderna, at a price of $6.14 per share, for an aggregate purchase price of $36.0 million, which closed concurrently with the execution of the Collaboration Agreement and resulted in Moderna becoming a related party. Under the Share Purchase Agreement, Moderna has the right, subject to certain terms and conditions, to purchase up to 3.06% of the outstanding shares of our common stock (on a post-closing basis) in connection with a future equity financing of at least $25.0 million by us.

Moderna Agreement Assessment

We assessed the promised goods and services under the Collaboration Agreement, in accordance with ASC 606. At inception, the Collaboration Agreement included one combined performance obligation, which includes the license to the ctLNP technology to target indications outside of the liver and the related research services to develop such technology, as the two items are not distinct in context of the contract. The Collaboration Agreement also provides Moderna with options to receive additional research services and options to receive exclusive licenses. The options to receive exclusive licenses allow Moderna to develop and commercialize product candidates that utilize our ctLNP and ceDNA technology for targets within the liver, as well as utilizing the ctLNP technology to be developed as part of the Collaboration Agreement and our ceDNA technology for targets outside the liver. These options are considered to be a priced at a discount to its standalone selling price and therefore are considered to be material rights.

The initial transaction price included a $40.0 million upfront fee, premium paid over the fair value of the common stock of $13.3 million in connection with shares issued and sold to Moderna under the Share Purchase Agreement, and estimated revenue associated with the payment for research services, including $7.5 million in prepaid research services. We utilized the expected amount method to determine the amount of reimbursement for these activities. We utilized the most likely amount method to determine the amount of consideration to include in the transaction price related to any variable consideration related to exclusivity fees, and milestones, and the royalty payments are constrained based on the royalty constraint. No amounts are included in the transaction price related to these elements.

We initially allocated the transaction price to each unit of account as follows:


Performance Obligations (in thousands)	Standalone Selling Price		Transaction Price Allocated
ctLNP technology and research license	$	52,500	$	42,576
First liver program commercialization option license		7,000		5,677
Second liver program commercialization option license		7,000		5,677
First non-liver program commercialization option license		11,700		9,488
Second non-liver program commercialization option license		11,700		9,488
Third liver or non-liver program commercialization option license		6,150		4,987
Total	$	96,050	$	77,893

The transaction price was allocated to each unit of account based on the relative estimated standalone selling prices, over which management has applied significant judgment, of each element. We developed the estimated standalone selling price for combined performance obligation and each of the options to receive licenses primarily based on the probability-weighted present value of expected future cash flows associated with each license related to each specific program and an estimate of the costs to provide services including a reasonable return. In developing such estimate, we also considered applicable market conditions and relevant entity-specific factors, including those factors contemplated in negotiating the agreement, the probability of success and the time needed to commercialize a product candidate pursuant to the associated license.

On a quarterly basis, we measure proportional performance of the combined performance obligation over time using an input method based on cost incurred relative to the total estimated costs by determining the proportion of effort incurred as a percentage of total effort we expect to expend. This ratio is then applied to the transaction price allocated to the combined performance obligation and each of the options to receive licenses. Any changes to these estimates will be recognized in the period in which they change as a cumulative catch up. All allocated consideration for the material rights is deferred until such time that Moderna exercises its options or the right to exercise the options expires. Upon exercise, we will determine the appropriate revenue recognition methodology and any other implications on the accounting treatment for the arrangement.

During the three months ended September 30, 2024, we recorded additional revenue related to a change in estimate due to revisions in the research plan resulting in a reduction in the estimated timeline of future research services and total estimated costs. The change in estimate resulted in a $6.8 million decrease in the allocated transaction price and a $3.8 million increase in collaboration revenue, a $3.8 million decrease in deferred revenue and a $0.06 decrease in net loss per share, basic and diluted, for both the three and nine months ended September 30, 2024.

The following table provides a summary of the transaction price allocated to each unit of account, in addition to revenue activity during the period:


Performance Obligations	Transaction Price Allocated		Revenue Recognized During		Revenue Recognized During		Deferred Revenue
(in thousands)	As of September 30, 2024		Three Months Ended September 30, 2024		Nine Months Ended September 30, 2024		As of September 30, 2024
ctLNP technology and research license	$	40,409	$	7,554	$	15,704	$	14,549
First liver program commercialization option license		5,388		—		—		4,526
Second liver program commercialization option license		5,388		—		—		4,526
First non-liver program commercialization option license		9,006		—		—		7,565
Second non-liver program commercialization option license		9,006		—		—		7,565
Third liver or non-liver program commercialization option license		4,734		—		—		3,976
Total	$	73,931	$	7,554	$	15,704	$	42,707

Net Loss per Share

9 Months Ended

Sep. 30, 2024

Net Loss per Share

Net Loss per Share

11. Net Loss per Share

We have generated a net loss in all periods presented, therefore the basic and diluted net loss per share attributable to common stockholders are the same as the inclusion of the potentially dilutive securities would be anti-dilutive. We excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated:


	September 30,
	2024	2023
Unvested restricted stock units	374,076	1,179,349
Stock options to purchase common stock	13,215,012	9,676,685
Total	13,589,088	10,856,034

Property and equipment, net

9 Months Ended

Sep. 30, 2024

Property and equipment, net.

Property and equipment, net

5. Property and equipment, net

Property and equipment, net consisted of the following:


	September 30,		December 31,
(in thousands)	2024		2023
Laboratory equipment	$	14,543	$	14,859
Computer equipment and software		1,422		1,447
Furniture and fixtures		1,293		1,293
Leasehold improvements		20,909		20,865
Construction in progress		112		7,030
		38,279		45,494
Less: Accumulated depreciation and amortization		(22,269)		(19,695)
Total	$	16,010	$	25,799

Depreciation and amortization expense for the three and nine months ended September 30, 2024 was 1.2 million and $3.8 million, respectively. Depreciation and amortization expense for the three and nine months ended September 30, 2023 was $1.3 million and $3.9 million, respectively.

In July 2021, we entered into a lease agreement for a manufacturing facility in Waltham, Massachusetts, or the Seyon Lease. On January 31, 2024, we notified Waltham CenterPoint I Investment Group, LLC, or Landlord, of termination of the Seyon Lease due to Landlord’s breach of its obligations to us under the Seyon Lease and returned possession of the premises to Landlord, effective January 31, 2024. On February 14, 2024, Landlord sent us a notice of the termination of the Seyon Lease due to our non-payment of rent. On February 20, 2024, Landlord served us with a complaint, filed in Massachusetts Superior Court, or the Court, with respect to the Seyon Lease. The complaint sought declaratory judgment that we unlawfully terminated the Seyon Lease and also asserted a claim for breach of contract damages. Following receipt of the complaint, we filed a counterclaim against Landlord asserting breach of contract and violation of Massachusetts General Law Chapter 93A. On October 29, 2024, the Court determined that although we did not have the right to terminate the Seyon Lease, Landlord’s subsequent termination was effective, and that we had alleged sufficient facts to state a claim for breach of contract and violation of Massachusetts General Law Chapter 93A by Landlord. We will continue to vigorously defend our rights with respect to this matter. During the nine months ended September 30, 2024, in connection with the termination of the Seyon Lease, we recorded a non-cash charge of $6.2 million in an impairment of construction in progress. For additional information, refer to Note 7, Leases.