0001558370-24-003309 | 10-K | XBRL Viewer

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Summary of Significant Accounting Policies - Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 129,566	$ 115,516
Restricted cash	1,083
Total cash, cash equivalents and restricted cash in the condensed consolidated statement of cash flows	$ 130,649	115,516	$ 137,703
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maturity period of highly liquid investments classified as cash and cash equivalents	90 days
Other long-term liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, net asset (liability)		262
Restricted Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, net asset (liability)	$ 1,083
Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, net asset (liability)	46,868	57,336
Level 1 \| Other long-term liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, net asset (liability)		262
Level 1 \| Restricted Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, net asset (liability)	1,083
Level 1 \| Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, net asset (liability)	$ 46,868	$ 57,336

Leases - Schedule of Components of Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases
Amortization of right-of-use assets	$ 1,124	$ 1,103
Interest on lease liabilities		1
Total finance lease cost	1,124	1,104
Operating lease cost	5,473	5,307
Short-term lease cost	159	154
Total lease cost	$ 6,756	$ 6,565

CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Ordinary Shares	Capital in Excess of Par Value	Accumulated Other Comprehensive Loss	Accumulated Deficit	Total
Beginning Equity Balance at Dec. 31, 2021	$ 2	$ 528,659	$ (2,671)	$ (340,589)	$ 185,401
Beginning Equity Balance (shares) at Dec. 31, 2021	44,548,925
Share based compensation activity		26,080			26,080
Share based compensation activity (shares)	185,770
Warrants issued in connection with note payable		2,273			2,273
Issuance of shares in connection with private placement, net of issuance costs		24,881			24,881
Issuance of shares in connection with private placement, net of issuance costs (shares)	3,742,514
Other comprehensive income			8,718		8,718
Net income (loss) for the year ended December 31				(129,615)	(129,615)
Ending Equity Balance at Dec. 31, 2022	$ 2	581,893	6,047	(470,204)	117,738
Ending Equity Balance (shares) at Dec. 31, 2022	48,477,209
Share based compensation activity		26,207			26,207
Share based compensation activity (shares)	309,755
Issuance of shares in connection with asset acquisition		209			209
Issuance of shares in connection with asset acquisitions (shares)	40,138
Issuance of shares in connection with private placement, net of issuance costs		85,532			85,532
Issuance of shares in connection with private placement, net of issuance costs (shares)	14,773,913
Other comprehensive income			(7,482)		(7,482)
Net income (loss) for the year ended December 31				(84,027)	(84,027)
Ending Equity Balance at Dec. 31, 2023	$ 2	$ 693,841	$ (1,435)	$ (554,231)	$ 138,177
Ending Equity Balance (shares) at Dec. 31, 2023	63,601,015

Accrued Expenses

12 Months Ended

Dec. 31, 2023

Accrued Expenses

Accrued Expenses

7. Accrued Expenses

Accrued expenses at December 31, 2023 and 2022 were comprised of the following (in thousands):


	December 31,		December 31,
	2023		2022
Compensation and benefits	$	12,129	$	9,600
Clinical trial costs		8,713		13,041
Professional fees		6,499		732
Research and development		5,834		7,400
Interest on Tranche 1 Notes		2,936		—
Manufacturing costs		2,634		4,326
Consulting		2,104		694
Fixed assets		1,472		3,093
Rent and facilities costs		142		—
Other		176		932
	$	42,639	$	39,818

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Taxes

Summary of Net Operating Loss Carryforwards


	Federal		State/City
United Kingdom	$	169,599	$	—
United States	$	65,549	$	14,741
Ireland	$	47,681	$	—
Other	$	29,399	$	—

Schedule of Company's Pre-Tax Earnings


	December 31, 2023		December 31, 2022
United Kingdom	$	12,881	$	(54,636)
United States		(63,017)		(54,513)
Ireland		(29,965)		(16,661)
Other		(3,926)		(3,805)
	$	(84,027)	$	(129,615)

Schedule of Reconciliation of Income Tax Benefit with Amounts at the U.K. Statutory Income Tax Rate


	December 31, 2023			December 31, 2022
Statutory rate	(19,746)	23.50	%	(24,627)	19.00	%
Permanent differences - other	2,391	(2.85)	%	2,323	(1.79)	%
RTP and other adjustment	(1,165)	1.39	%	1,244	(0.96)	%
State and local rate, net of federal tax	(698)	0.83	%	(5,660)	4.37	%
U.K. tax credit	(4,028)	4.79	%	2,296	(1.77)	%
U.S. tax credit	(9,830)	11.70	%	(2,436)	1.88	%
Foreign tax rate differential	4,558	(5.42)	%	195	(0.15)	%
UK rate change (25% & 19%, respectively)	239	(0.28)	%	(1,973)	1.52	%
US state rate change	15,394	(18.32)	%	(3)	0.00	%
Section 162(m) deferred adjustment	2,728	(3.25)	%	1,386	(1.07)	%
Disallowed interest	2,812	(3.35)	%	—	0.00	%
Change in valuation allowance	7,345	(8.74)	%	27,255	(21.03)	%
Actual income tax benefit effective tax rate	—	0.00	%	—	0.00	%

Schedule of Expense/(Benefit) for Income Taxes from Continuing Operations


	December 31, 2023	December 31, 2022
Current Tax Expense/(Benefit)
United Kingdom	—	—
United States	—	—
Other	—	—
Total Current	—	—
Deferred Tax Expense/(Benefit)
United Kingdom	2,393	(8,708)
United States	(6,251)	(17,466)
Ireland	(3,963)	(1,498)
Netherlands	(1,840)	1,717
Total Deferred	(9,661)	(25,955)
Change in Valuation Allowance	9,661	25,955
Total Income Tax Expense/(Benefit)	—	—

Schedule of Deferred Tax Assets and Liabilities


	December 31, 2023		December 31, 2022
Deferred Tax Assets:
Net operating loss carryforwards	$	70,650	$	74,350
Capitalized research and development		19,606		16,288
Share-based compensation		14,290		13,684
R&D credit		21,687		10,837
Lease liability		4,070		6,461
Other		1,121		3,745
Deferred tax assets		131,424		125,365

Deferred Tax Liabilities:
Indefinite-lived intangibles and fixed assets		—		(186)
Depreciation		(1,763)		(2,935)
Right of use assets		(3,777)		(6,207)
Less: valuation allowance		(125,884)		(116,223)
Net deferred tax liability	$	—	$	(186)

Schedule of Unrecognized Tax Benefits


	December 31, 2023		December 31, 2022
Unrecognized tax benefits as of January 1	$	937	$	666
Gross increases/(decreases) related to current year		756		279
Gross increases/(decreases) related to prior years		336		(8)
Foreign currency translation		—		—
Unrecognized tax positions as of December 31	$	2,029	$	937

Income Taxes - Summary of Net Operating Loss Carryforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Loss before income taxes	$ (84,027)	$ (129,615)
United Kingdom
Operating Loss Carryforwards [Line Items]
Loss before income taxes	12,881	(54,636)
United States
Operating Loss Carryforwards [Line Items]
Loss before income taxes	(63,017)	(54,513)
Ireland
Operating Loss Carryforwards [Line Items]
Loss before income taxes	(29,965)	(16,661)
Other
Operating Loss Carryforwards [Line Items]
Loss before income taxes	(3,926)	(3,805)
Federal \| Research and Development Tax Credits
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	20,300
Federal \| United Kingdom
Operating Loss Carryforwards [Line Items]
NOL carryforwards	169,599
Federal \| United States
Operating Loss Carryforwards [Line Items]
NOL carryforwards	65,549
Federal \| Ireland
Operating Loss Carryforwards [Line Items]
NOL carryforwards	47,681
Federal \| Other
Operating Loss Carryforwards [Line Items]
NOL carryforwards	29,399
State/City \| United States
Operating Loss Carryforwards [Line Items]
NOL carryforwards		$ 14,741
Increase (decrease) in NOL carryforwards	(114,000)
State/City \| Netherlands
Operating Loss Carryforwards [Line Items]
Increase (decrease) in NOL carryforwards	3,700
U.K. \| Research and Development Tax Credits
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	$ 3,400

Equity Method and Other Investments - Summary of Investments (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Schedule of Equity Method Investments [Line Items]
Carrying Value	$ 6,766
Cost Basis	$ 6,665
Visiogene LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage	25.00%
Carrying Value	$ 5,150
Cost Basis	$ 5,165
Other Investments
Schedule of Equity Method Investments [Line Items]
Ownership percentage	1.60%
Carrying Value	$ 1,616
Cost Basis	$ 1,500

Intangible Assets - Amortization Expense (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Amortization expense
2024	$ 285
2025	285
2026	285
2027	263
Total	$ 1,118

Share-Based Compensation - Schedule of Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Expense [Line Items]
Total share-based compensation	$ 27,716	$ 28,623
Research and Development Expenses
Share Based Compensation Expense [Line Items]
Total share-based compensation	12,780	14,165
General and Administrative Expenses
Share Based Compensation Expense [Line Items]
Total share-based compensation	$ 14,936	$ 14,458

Leases - Schedule of Consolidated Balance Sheets for Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Operating leases
Right-of-use asset	$ 15,910	$ 20,109
Capitalized lease obligations	17,145	21,215
Finance leases
Right-of-use asset	$ 24,432	$ 24,718
Weighted-average remaining lease term
Operating leases	4 years 3 months 18 days	5 years 7 months 6 days
Finance leases	174 years 9 months 18 days	175 years 9 months 18 days
Weighted-average discount rate
Operating leases	8.80%	8.80%
Finance leases	8.00%	8.00%

Summary of Significant Accounting Policies - IDA Ireland Grant (Details) $ in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2021 EUR (€)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 EUR (€)
IDA Ireland Financial Assistance Grants \| Research and Development Expenses
Government Assistance [Line Items]
Recognized grant income \| $		$ 1.0
IDA Ireland Financial Assistance Grants \| Maximum
Government Assistance [Line Items]
Termination period (upon completion of capital investment)	5 years
IDA Ireland Financial Assistance Grants \| Minimum
Government Assistance [Line Items]
Termination period (from last grant payment)	5 years
IDA Ireland Employment Grants
Government Assistance [Line Items]
Grant funding received		0.6	€ 500,000
IDA Ireland Employment Grants \| Maximum
Government Assistance [Line Items]
Grant funding for each new job created	€ 1,000,000.0
IDA Ireland Employment Grants \| Minimum
Government Assistance [Line Items]
Grant funding for each new job created	€ 10,000
Aggregate number of new jobs required to receive Grant benefits	100
Vacant job duration prompting repayment of grant funding	6 months
IDA Ireland Capital Grants
Government Assistance [Line Items]
Grant funding received		$ 0.4	€ 400,000
IDA Ireland Capital Grants \| Maximum
Government Assistance [Line Items]
Grant amount for machinery and equipment	€ 1,200,000
IDA Ireland Capital Grants \| Minimum
Government Assistance [Line Items]
Grant amount for machinery and equipment (percent of actual expenditure)	4.00%
Aggregate number of new jobs required to receive Grant benefits	100
Expenditure requirement on eligible machinery and equipment	€ 30,000,000.0

Income Taxes - Summary of Reconciliation of Income Tax Benefit with Amounts at the U.K. Statutory Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Change in valuation allowance	$ 9,661	$ 25,955
U.K.
Actual income tax benefit effective tax rate	25.00%	19.00%
U.K. \| HMRC
Statutory rate	$ (19,746)	$ (24,627)
Permanent differences - other	2,391	2,323
RTP and other adjustments	(1,165)	1,244
State and local rate, net of federal tax	(698)	(5,660)
U.K. tax credit	(4,028)	2,296
U.S. tax credit	(9,830)	(2,436)
Foreign tax rate differential	4,558	195
UK rate change (19% & 25% at expected DTA turn)	239	(1,973)
US state rate change	15,394	(3)
Section 162(m) deferred adjustment	2,728	1,386
Disallowed interest	2,812
Change in valuation allowance	$ 7,345	$ 27,255
Tax rate	23.50%	19.00%
Permanent differences - other	(2.85%)	(1.79%)
RTP and other adjustments	1.39%	(0.96%)
State and local rate, net of federal tax	0.83%	4.37%
U.K. tax credit	4.79%	(1.77%)
U.S. tax credit	11.70%	1.88%
Foreign tax rate differential	(5.42%)	(0.15%)
UK rate change (19% & 25% at expected DTA turn)	(0.28%)	1.52%
US state rate change	(18.32%)	0.00%
Section 162(m) deferred adjustment	(3.25%)	(1.07%)
Disallowed interest	(3.35%)	0.00%
Change in valuation allowance	(8.74%)	(21.03%)
Actual income tax benefit effective tax rate	0.00%	0.00%
U.K. \| HMRC \| Tax Year 2022
Tax rate		19.00%
U.K. \| HMRC \| Tax Year 2023
Tax rate	25.00%

Ordinary Shares (Details) - USD ($)					12 Months Ended
Ordinary Shares (Details) - USD ($)	Oct. 30, 2023	May 05, 2023	May 03, 2023	Nov. 09, 2022	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Common stock, shares issued					63,601,015	48,477,209
Private Placement
Class of Stock [Line Items]
Stock issuance costs					$ 6,418,000
Accredited Investors \| Private Placement
Class of Stock [Line Items]
Common stock, shares issued			10,773,913
Aggregate Offer Price			$ 5.75
Proceeds from Issuance of Private Placement		$ 62,000,000.0
Stock issuance costs		$ 4,100,000
Sanofi Foreign Participations B.V. \| Private Placement
Class of Stock [Line Items]
Common stock, shares issued	4,000,000
Aggregate Offer Price	$ 7.50
Proceeds from Issuance of Private Placement	30,000,000.0
Stock issuance costs	$ 2,300,000
JJDC \| Private Placement
Class of Stock [Line Items]
Common stock, shares issued				3,742,514
Aggregate Offer Price				$ 6.68
Proceeds from Issuance of Private Placement				$ 25,000,000.0

- 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.

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+ Details

Share-Based Compensation - Schedule of Grant Date Fair Values of the Share Options Granted Black-Scholes Valuation Model (Details) - Employee Stock Option	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	3.86%	1.56%
Risk-free interest rate, maximum	4.48%	4.23%
Expected volatility	72.00%	80.00%
Expected dividend yield	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	3 years 7 months 6 days	5 years 6 months
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 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.

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+ Details

Share-Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Compensation

Share-Based Compensation

8. Share-Based Compensation

Equity Incentive Plans

The Company’s 2018 Incentive Award Plan and 2016 Equity Incentive Plan (collectively, the “Plans”), were adopted by the Company’s board of directors and shareholders. Under the Plans, the Company has granted share options and restricted share units (“RSUs”) to selected officers, employees, non-employee members of the Company’s board of directors and non-employee consultants. The Company’s board of directors or a committee thereof administers the Plans. Upon the adoption of the 2018 Incentive Award Plan, the Company ceased issuing awards under the 2016 Equity Incentive Plan. The number of shares available for issuance under the 2018 Incentive Award Plan are increased on January 1 of each calendar year beginning in 2019 and ending in and including 2028, by an amount equal to the lesser of (A) 4% of the ordinary shares outstanding on the final day of the immediately preceding calendar year and (B) a smaller number of shares determined by the Company's board of directors. Under the 2018 Incentive Award Plan the Company initially reserved up to 3,054,996 shares for issuance, which has been increased to 11,110,748 as of December 31, 2023. As of December 31, 2023, 310,488 shares remain available for future issuance. In January 2024, the number of shares available for issuance under the 2018 Incentive Award Plan increased by 2,544,040 shares. Also, in January 2024, the Company’s board of directors approved up to 2,675,000 options and restricted share units to be granted to certain executives, employees and consultants, in each case, under the 2018 Incentive Award Plan.

Options

A summary of the Company’s share option activity related to employees, non-employee members of the board of directors and non-employee consultants as of and for the years ended December 31, 2023 and 2022 is as follows (in thousands, except share and per share amounts):


					Weighted-
			Weighted-		Average
			Average		Remaining
		Number of	Exercise		Contractual
		Options	Price		Term (years)
Outstanding at December 31, 2022		6,858,409	$	14.03	6.86	years
Granted		1,546,840	$	8.49
Exercised		(3,864)	$	2.64
Forfeited		(174,678)	$	14.95
Outstanding at December 31, 2023		8,226,707	$	12.96	6.35	years
Options exercisable at December 31, 2023		5,709,190	$	13.30	5.40	years
Options vested and expected to vest at December 31, 2023		8,226,707	$	12.96	6.35	years
Aggregate intrinsic value of options outstanding as of December 31, 2023	$	2,262
Aggregate intrinsic value of options exercisable as of December 31, 2023	$	2,228

Options granted under the Plans have a maximum contractual term of ten years. Options granted generally vest 25% on the first anniversary of the date of grant and the balance ratably over the next 36 months. Options granted to directors when they join the board generally vest in 36 equal monthly installments following the date of grant, and annual options granted to directors generally vest on the earlier of the first anniversary of the date of grant or the day before the Company’s next annual meeting of shareholders after the date of grant.

The company recorded the following share-based compensation expense in connection with the options for the years ended December 31, 2023 and 2022 (in thousands):


	Years Ended December 31,
	2023		2022
Research and development	$	8,577	$	10,431
General and administrative		5,054		5,654
Total share-based compensation	$	13,631	$	16,085

The total fair value of options vested during the years ended December 31, 2023 and 2022 was $15.3 million and $16.2 million, respectively.

The weighted average grant date fair value of options granted during the years ended December 31, 2023 and 2022 was $5.67 and $12.81, respectively. The grant date fair values of the share options granted were estimated using the Black-Scholes option valuation model with the following ranges of assumptions (see Note 2):


	2023	2022
Risk-free interest rate	3.86 - 4.48%	1.56 - 4.23%
Expected volatility	72%	80%
Expected dividend yield	0%	0%
Expected term (in years)	3.6 - 6.1	5.5 - 6.1

As of December 31, 2023, the total compensation expense relating to unvested options granted that had not yet been recognized was $18.3 million, which is expected to be recognized over a period of 3.7 years. The Company will issue shares upon exercise of options from ordinary shares reserved under the Plans.

Restricted Share Units

A summary of the Company’s RSU activity related to employees, non-employee members of the board of directors and non-employee consultants for the years ended December 31, 2023 and 2022 is as follows:


		Weighted-
	Number of	Average
	Restricted	Grant Date
	Share Units	Fair Value
Outstanding at December 31, 2022	2,182,500	$	18.59
Granted	1,097,500	$	8.52
Vested	(618,750)	$	15.17
Outstanding at December 31, 2023	2,661,250	$	15.24

RSUs granted generally vest 50% on the second anniversary of the date of grant and 25% on the third and fourth anniversaries of the date of grant. Annual RSUs granted to directors generally vest in a single installment on the earliest to occur of the first anniversary of the grant date or the day immediately prior to the date of the next annual meeting of the Company’s shareholders occurring after the date of grant. The RSUs granted to the directors in June 2021 will be paid on or within 30 days after the date a director ceases to serve on the board. For RSUs granted in future years, the directors may elect whether to defer the payment of their annual RSU awards under the Deferred Compensation Plan for Non-Employee Directors, which was adopted by the board on December 17, 2021. The related share-based compensation expense, which is recognized ratably over the requisite service period, is included in general and administrative and research and development expenses, as applicable, in the consolidated statements of operations and comprehensive loss.

The company recorded the following share-based compensation expense in connection with the RSUs for the years ended December 31, 2023 and 2022 (in thousands):


	Years Ended December 31,
	2023		2022
Research and development	$	4,203	$	3,734
General and administrative		9,882		8,804
Total share-based compensation	$	14,085	$	12,538

As of December 31, 2023, the total compensation expense relating to unvested RSUs granted that had not yet been recognized was $25.3 million, which is expected to be recognized over a period of 3.4 years

To satisfy employee minimum statutory tax withholding requirements for restricted share units that vest, the Company withholds a portion of the vesting ordinary shares. During the years ended December 31, 2023 and 2022,

the Company withheld 237,859 and 128,812 ordinary shares with a total value of approximately $1.5 million and $2.8 million, respectively. These amounts are presented as a cash outflow from financing activities in the accompanying consolidated statement of cash flows.

During the years ended December 31, 2023 and 2022 the Company recognized total share-based compensation expense in the accompanying consolidated statements of operations and comprehensive loss as follows (in thousands):


	Years Ended December 31,
	2023		2022
Research and development	$	12,780	$	14,165
General and administrative		14,936		14,458
Total share-based compensation	$	27,716	$	28,623

During the year ended December 31, 2023, the Company modified certain awards for six participants and recognized $0.3 million related to the modifications, $0.1 million of which was recognized in research and development expense and $0.2 million was recognized in general and administrative expense. During the year ended December 31, 2022, the Company modified certain awards for three participants and recognized $0.3 million related to the modifications, $0.2 million of which was recognized in research and development expense and $0.1 million was recognized in general and administrative expense. The terms of such modifications included, on an award-by-award basis, acceleration of the vesting period and/or extensions of the post-employment period to exercise.

The Company does not expect to realize any tax benefits from its share option activity or the recognition of share-based compensation expense because the Company currently has net operating losses and has a full valuation allowance against its deferred tax assets. Accordingly, no amounts related to excess tax benefits have been reported in cash flows from operations or cash flows from financing activities for the years ended December 31, 2023 and 2022.

Summary of Significant Accounting Policies - Non-Current Assets by Geographical Area (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Non-current assets	$ 157,356	$ 156,170
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Non-current assets	11,071	14,382
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Non-current assets	33,798	36,775
European Union
Revenues from External Customers and Long-Lived Assets [Line Items]
Non-current assets	$ 112,487	$ 105,013

Employee Benefit Plans

12 Months Ended

Dec. 31, 2023

Employee Benefit Plans

Employee Benefit Plans

15. Employee Benefit Plans

United States

On January 1, 2017, Meira LLC adopted a defined contribution retirement plan that complies with Section 401(k) of the Internal Revenue Code. All Meira LLC employees over the age of 21 are eligible to participate in the plan after three consecutive months of service. Employees are able to defer a portion of their pay into the plan on the first day of the month or after the day all age and service requirements have been met. The plan provides for a Company matching contribution. All eligible employees receive an employer matching contribution equal to the lesser of the amount the employee contributes to the plan or 6% of their salary up to the annual IRS limit.

United Kingdom

On August 1, 2016, Meira UK II adopted a defined contribution group personal pension plan that complies with HMRC for tax relief. All Meira UK II employees are eligible to participate in the plan upon joining the company and providing the required services. All eligible employees, if they elect to join the pension scheme, receive an employer pension contribution equal to 7.5% to 10.0% of their pensionable earnings. Currently, employees are required to contribute 0.5%, to meet minimum legal pension funding levels of 8%, but may make optional contributions up to the annual allowance HMRC limits.

Netherlands

Meira Netherlands operates a defined contribution pension. All of its employees participate in the plan. All eligible employees receive an employer pension contribution and are also required to contribute.

Ireland

On November 20, 2020, MeiraGTx Ireland adopted a defined contribution pension plan. All MeiraGTx Ireland employees are eligible to participate in the plan upon joining the Company. All eligible employees, if they elect to join the pension scheme, receive an employer pension contribution. The Company’s current contribution, exclusive of an employee match, is 4.5%, which exceeds Revenue Ireland requirements.

Belgium

Meira Belgium operates a defined contribution pension plan. All eligible employees receive an employer pension contribution of 8% of their annual salary. Employees do not make contributions to the plan.

During the years ended December 31, 2023 and 2022, employer contributions to all plans were $2.5 million and $2.0 million, respectively.

Principal Business Activity

12 Months Ended

Dec. 31, 2023

Principal Business Activity

Principal Business Activity

1. Principal Business Activity

The Company

MeiraGTx Holdings plc and subsidiaries (the “Company” or “Meira Holdings”), an exempted company incorporated under the laws of the Cayman Islands, is a vertically integrated, clinical-stage gene therapy company with a broad pipeline of late stage clinical programs supported by end-to-end manufacturing capabilities. The Company has an internally developed manufacturing platform process, internal plasmid production for GMP, two GMP viral vector production facilities as well as an in-house Quality Control hub for stability and release, all fit for IND through commercial supply. The Company has core capabilities in viral vector design and optimization and a potentially transformative riboswitch gene regulation platform technology that allows for the precise, dose-responsive control of gene expression by oral small molecules. The Company is focusing the riboswitch platform on delivery of metabolic peptides including GLP-1, GIP, glucagon and PYY using oral small molecules, as well as cell therapy for oncology and autoimmune diseases. Although initially focusing on the eye, central nervous system, and salivary gland, the Company has developed the technology to apply genetic medicine to more common diseases, increasing efficacy, addressing novel targets, and expanding access in some of the largest disease areas where the unmet need remains great. The Company also owns and operates a good manufacturing practices, or GMP, multi-product, multi-viral vector manufacturing facility in London, United Kingdom (“UK”), which includes fill and finish capabilities and can supply the Company’s clinical and potential commercial material. Additionally, the Company’s second, large scale viral vector manufacturing facility and its first plasmid and DNA production facility in Shannon, Ireland, both of which are designed to meet GMP requirements, came online in 2022.

Asset Purchase and Related Agreements with Janssen Pharmaceuticals, Inc.

On January 30, 2019, the Company entered into a collaboration, option and license agreement with Janssen Pharmaceuticals, Inc. (“Janssen”), one of the Janssen Pharmaceuticals Companies of Johnson & Johnson (the “Collaboration Agreement”), for the research, development and commercialization of gene therapies for the treatment of inherited retinal diseases (“IRD”). Under the terms of the Collaboration Agreement, the Company received an upfront payment of $100.0 million in March 2019 and a $30.0 million milestone payment in December 2021. The Company also received funding for certain research, manufacturing, clinical development and commercialization costs, and had the potential to obtain additional milestone payments upon the achievement of such milestones and royalties on future net sales of products. On December 20, 2023, the Company entered into an Asset Purchase Agreement (“Asset Purchase Agreement”) with Janssen pursuant to which the Company sold and assigned to Janssen, and Janssen purchased and assumed, that certain License Agreement, dated February 5, 2019, by and between UCL Business Plc (now UCL Business Ltd.) (“UCLB”), on the one hand, and MeiraGTx UK II Limited and MeiraGTx Limited, on the other hand (the “UCLB RPGR License Agreement”), relating to the research, development, manufacture and exploitation of the RPGR Product, and other related assets as described in the Asset Purchase Agreement. In connection with entering into the Asset Purchase Agreement, the Company entered into a Termination Agreement with Janssen terminating the Collaboration Agreement. The Company and Janssen also entered into a Supply Agreement on December 20, 2023 pursuant to which the Company agreed to manufacture and supply the RPGR Product for Janssen.

Under the Asset Purchase Agreement, Janssen paid the Company a non-refundable upfront cash payment of $65.0 million in December 2023. Additionally, pursuant to and subject to the terms and conditions set forth in the Asset Purchase Agreement, Janssen agreed to pay the Company future contingent consideration of up to an aggregate of $350.0 million, as follows: (i) a milestone payment of $50.0 million in connection with the achievement of the initiation of the extension study for the Phase 3 LUMEOS clinical trial for the RPGR Product, which milestone was achieved during the first quarter of 2024; (ii) $10.0 million upon completion of certain specified development services for the drug substance for the RPGR Product; (iii) $5.0 million upon completion of certain specified development services for the drug product for the RPGR Product; (iv) $175.0 million upon the first commercial sale of an RPGR Product in the United States; (v) $75.0 million upon the first commercial sale of an RPGR Product in at

least one of the United Kingdom, France, Germany, Spain and Italy; (vi) $25.0 million upon completion of the transfer of certain manufacturing technology for drug substance and drug product from the Company to Janssen; and (vii) $10.0 million upon regulatory approval of a Janssen-selected manufacturing facility in each of the United States and European Union for commercial manufacture of the RPGR Product. Janssen is also responsible for any royalty or milestone amounts that become payable on the RPGR Product under the UCLB RPGR License Agreement.

Basis of Presentation

The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).

Liquidity

The Company has not yet achieved profitable operations. There is no assurance that profitable operations, if ever achieved, could be sustained on a continuing basis. In addition, development activities, clinical and preclinical testing, and commercialization of the Company’s product candidates will require significant additional financing. The Company’s accumulated deficit at December 31, 2023 totaled $554.2 million, and management expects to incur substantial losses in future periods. The success of the Company is subject to certain risks and uncertainties, including among others, uncertainty of product development; competition in the Company’s field of use; uncertainty of capital availability; uncertainty in the Company’s ability to enter into agreements with collaborative partners; expanding and protecting the Company’s intellectual property portfolio; dependence on third parties; and dependence on key personnel. For the year ended December 31, 2023, the Company used $105.4 million in cash flows from operations and there are no assurances that the Company will generate positive cash flows in the future. Additionally, there are no assurances that the Company will be successful in obtaining an adequate level of financing for the development and commercialization of its product candidates.

As of December 31, 2023, the Company had cash, cash equivalents and restricted cash in the amount of $130.6 million, which consisted of depository and money market accounts held at large international banks. The Company estimates that its cash and cash equivalents on hand and accounts receivable – related party at December 31, 2023 will be sufficient to cover its expenses for at least the next twelve months from the date of issuance of these consolidated financial statements.

Risks and Uncertainties

The Company operates in an industry that is subject to intense competition, government regulation and rapid technological change. The Company’s operations are subject to significant risk and uncertainties including financial, operational, technological, regulatory and other risks, including the potential risk of business failure.

The Company’s capital resources and operations to date have been funded primarily with the proceeds from the Collaboration Agreement, Asset Purchase Agreement and private and public equity offerings, as well as the proceeds from the debt financing described in Note 13. In the future, the Company may seek to raise additional capital through equity offerings, debt financings, marketing and distribution arrangements and other collaborations, strategic alliances and licensing arrangements or other sources to enable it to complete the development and potential commercialization of its product candidates.

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accrued Expenses
Compensation and benefits	$ 2,634	$ 4,326
Clinical trial costs	12,129	9,600
Professional fees	2,936
Research and development	8,713	13,041
Interest on Tranche 1 Notes	6,499	732
Manufacturing costs	5,834	7,400
Consulting	1,472	3,093
Fixed assets	2,104	694
Rent and facilities costs	142
Other	176	932
Accrued expenses	$ 42,639	$ 39,818

Leases (Tables)

12 Months Ended

Dec. 31, 2023

Leases

Schedule of Components of Lease Cost


	Years Ended December 31,
	2023		2022
Finance lease cost
Amortization of right-of-use assets	$	1,124	$	1,103
Interest on lease liabilities		—		1
Total finance lease cost		1,124		1,104
Operating lease cost		5,473		5,307
Short-term lease cost		159		154
Total lease cost	$	6,756	$	6,565

Schedule of Amounts Reported in the Consolidated Balance Sheets for Leases


	December 31,			December 31,
	2023			2022
Operating leases
Right-of-use asset	$	15,910		$	20,109
Capitalized lease obligations	$	17,145		$	21,215
Finance leases
Right-of-use asset	$	24,432		$	24,718
Capitalized lease obligations	$	—		$	—
Weighted-average remaining lease term
Operating leases		4.3	years		5.6	years
Finance leases		174.8	years		175.8	years
Weighted-average discount rate
Operating leases		8.8	%		8.8	%
Finance leases		8.0	%		8.0	%

Schedule of Other Information Related to Leases


	Years Ended December 31,
	2023		2022
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from finance leases	$	—	$	52
Operating cash flows from operating leases	$	5,662	$	5,384
Financing cash flows from finance leases	$	—	$	—

Right-of-use assets obtained in exchange for lease liabilities
Operating leases	$	—	$	1,793

Schedule of Future Minimum Payments Under Non-cancellable Leases


	Operating Leases
2024	$	5,565
2025		5,524
2026		5,623
2027		1,626
2028		1,335
Thereafter		706
Total undiscounted lease payments	$	20,379
Less: Imputed interest		(3,234)
Total lease liabilities	$	17,145

Leases - Schedule of Other Information Related to Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from finance leases		$ 52
Operating cash flows from operating leases	$ 5,662	5,384
Right-of-use assets obtained in exchange for lease liabilities
Right-of-use assets obtained in exchange for lease liabilities		$ 1,793

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2023

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Consolidation

The accompanying consolidated financial statements include the accounts of Meira Holdings and its wholly owned subsidiaries:

MeiraGTx Limited, a limited company incorporated under the laws of England and Wales;

MeiraGTx, LLC, a Delaware limited liability company (“Meira LLC”);

MeiraGTx UK II Limited, a limited company incorporated under the laws of England and Wales (“Meira UK II”);

MeiraGTx Ireland DAC, a designated activity company incorporated under the laws of Ireland (“Meira Ireland”);

MeiraGTx Netherlands B.V., a private company with limited liability incorporated under the laws of the Netherlands (“Meira Netherlands”);

MeiraGTx Belgium, a private company with limited liability incorporated under the laws of Belgium (“Meira Belgium”);

BRI-Alzan, Inc., a Delaware corporation (“BRI-Alzan”);

MeiraGTx Bio Inc., a Delaware corporation (“Meira Bio”);

MeiraGTx B.V., a private company with limited liability incorporated under the laws of the Netherlands (“Meira B.V.”);

MeiraGTx Neurosciences, Inc., a Delaware corporation (“Meira Neuro”);

MeiraGTx Therapeutics, Inc., a Delaware corporation (“Meira Therapeutics”); and

MeiraGTx UK Limited, a limited company incorporated under the laws of England and Wales (“Meira UK”).

All intercompany balances and transactions between the consolidated companies have been eliminated in consolidation.

Use of Estimates

Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these consolidated financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes and management must select an amount that falls within that range of reasonable estimates. This process may result in actual results differing materially from those estimated amounts used in the preparation of the financial statements if these results differ from historical experience, or other assumptions do not turn out to be substantially accurate, even if such assumptions are reasonable when made. In preparing these consolidated financial statements, management used significant estimates in the following areas, among others: collaboration revenue, fair value of nonfinancial assets, stand-alone selling price and material rights in connection with the Asset Purchase and Commercial Supply Agreements, the accounting for research and development costs, share-based compensation, leases, asset retirement obligations, fair value of financial instruments and tax incentive receivable.

Cash and Cash Equivalents

The Company considers all highly liquid instruments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. Cash and cash equivalents consist of checking and money market accounts held at large international banks that are readily convertible into cash.

Restricted Cash

Restricted cash represents a guarantee put in place as required by the terms of the research and innovation grant from IDA Ireland which offers financial assistance in establishing the Company’s operations in Shannon, Ireland. The following table provides a reconciliation of the components of cash and cash equivalents and restricted cash reported in the Company’s consolidated balance sheets to the total of the amount presented in the consolidated statements of cash flows (in thousands):


	December 31,		December 31,
	2023		2022
Cash and cash equivalents	$	129,566	$	115,516
Restricted cash		1,083		—
Total cash, cash equivalents and restricted cash in the condensed consolidated statement of cash flows	$	130,649	$	115,516

Financial Instruments

The carrying value of accounts receivable-related party, tax incentive receivable, other current assets, and accounts payable reported in the consolidated balance sheets equal or approximate fair value due to their short maturities.

Tax Incentive Receivable

Meira UK II is eligible to participate in a UK research and development tax incentive programs under which it is eligible to receive a cash refund from His Majesty’s Revenue & Customs (“HMRC”) for a percentage of the qualified research and development costs expended by Meira UK II under the small and medium sized enterprises (“SME”) program and the research and development expenditures credit (“RDEC”) program. The SME cash refund is available to companies with less than 500 employees and annual aggregate revenue of less than 100.0 million euros or total aggregate assets less than 86.0 million euros during the reimbursable period. The Company’s estimate of the amount of cash refund it expects to receive related to the SME and RDEC programs is included in tax incentive receivable in the accompanying consolidated balance sheets and such amounts are recorded as a reduction of research and development expense in the statements of operations. During the years ended December 31, 2023 and 2022, the Company recorded reductions to research and development expenses of $2.9 million and $6.8 million, respectively.

In addition, the Company incurs Value Added Tax (“VAT”) on services provided by UK and EU vendors, which it is entitled to reclaim. The Company’s estimate of the amount of cash refund it expects to receive related to VAT was $0.6 million and $1.1 million as of December 31, 2023 and 2022, respectively, which is included in other current assets in the accompanying consolidated balance sheets.

Fair Value Measurements

Fair value is defined as the price that would be received upon sale of an asset or paid upon transfer of a liability in an orderly transaction between market participants at the measurement date and in the principal or most advantageous market for that asset or liability. The fair value should be calculated based on assumptions that market participants would use in pricing the asset or liability, not on assumptions specific to the entity. In addition, the fair value of liabilities should include consideration of non-performance risk including the Company’s own credit risk.

The Company follows ASC Topic 820, Fair Value Measurements and Disclosures, or ASC 820, for application to financial assets and liabilities. In addition to defining fair value, the standard expands the disclosure requirements around fair value and establishes a fair value hierarchy for valuation inputs. The hierarchy prioritizes the inputs into

three levels based on the extent to which inputs used in measuring fair value are observable in the market. Each fair value measurement is reported in one of the three levels which are determined by the lowest level input that is significant to the fair value measurement in its entirety. These levels are:

●

Level 1: Observable inputs such as quoted prices in active markets for identical assets the reporting entity has the ability to access as of the measurement date;

●

Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and

●

Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

The table below represents the values of the Company’s financial assets and liabilities that are required to be measured at fair value on a recurring basis (in thousands):


	Fair Value Measurement Using:
			Significant		Significant Other		Significant
	December 31,		Observable Inputs		Observable Inputs		Unobservable
Description	2023		(Level 1)		(Level 2)		(Level 3)
Cash equivalents	$	46,868	$	46,868	$	—	$	—
Restricted cash	$	1,083	$	1,083	$	—	$	—


	Fair Value Measurement Using:
			Significant		Significant Other		Significant
	December 31,		Observable Inputs		Observable Inputs		Unobservable
Description	2022		(Level 1)		(Level 2)		(Level 3)
Cash equivalents	$	57,336	$	57,336	$	—	$	—
Other long-term liabilities	$	262	$	262	$	—	$	—

Equity Method and Other Investments

The Company accounts for equity investments under the equity method of accounting when the requirements for consolidation are not met, and the Company has significant influence over the operations of the investee. Equity method investments are initially recorded at cost and subsequently adjusted for the Company’s share of net income or loss and cash contributions and distributions and are included in equity method and other investments in the accompanying consolidated balance sheets. Equity investments that do not result in consolidation and are not accounted for under the equity method are measured at fair value, with any changes in fair value recognized in net income (loss). For any such investments that do not have readily determinable fair values, the Company elects the measurement alternative to measure the investments at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. Equity method investments are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. If it is determined that a loss in value of the equity method investment is other than temporary, an impairment loss is measured based on the excess of the carrying amount of an investment over its estimated fair value. Impairment analyses are based on current plans, intended holding periods, and available information at the time the analysis is prepared.

Concentrations of Credit Risk

The Company maintains its cash and cash equivalents primarily in depository and money market accounts within two large financial institutions in the United States and one large financial institution in the United Kingdom and Ireland. Cash balances deposited at these major financial banking institutions exceed the insured limit. The

Company has not experienced any losses on its bank deposits and believes these deposits do not expose the Company to any significant credit risk.

Intangible Assets

Intangible assets consist of purchased rights to licensed technology as it relates to the Company’s manufacturing processes and has future alternative use in the Company’s operations. The licensed technology is being amortized on a straight-line basis over 7 years, which represents the estimated periods of benefit and the expected pattern of consumption (see Note 6).

Property, Plant and Equipment, Net

Property, plant and equipment are stated at cost, net of accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the respective assets. Leasehold improvements are depreciated over the lesser of their useful lives or the term of the lease (see Note 5).

The estimated useful lives of the asset categories are as follows:


Asset Category		Useful Lives
Computer and office equipment		3 years
Laboratory equipment		5 years
Manufacturing equipment		7 years
Furniture and fixtures		5 years
Leasehold improvements		lesser of useful life or remaining term of lease

Expenditures for leasehold improvements are capitalized, and expenditures for maintenance and repairs are expensed to operations as incurred.

ASC Topic 360, Property, Plant and Equipment, addresses the financial accounting and reporting for impairment or disposal of long-lived assets. The Company reviews the recorded values of long-lived assets for impairment whenever events or changes in business circumstances indicate that the carrying amount of an asset or group of assets may not be fully recoverable. The Company did not record any material impairment charges in 2023 or 2022.

Leases

The Company accounts for leases in accordance with ASC 842. The Company determines if an arrangement is a lease at contract inception. A lease exists when a contract conveys the right to control the use of identified property, plant, or equipment for a period of time in exchange for consideration. The definition of a lease embodies two conditions: (1) there is an identified asset in the contract that is land or a depreciable asset (i.e., property, plant, and equipment), and (2) the Company has the right to control the use of the identified asset. The Company accounts for the lease and non-lease components as a single lease component.

From time to time the Company enters into direct financing lease arrangements that include a lessee obligation to purchase the leased asset at the end of the lease term, a bargain purchase option, or provides for minimum lease payments with a present value of 90% or more of the fair value of the leased asset at the date of lease inception.

Operating leases where the Company is the lessee are included in right-of-use (“ROU”) assets – operating leases and lease obligations are included on the Company’s consolidated balance sheets. The lease obligations are initially and subsequently measured at the present value of the unpaid lease payments at the lease commencement date and subsequent reporting periods.

Finance leases where the Company is the lessee are included in ROU assets – finance leases, net and lease obligations on the Company’s consolidated balance sheets. The lease obligations are initially measured in the same manner as for operating leases and are subsequently measured at amortized cost using the effective interest method.

Key estimates and judgments include how the Company determined (1) the discount rate used to discount the unpaid lease payments to present value, (2) lease term and (3) lease payments.

ASC 842 requires a lessee to discount its unpaid lease payments using the interest rate implicit in the lease or, if that rate cannot be readily determined, its incremental borrowing rate. As most of the Company’s leases where it is the lessee do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The Company’s incremental borrowing rate for a lease is the rate of interest it would have to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. The Company uses the implicit rate when readily determinable.

The lease term for all of the Company’s leases includes the non-cancellable period of the lease plus any additional periods covered by either a lessee option to extend (or not to terminate) the lease that is reasonably certain to be exercised, or an option to extend (or not to terminate) the lease controlled by the lessor.

The ROU asset is initially measured at cost, which comprises the initial amount of the lease liability adjusted for lease payments made at or before the lease commencement date less any lease incentives received.

For operating leases, the ROU asset is subsequently measured throughout the lease term at the carrying amount of the lease liability, minus any accrued lease payments, less the unamortized balance of lease incentives received. Lease expense for lease payments is recognized on a straight-line basis over the lease term.

For finance leases, the ROU asset is subsequently amortized using the straight-line method from the lease commencement date to the earlier of the end of its useful life or the end of the lease term unless the lease transfers ownership of the underlying asset, or the Company is reasonably certain to exercise an option to purchase the underlying asset. In those cases, the ROU asset is amortized over the useful life of the underlying asset. Amortization of the ROU asset is recognized and presented separately from interest expense on the lease liability.

The Company has elected not to recognize ROU assets and lease liabilities for all short-term leases that have a lease term of 12 months or less at lease commencement. Lease payments associated with short-term leases are recognized as an expense on a straight-line basis over the lease term.

Asset Retirement Obligations

Accounting for asset retirement obligations requires legal obligations associated with the retirement of long-lived assets to be recognized at fair value when incurred and capitalized as part of the related long-lived asset. In the absence of quoted market prices, the Company estimates the fair value of its asset retirement obligations using Level 3 present value techniques, in which estimates of future cash flows associated with retirement activities are discounted using a credit-adjusted risk-free rate. Asset retirement obligations currently reported on the Company’s consolidated balance sheets were measured during a period of historically low interest rates. The impact on measurements of new asset retirement obligations using different rates in the future may be significant.

The Company uses estimates to determine the asset retirement obligations at the end of the lease term and discounts such asset retirement obligations using an estimated discount rate. Interest on the discounted asset retirement obligation is amortized over the term of the lease using the effective interest method and is recorded as interest expense in the consolidated statements of operations and comprehensive loss.

The change in asset retirement obligations is as follows (in thousands):


	For the Years Ended December 31,
	2023		2022
Balance at beginning of period	$	2,179	$	2,081
Additional asset retirement obligations incurred during the period		—		9
Amortization of interest		177		168
Effects of exchange rate changes		45		(79)
Balance at end of period	$	2,401	$	2,179

IDA Ireland Grant

In August 2021, Meira Ireland entered into an agreement pursuant to which it received a grant from IDA Ireland for financial assistance in establishing its operations in Shannon, Ireland. Under the terms of the grant, Meira Ireland is eligible to receive the lesser of €1.0 million or €10,000 for each job created (the “employment grant”) and the lesser of €1.2 million or 4% of the actual expenditure on the provision of machinery and equipment (the “capital grant”). Meira Ireland may apply for a drawdown of the employment grant once a job has been created and the position has been held for a period of at least one month, and may apply for a drawdown of the capital grant once an eligible asset has been purchased and installed, conditioned on the creation of a cumulative number of jobs by the end of the immediately preceding year. An aggregate of 100 jobs must be created to receive the maximum benefit under the capital grant. An application for a drawdown must be accompanied by an audit certification for compliance with the terms of the grant. The Company has a guarantee in place with a bank in favor of IDA Ireland, pursuant to which it restricts cash in the amount of claims made under the grant such that the Company maintains the funds to cover any portion of the grant income that may become repayable in the future. This amount is presented as restricted cash in the accompanying consolidated balance sheet. All expenditures must be completed by December 31, 2024, and the agreement terminates on the later of five years from the date of the last payment from the grant or five years from completion of the capital investment, which is expenditure of at least €30.0 million on eligible machinery and equipment.

The Company recognizes grant income when there is reasonable assurance that the Company will comply with the conditions attached to the grant and that it will receive the grant. Grant income from the employment grant is recognized as a deduction from the amount of the related expense, and grant income from the capital grant is deducted from the carrying amount of the related asset and recognized in income over the asset’s useful life in the form of a reduced depreciation charge. The Company received its first drawdown under the grant in 2023, which was comprised of $0.6 million (€0.5 million) for the employment grant and $0.4 million (€0.4 million) for the capital grant. During the year ended December 31, 2023, the Company recognized $1.0 million of grant income as a reduction of research and development expenses in the accompanying consolidated statements of operations and comprehensive loss.

During the five-year period ending on the termination of the grant agreement, Meira Ireland must maintain compliance with the terms of the grant. If the total number of jobs is less than 100 at the time of IDA Ireland’s annual review, the Company may have to repay a portion of the capital grant, and if a job for which the Company received employment grant funding remains vacant for a period in excess of six calendar months, the Company may have to repay the employment grant received for that job.

Share-Based Compensation Expense

Options

The Company grants share options to employees, non-employee members of the Company’s board of directors and non-employee consultants as compensation for services performed. Employee and non-employee members of the board of directors’ awards of share-based compensation are accounted for in accordance with ASC 718, Compensation – Stock Compensation, or ASC 718. The Company accounts for forfeitures of stock option awards as they occur. ASC 718 requires all share-based payments to employees and non-employee directors, including grants of share options, to be recognized in the consolidated statement of operations and comprehensive loss based on their grant date fair values. The grant date fair value of share options is estimated using the Black-Scholes option valuation model.

Using this model, fair value is calculated based on assumptions with respect to (i) the fair value of the Company’s ordinary shares on the grant date; (ii) expected volatility of the Company’s ordinary share price, (iii) the periods of time over which the optionees are expected to hold their options prior to exercise (expected term), (iv) expected dividend yield on the Company’s ordinary shares, and (v) risk-free interest rates.

The assumptions underlying these valuations represented management’s best estimate, which involved inherent uncertainties and the application of management’s judgment. As a result, if the Company had used different assumptions or estimates, the fair value of its ordinary shares and its share-based compensation expense could have been materially different.

The expected term of share options granted to the optionees is determined using the average of the vesting period and contractual life of the option, an accepted method for the Company’s option grants under the Securities and Exchange Commission’s (“SEC”) Staff Accounting Bulletin No. 107 and No. 110, Share-Based Payment.

The Company believes that its future volatility could differ materially during the expected term from the volatility that would be calculated from its historical share prices to date. Consequently, expected volatility is based on an analysis of guideline companies and the Company’s own volatility in accordance with ASC 718. The expected dividend yield is zero as the Company has never paid dividends and does not currently anticipate paying any in the foreseeable future. Risk-free interest rates are based on quoted U.S. Treasury rates for securities with maturities approximating the option’s expected term.

Restricted Share Units

The Company grants restricted share units (“RSUs”) to employees, non-employee members of the Company’s board of directors and non-employee consultants as compensation for services performed. Awards of RSUs are accounted for in accordance with ASC 718, Compensation – Stock Compensation, or ASC 718. ASC 718 requires all share-based payments to employees, non-employee members of the Company’s board of directors and non-employee consultants, including grants of RSUs, to be recognized in the consolidated statement of operations and comprehensive loss based on their grant date fair values. The grant date fair value of RSUs is determined using the closing market price of the Company’s ordinary shares on the date of grant.

Collaboration Arrangements

The Company evaluates its collaborative arrangements pursuant to ASC 808, Collaborative Arrangements (“ASC 808”) and ASC 606, Revenue from Contracts with Customers (“ASC 606”). The Company considers the nature and contractual terms of collaborative arrangements and assesses whether the arrangement involves a joint operating activity pursuant to which the Company is an active participant and is exposed to significant risks and rewards with respect to the arrangement. If the Company is an active participant and is exposed to significant risks and rewards

with respect to the arrangement, the Company accounts for the arrangement as a collaboration under ASC 808. To date, the Company has entered into two separate collaboration agreements, both of which are with Janssen, which were determined to be within the scope of ASC 808.

ASC 808 does not address recognition or measurement matters related to collaborative arrangements. Payments between participants pursuant to a collaborative arrangement that are within the scope of other authoritative accounting literature on income statement classification are accounted for using the relevant provisions of that literature. If the Company concludes that some or all aspects of the arrangement are within the scope of ASC 808 and do not represent a transaction with a customer, the Company recognizes its allocation of the shared costs incurred with respect to the jointly conducted activities pursuant to ASC 730, Research and Development. If the Company concludes that some or all aspects of the arrangement represent a transaction with a customer, the Company accounts for those aspects of the arrangement within the scope of ASC 606. If the payments are not within the scope of other authoritative accounting literature, the income statement classification for the payments is based on an analogy to authoritative accounting literature or if there is no appropriate analogy, a reasonable, rational and consistently applied accounting policy election. Payments received from a collaboration partner to which this policy applies may include upfront payments in respect of a license of intellectual property, development and commercialization-based milestones, and royalties.

Refer to the discussion in Note 11 for further information related to the accounting for the Collaboration Agreement.

Revenue Recognition

The Company evaluates the promised goods or services to determine which promises, or group of promises, represent performance obligations in contracts with the Company’s. In contemplation of whether a promised good or service meets the criteria required of a performance obligation, the Company considers the stage of development of the underlying intellectual property, the capabilities and expertise of the customer relative to the underlying intellectual property, and whether the promised goods or services are integral to or dependent on other promises in the contract. When accounting for an arrangement that contains multiple performance obligations, the Company must develop judgmental assumptions, which may include market conditions, reimbursement rates for personnel costs, development timelines and probabilities of regulatory success to determine the stand-alone selling price for each performance obligation identified in the contract.

When the Company concludes that a contract should be accounted for as a combined performance obligation and recognized over time, the Company must then determine the period over which revenue should be recognized and the method by which to measure revenue. The Company generally recognizes revenue using a cost-based input method.

At inception, the Company determines whether contracts are within the scope of ASC 606 or other topics. For contracts that are determined to be within the scope of ASC 606, the Company recognizes revenue when its customer or collaborator obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services. To determine revenue recognition the Company performs the following five steps:

identify the contract(s) with a customer;

ii.

identify the performance obligations in the contract;

iii.

determine the transaction price;

iv.

allocate the transaction price to the performance obligations within the contract; and

recognize revenue when (or as) the entity satisfies a performance obligation.

The Company only applies the five-step model to contracts when it determines that it is probable it will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer.

At contract inception, the Company assesses the goods or services promised within the contract to determine whether each promised good or service is a performance obligation. The promised goods or services in the Company’s arrangements typically consist of a license to the Company’s intellectual property and research, development and manufacturing services. The Company may provide options to additional items in such arrangements, which are accounted for as separate contracts when the customer elects to exercise such options, unless the option provides a material right to the customer. Performance obligations are promises in a contract to transfer a distinct good or service to the customer that (i) the customer can benefit from on its own or together with other readily available resources, and (ii) is separately identifiable from other promises in the contract. Goods or services that are not individually distinct performance obligations are combined with other promised goods or services until such combined group of promises meet the requirements of a performance obligation.

The Company determines transaction price based on the amount of consideration the Company expects to receive for transferring the promised goods or services in the contract. Consideration may be fixed, variable, or a combination of both. At contract inception for arrangements that include variable consideration, the Company estimates the probability and extent of consideration it expects to receive under the contract utilizing either the most likely amount method or expected amount method, whichever best estimates the amount expected to be received. The Company then considers any constraints on the variable consideration and includes in the transaction price variable consideration to the extent it is deemed probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved.

The Company then allocates the transaction price to each performance obligation based on the relative standalone selling price and recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) control is transferred to the customer and the performance obligation is satisfied. For performance obligations which consist of licenses and other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition.

If there are multiple performance obligations, the Company allocates the transaction price to each performance obligation based on their estimated standalone selling prices (“SSP”). The Company estimates the SSP for each performance obligation by considering information such as market conditions, entity-specific factors, and information about its customer that is reasonably available. The Company considers estimation approaches that allow it to maximize the use of observable inputs. These estimation approaches may include the adjusted market assessment approach, the expected cost plus a margin approach or the residual approach. The Company also considers whether to use a different estimation approach or a combination of approaches to estimate the SSP for each performance obligation. Developing certain assumptions (e.g., treatable patient population, expected market share, probability of success and product profitability, and discount rate based on weighted-average cost of capital) to estimate the SSP of a performance obligation requires significant judgment.

The Company records amounts as accounts receivable when the right to consideration is deemed unconditional. When consideration is received, or such consideration is unconditionally due, from a customer prior to transferring goods or services to the customer under the terms of a contract, a contract liability is recorded as deferred revenue.

Amounts received prior to satisfying the revenue recognition criteria are recognized as deferred revenue in the Company’s consolidated balance sheet. Amounts expected to be recognized as revenue within the 12 months

following the balance sheet date are classified as deferred revenue – related party, current. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue – related party.

The Company’s collaboration and revenue arrangements include the following:

Up-front License Fees: If a license is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from nonrefundable, up-front fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, up-front fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition.

Milestone Payments: At the inception of an agreement that includes research and development milestone payments, the Company evaluates each milestone to determine when and how much of the milestone to include in the transaction price. The Company first estimates the amount of the milestone payment that the Company could receive using either the expected value or the most likely amount approach. The Company primarily uses the most likely amount approach as that approach is generally most predictive for milestone payments with a binary outcome. Then, the Company considers whether any portion of that estimated amount is subject to the variable consideration constraint (that is, whether it is probable that a significant reversal of cumulative revenue would not occur upon resolution of the uncertainty.) The Company updates the estimate of variable consideration included in the transaction price at each reporting date which includes updating the assessment of the likely amount of consideration and the application of the constraint to reflect current facts and circumstances.

Royalties: For arrangements that include sales-based royalties, including milestone payments based on a level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any revenue related to sales-based royalties or milestone payments based on the level of sales.

Research and Development Services: The Company is incurring research and development costs, with Janssen responsible for up to 100% of the costs, depending on the type of research and development services being performed. The Company records costs associated with the development activities as research and development expenses in the consolidated statement of operations and comprehensive loss consistent with ASC 730, Research and Development. The reimbursement of the research and development costs by Janssen is representative of the joint risk sharing nature of the arrangement. The Company considered the guidance in ASC 808 and recognizes the payments received from Janssen as a reduction to research and development expense when the related costs are incurred.

Manufacturing Supply Services: Arrangements that include a promise for future supply of drug substance or drug product for either clinical development or commercial supply at the customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the licensee and if so, they are accounted for as separate performance obligations at the outset of the arrangement.

Customer Options: Customer options are evaluated at contract inception to determine whether those options provide a material right (i.e., an optional good or service offered for free or at a discount) to the customer. If the customer options represent a material right, the material right is treated as a separate performance obligation at the outset of the arrangement. The Company allocates the transaction price to material rights based on the standalone selling price. As a practical alternative to estimating the standalone selling price of a material right when the underlying goods or services are both (i) similar to the original goods or services in the contract and (ii) provided in accordance

with the terms of the original contract, the Company allocates the total amount of consideration expected to be received from the customer to the total goods or services expected to be provided to the customer. Amounts allocated to any material right are recognized as revenue when or as the related future goods or services are transferred or when the option expires.

Research and Development

Research and development costs are charged to expense as incurred. These costs include, but are not limited to, employee-related expenses, including salaries, benefits and travel of the Company’s research and development personnel; expenses incurred under agreements with contract research organizations and investigative sites that conduct clinical and preclinical studies and for the drug product for the clinical studies and preclinical activities; facilities; supplies; rent, insurance, certain legal fees, share-based compensation, depreciation, other costs associated with clinical and preclinical activities and regulatory operations and acquisition of in process research and development write-offs. Research funding under collaboration agreements and refundable research and development credits / tax credits are recorded as an offset to these costs.

Costs for certain development activities, such as Company funded outside research programs, are recognized based on an evaluation of the progress to completion of specific tasks with respect to their actual costs incurred. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the consolidated financial statements as prepaid or accrued research and development expenses, as the case may be.

Foreign Currencies

The Company’s consolidated financial statements are presented in U.S. dollars, the reporting currency of the Company. The financial position and results of operations of Meira UK II, Meira Ireland, Meira Netherlands, Meira Belgium and Meira B.V. are measured using the foreign subsidiaries’ local currency as the functional currency. These entities’ cash accounts holding U.S. dollars and intercompany payables and receivables are remeasured based upon the exchange rate at the date of remeasurement with the resulting gain or loss included in the consolidated statements of operations and comprehensive loss. Expenses of such subsidiaries have been translated into U.S. dollars at average exchange rates prevailing during the period. Assets and liabilities have been translated at the rates of exchange on the consolidated balance sheet dates. The resulting translation gain and loss adjustments are recorded directly as a separate component of shareholders’ equity and as other comprehensive (loss) income on the consolidated statements of operations and comprehensive loss.

Income Taxes

Income taxes are recorded in accordance with ASC Topic 740, Income Taxes, or ASC 740, which provides for deferred taxes using an asset and liability approach. The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Realization of net deferred tax assets is dependent on future taxable income. Valuation allowances are provided if, based upon the weight of available evidence, it is more likely than not that some, or all, of the deferred tax assets will not be realized. Realization of net deferred tax assets is dependent on future taxable income (see Note 10).

The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances.

As of December 31, 2023 and 2022, the Company recorded unrecognized tax positions of $2.0 and $0.9 million, respectively. No interest and penalties have been accrued relative to the unrecognized tax positions.

The Company is required to estimate income taxes in each of the jurisdictions in which it operates.

Net Loss per Ordinary Share

Basic net loss per ordinary share is computed by dividing net loss by the weighted average number of shares of the Company’s ordinary shares outstanding during the period of computation. Diluted net loss per ordinary share is computed similar to basic net loss per share except that the denominator is increased to include the number of additional ordinary shares that would have been outstanding if the ordinary share equivalents had been issued at the beginning of the year and if the additional ordinary shares were dilutive (treasury stock method) or the two-class method, whichever is more dilutive. For all periods presented, basic and diluted net loss per ordinary share are the same as any additional ordinary share equivalents would be anti-dilutive.

The following securities are considered to be ordinary share equivalents, but were not included in the computation of diluted net loss per ordinary share because to do so would have been anti-dilutive:


	December 31,	December 31,
	2023	2022
Share options	8,226,707	6,858,409
Restricted share units	2,661,250	2,182,500
Deferred share units	185,000	110,000
Warrants	700,000	700,000
Restricted ordinary shares subject to forfeiture	—	14,049
	11,772,957	9,864,958

Other Comprehensive Income (Loss)

Other comprehensive income (loss) is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. The only component of other comprehensive income (loss) impacting the Company is foreign currency translation.

Segment Information

Management has concluded it has a single reporting segment for purposes of reporting financial condition and results of operations.

The Company’s license revenue, research funding and deferred revenue from the Collaboration Agreement were generated in the United Kingdom.

The following table summarizes long-lived assets by geographical area (in thousands):


	December 31,		December 31,
	2023		2022
United States	$	11,071	$	14,382
United Kingdom		33,798		36,775
European Union		112,487		105,013
	$	157,356	$	156,170

Recent Accounting Pronouncements Adopted

In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which adds a new Topic 326 to the Codification and removes the thresholds that companies apply to measure credit losses on financial instruments measured at amortized cost, such as loans, receivables, and held-to-maturity debt securities. Under current GAAP, companies generally recognize credit losses when it is probable that the loss has been incurred. The revised guidance will remove all recognition thresholds and will require companies to recognize an allowance for credit losses for the difference between the amortized cost basis of a financial instrument and the amount of amortized cost that the company expects to collect over the instrument’s contractual life. ASU 2016-13 also amends the credit loss measurement guidance for available-for-sale debt securities and beneficial interests in securitized financial assets. The guidance is applicable for fiscal years beginning after December 15, 2019 and interim periods within those years, however, the FASB extended the effective date for smaller reporting companies to fiscal years beginning after December 15, 2022. The Company adopted this standard effective January 1, 2023 and it did not have an impact on the Company’s consolidated financial statements.

Recent Accounting Pronouncements Not Yet Adopted

In October 2023, the FASB issued ASU 2023-06, Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative. This update includes a number of amendments to clarify or improve disclosure and presentation requirements of a variety of topics in order to allow users to more easily compare entities subject to the SEC’s existing disclosures with those entities that were not previously subject to the requirements and to align the requirements in the FASB accounting standard codification with the SEC’s regulations. The effective date for each amendment will be the date on which the SEC’s removal of that related disclosure requirement from Regulation S-X or Regulation S-K becomes effective, with early adoption prohibited. The Company is currently evaluating the impact of these amendments.

In November 2023, the FASB issued ASU 2023-07, Segment Reporting - Improvements to Reportable Segment Disclosures, which updates reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses and information used to assess segment performance. The amendments in this update are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The Company is still in the process of determining the effect this ASU will have on the consolidated financial statements.

In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures, which requires that an entity disclose specific categories in the effective tax rate reconciliation as well as provide additional information for reconciling items that meet a quantitative threshold. Further, the ASU requires certain disclosures of state versus federal income tax expense and taxes paid. This ASU is effective for fiscal years beginning after December 15, 2024. The Company does not expect the adoption of this ASU to have a material impact on its consolidated financial statements.

Prepaid Expenses

12 Months Ended

Dec. 31, 2023

Prepaid Expenses

Prepaid Expenses

4. Prepaid Expenses

Prepaid expenses at December 31, 2023 and 2022 consist of the following (in thousands):


	December 31,		December 31,
	2023		2022
Clinical trial costs	$	1,530	$	3,411
Dues and license fees		1,439		909
Insurance		861		1,485
Research and development		685		1,220
Facilities costs		630		539
Consulting		243		—
Manufacturing costs		38		347
Other		199		222
	$	5,625	$	8,133

Equity Method and Other Investments (Tables)

12 Months Ended

Dec. 31, 2023

Equity Method and Other Investments

Schedule of equity method and other investments


		December 31, 2023
Investee	Investment Type	Ownership Percentage		Carrying Value		Cost Basis
Visiogene LLC	Equity Method Investment	25	%	$	5,150	$	5,165
Other	Equity Investment	1.6	%		1,616		1,500
Total equity method and other investments				$	6,766	$	6,665

Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2023

Related Party Transactions

Schedule of Deferred Revenue Recognition


Deferred revenue at December 31, 2021	$	64,866
Deferred revenue recognized as license revenue during the year ended December 31, 2022		(15,920)
Effects of exchange rate changes		(6,387)
Deferred revenue at December 31, 2022	$	42,559
Deferred revenue recognized as license revenue during the year ended December 31, 2023		(14,017)
Effects of exchange rate changes		2,033
Remaining deferred revenue under the Collaboration Agreement		30,575
Standalone selling price allocated to performance obligations		7,469
Effects of exchange rate changes		(1,101)
Deferred revenue at December 31, 2023	$	36,943

Commitments and Contingencies (Details)	Dec. 31, 2023
Commitments and Contingencies
Number of new material commitments	0

Summary of Significant Accounting Policies - Anti-dilutive Securities Excluded from EPS (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from EPS	11,772,957	9,864,958
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from EPS	8,226,707	6,858,409
Restricted Share Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from EPS	2,661,250	2,182,500
Stock Appreciation Rights (SARs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from EPS	185,000	110,000
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from EPS	700,000	700,000
Restricted Ordinary Shares Subject to Forfeiture
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from EPS		14,049

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Taxes

Income Taxes

10. Income Taxes

For the years ended December 31, 2023 and 2022, the Company recognized a tax benefit of $0.

As of December 31, 2023, the Company had U.S. federal and state net operating losses (“NOLs”) and foreign carryforward tax losses which are available to reduce future taxable income of (in thousands):


	Federal		State/City
United Kingdom	$	169,599	$	—
United States	$	65,549	$	14,741
Ireland	$	47,681	$	—
Other	$	29,399	$	—

All of the Company’s carryforward tax losses will be indefinitely carried forward. Also, as of December 31, 2023, the Company had orphan drug and research and development credits in the U.S. in the amount of $20.3 million which will begin to expire in 2036 and research and development credits of $3.4 million in the UK which can be carried forward indefinitely. Due to changes in apportionment and legislative changes, state NOLs decreased by $114.0 million, and Netherlands NOLs increased by $3.7 million. The U.S. NOLs and UK carryforward tax losses may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders, as defined under Section 382 of the Internal Revenue Code, as well as UK tax rules. This could limit the amount of NOLs and carryforward tax losses that the Company can utilize annually to offset future taxable income or tax liabilities. As of December 31, 2022, the Company had performed such an analysis and determined that there were no limitations in the UK. However, for U.S. purposes, the Company determined that a

change of ownership occurred in April 2016 and again in June 2018, but there was not a limit for utilizing these losses to offset the 2022 income.

The Company’s pre-tax income (loss) is as follows (in thousands):


	December 31, 2023		December 31, 2022
United Kingdom	$	12,881	$	(54,636)
United States		(63,017)		(54,513)
Ireland		(29,965)		(16,661)
Other		(3,926)		(3,805)
	$	(84,027)	$	(129,615)

The Company is subject to the corporate tax rate in the UK as a limited UK corporation.

The following table summarizes a reconciliation of income tax benefit compared with the amounts at the UK statutory income tax rate (in thousands):


	December 31, 2023			December 31, 2022
Statutory rate	(19,746)	23.50	%	(24,627)	19.00	%
Permanent differences - other	2,391	(2.85)	%	2,323	(1.79)	%
RTP and other adjustment	(1,165)	1.39	%	1,244	(0.96)	%
State and local rate, net of federal tax	(698)	0.83	%	(5,660)	4.37	%
U.K. tax credit	(4,028)	4.79	%	2,296	(1.77)	%
U.S. tax credit	(9,830)	11.70	%	(2,436)	1.88	%
Foreign tax rate differential	4,558	(5.42)	%	195	(0.15)	%
UK rate change (25% & 19%, respectively)	239	(0.28)	%	(1,973)	1.52	%
US state rate change	15,394	(18.32)	%	(3)	0.00	%
Section 162(m) deferred adjustment	2,728	(3.25)	%	1,386	(1.07)	%
Disallowed interest	2,812	(3.35)	%	—	0.00	%
Change in valuation allowance	7,345	(8.74)	%	27,255	(21.03)	%
Actual income tax benefit effective tax rate	—	0.00	%	—	0.00	%

The Expense/(Benefit) for income taxes from continuing operations consists of the following (in thousands):


	December 31, 2023	December 31, 2022
Current Tax Expense/(Benefit)
United Kingdom	—	—
United States	—	—
Other	—	—
Total Current	—	—
Deferred Tax Expense/(Benefit)
United Kingdom	2,393	(8,708)
United States	(6,251)	(17,466)
Ireland	(3,963)	(1,498)
Netherlands	(1,840)	1,717
Total Deferred	(9,661)	(25,955)
Change in Valuation Allowance	9,661	25,955
Total Income Tax Expense/(Benefit)	—	—

Deferred Tax Assets/(Liabilities) (in thousands):


	December 31, 2023		December 31, 2022
Deferred Tax Assets:
Net operating loss carryforwards	$	70,650	$	74,350
Capitalized research and development		19,606		16,288
Share-based compensation		14,290		13,684
R&D credit		21,687		10,837
Lease liability		4,070		6,461
Other		1,121		3,745
Deferred tax assets		131,424		125,365

Deferred Tax Liabilities:
Indefinite-lived intangibles and fixed assets		—		(186)
Depreciation		(1,763)		(2,935)
Right of use assets		(3,777)		(6,207)
Less: valuation allowance		(125,884)		(116,223)
Net deferred tax liability	$	—	$	(186)

ASC 740 requires a valuation allowance to reduce the deferred tax assets reported if, based on the weight of available evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. After consideration of all the evidence, both positive and negative, the Company has recorded a full valuation allowance, after consideration of the reversal of the deferred tax liabilities for the ROU assets and fixed assets, against its deferred tax assets at December 31, 2023 and 2022 because the Company's management has determined that is it more likely than not that these assets will not be fully realized.

Changes to the UK corporation tax rates have been announced which will impact future accounting periods. Finance Act 2021 increases the UK corporation tax rate from 19% to 25% effective April 1, 2023 for companies with profits in excess of GBP 250,000. As the Company does not expect to be able to utilize its carryforward tax losses in the UK until after April 2023, the deferred tax has been calculated using a tax rate of 25%.

As of December 31, 2023 and 2022, the Company recorded unrecognized tax positions of $2.0 million and $0.9 million, respectively. The unrecognized tax positions are netted with deferred tax assets above with full valuation allowance. The changes to unrecognized tax positions for 2023 and 2022 were as follows (in thousands):


	December 31, 2023		December 31, 2022
Unrecognized tax benefits as of January 1	$	937	$	666
Gross increases/(decreases) related to current year		756		279
Gross increases/(decreases) related to prior years		336		(8)
Foreign currency translation		—		—
Unrecognized tax positions as of December 31	$	2,029	$	937

The Company will recognize interest and penalties related to uncertain tax positions in income tax expense. As of December 31, 2023 and 2022, the Company had no accrued interest or penalties related to uncertain tax positions and no amounts have been recognized in the Company's statements of operations and comprehensive loss.

The Company files income tax returns in the United States, UK, various foreign jurisdictions and various U.S. state jurisdictions. In the U.S., all years remain subject to examination. The earliest year subject to examination in the UK is 2020.

MeiraGTx Holdings plc is a UK tax resident with no earnings in its foreign subsidiaries and the Company does not expect any temporary basis difference in its investment in these subsidiaries to reverse in the foreseeable future. Therefore, the Company has not recorded deferred taxes on the outside basis difference in its foreign subsidiaries. It is not probable to compute the amounts, if any.

- 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
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Summary of Significant Accounting Policies - Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Summary of Significant Accounting Policies
Unrecognized tax positions	$ 2,029	$ 937	$ 666
Unrecognized tax benefits, income tax penalties and interest accrued	$ 0

Income Taxes - Schedule of Expense/(Benefit) for Income Taxes from Continuing Operations (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Total Deferred	$ (9,661,000)	$ (25,955,000)
Change in Valuation Allowance	9,661,000	25,955,000
United Kingdom
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Foreign	2,393,000	(8,708,000)
United States
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
United States	(6,251,000)	(17,466,000)
Netherlands
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Foreign	(1,840,000)	1,717,000
Federal
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Total Income Tax Expense (Benefit)	$ 0	$ 0

Leases - Schedule of Future Minimum Lease Payments Under Non-Cancellable Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Operating Leases
2024	$ 5,565
2025	5,524
2026	5,623
2027	1,626
2028	1,335
Thereafter	706
Total undiscounted lease payments	20,379
Less: Imputed interest	(3,234)
Operating lease liability	$ 17,145	$ 21,215

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
CURRENT ASSETS:
Cash and cash equivalents	$ 129,566	$ 115,516
Accounts receivable - related party	10,138	21,334
Prepaid expenses	5,625	8,133
Tax incentive receivable	13,277	7,689
Other current assets	1,016	1,667
Total Current Assets	159,622	154,339
Property, plant and equipment, net	115,896	109,266
Intangible assets, net	1,118	1,335
In-process research and development		742
Restricted cash	1,083
Other assets	1,917	1,402
Equity method and other investments	6,766	6,326
Right-of-use assets - operating leases, net	15,910	20,109
Right-of-use assets - finance leases, net	24,432	24,718
TOTAL ASSETS	326,744	318,237
CURRENT LIABILITIES:
Accounts payable	16,042	16,616
Accrued expenses	42,639	39,818
Lease obligations, current	4,193	3,884
Deferred revenue - related party, current	2,926	15,123
Other current liabilities	1,278	6,631
Total Current Liabilities	67,078	82,072
Deferred revenue - related party	34,017	27,436
Lease obligations	12,952	17,331
Asset retirement obligations	2,401	2,179
Deferred income tax liability		186
Note payable, net	72,119	71,033
Other long-term liabilities		262
TOTAL LIABILITIES	188,567	200,499
SHAREHOLDERS' EQUITY:
Ordinary Shares, $0.00003881 par value, 1,288,327,750 authorized, 63,601,015 and 48,477,209 shares issued and outstanding at December 31, 2023 and December 31, 2022, respectively	2	2
Capital in excess of par value	693,841	581,893
Accumulated other comprehensive income	(1,435)	6,047
Accumulated deficit	(554,231)	(470,204)
Total Shareholders' Equity	138,177	117,738
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 326,744	$ 318,237

Related Party Transactions

12 Months Ended

Dec. 31, 2023

Related Party Transactions

Related Party Transactions

11. Related Party Transactions

Relationship with Janssen Pharmaceuticals, Inc.

Collaboration Agreement

On January 30, 2019, the Company entered into a Collaboration Agreement with Janssen for the research, development and commercialization of gene therapies for the treatment of IRD. Under the agreement, Janssen paid the Company a non-refundable upfront fee of $100.0 million. Janssen and the Company agreed to collaborate to develop the Company’s clinical programs in retinitis pigmentosa and two genetic forms of achromatopsia and Janssen had the exclusive right to commercialize these three product candidates (“Clinical IRD Product Candidates”) globally.

Pursuant to the Collaboration Agreement, the Company and Janssen also agreed on a research collaboration to develop a pipeline of preclinical inherited retinal disease gene therapy candidates (“Research IRD Product Candidates”). The parties agreed to select and prioritize the Research IRD Product Candidates and Janssen had the right to opt-in for a fee for each of the specified targets (each an “Option Target”) to obtain certain development, manufacturing and commercialization rights for the Research IRD Product Candidates.

Unless terminated earlier under certain termination clauses, the Collaboration Agreement was to continue in effect, on a product-by-product and country-by-country basis, until such time as the royalty terms expired in such country. The Company had determined enforceable rights existed in the Collaboration Agreement as the termination clauses were substantive termination penalties by way of the non-refundable upfront fee and the reversion of any licensed intellectual property granted to Janssen upon the termination of the agreement.

Under the Collaboration Agreement, the Company and Janssen were jointly developing Clinical IRD Product Candidates to permit Janssen to commercialize such Clinical IRD Product Candidates under an exclusive license from the Company. In general, the Company had the primary responsibility to develop each Clinical IRD Product Candidate in accordance with the development plan for each Clinical IRD Product Candidate, including where applicable, conducting any necessary research in order to submit the applicable regulatory filings to regulatory authorities. The Company agreed to manufacture these products in its GMP manufacturing facilities for both clinical and commercial supply. Janssen agreed to pay 100% of the clinical and commercialization costs of the products and the Company was eligible to receive untiered 20% royalties on net sales of products and additional development and commercialization milestones up to $340.0 million. The Company received a milestone payment of $30.0 million in December 2021. In connection with entering into the Asset Purchase Agreement, the Company entered into a Termination Agreement with Janssen terminating the Collaboration Agreement.

Asset Purchase and Related Agreements

On December 20, 2023, the Company entered into the Asset Purchase Agreement with Janssen pursuant to which the Company sold and assigned to Janssen, and Janssen purchased and assumed, the UCLB RPGR License Agreement relating to the research, development, manufacture and exploitation of the RPGR Product, and other related assets as described in the Asset Purchase Agreement. Simultaneously, the Company and Janssen also entered into a Supply Agreement pursuant to which the Company agreed to manufacture and supply the RPGR Product for Janssen. Under the Supply Agreement, MeiraGTx UK II, together with its affiliates, will manufacture commercial supply of the RPGR Product for Janssen for an initial term of four years, with Janssen having an option to extend

the Supply Agreement for a fifth year upon written notification. Janssen may terminate the Supply Agreement for convenience upon 90 days’ written notice with payment of a termination fee. Under the Asset Purchase Agreement, Janssen paid the Company a non-refundable upfront fee of $65.0 million in December 2023 and the Company is eligible to receive fees from commercial supply of the RPGR Product and in addition, milestones of up to $350.0 million, as follows: (i) a milestone payment of $50.0 million in connection with the achievement of the initiation of the extension study for the Phase 3 LUMEOS clinical trial for the RPGR Product, which milestone was achieved during the first quarter of 2024; (ii) $10.0 million upon completion of certain specified development services for the drug substance for the RPGR Product; (iii) $5.0 million upon completion of certain specified development services for the drug product for the RPGR Product; (iv) $175.0 million upon the first commercial sale of an RPGR Product in the United States; (v) $75.0 million upon the first commercial sale of an RPGR Product in at least one of the United Kingdom, France, Germany, Spain and Italy; (vi) $25.0 million upon completion of the transfer of certain manufacturing technology for drug substance and drug product from the Company to Janssen; and (vii) $10.0 million upon regulatory approval of a Janssen-selected manufacturing facility in each of the United States and European Union for commercial manufacture of the RPGR Product. Janssen is also responsible for any royalty or milestone amounts that become payable on the RPGR Product under the UCLB RPGR License Agreement.

Revenue Recognition under the Janssen Agreements

Collaboration Agreement

The Company evaluated the potential performance obligations in the Collaboration Agreement pursuant to ASC 606, which included the exclusive license to Clinical IRD Product Candidates, the research, development and manufacturing services (“the services”), and the participation in various joint committees and determined that none of the performance obligations by themselves were distinct. Goods and services that are not distinct are bundled with other goods or services in the contract until a bundle of goods or services that is distinct is created. The services, when combined with the licenses, represent a bundle and should be accounted for as a single performance obligation due to the relevance of the services to the value of the early-stage license and the potential for the intellectual property to be significantly modified during the services period. The Company also evaluated whether or not the right to purchase exclusive option rights for specified Research IRD Product Candidates represents future performance obligations and concluded that these represent a separate buyer decision at market rates, rather than a material right performance obligation. As such, these options have been excluded from the initial allocation of transaction price and the Company will account for these options as separate contracts when and if Janssen elects to exercise the options.

Under ASC 606, the Company recognized collaboration revenue using the cost-to-cost input method, which it believes best depicts the transfer of control to the customer. Under the cost-to-cost input method, the extent of progress towards completion is measured based on the ratio of actual costs incurred to the total estimated costs expected upon satisfying the combined performance obligation by the potential product candidate. Under this method, revenue is being recorded as a percentage of the estimated transaction price based on the extent of progress towards completion. Under ASC 606, the estimated transaction price includes variable consideration subject to constraints. The Company does not include variable consideration to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will occur when any uncertainty associated with the variable consideration is resolved. The estimate of the Company’s measure of progress and estimate of variable consideration to be included in the transaction price will be updated at each reporting date as a change in estimate. The amount related to the unsatisfied portion will be recognized as that portion is satisfied over time.

Under ASC 606 the Company accounts for (i) the licenses it conveyed with respect to the Clinical IRD Product Candidates and (ii) its obligations to perform services as a single performance obligation under the Collaboration Agreement with Janssen on a product candidate basis. Janssen’s right to purchase exclusive options to obtain certain development, manufacturing and commercialization rights are accounted for separately as they do not represent material rights, based on the criteria of ASC 606. Upon the exercise of any purchased option by Janssen, the

contract promises associated with an Option Target would use a separate cost-to-cost model for purposes of revenue recognition under ASC 606.

In 2019, the Company received a $100.0 million non-refundable upfront fee from Janssen and during the year ended December 31, 2021, the Company received a $30.0 million milestone payment. The Company allocated these amounts plus other variable consideration not subject to constraint to each identified performance obligation using a combination of methods allowable under ASC 606. The Company applies the practical expedient in Topic 606 and does not include disclosures regarding amounts for variable consideration allocated to wholly-unsatisfied performance obligations or wholly-unsatisfied distinct goods that form part of a single performance obligation, if any. This variable consideration includes expected reimbursement of research and development costs.

Asset Purchase and Related Agreements

The agreements entered into in December 2023 were executed at the same time and were negotiated with a single commercial objective; therefore, the contracts were combined and accounted for as a single contract. These agreements were accounted for as a termination of the existing Collaboration Agreement and the creation of a new contract where the transaction price includes the remaining deferred revenue – related party from the terminated agreement of $30.6 million, the fixed upfront payment of $65.0 million under the Asset Purchase Agreement, and an aggregate of $1.8 million estimated variable consideration for transition services, offset by a credit of $5.1 million for pre-funded inventory, totaling $92.3 million. The transaction price was allocated to four performance obligations on a relative SSP basis, subject to certain exceptions for discounts and variable consideration. As the SSPs are not directly observable for any of the distinct goods and services, the SSPs were estimated based on a valuation. The total transaction price of $92.3 million was allocated to the performance obligations with respect to SSPs as follows: process performance qualification (“PPQ”) services in the amount of $2.9 million, material rights representing the commercial supply of RPGR Product and an in-substance contract renewal option in the amount of $6.9 million, manufacturing technology transfer in the amount of $28.7 million, and the sale of nonfinancial assets representing the sale and transfer of all the Company’s right, title, and interest in the intellectual property related to the RPGR Product and the assignment of the UCLB RPGR License Agreement to Janssen in the amount of $53.8 million.

The transaction price allocated to PPQ services will be recognized over time using an inputs method measure of progress. The transaction price allocated to the material right for the commercial supply of RPGR Product will be recorded as deferred revenue until Janssen exercises its option to purchase supply and the Company transfers control of such supply to Janssen. The transaction price allocated to the in-substance renewal option (material right) will be recorded as deferred revenue until Janssen exercises the option and the Company transfers control of the underlying goods or services to Janssen. The Company will account for the exercise of the in-substance renewal option (material right) as a continuation of the existing contract (i.e., a change in the transaction price). The transaction price allocated to the technology transfer will be recognized over time using an inputs method measure of progress. The Company will recognize a gain for the difference between the carrying amount of the nonfinancial assets and the consideration allocated to that unit of account when control of the nonfinancial assets transfers in accordance with ASC 610-20, Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets.

During the year ended December 31, 2023, the Company recognized a gain of $54.2 million related to the sale of nonfinancial assets which is included in other income in the consolidated statement of operations and comprehensive loss.

As of December 31, 2023, the aggregate transaction price allocated to unsatisfied performance obligations was $36.9 million which the Company expects to recognize over an estimated period of approximately 4.0 years.

A summary of the deferred revenue recognition is as follows (in thousands):


Deferred revenue at December 31, 2021	$	64,866
Deferred revenue recognized as license revenue during the year ended December 31, 2022		(15,920)
Effects of exchange rate changes		(6,387)
Deferred revenue at December 31, 2022	$	42,559
Deferred revenue recognized as license revenue during the year ended December 31, 2023		(14,017)
Effects of exchange rate changes		2,033
Remaining deferred revenue under the Collaboration Agreement		30,575
Standalone selling price allocated to performance obligations		7,469
Effects of exchange rate changes		(1,101)
Deferred revenue at December 31, 2023	$	36,943

During the years ended December 31, 2023 and 2022, the Company recognized $14.0 million and $15.9 million, respectively, of deferred revenue – related party in connection with the Collaboration Agreement as license revenue. The remaining deferred revenue – related party from the terminated Collaboration Agreement of $30.6 million was included in the overall transaction price of the agreements entered into in December 2023.

The Company also recognized $70.4 million and $73.3 million during the years ended December 31, 2023 and 2022, respectively, related to the reimbursement of research and development expenses under the Collaboration Agreement.

Private Placement

On February 27, 2019, in connection with a private placement, the Company issued 2,898,550 ordinary shares to JJDC, the investment arm of Johnson & Johnson and owner of Janssen, on the same terms and conditions as the other investors in the offering. After the offering, JJDC became a related party. On November 9, 2022, the Company entered into a securities purchase agreement with JJDC, pursuant to which the Company, in a private placement, agreed to issue and sell to JJDC an aggregate of 3,742,514 ordinary shares at a purchase price of $6.68 per share, for gross proceeds of approximately $25.0 million.

Debt Financing

On August 2, 2022 the Company, as borrower, and Meira UK II and Meira Ireland, as guarantors (the “Subsidiary Guarantors”), entered into a senior secured financing arrangement (the “Financing Agreement”) by and among the Company, the Subsidiary Guarantors, the lenders and other parties from time to time party thereto and Perceptive Credit Holdings III, LP, as administrative agent and lender (“Perceptive”). On December 19, 2022, the Financing Agreement was converted to a notes purchase agreement and guaranty (the “Notes Purchase Agreement”) between the same parties and under substantially the same terms and conditions as the Financing Agreement, subject to certain customary note constitution terms. Perceptive Advisors, LLC, an affiliate of Perceptive, is a 18.0% holder of the ordinary shares of the Company. Additionally, Ellen Hukkelhoven, Ph.D., a director of the Company, is an employee of Perceptive Advisors, LLC. Refer to the discussion in Note 13 for further information related to the accounting for the debt financing.

May 2023 Private Placement

On May 3, 2023, the Company issued 10,773,913 ordinary shares in a private placement for gross proceeds of $62.0 million, excluding offering costs of approximately $4.1 million. Perceptive Advisors, LLC and Adage Capital Partners, L.P. a greater than 5% holder of the ordinary shares of the Company, purchased 4,347,826 and 1,565,217 of the ordinary shares, respectively, issued on the same terms and conditions as the other investors in the offering.

- 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
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-6

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

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

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(g)(3))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(e))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//850/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

+ Details

Subsequent Event - (Details) $ in Millions	3 Months Ended
Subsequent Event - (Details) $ in Millions	Mar. 31, 2024 USD ($)
Subsequent Events \| Janssen Pharmaceuticals Inc \| Asset Purchase Agreement
Subsequent Event [Line Items]
Milestone funding for extension of RPGR product clinical trials	$ 50.0

Related Party Transactions - Collaboration and License Agreements (Details) - USD ($) $ in Thousands		1 Months Ended				3 Months Ended	12 Months Ended
	Dec. 20, 2023	Dec. 31, 2023	Dec. 31, 2021	Mar. 31, 2019	Jan. 30, 2019	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Common stock, shares issued		63,601,015					63,601,015	48,477,209
Shares issued to related party		63,601,015					63,601,015	48,477,209
Gain on sale of nonfinancial assets							$ 54,208
Other Income
Related Party Transaction [Line Items]
Gain on sale of nonfinancial assets							54,200
Private Placement
Related Party Transaction [Line Items]
Offering costs							6,418
Clinical IRD Product Candidate development
Related Party Transaction [Line Items]
Milestone payments							30,000
Clinical IRD Product Candidate development \| Maximum
Related Party Transaction [Line Items]
Additional development and commercialization milestones					$ 340,000
Clinical IRD Product Candidate development \| Collaboration Agreement
Related Party Transaction [Line Items]
Royalties receivable, as a percentage					20.00%
Janssen Pharmaceuticals Inc \| Collaboration Agreement
Related Party Transaction [Line Items]
Deferred revenue recognized as license revenue during the period							(14,017)	$ (15,920)
Reimbursement of research and development expenses							70,400	73,300
Initial funding				$ 100,000
Milestone funding			$ 30,000
Janssen Pharmaceuticals Inc \| Collaboration Agreement \| License revenue - related party
Related Party Transaction [Line Items]
Deferred revenue - related party recognized							$ 14,000	$ 15,900
Janssen Pharmaceuticals Inc \| Asset Purchase Agreement
Related Party Transaction [Line Items]
Initial agreement term	4 years
Written days-notice to terminate agreement	90 days
Non-refundable upfront cash funding	$ 65,000
Contingent Funding Available	350,000
Milestone funding for development of drug substances	10,000
Milestone funding for development of drug products	5,000
Milestone funding for sale of drug products in the US	175,000
Milestone funding for sale of drug products in the UK, France, Germany, Spain and Italy	75,000
Milestone funding for transfer of manufacturing technology	25,000
Milestone funding upon regulatory approval	10,000
Janssen Pharmaceuticals Inc \| UCLB RPGR License Agreement
Related Party Transaction [Line Items]
Deferred revenue - related party included in contract price of license agreement	30,600
Variable consideration for services included in contract price of license agreement	1,800
Asset purchase agreement funding included in contract price of license agreement	65,000
Contract price of license agreement	$ 92,300	$ 92,300
Offsetting credit for transition services		5,100
Performance obligation for process performance qualification services		2,900
Performance obligation for commercial supply of RPGR product		6,900
Performance obligation for manufacturing technology transfer		28,700
Performance obligation for sale of nonfinancial assets		$ 53,800
Janssen Pharmaceuticals Inc \| Research, development and commercialization of gene therapies
Related Party Transaction [Line Items]
Collaboration agreement upfront payment					$ 100,000
Janssen Pharmaceuticals Inc \| Clinical IRD Product Candidate development \| Collaboration Agreement
Related Party Transaction [Line Items]
Percentage of costs payable on annual net sales of licensed product statement					100.00%
Subsequent Events \| Janssen Pharmaceuticals Inc \| Asset Purchase Agreement
Related Party Transaction [Line Items]
Milestone funding for extension of RPGR product clinical trials						$ 50,000

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Summary of Significant Accounting Policies

Schedule of Restricted Cash


	December 31,		December 31,
	2023		2022
Cash and cash equivalents	$	129,566	$	115,516
Restricted cash		1,083		—
Total cash, cash equivalents and restricted cash in the condensed consolidated statement of cash flows	$	130,649	$	115,516

Schedule of Financial Assets and Liabilities Measured at Fair Value


	Fair Value Measurement Using:
			Significant		Significant Other		Significant
	December 31,		Observable Inputs		Observable Inputs		Unobservable
Description	2023		(Level 1)		(Level 2)		(Level 3)
Cash equivalents	$	46,868	$	46,868	$	—	$	—
Restricted cash	$	1,083	$	1,083	$	—	$	—


	Fair Value Measurement Using:
			Significant		Significant Other		Significant
	December 31,		Observable Inputs		Observable Inputs		Unobservable
Description	2022		(Level 1)		(Level 2)		(Level 3)
Cash equivalents	$	57,336	$	57,336	$	—	$	—
Other long-term liabilities	$	262	$	262	$	—	$	—

Schedule of Estimated Useful Lives of Assets


Asset Category		Useful Lives
Computer and office equipment		3 years
Laboratory equipment		5 years
Manufacturing equipment		7 years
Furniture and fixtures		5 years
Leasehold improvements		lesser of useful life or remaining term of lease

Schedule of Change in Asset Retirement Obligations


	For the Years Ended December 31,
	2023		2022
Balance at beginning of period	$	2,179	$	2,081
Additional asset retirement obligations incurred during the period		—		9
Amortization of interest		177		168
Effects of exchange rate changes		45		(79)
Balance at end of period	$	2,401	$	2,179

Schedule of Securities Excluded from Computation of Diluted Net Loss per Share


	December 31,	December 31,
	2023	2022
Share options	8,226,707	6,858,409
Restricted share units	2,661,250	2,182,500
Deferred share units	185,000	110,000
Warrants	700,000	700,000
Restricted ordinary shares subject to forfeiture	—	14,049
	11,772,957	9,864,958

Schedule of Long-lived Assets by Geographical Area


	December 31,		December 31,
	2023		2022
United States	$	11,071	$	14,382
United Kingdom		33,798		36,775
European Union		112,487		105,013
	$	157,356	$	156,170

CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY (Parenthetical) - Private Placement - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Stock issuance costs	$ 6,418
Ordinary Shares
Stock issuance costs		$ 119

Related Party Transactions - Performance Obligation (Details) - UCLB RPGR License Agreement - Janssen Pharmaceuticals Inc - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 $ in Millions	Dec. 31, 2023 USD ($)
Related Party Transaction [Line Items]
Unsatisfied performance obligation, amount	$ 36.9
Unsatisfied performance obligation, expected recognition period	4 years

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
License revenue - related party	$ 14,017	$ 15,920
Operating expenses:
General and administrative	47,293	46,550
Research and development	103,785	85,725
Total operating expenses	151,078	132,275
Loss from operations	(137,061)	(116,355)
Other non-operating income (expense):
Foreign currency loss	9,300	(9,452)
Interest income	2,272	777
Interest expense	(13,245)	(4,946)
Gain on sale of nonfinancial assets	54,208
Fair value adjustments	499	361
Net income (loss)	(84,027)	(129,615)
Other comprehensive income (loss):
Foreign currency translation gain	(7,482)	8,718
Comprehensive income (loss)	(91,509)	(120,897)
Net income (loss)	$ (84,027)	$ (129,615)
Basic net loss per ordinary share	$ (1.49)	$ (2.87)
Diluted net loss per ordinary share	$ (1.49)	$ (2.87)
Weighted-average number of ordinary shares outstanding, basic	56,486,525	45,177,857
Weighted-average number of ordinary shares outstanding, diluted	56,486,525	45,177,857

Principal Business Activity (Details) - USD ($) $ in Thousands		1 Months Ended		3 Months Ended	12 Months Ended
	Dec. 20, 2023	Dec. 31, 2021	Mar. 31, 2019	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Accumulated deficit					$ (554,231)	$ (470,204)
Cash flows from operations					(105,365)	(73,098)
Cash, cash equivalents		$ 137,703			$ 130,649	$ 115,516
Janssen Pharmaceuticals Inc \| Collaboration Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Initial funding			$ 100,000
Milestone funding		$ 30,000
Janssen Pharmaceuticals Inc \| Asset Purchase Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable upfront cash funding	$ 65,000
Milestone funding for development of drug substances	10,000
Milestone funding for development of drug products	5,000
Milestone funding for sale of drug products in the US	175,000
Milestone funding for sale of drug products in the UK, France, Germany, Spain and Italy	75,000
Milestone funding for transfer of manufacturing technology	25,000
Milestone funding upon regulatory approval	10,000
Minimum \| Janssen Pharmaceuticals Inc \| Collaboration Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Offsetting expense, period					12 months
Maximum \| Janssen Pharmaceuticals Inc \| Asset Purchase Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contingent Funding Available	$ 350,000
Subsequent Events \| Janssen Pharmaceuticals Inc \| Asset Purchase Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone funding for extension of RPGR product clinical trials				$ 50,000

Commitments and Contingencies

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies

Commitments and Contingencies

14. Commitments and Contingencies

There were no new material commitments or contingencies entered into during the year ended December 31, 2023.

Related Party Transactions - Financing Agreement (Details) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	May 03, 2023	Nov. 09, 2022	Dec. 31, 2023	Dec. 31, 2022	Aug. 02, 2022	Feb. 27, 2019
Related Party Transaction [Line Items]
Common stock, shares issued			63,601,015	48,477,209
Private Placement
Related Party Transaction [Line Items]
Offering costs			$ 6,418
Private Placement \| Ordinary Shares
Related Party Transaction [Line Items]
Offering costs				$ 119
JJDC \| Private Placement \| Ordinary Shares
Related Party Transaction [Line Items]
Common stock, shares issued						2,898,550
JJDC \| Secured Financing Agreement \| Private Placement \| Ordinary Shares
Related Party Transaction [Line Items]
Common stock, shares issued		3,742,514
Common stock, price per share		$ 6.68
Proceeds from Issuance of Private Placement		$ 25,000
Perceptive Advisors, LLC \| Ordinary Shares
Related Party Transaction [Line Items]
Common stock, shares issued	4,347,826
Perceptive Advisors, LLC \| Secured Financing Agreement
Related Party Transaction [Line Items]
Equity ownership in outstanding ordinary shares					18.00%
Adage Capital Partners, L.P. \| Ordinary Shares
Related Party Transaction [Line Items]
Common stock, shares issued	1,565,217
Perceptive Advisors, LLC and Adage Capital Partners, L.P. \| Ordinary Shares \| Minimum
Related Party Transaction [Line Items]
Third-party equity ownership in outstanding ordinary shares	5.00%
Perceptive Advisors, LLC and Adage Capital Partners, L.P. \| Private Placement
Related Party Transaction [Line Items]
Common stock, shares issued	10,773,913
Proceeds from Issuance of Private Placement	$ 62,000
Offering costs	$ 4,100

Equity Method and Other Investments

12 Months Ended

Dec. 31, 2023

Equity Method and Other Investments

Equity Method and Other Investments

3. Equity Method and Other Investments

The Company’s investments consist of the following (in thousands):


		December 31, 2023
Investee	Investment Type	Ownership Percentage		Carrying Value		Cost Basis
Visiogene LLC	Equity Method Investment	25	%	$	5,150	$	5,165
Other	Equity Investment	1.6	%		1,616		1,500
Total equity method and other investments				$	6,766	$	6,665

Visiogene LLC

On January 4, 2021, the Company and Visiogene LLC (“Visiogene”) entered into a License and Investment Agreement (“Visiogene License Agreement”) for an exclusive, worldwide license to certain of Visiogene’s intellectual property relating to ocular gene therapy. Concurrently, the Company and Visiogene entered into a Preferred Unit Purchase Agreement (“Visiogene Unit Agreement”) pursuant to which the Company purchased 3,000,000 Visiogene preferred units. In connection with the two Visiogene agreements, the Company paid $5.0 million in cash and issued to Visiogene 75,000 ordinary shares of the Company with a fair market value of $1.2 million based on the closing price of the Company’s ordinary shares on the date of closing.

The Company accounted for the payments under the Visiogene License Agreement and Visiogene Unit Agreement as a basket transaction and allocated $1.0 million to the Visiogene License Agreement and the remaining $5.2 million was allocated to the Visiogene preferred units. The $1.0 million allocated to the Visiogene License Agreement was expensed as acquired in-process research and development as the Company determined there was no alternative future use. The Company accounts for this investment using the equity method of accounting.

During the years ended December 31, 2023 and 2022, the Company recorded de minimis research and development expenses related to the Company’s share of Visiogene’s losses.

Other Equity Investment

During the years ended December 31, 2023 and 2022, the Company recognized a $0.5 million increase in carrying value and $0.3 million impairment, respectively due to a change in the value of the Company’s investment. The change in carrying value was recorded as a fair value adjustment for the years ended December 31, 2023 and 2022.

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (84,027)	$ (129,615)

- Definition

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

+ References

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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481687/323-10-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-28

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482765/220-10-50-6

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-8

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-9

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
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+ Details

Income Taxes - Unrecognized Tax Positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Taxes
Unrecognized tax benefits, beginning balance	$ 937	$ 666
Gross increases/(decreases) related to current year	756	279
Gross increases/(decreases) related to prior years	336
Gross increases/(decreases) related to prior years		(8)
Unrecognized tax benefits, ending balance	$ 2,029	$ 937

Leases

12 Months Ended

Dec. 31, 2023

Leases

Leases

12. Leases

The Company has commitments under operating leases for laboratory, warehouse, clinical trial sites and office space. The Company also has finance leases for manufacturing space and office equipment. The Company’s leases have initial lease terms ranging from 3 years to 191 years. Certain lease agreements contain provisions for future rent increases. Payments due under the lease contracts include fixed payments.

Total rent expense recorded under these leases was $5.5 million and $5.3 million for the years ended December 31, 2023 and 2022, respectively.

On August 4, 2020, Meira Ireland entered into two agreements with Shannon Commercial Enterprises DAC trading as Shannon Commercial Properties, to acquire two properties in the Shannon Free Zone in Shannon, Ireland for an aggregate price of €18 million, or approximately $21.2 million. These properties were acquired to serve as the Company’s second, large scale GMP viral vector manufacturing facility and its first GMP plasmid and DNA production facility.

The closing for the first building occurred in August 2020 and the closing for the second building occurred in January 2021. The total cost of the first and second buildings, including taxes and legal fees, was €11.9 million and €7.5 million, or approximately $13.8 million and $8.9 million, respectively, and have been recorded as right of use assets in the consolidated balance sheets. There is no corresponding lease liability as the Company paid the full cost on the date of the closings.

At the closings, Meira Ireland entered into a lease for each property providing for a long leasehold interest of approximately 191 years.

The leases also include customary terms and conditions, with a nominal annual lease cost and annual maintenance fees of approximately €0.3 million, or approximately $0.4 million, in the aggregate, which amount is subject to change depending on the annual maintenance costs within the Shannon Free Zone development.

During the year ended December 31, 2022, the Company recognized three operating leases for locations in connection with its clinical trials for its IRD product candidates and office and warehouse space, with initial lease terms between 3 years and 9 years. Payments due under the lease contracts include fixed payments. In conjunction with these operating leases, the Company recognized initial operating lease right-of-use assets in the amount of $1.8 million and corresponding lease liabilities in the amount of $1.8 million which are included in the right-of-use assets and lease obligations in the consolidated balance sheets as of December 31, 2022.

The components of lease cost for the years ended December 31, 2023 and 2022 are as follows (in thousands):


	Years Ended December 31,
	2023		2022
Finance lease cost
Amortization of right-of-use assets	$	1,124	$	1,103
Interest on lease liabilities		—		1
Total finance lease cost		1,124		1,104
Operating lease cost		5,473		5,307
Short-term lease cost		159		154
Total lease cost	$	6,756	$	6,565

Amounts reported in the consolidated balance sheets for leases where the Company is the lessee as of December 31, 2023 and 2022 were as follows (in thousands):


	December 31,			December 31,
	2023			2022
Operating leases
Right-of-use asset	$	15,910		$	20,109
Capitalized lease obligations	$	17,145		$	21,215
Finance leases
Right-of-use asset	$	24,432		$	24,718
Capitalized lease obligations	$	—		$	—
Weighted-average remaining lease term
Operating leases		4.3	years		5.6	years
Finance leases		174.8	years		175.8	years
Weighted-average discount rate
Operating leases		8.8	%		8.8	%
Finance leases		8.0	%		8.0	%

Other information related to leases as of the years ended December 31, 2023 and 2022 are as follows (in thousands):


	Years Ended December 31,
	2023		2022
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from finance leases	$	—	$	52
Operating cash flows from operating leases	$	5,662	$	5,384
Financing cash flows from finance leases	$	—	$	—

Right-of-use assets obtained in exchange for lease liabilities
Operating leases	$	—	$	1,793

Future minimum lease payments under non-cancellable leases as of December 31, 2023 are as follows (in thousands):


	Operating Leases
2024	$	5,565
2025		5,524
2026		5,623
2027		1,626
2028		1,335
Thereafter		706
Total undiscounted lease payments	$	20,379
Less: Imputed interest		(3,234)
Total lease liabilities	$	17,145

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2023

Summary of Significant Accounting Policies

Consolidation

The accompanying consolidated financial statements include the accounts of Meira Holdings and its wholly owned subsidiaries:

MeiraGTx Limited, a limited company incorporated under the laws of England and Wales;

MeiraGTx, LLC, a Delaware limited liability company (“Meira LLC”);

MeiraGTx UK II Limited, a limited company incorporated under the laws of England and Wales (“Meira UK II”);

MeiraGTx Ireland DAC, a designated activity company incorporated under the laws of Ireland (“Meira Ireland”);

MeiraGTx Netherlands B.V., a private company with limited liability incorporated under the laws of the Netherlands (“Meira Netherlands”);

MeiraGTx Belgium, a private company with limited liability incorporated under the laws of Belgium (“Meira Belgium”);

BRI-Alzan, Inc., a Delaware corporation (“BRI-Alzan”);

MeiraGTx Bio Inc., a Delaware corporation (“Meira Bio”);

MeiraGTx B.V., a private company with limited liability incorporated under the laws of the Netherlands (“Meira B.V.”);

MeiraGTx Neurosciences, Inc., a Delaware corporation (“Meira Neuro”);

MeiraGTx Therapeutics, Inc., a Delaware corporation (“Meira Therapeutics”); and

MeiraGTx UK Limited, a limited company incorporated under the laws of England and Wales (“Meira UK”).

All intercompany balances and transactions between the consolidated companies have been eliminated in consolidation.

Use of Estimates

Cash and Cash Equivalents

Restricted Cash


	December 31,		December 31,
	2023		2022
Cash and cash equivalents	$	129,566	$	115,516
Restricted cash		1,083		—
Total cash, cash equivalents and restricted cash in the condensed consolidated statement of cash flows	$	130,649	$	115,516

Financial Instruments

Tax Incentive Receivable

Fair Value Measurements

●

Level 1: Observable inputs such as quoted prices in active markets for identical assets the reporting entity has the ability to access as of the measurement date;

●

Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and

●

Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

The table below represents the values of the Company’s financial assets and liabilities that are required to be measured at fair value on a recurring basis (in thousands):


	Fair Value Measurement Using:
			Significant		Significant Other		Significant
	December 31,		Observable Inputs		Observable Inputs		Unobservable
Description	2023		(Level 1)		(Level 2)		(Level 3)
Cash equivalents	$	46,868	$	46,868	$	—	$	—
Restricted cash	$	1,083	$	1,083	$	—	$	—


	Fair Value Measurement Using:
			Significant		Significant Other		Significant
	December 31,		Observable Inputs		Observable Inputs		Unobservable
Description	2022		(Level 1)		(Level 2)		(Level 3)
Cash equivalents	$	57,336	$	57,336	$	—	$	—
Other long-term liabilities	$	262	$	262	$	—	$	—

Equity Method and Other Investments

Concentrations of Credit Risk

Company has not experienced any losses on its bank deposits and believes these deposits do not expose the Company to any significant credit risk.

Intangible Assets

Intangible Assets

Property, Plant and Equipment, Net

The estimated useful lives of the asset categories are as follows:


Asset Category		Useful Lives
Computer and office equipment		3 years
Laboratory equipment		5 years
Manufacturing equipment		7 years
Furniture and fixtures		5 years
Leasehold improvements		lesser of useful life or remaining term of lease

Expenditures for leasehold improvements are capitalized, and expenditures for maintenance and repairs are expensed to operations as incurred.

Leases

Key estimates and judgments include how the Company determined (1) the discount rate used to discount the unpaid lease payments to present value, (2) lease term and (3) lease payments.

Asset Retirement Obligations

The change in asset retirement obligations is as follows (in thousands):


	For the Years Ended December 31,
	2023		2022
Balance at beginning of period	$	2,179	$	2,081
Additional asset retirement obligations incurred during the period		—		9
Amortization of interest		177		168
Effects of exchange rate changes		45		(79)
Balance at end of period	$	2,401	$	2,179

IDA Ireland Grant

Share-Based Compensation Expense

Options

Restricted Share Units

Collaboration Arrangements

Refer to the discussion in Note 11 for further information related to the accounting for the Collaboration Agreement.

Revenue Recognition

identify the contract(s) with a customer;

ii.

identify the performance obligations in the contract;

iii.

determine the transaction price;

iv.

allocate the transaction price to the performance obligations within the contract; and

recognize revenue when (or as) the entity satisfies a performance obligation.

The Company’s collaboration and revenue arrangements include the following:

Research and Development

Foreign Currencies

Income Taxes

The Company is required to estimate income taxes in each of the jurisdictions in which it operates.

Net Loss per Ordinary Share


	December 31,	December 31,
	2023	2022
Share options	8,226,707	6,858,409
Restricted share units	2,661,250	2,182,500
Deferred share units	185,000	110,000
Warrants	700,000	700,000
Restricted ordinary shares subject to forfeiture	—	14,049
	11,772,957	9,864,958

Other Comprehensive Income (Loss)

Segment Information

Management has concluded it has a single reporting segment for purposes of reporting financial condition and results of operations.

The Company’s license revenue, research funding and deferred revenue from the Collaboration Agreement were generated in the United Kingdom.

The following table summarizes long-lived assets by geographical area (in thousands):


	December 31,		December 31,
	2023		2022
United States	$	11,071	$	14,382
United Kingdom		33,798		36,775
European Union		112,487		105,013
	$	157,356	$	156,170

Recent Accounting Pronouncements Adopted

Recent Accounting Pronouncements Not Yet Adopted

Equity Method and Other Investments - Additional Information (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 04, 2021	Dec. 31, 2023	Dec. 31, 2022
Visiogene LLC
Schedule of Equity Method Investments [Line Items]
Number of preferred units acquired	3,000,000
Cash consideration	$ 5.0
Ordinary shares issued in connection with a license agreement (in shares)	75,000
Value of shares issued	$ 1.2
Visiogene LLC \| Visiogene License Agreement
Schedule of Equity Method Investments [Line Items]
Allocation of payments	1.0
Investment allocated amount expensed	1.0
Visiogene LLC \| Visiogene Unit Agreement
Schedule of Equity Method Investments [Line Items]
Allocation of payments	$ 5.2
Other Investments
Schedule of Equity Method Investments [Line Items]
Impairment due to dilution in ownership percentage			$ 0.3
Impairment recognized as adjustment to fair value		$ 0.5

Income Taxes - Schedule of Expense (Benefit) for Income Taxes from Continuing Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Deferred Tax Expense/(Benefit)
Total Deferred	$ (9,661)	$ (25,955)
Change in Valuation Allowance	9,661	25,955
United Kingdom
Deferred Tax Expense/(Benefit)
Foreign	2,393	(8,708)
United States
Deferred Tax Expense/(Benefit)
United States	(6,251)	(17,466)
Netherlands
Deferred Tax Expense/(Benefit)
Foreign	(1,840)	1,717
Ireland
Deferred Tax Expense/(Benefit)
Foreign	$ (3,963)	$ (1,498)

Ordinary Shares

12 Months Ended

Dec. 31, 2023

Ordinary Shares

Ordinary Shares

9. Ordinary Shares

2023

May 2023 Private Placement

On May 3, 2023, the Company entered into a securities purchase agreement with certain accredited investors, pursuant to which the Company, in a private placement, agreed to issue and sell an aggregate of 10,773,913 ordinary shares at a purchase price of $5.75 per share, for gross proceeds of approximately $62.0 million and incurred issuance costs of approximately $4.1 million. The closing occurred on May 5, 2023.

Sanofi Private Placement

On October 30, 2023, the Company entered into an Investment Agreement with Sanofi Foreign Participations B.V., a wholly-owned subsidiary of Sanofi, and solely for the limited purposes set forth therein, Sanofi, pursuant to which, the Company, in a private placement, issued an aggregate of 4,000,000 ordinary shares, at a purchase price of $7.50 per share for gross proceeds of $30.0 million and incurred issuance costs of approximately $2.3 million.

2022

Private Placement

On November 9, 2022, the Company entered into a securities purchase agreement with Johnson & Johnson Innovation – JJDC, Inc. (“JJDC”), the investment arm of Johnson & Johnson, pursuant to which the Company, in a private placement, agreed to issue and sell to JJDC an aggregate of 3,742,514 ordinary shares at a purchase price of $6.68 per share, for gross proceeds of approximately $25.0 million.

- 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
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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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-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-16

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (b)
-Publisher FASB
-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 Financing (Details) - USD ($)		12 Months Ended
Debt Financing (Details) - USD ($)	Aug. 02, 2022	Dec. 31, 2023	Dec. 31, 2022
Line of Credit Facility [Line Items]
Common stock, shares issued		63,601,015	48,477,209
Perceptive Credit Holdings \| Note Purchase Agreement \| Term Loan
Line of Credit Facility [Line Items]
Cash liquidity requirement		$ 3,000,000.0
Shares available through warrants	$ 400,000
Warrant exercise price	$ 15.00
Common stock, shares issued	300,000
Aggregate Offer Price	$ 20.00
Unamortized debt discount, warrants		2,300,000
Unamortized debt discount, legal costs		2,100,000
Unamortized debt discount, gross		4,400,000
Amortization of debt discount		1,100,000	$ 400,000
Remaining unamortized discount on debt, total		2,900,000
Perceptive Credit Holdings \| Note Purchase Agreement \| Term Loan - Tranche I
Line of Credit Facility [Line Items]
Initial face amount	75,000,000.0
Unused borrowing capacity	$ 25,000,000.0
Term loan outstanding amount		$ 75,000,000.0
SOFR adjustment term	1 month
Interest rate at period-end		15.32%
Increase in accrued interest		$ 3,000,000.0
Interest expense on debt		11,300,000	$ 4,000,000.0
Obligations secured by UK and Ireland subsidiaries		$ 3,000,000.0
Perceptive Credit Holdings \| Note Purchase Agreement \| Term Loan - Tranche I \| Base variable rate
Line of Credit Facility [Line Items]
Stated interest rate	10.00%
Perceptive Credit Holdings \| Note Purchase Agreement \| Term Loan - Tranche I \| SOFR
Line of Credit Facility [Line Items]
Floor percentage	1.00%

Share-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended		24 Months Ended
	Feb. 28, 2023	Jan. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2022	Dec. 31, 2020	Jan. 01, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average remaining contractual life of options, outstanding			6 years 4 months 6 days	6 years 10 months 9 days
Fair value of options, Vested			$ 15,300	$ 16,200
Weighted-average grant date fair value of options granted			$ 5.67	$ 12.81
Period expected to realize unrecognized compensation expense			3 years 8 months 12 days
Total share-based compensation			$ 27,716	$ 28,623
Excess tax benefits in cash flows from operations					$ 0
Excess tax benefits in cash flows from financing activities					$ 0
General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation			14,936	14,458
Research and Development Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation			$ 12,780	14,165
2018 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual percent increase in available shares under equity incentive plan							4.00%
Shares reserved for issuance			11,110,748			3,054,996
Additional shares reserved for issuance		2,544,040
Shares available for future issuance			310,488
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period expected to realize unrecognized compensation expense			3 years 4 months 24 days
Total compensation expense not yet recognized relating to unvested RSUs			$ 25,300
Total share-based compensation			$ 14,085	$ 12,538
Withheld ordinary shares			237,859	128,812
Taxes withheld on issuance of share-based awards			$ 1,500	$ 2,800
Restricted Share Units \| General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation			9,882	8,804
Restricted Share Units \| Research and Development Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation			4,203	3,734
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unvested options compensation expense not yet recognized			18,300
Total share-based compensation			13,631	16,085
Employee Stock Option \| General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation			5,054	5,654
Employee Stock Option \| Research and Development Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation			$ 8,577	10,431
Employee Stock Option \| 2018 Incentive Award Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average remaining contractual life of options, outstanding			10 years
Directors \| Employee Stock Option \| 2018 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			36 months
Certain executives, employees and consultants \| Restricted Share Units \| 2018 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares reserved for issuance	2,675,000
Three Participants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Modifications to share-based compensation				300
Three Participants \| General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Modifications to share-based compensation				100
Three Participants \| Research and Development Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Modifications to share-based compensation				$ 200
Six Participants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Modifications to share-based compensation			$ 300
Six Participants \| General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Modifications to share-based compensation			200
Six Participants \| Research and Development Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Modifications to share-based compensation			$ 100
First Anniversary \| Employee Stock Option \| 2018 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Second Anniversary \| Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			50.00%
Third Anniversary \| Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Fourth Anniversary \| Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Over Three Years \| Employee Stock Option \| 2018 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			36 months

Related Party Transactions - Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Operating lease rent expenses	$ 5,500	$ 5,300
Other current liabilities	1,278	6,631
Cash paid	$ 5,662	$ 5,384

Employee Benefit Plans - Additional Information (Details) - USD ($) $ in Millions			12 Months Ended
	Jan. 01, 2017	Aug. 01, 2016	Dec. 31, 2023	Dec. 31, 2022
Compensation And Retirement Disclosure [Line Items]
Defined benefit plan, plan assets, contributions by employer			$ 2.5	$ 2.0
United States
Compensation And Retirement Disclosure [Line Items]
Defined contribution plan, annual contributions per employee, percent	6.00%
United States \| Minimum
Compensation And Retirement Disclosure [Line Items]
Defined contribution plan, employee eligibility age	21 years
United Kingdom \| Minimum
Compensation And Retirement Disclosure [Line Items]
Defined contribution plan, annual contributions per employee, percent		0.50%
Defined Benefit plan, employer matching contribution, percent		7.50%
United Kingdom \| Maximum
Compensation And Retirement Disclosure [Line Items]
Defined contribution plan, annual contributions per employee, percent		8.00%
Defined Benefit plan, employer matching contribution, percent		10.00%
Country_IE
Compensation And Retirement Disclosure [Line Items]
Defined contribution plan, employer contribution exclusive of employee match, percent			4.50%
Belgium
Compensation And Retirement Disclosure [Line Items]
Defined contribution plan, employer contribution exclusive of employee match, percent			8.00%

Summary of Significant Accounting Policies - Tax Incentives (Details) € in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023 EUR (€)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 EUR (€)	Dec. 31, 2022 USD ($)
SME tax incentive program \| Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of employees		500	500
Annual aggregate revenue \| €	€ 100.0
Aggregate total assets \| €			€ 86.0
Other Current Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Research & Development tax incentive receivable \| $		$ 2.9		$ 6.8
VAT receivable \| $		$ 0.6		$ 1.1

Share-Based Compensation - Summary of Restricted Share Units (Details) - Restricted Share Units	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Number of restricted share units
Number of restricted share units, Beginning balance \| shares	2,182,500
Number of restricted share units, Granted \| shares	1,097,500
Number of restricted share units, Vested \| shares	(618,750)
Number of restricted share units, Ending balance \| shares	2,661,250
Weighted-average grant date fair value
Weighted-average grant date fair value, Beginning balance \| $ / shares	$ 18.59
Weighted-average grant date fair value, Granted \| $ / shares	8.52
Weighted-average grant date fair value, Vested \| $ / shares	15.17
Weighted-average grant date fair value, Ending balance \| $ / shares	$ 15.24

Subsequent Event

12 Months Ended

Dec. 31, 2023

Subsequent Event

Subsequent Event

16. Subsequent Event

In the first quarter of 2024, the Company received a milestone payment of $50.0 million in connection with the Asset Purchase Agreement with Janssen for the achievement of the initiation of the extension study for the Phase 3 LUMEOS clinical trial for the RPGR Product.

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
CONSOLIDATED BALANCE SHEETS
Common stock, par value	$ 0.00003881
Common stock, shares authorized	1,288,327,750
Common stock, shares issued	63,601,015	48,477,209
Common stock, shares outstanding	63,601,015	48,477,209

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2023	Mar. 07, 2024	Jun. 30, 2023
Document And Entity Information [Abstract]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2023
Entity File Number	001-38520
Entity Registrant Name	MEIRAGTX HOLDINGS PLC
Entity Incorporation, State or Country Code	E9
Entity Tax Identification Number	98-1448305
Entity Address, Address Line One	450 East 29th Street
Entity Address, Address Line Two	14th Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10016
City Area Code	646
Local Phone Number	860-7985
Title of 12(b) Security	Ordinary Shares, $0.00003881 par value per share
Trading Symbol	MGTX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Interactive Data Current	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Public Float			$ 259,944,229
Entity Common Stock, Shares Outstanding		64,217,166
Auditor Name	Ernst & Young LLP
Auditor Firm ID	42
Auditor Location	Jericho, New York
Entity Central Index Key	0001735438
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false

Summary of Significant Accounting Policies - Revenue Recognition (Details)	12 Months Ended
	Dec. 31, 2023
Janssen Pharmaceuticals Inc \| Collaboration Agreement
Revenue Recognition, Milestone Method [Line Items]
Percentage of incurred R&D costs to be reimbursed by third parties	100

Intangible Assets

12 Months Ended

Dec. 31, 2023

Intangible Assets

Intangible Assets

6.	Intangible Assets

In November 2020, the Company entered into a non-exclusive, royalty-free technology license agreement that required the Company to pay an upfront payment to the licensor of $2.1 million. The Company accounted for the transaction as an asset acquisition and recorded an intangible asset as it was determined to have alternative future uses in connection with the Company’s manufacturing capabilities.

The following table presents the details of the Company’s intangible assets as of December 31, 2023 and 2022 (in thousands):


	December 31,		December 31,
	2023		2022
Licensed Technology	$	2,000	$	1,900
Less: Accumulated amortization		(882)		(565)
	$	1,118	$	1,335

The intangible asset is being amortized over a period of seven years. Amortization expense of $0.3 million and $0.2 million was recorded as a component of research and development expenses for the years ended December 31, 2023 and 2022, respectively.

As of December 31, 2023, the expected amortization expense for the next four years is as follows (in thousands):


	Amortization
	Expense
2024	$	285
2025		285
2026		285
2027		263
Total amortization	$	1,118

Share-Based Compensation - Summary of Company's Share Option Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Number of Options
Number of options, Beginning balance	6,858,409
Number of options, Granted	1,546,840
Number of options, Exercised	(3,864)
Number of options, Forfeited	(174,678)
Number of options, Ending balance	8,226,707	6,858,409
Weighted-Average Exercise Price
Weighted-average exercise price, Beginning balance	$ 14.03
Weighted-average exercise price, Granted	8.49
Weighted-average exercise price, Exercised	2.64
Weighted-average exercise price, Forfeited	14.95
Weighted-average exercise price, Ending balance	$ 12.96	$ 14.03
Options additional disclosures
Number of options, Options exercisable	5,709,190
Weighted-average exercise price, Options exercisable	$ 13.30
Weighted-average remaining contractual life of options, outstanding	6 years 4 months 6 days	6 years 10 months 9 days
Weighted-average remaining contractual life of options, exercisable	5 years 4 months 24 days
Number of options, Options vested and expected to vest	8,226,707
Weighted-average exercise price, Options vested and expected to vest	$ 12.96
Weighted-average remaining contractual life, Options vested and expected to vest	6 years 4 months 6 days
Aggregate intrinsic value, options outstanding	$ 2,262
Aggregate intrinsic value, options exercisable	$ 2,228

Property, Plant and Equipment, net (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment, net

Schedule of Property, Plant and Equipment, net


	December 31,		December 31,
	2023		2022
Leasehold improvements	$	103,082	$	91,053
Manufacturing equipment		22,646		17,373
Laboratory equipment		15,389		13,804
Computer and office equipment		7,370		6,787
Furniture and fixtures		734		642
		149,221		129,659
Less: Accumulated depreciation and amortization		(33,325)		(20,393)
	$	115,896	$	109,266

Insider Trading Arrangements	12 Months Ended
Insider Trading Arrangements	Dec. 31, 2023
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

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net loss	$ (84,027)	$ (129,615)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	27,716	28,623
Foreign currency (gain) loss	(9,300)	9,452
Depreciation and amortization	13,730	8,723
Net change in right-of-use assets and liabilities	(222)	(153)
Loss on disposal of equipment, furniture and fixtures	13
Loss on equity method investment	6
Amortization of interest on asset retirement obligations	177	168
Amortization of debt discount	1,083	444
Fair value adjustment	(499)	(361)
Impairment of acquired in-process research and development and right-of-use assets	1,149
Gain on sale of nonfinancial assets	(54,208)
(Increase) decrease in operating assets:
Accounts receivable - related party	9,975	1,032
Prepaid expenses	2,690	(329)
Tax incentive receivable	(5,148)	4,139
Other current assets	222	519
Other assets, net	(1,809)	(173)
Increase (decrease) in operating liabilities:
Accounts payable	2,330	3,737
Accrued expenses	(382)	12,610
Other current liabilities	(1,355)	4,006
Deferred revenue - related party	(7,506)	(15,920)
Net cash used in operating activities	(105,365)	(73,098)
Cash flows from investing activities:
Purchase of property, plant and equipment	(20,174)	(44,963)
Proceeds from sale of nonfinancial assets	54,208
Net cash used in investing activities	34,034	(44,963)
Cash flows from financing activities:
Exercise of share options	10	231
Payments of withholdings on shares withheld for income taxes	(1,519)	(2,774)
Proceeds from issuance of ordinary shares	91,950	25,000
Proceeds from issuance of note payable		75,000
Payment of issuance costs	(6,418)	(2,257)
Net cash provided by financing activities	84,023	95,200
Net decrease in cash, cash equivalents and restricted cash	12,692	(22,861)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	2,441	674
Cash, cash equivalents and restricted cash at beginning of the period	115,516	137,703
Cash, cash equivalents and restricted cash at end of the period	130,649	115,516
Supplemental disclosure of non-cash transactions:
Fixed asset acquisition included in accounts payable and accrued expenses at end of the period	2,607	7,106
Right-of-use assets obtained in exchange for lease liabilities		1,793
Asset retirement obligations incurred in connection with leases		9
Warrants issued in connection with note payable		2,273
Issuance of shares in connection with asset acquisition	209
Supplemental disclosure of cash flow information:
Cash paid for interest	$ 13,054	$ 329

Property, Plant and Equipment, net

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment, net

Property, Plant and Equipment, net

5. Property, Plant and Equipment, net

Property, plant and equipment, net at December 31, 2023 and 2022 consist of the following (in thousands):


	December 31,		December 31,
	2023		2022
Leasehold improvements	$	103,082	$	91,053
Manufacturing equipment		22,646		17,373
Laboratory equipment		15,389		13,804
Computer and office equipment		7,370		6,787
Furniture and fixtures		734		642
		149,221		129,659
Less: Accumulated depreciation and amortization		(33,325)		(20,393)
	$	115,896	$	109,266

In connection with certain operating leases, the Company has determined that it has asset retirement obligations in the aggregate amount of $3.9 million at the end of those leases. The Company discounted the asset retirement obligations using an 8% discount rate and recorded an asset retirement obligation in the aggregate amount of $1.8 million, which is included in leasehold improvements and is being amortized over the term of the respective leases.

Depreciation and amortization expense related to property, plant and equipment was $12.3 million and $7.3 million for the years ended December 31, 2023 and 2022, respectively.

Prepaid Expenses (Tables)

12 Months Ended

Dec. 31, 2023

Prepaid Expenses

Summary of Prepaid Expenses


	December 31,		December 31,
	2023		2022
Clinical trial costs	$	1,530	$	3,411
Dues and license fees		1,439		909
Insurance		861		1,485
Research and development		685		1,220
Facilities costs		630		539
Consulting		243		—
Manufacturing costs		38		347
Other		199		222
	$	5,625	$	8,133

Related Party Transactions - Revenue Recognition (Details) - Janssen Pharmaceuticals Inc - Collaboration Agreement - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Deferred revenue at the beginning	$ 42,559	$ 64,866
Deferred revenue recognized as license revenue during the period	(14,017)	(15,920)
Remaining deferred revenue under the Collaboration Agreement	30,575
Standalone selling price allocated to performance obligations	7,469
Effects of exchange rate changes	(1,101)	(6,387)
Effects of exchange rate changes	2,033
Deferred revenue at the end	$ 36,943	$ 42,559

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred Tax Assets:
Net operating loss carryforwards	$ 70,650	$ 74,350
Capitalized research and development	19,606	16,288
Share-based compensation	14,290	13,684
R&D credit	21,687	10,837
Lease liability	4,070	6,461
Other	1,121	3,745
Deferred tax assets	131,424	125,365
Deferred Tax Liabilities:
Indefinite-lived intangibles and fixed assets		(186)
Depreciation	(1,763)	(2,935)
Right of use assets	(3,777)	(6,207)
Less: valuation allowance	$ (125,884)	(116,223)
Net deferred tax liability		$ (186)

Prepaid Expenses - Summary of Prepaid Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Prepaid Expenses
Clinical trial costs	$ 1,530	$ 3,411
Dues and license fees	1,439	909
Insurance	861	1,485
Research and development	685	1,220
Facilities costs	630	539
Consulting	243
Manufacturing costs	38	347
Other	199	222
Total prepaid expenses	$ 5,625	$ 8,133

Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2023

Intangible Assets

Schedule of Intangible Assets


	December 31,		December 31,
	2023		2022
Licensed Technology	$	2,000	$	1,900
Less: Accumulated amortization		(882)		(565)
	$	1,118	$	1,335

Schedule of Amortization Expense


	Amortization
	Expense
2024	$	285
2025		285
2026		285
2027		263
Total amortization	$	1,118

Debt Financing

12 Months Ended

Dec. 31, 2023

Debt Financing

Debt Financing

13. Debt Financing

On August 2, 2022 the Company, and the Subsidiary Guarantors, entered into the Financing Agreement with Perceptive. On December 19, 2022, the Financing Agreement was converted to a Notes Purchase Agreement between the same parties and under substantially the same terms and conditions as the Financing Agreement, subject to certain customary note constitution terms. The Company and the Subsidiary Guarantors entered into a

Consent and Amendment with Perceptive on August 10, 2023 (the “First Consent and Amendment), and the Company and the Subsidiary Guarantors entered into a second Consent and Amendment with Perceptive on December 20, 2023.

The Notes Purchase Agreement provides for an initial $75.0 million notes issuance (the “Tranche 1 Notes”). Pursuant to the First Consent and Amendment, the Company may request in its sole discretion, and Perceptive has agreed to subscribe to purchase upon such request, an additional $25.0 million notes issuance (the “Tranche 2 Notes”) at any time before August 2, 2024 subject to the terms of the Notes Purchase Agreement. Previously, the Company’s request for issuance of the Tranche 2 Notes was to be determined at Perceptive’s sole discretion. The Notes Purchase Agreement matures on August 2, 2026 and is interest-only during the term. The Company has the option to redeem outstanding principal notes at any time along with an applicable early redemption fee. Under each of the First Consent and Amendment and the Second Consent and Amendment, the Notes Purchase Agreement was amended to increase the applicable early redemption fee. Outstanding amounts under the Notes Purchase Agreement bear interest at a fluctuating rate per annum equal to 10.00% plus the secured overnight financing rate administered by the Federal Reserve Bank of New York for a one-month tenor, subject to a 1.00% floor. The annual interest rate was 15.32% at December 31, 2023. As of December 31, 2023, the outstanding balance of the Tranche 1 Notes was $75.0 million plus accrued interest of $3.0 million. During the years ended December 31, 2023 and 2022, the Company recorded interest expense of $11.3 million and $4.0 million, respectively.

The Company’s obligations under the Notes Purchase Agreement are secured by the Company’s London, UK and Shannon, Ireland manufacturing facilities, $3.0 million of the Company’s cash and the bank accounts of the Subsidiary Guarantors, and the issued and outstanding equity interests of the Subsidiary Guarantors.

The Notes Purchase Agreement imposes certain covenants and restrictions on the Company and the Subsidiary Guarantors, including restrictions pertaining to: (i) the incurrence of additional indebtedness, (ii) limitations on liens, (iii) limitations on certain investments, (iv) making distributions, dividends and other payments, (v) mergers, consolidations and acquisitions, (vi) dispositions of assets, (vii) the Company’s maintenance of at least $3.0 million in a U.S. bank account, (viii) transactions with affiliates, (ix) changes to governing documents, (x) changes to certain agreements and leases and (xi) changes in control; however, certain of these restrictions contain exceptions which allow the Company to license, sell and monetize assets in its AAV-hAQP1 program in development to treat radiation-induced xerostomia, its AAV-GAD program in development to treat Parkinson’s disease and its gene regulation platform technologies.

In connection with entering into the Financing Agreement, the Company granted warrants to Perceptive to purchase up to (i) 400,000 ordinary shares of the Company at an exercise price of $15.00 per share and (ii) 300,000 ordinary shares of the Company at an exercise price of $20.00 per share. The warrants are exercisable immediately and expire on August 2, 2027. The Company recorded a debt discount of $2.3 million for the allocated fair value of the warrants.

The Company also capitalized certain lender and legal costs associated with the Notes Purchase Agreement totaling $2.1 million, which were recorded as a discount to the loan. The aggregate discount of $4.4 million is being amortized to interest expense over the term of the Notes Purchase Agreement. The Company amortized $1.1 million and $0.4 million of the discount to interest expense during the years ended December 31, 2023 and 2022, respectively. At December 31, 2023, the remaining unamortized discount was $2.9 million.

- 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
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 470
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//470/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

+ Details

Property, Plant and Equipment, net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 149,221	$ 129,659
Less: Accumulated depreciation	(33,325)	(20,393)
Property, plant and equipment, net	115,896	109,266
Depreciation and amortization expense	12,300	7,300
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	103,082	91,053
Manufacturing Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	22,646	17,373
Laboratory Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	15,389	13,804
Computer and Office Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	7,370	6,787
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 734	$ 642

Intangible Assets (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
Intangible Assets (Details) - USD ($) $ in Thousands	Nov. 30, 2020	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Total		$ 1,118
Licensed Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		2,000	$ 1,900
Less: Accumulated Amortization		(882)	(565)
Total		$ 1,118	1,335
Upfront payment for intangible assets	$ 2,100
Intangible assets amortization period		7 years
Intangible asset amortization		$ 300	$ 200

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2023

Accrued Expenses

Schedule of Accrued Expenses


	December 31,		December 31,
	2023		2022
Compensation and benefits	$	12,129	$	9,600
Clinical trial costs		8,713		13,041
Professional fees		6,499		732
Research and development		5,834		7,400
Interest on Tranche 1 Notes		2,936		—
Manufacturing costs		2,634		4,326
Consulting		2,104		694
Fixed assets		1,472		3,093
Rent and facilities costs		142		—
Other		176		932
	$	42,639	$	39,818

Summary of Significant Accounting Policies - Asset Retirement Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Asset Retirement Obligation [Abstract]
Asset retirement obligations at beginning of period	$ 2,179
Additional asset retirement obligations incurred during the period		$ 9
Amortization of interest on asset retirement obligations	177	168
Effects of exchange rate on asset retirement obligations	45	(79)
Asset retirement obligations at end of period	$ 2,401	$ 2,179

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share Option Activity


					Weighted-
			Weighted-		Average
			Average		Remaining
		Number of	Exercise		Contractual
		Options	Price		Term (years)
Outstanding at December 31, 2022		6,858,409	$	14.03	6.86	years
Granted		1,546,840	$	8.49
Exercised		(3,864)	$	2.64
Forfeited		(174,678)	$	14.95
Outstanding at December 31, 2023		8,226,707	$	12.96	6.35	years
Options exercisable at December 31, 2023		5,709,190	$	13.30	5.40	years
Options vested and expected to vest at December 31, 2023		8,226,707	$	12.96	6.35	years
Aggregate intrinsic value of options outstanding as of December 31, 2023	$	2,262
Aggregate intrinsic value of options exercisable as of December 31, 2023	$	2,228

Schedule of Inputs Used in Determining Fair Value of Share Options


	2023	2022
Risk-free interest rate	3.86 - 4.48%	1.56 - 4.23%
Expected volatility	72%	80%
Expected dividend yield	0%	0%
Expected term (in years)	3.6 - 6.1	5.5 - 6.1

Schedule of Restricted Share Unit (RSU) Activity


		Weighted-
	Number of	Average
	Restricted	Grant Date
	Share Units	Fair Value
Outstanding at December 31, 2022	2,182,500	$	18.59
Granted	1,097,500	$	8.52
Vested	(618,750)	$	15.17
Outstanding at December 31, 2023	2,661,250	$	15.24

Schedule of Share-Based Compensation Expense


	Years Ended December 31,
	2023		2022
Research and development	$	12,780	$	14,165
General and administrative		14,936		14,458
Total share-based compensation	$	27,716	$	28,623

Employee Stock Option

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-Based Compensation Expense


	Years Ended December 31,
	2023		2022
Research and development	$	8,577	$	10,431
General and administrative		5,054		5,654
Total share-based compensation	$	13,631	$	16,085

Restricted Share Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-Based Compensation Expense


	Years Ended December 31,
	2023		2022
Research and development	$	4,203	$	3,734
General and administrative		9,882		8,804
Total share-based compensation	$	14,085	$	12,538

- 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

Property, Plant and Equipment, net - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2020	Jan. 01, 2019
Property, Plant and Equipment [Line Items]
Asset retirement obligations	$ 2,401	$ 2,179	$ 2,081
Operating Sublease
Property, Plant and Equipment [Line Items]
Asset retirement obligations, discounted rate	8.00%
Asset retirement obligations	$ 1,800			$ 3,900

Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Details)	Dec. 31, 2023
Licensed Technology
Property, Plant and Equipment [Line Items]
Intangible assets amortization period	7 years
Computer and Office Equipment
Property, Plant and Equipment [Line Items]
Property and equipment estimated useful life	3 years
Laboratory Equipment
Property, Plant and Equipment [Line Items]
Property and equipment estimated useful life	5 years
Manufacturing Equipment
Property, Plant and Equipment [Line Items]
Property and equipment estimated useful life	7 years
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property and equipment estimated useful life	5 years

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Examination [Line Items]
Unrecognized Tax Benefits	$ 2,029,000	$ 937,000	$ 666,000
Unrecognized tax benefits, income tax penalties and interest accrued	0
Federal
Income Tax Examination [Line Items]
Income tax expense (benefit)	0	0
Unrecognized Tax Benefits	2,000,000.0	900,000
Unrecognized tax benefits, income tax penalties and interest accrued	$ 0	$ 0
U.K.
Income Tax Examination [Line Items]
Effective income tax rate	25.00%	19.00%

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Leases - Additional Information (Details) € in Millions			12 Months Ended
Leases - Additional Information (Details) € in Millions	Aug. 04, 2020 USD ($) contract property	Aug. 04, 2020 EUR (€) contract property	Dec. 31, 2023 USD ($)	Dec. 31, 2023 EUR (€)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 EUR (€)
Lessee, Lease, Description [Line Items]
Operating lease rent expenses			$ 5,500,000		$ 5,300,000
Right-of-use asset			15,910,000		20,109,000
Operating lease liability			$ 17,145,000		21,215,000
Janssen Pharmaceuticals Inc
Lessee, Lease, Description [Line Items]
Number of operating leases			3
Right-of-use asset			$ 1,800,000
Operating lease liability			1,800,000
Meira Ireland [Member] \| Shannon Free Zone [Member]
Lessee, Lease, Description [Line Items]
Number of agreements \| contract	2	2
Number of properties \| property	2	2
Purchase price consideration	$ 21,200,000	€ 18.0
Annual lease cost and annual maintenance fees			400,000	€ 0.3
Operating lease liability			$ 0
Meira Ireland [Member] \| Shannon Free Zone [Member] \| Building one
Lessee, Lease, Description [Line Items]
Capitalized building costs					13,800,000	€ 11.9
Meira Ireland [Member] \| Shannon Free Zone [Member] \| Building two
Lessee, Lease, Description [Line Items]
Capitalized building costs					$ 8,900,000	€ 7.5
Minimum
Lessee, Lease, Description [Line Items]
Lease term			3 years	3 years
Minimum \| Janssen Pharmaceuticals Inc
Lessee, Lease, Description [Line Items]
Operating lease, term of contract			3 years
Maximum
Lessee, Lease, Description [Line Items]
Lease term			191 years	191 years
Maximum \| Janssen Pharmaceuticals Inc
Lessee, Lease, Description [Line Items]
Operating lease, term of contract			9 years
Maximum \| Meira Ireland [Member] \| Shannon Free Zone [Member]
Lessee, Lease, Description [Line Items]
Lease term			191 years	191 years