uniQure (QURE) 10-K 28 Feb 24 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Feb. 23, 2024	Jun. 30, 2023
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Document Transition Report	false
Entity File Number	001-36294
Entity Registrant Name	uniQure N.V.
Entity Incorporation, State or Country Code	P7
Entity Tax Identification Number	00-0000000
Entity Address, Address Line One	Paasheuvelweg 25
Entity Address, City or Town	Amsterdam
Entity Address, Country	NL
Entity Address, Postal Zip Code	1105 BP
City Area Code	31
Local Phone Number	20-240-6000
Title of 12(b) Security	Ordinary shares, par value €0.05 per share
Trading Symbol	QURE
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
ICFR Auditor Attestation Flag	true
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 546,670
Entity Common Stock, Shares Outstanding		47,838,275
Auditor Name	KPMG Accountants N.V.
Auditor Firm ID	1012
Auditor Location	Amstelveen, The Netherlands
Entity Central Index Key	0001590560
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 241,360	$ 228,012
Current investment securities	376,532	124,831
Accounts receivable and contract asset	4,193	102,376
Inventories, net	12,024	6,924
Prepaid expenses	15,089	11,817
Other current assets and receivables	2,655	2,814
Total current assets	651,853	476,774
Non-current assets
Property, plant and equipment, net	46,548	50,532
Non-current investment securities		39,984
Operating lease right-of-use assets	28,789	32,726
Intangible assets, net	60,481	58,778
Goodwill	26,379	25,581
Deferred tax assets, net	12,276	14,528
Other non-current assets	5,363	6,061
Total non-current assets	179,836	228,190
Total assets	831,689	704,964
Current liabilities
Accounts payable	6,586	10,984
Accrued expenses and other current liabilities	30,534	30,571
Current portion of contingent consideration	28,211	25,982
Current portion of operating lease liabilities	8,344	8,382
Total current liabilities	73,675	75,919
Non-current liabilities
Long-term debt	101,749	102,791
Liability from royalty financing agreement	394,241
Operating lease liabilities, net of current portion	28,316	31,719
Contingent consideration, net of current portion	14,795	9,334
Deferred tax liability, net	7,543	8,257
Other non-current liabilities	3,700	935
Total non-current liabilities	550,344	153,036
Total liabilities	624,019	228,955
Commitments and contingencies
Shareholders' equity
Ordinary shares, €0.05 par value: 80,000,000 shares authorized as of December 31, 2023 and December 31, 2022 and 47,833,830 and 46,968,032 ordinary shares issued and outstanding as of December 31, 2023 and December 31, 2022, respectively	2,883	2,838
Additional paid-in-capital	1,148,749	1,113,393
Accumulated other comprehensive loss	(53,553)	(58,291)
Accumulated deficit	(890,409)	(581,931)
Total shareholders' equity	207,670	476,009
Total liabilities and shareholders' equity	$ 831,689	$ 704,964

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - € / shares	Dec. 31, 2023	Dec. 31, 2022
CONSOLIDATED BALANCE SHEETS
Ordinary shares, par value (in euros per share)	€ 0.05	€ 0.05
Ordinary shares, authorized	80,000,000	80,000,000
Ordinary shares, issued	47,833,830	46,968,032
Ordinary shares, outstanding	47,833,830	46,968,032

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS AND INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Total revenues	$ 15,843	$ 106,483	$ 524,002
Operating expenses:
Cost of license revenues	(65)	(1,254)	(24,976)
Cost of contract manufacturing revenues	(13,563)	(2,089)
Research and development expenses	(214,864)	(197,591)	(143,548)
Selling, general and administrative expenses	(74,591)	(55,059)	(56,290)
Total operating expenses	(303,083)	(255,993)	(224,814)
Other income	6,059	7,171	12,306
Other expense	(1,690)	(820)	(876)
(Loss) / income from operations	(282,871)	(143,159)	310,618
Interest income	19,562	609	162
Interest expense	(41,557)	(11,704)	(7,474)
Foreign currency (losses) / gains, net	(1,691)	23,235	29,660
Other non-operating gains / (losses), net		2,760	(160)
(Loss) / income before income tax (expense) / benefit	(306,557)	(128,259)	332,806
Income tax (expense) / benefit	(1,921)	1,470	(3,217)
Net (loss) / income	(308,478)	(126,789)	329,589
Other comprehensive income / (loss):
Foreign currency translation gains / (losses), net	6,874	(29,435)	(38,763)
Defined benefit pension loss, net of taxes	(2,136)
Total comprehensive (loss) / income	$ (303,740)	$ (156,224)	$ 290,826
Earnings per ordinary share - basic
Basic net (loss) / income per ordinary share	$ (6.47)	$ (2.71)	$ 7.17
Earnings per ordinary share - diluted
Diluted net (loss) / income per ordinary share	$ (6.47)	$ (2.71)	$ 7.04
Weighted average shares - basic	47,670,986	46,735,045	45,986,467
Weighted average shares - diluted	47,670,986	46,735,045	46,840,972
License revenues
Total revenues	$ 2,758	$ 100,000	$ 517,400
Contract manufacturing revenues
Total revenues	10,835	1,717	0
Collaboration revenues
Total revenues	$ 2,250	$ 4,766	$ 6,602

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Ordinary shares	Additional paid-in capital	Accumulated other comprehensive income /(loss)	Accumulated deficit	Total
Beginning balance at Dec. 31, 2020	$ 2,711	$ 1,016,018	$ 9,907	$ (784,731)	$ 243,905
Beginning balance (in shares) at Dec. 31, 2020	44,777,799
Increase (decrease) in shareholders' equity
Income (Loss) for the period				329,589	329,589
Other comprehensive income (loss), net			(38,763)		(38,763)
Issuance of ordinary shares	$ 55	29,509			29,564
Issuance of ordinary shares (in shares)	921,730
Income tax benefit of past share issuance cost		3,047			3,047
Exercises of share options	$ 15	2,638			2,653
Exercises of share options (in shares)	241,496
Restricted and performance share units distributed during the period	$ 21	(21)
Restricted and performance share units distributed during the period (in shares)	352,886
Share-based compensation expense		25,635			25,635
Issuance of ordinary shares relating to employee stock purchase plan		146			146
Issuance of ordinary shares relating to employee stock purchase plan (in shares)	4,724
Ending balance at Dec. 31, 2021	$ 2,802	1,076,972	(28,856)	(455,142)	595,776
Ending balance (in shares) at Dec. 31, 2021	46,298,635
Increase (decrease) in shareholders' equity
Income (Loss) for the period				(126,789)	(126,789)
Other comprehensive income (loss), net			(29,435)		(29,435)
Income tax benefit of past share issuance cost		808			808
Exercises of share options	$ 8	1,272			1,280
Exercises of share options (in shares)	152,356
Restricted and performance share units distributed during the period	$ 27	(27)
Restricted and performance share units distributed during the period (in shares)	505,799
Share-based compensation expense		34,204			34,204
Issuance of ordinary shares relating to employee stock purchase plan	$ 1	164			165
Issuance of ordinary shares relating to employee stock purchase plan (in shares)	11,242
Ending balance at Dec. 31, 2022	$ 2,838	1,113,393	(58,291)	(581,931)	$ 476,009
Ending balance (in shares) at Dec. 31, 2022	46,968,032				46,968,032
Increase (decrease) in shareholders' equity
Income (Loss) for the period				(308,478)	$ (308,478)
Other comprehensive income (loss), net			4,738		4,738
Exercises of share options	$ 1	129			130
Exercises of share options (in shares)	14,070
Restricted and performance share units distributed during the period	$ 43	(43)
Restricted and performance share units distributed during the period (in shares)	832,530
Share-based compensation expense		35,093			35,093
Issuance of ordinary shares relating to employee stock purchase plan	$ 1	177			178
Issuance of ordinary shares relating to employee stock purchase plan (in shares)	19,198
Ending balance at Dec. 31, 2023	$ 2,883	$ 1,148,749	$ (53,553)	$ (890,409)	$ 207,670
Ending balance (in shares) at Dec. 31, 2023	47,833,830				47,833,830

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Cash flows from operating activities
Net (loss) / income	$ (308,478)	$ (126,789)	$ 329,589
Adjustments to reconcile net (loss) / income to net cash (used in) / generated from operating activities:
Depreciation, amortization and impairment	11,900	8,537	7,299
Amortization of premium/discount on investment securities	(10,917)
Share-based compensation expense	35,093	34,204	25,635
Royalty financing agreement interest expense	26,933
Deferred tax expense / (income)	1,921	(1,470)	3,210
Changes in fair value of contingent consideration and derivative financial instrument, net	15,895	4,320	6,843
Unrealized foreign exchange gains, net	(2,206)	(22,083)	(31,335)
Other items, net	4,721	1,605	(2,800)
Changes in operating assets and liabilities:
Accounts receivable, prepaid expenses, and other current assets and receivables	(1,323)	(4,083)	(3,959)
Contract asset related to CSL Behring milestone payments	100,000	(45,000)	(55,000)
Inventories	(6,740)	(6,924)
Accounts payable	(4,169)	9,238	(727)
Accrued expenses, other liabilities, and operating leases	(6,645)	3,385	9,204
Contingent consideration milestone payment	(1,914)
Net cash (used in) / generated from operating activities	(145,929)	(145,060)	287,959
Cash flows from investing activities
Investment in debt securities	(366,439)	(163,146)
Proceeds on maturity of debt securities	167,907
Purchases of property, plant, and equipment	(7,154)	(17,688)	(17,438)
Acquisition of uniQure France SAS, net of cash acquired		(1,900)	(49,949)
Net cash used in investing activities	(205,686)	(182,734)	(67,387)
Cash flows from financing activities
Proceeds from issuance of ordinary shares			30,899
Share issuance costs from issuance of ordinary shares			(1,334)
Proceeds from royalty financing agreement	374,350
Payment of debt issuance costs	(4,288)
Repayment of debt acquired through acquisition of uniQure France SAS			(1,572)
Proceeds from loan increment, net of debt issuance costs			64,067
Proceeds from issuance of ordinary shares related to employee stock option and purchase plans	308	1,445	2,798
Contingent consideration milestone payment	(7,649)
Net cash generated from financing activities	362,721	1,445	94,858
Currency effect on cash, cash equivalents and restricted cash	2,265	(1,831)	(3,757)
Net increase / (decrease) in cash, cash equivalents and restricted cash	13,371	(328,180)	311,673
Cash, cash equivalents and restricted cash at beginning of period	231,173	559,353	247,680
Cash, cash equivalents and restricted cash at the end of period	244,544	231,173	559,353
Cash and cash equivalents	241,360	228,012	556,256
Restricted cash related to leasehold and other deposits	3,184	3,161	3,097
Total cash, cash equivalents and restricted cash	244,544	231,173	559,353
Supplemental cash flow disclosures:
Cash paid for interest	(16,878)	(9,247)	(6,539)
Non-cash decrease in accounts payables and accrued expenses and other current liabilities related to purchases of property, plant, and equipment	$ (513)	$ (964)	$ 1,488

General business information

General business information	12 Months Ended
	Dec. 31, 2023
General business information
General business information	1. ​ uniQure (the “Company”) was incorporated on January 9, 2012 as a private company with limited liability ( besloten vennootschap met beperkte aansprakelijkheid naamloze vennootschap ​ The Company is registered in the trade register of the Dutch Chamber of Commerce ( Kamer van Koophandel ​ The Company’s ordinary shares are listed on the Nasdaq Global Select Market and trade under the symbol “QURE.”

Summary of significant accounti

Summary of significant accounting policies	12 Months Ended
	Dec. 31, 2023
Summary of significant accounting policies
Summary of significant accounting policies	2. ​ 2.1 Basis of preparation ​ The Company prepared its consolidated financial statements in compliance with generally accepted accounting principles in the United States (“U.S. GAAP”). Any reference in these notes to applicable guidance is meant to refer to authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). ​ The consolidated financial statements have been prepared under the historical cost convention, except for derivative financial instruments and contingent consideration, which are recorded at fair value through profit or loss. ​ The consolidated financial statements are presented in United States (“U.S.”) dollars ($), except where otherwise indicated. Transactions denominated in currencies other than U.S. dollars are presented in the transaction currency with the U.S. dollar amount included in parenthesis, converted at the foreign exchange rate as of the transaction date. ​ The consolidated financial statements presented have been prepared on a going concern basis based on the Company’s cash and cash equivalents as of December 31, 2023 and the Company’s budgeted cash flows for the twelve months following the issuance date. ​ 2.2 ​ The preparation of consolidated financial statements, in conformity with U.S. GAAP and Securities and Exchange Commission (“SEC”) rules and regulations, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the consolidated financial statements and reported amounts of revenues and expenses during the reporting period. Estimates and assumptions are primarily made in relation to contingent consideration related to the acquisition of uniQure France SAS, the treatment of revenue to be recognized under the commercialization and license agreement entered into (“CSL Behring Agreement”) between the Company and CSL Behring LLC (“CSL Behring”), and the assessment of a valuation allowance on the Company’s deferred tax assets in the Netherlands. If actual results differ from the Company’s estimates, or to the extent these estimates are adjusted in future periods, the Company’s results of operations could either benefit from, or be adversely affected by, any such change in estimate. ​ 2.3 ​ The principal accounting policies applied in the preparation of these consolidated financial statements are set out below. These policies have been consistently applied to all the years presented, unless otherwise stated. ​ 2.3.1 ​ The consolidated financial statements comprise the financial statements of the Company and its subsidiaries. Subsidiaries are all entities over which the Company has a controlling financial interest either through variable interest or through voting interest. Currently, the Company has no involvement with variable interest entities. ​ Inter-company transactions, balances, income, and expenses on transactions between uniQure entities are eliminated in consolidation. Profits and losses resulting from inter-company transactions that are recognized in assets are also eliminated. Accounting policies of subsidiaries have been changed where necessary to ensure consistency with the policies adopted by the Company. ​ 2.3.2 ​ The Company presents assets and liabilities in the consolidated balance sheets based on current and non-current classification. ​ The term current assets is used to designate cash and other assets, or resources commonly identified as those that are reasonably expected to be realized in cash or sold or consumed during the normal operating cycle of the business. The Company’s normal operating cycle is twelve months. All other assets are classified as non-current. ​ The term current liabilities is used principally to designate obligations whose liquidation is reasonably expected to require the use of existing resources properly classifiable as current assets, or the creation of other current liabilities. Current liabilities are expected to be settled in the normal operating cycle. The Company classifies all other liabilities as non-current. ​ Deferred tax assets and liabilities are classified as non-current assets and liabilities, if any. ​ 2.3.3 ​ The functional currency of the Company and each of its entities (except for uniQure Inc. and Corlieve AG) is the euro (€). This represents the currency of the primary economic environment in which the entities operate. The functional currency of uniQure Inc. is the U.S. dollar ($) and the functional currency of Corlieve AG is the Swiss Franc (CHF). The consolidated financial statements are presented in U.S. dollars. ​ Foreign currency transactions are measured and recorded in the functional currency using the exchange rates prevailing at the dates of the transactions. Foreign exchange gains and losses resulting from the settlement of such transactions and from the re-measurement of monetary assets and liabilities denominated in foreign currencies at exchange rates prevailing at balance sheet date are recognized in profit and loss. ​ Upon consolidation, the assets and liabilities of foreign operations are translated into the functional currency of the shareholding entity at the exchange rates prevailing at the balance sheet date; items of income and expense are translated at monthly average exchange rates. The consolidated assets and liabilities are translated from uniQure N.V.’s functional currency, euro, into the reporting currency U.S. dollar at the exchange rates prevailing at the balance sheet date; items of income and expense are translated at monthly average exchange rates. Issued capital and additional paid-in capital are translated at historical rates with differences to the balance sheet date rate recorded as translation adjustments in other comprehensive income / loss. The exchange differences arising on translation for consolidation are recognized in “accumulated other comprehensive income / loss”. On disposal of a foreign operation, the component of other comprehensive income / loss relating to that foreign operation is recognized in profit or loss. ​ 2.3.4 ​ The Company measures certain assets and liabilities at fair value, either upon initial recognition or for subsequent accounting or reporting. ASC 820, Fair Value Measurements and Disclosures ​ ● Level 1 - Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company can access at the measurement date. ​ ● Level 2 - Valuations based on quoted prices for similar assets or liabilities in markets that are not active or models for which the inputs are observable, either directly or indirectly. ​ ● Level 3 - Valuations that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and are unobservable. ​ To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. ​ Items measured at fair value on a recurring basis include financial instruments and contingent consideration (Note 7, “ Fair value measurement ​ 2.3.5 uniQure France SAS transaction ​ On June 21, 2021, we entered into a share and purchase agreement (“SPA”) to acquire all of the outstanding ordinary shares of uniQure France SAS (formerly Corlieve Therapeutics SAS), a privately held French gene therapy company (“uniQure France SAS Transaction”). On July 30, 2021 (“Acquisition Date”), the Company acquired uniQure France SAS. The Company evaluated the uniQure France SAS transaction as to whether or not the transaction should be accounted for as a business combination or asset acquisition. Refer to Note 3 “ uniQure France SAS transaction ​ a. Goodwill ​ Goodwill represents the excess of the fair value of the consideration transferred over the fair value of the net assets assumed in a business combination. Goodwill is not amortized but is evaluated for impairment on an annual basis and between annual tests if the Company becomes aware of any events occurring or changes in circumstances that would more likely than not reduce the fair value of the reporting unit below its carrying amount. As of December 31, 2023, 2022 and 2021, the Company has not recognized any impairment charges related to goodwill. ​ Refer to Note 3 “ uniQure France SAS transaction ​ b. Acquired research and development ​ The Company identified various licenses that combined with the results of the research and development activities conducted in relation to its target candidate for the treatment of temporal lobe epilepsy (“AMT-260”) since incorporation of uniQure France SAS in 2019 constitute an In-process research and development intangible asset (“IPR&D Intangible Asset”). The IPR&D Intangible Asset is considered to be indefinite-lived until the completion or abandonment of the associated research and development efforts and is not amortized. If and when development is completed, which generally occurs when regulatory approval to market a product is obtained, the associated asset would be deemed finite-lived and would then be amortized based on its respective useful life at that point in time. For the years ended December 31, 2023, 2022 and 2021, the Company has not recognized any impairment charges related to the IPR&D Intangible Asset. In case of abandonment, the IPR&D Intangible Asset will be written-off. In accordance with ASC 350, Intangibles – Goodwill and Other, the Company tests indefinite-lived intangible assets for impairment on an annual basis and between annual tests if the Company becomes aware of any events occurring or changes in circumstances that would indicate the fair value of the IPR&D Intangible Asset is below its carrying amount. ​ Refer to Note 3 “ uniQure France SAS transaction ​ c. Contingent consideration ​ Each reporting period, the Company revalues the contingent consideration obligations associated with the uniQure France SAS transaction to their fair value and records changes in the fair value within research and development expenses. Changes in contingent consideration obligations result from changes in assumptions regarding the probabilities of achieving the relevant milestones, or probability of success (“POS”), the estimated timing of achieving such milestones, and the interest rate to discount the payments. Payments of portions of contingent consideration initially recorded as of the acquisition date are recorded as cash flows from financing activities, and payments, or the portion of the milestone payments representing changes in the fair value of contingent consideration subsequent to the initial recognition are recorded as cash flows from operating activities. ​ Refer to Note 3 “ uniQure France SAS transaction ​ 2.3.6 ​ The consolidated statements of cash flows have been prepared using the indirect method. The cash disclosed in the consolidated statements of cash flows is comprised of cash and cash equivalents and restricted cash. Cash and cash equivalents include bank balances, demand deposits and other short-term highly liquid investments (with maturities of less than three months at the time of purchase) that are readily convertible into a known amount of cash and are subject to an insignificant risk of fluctuation in value. ​ Cash flows denominated in foreign currencies have been translated at the average exchange rates. Exchange differences, if any, affecting cash and cash equivalents are shown separately in the consolidated statements of cash flows. Interest paid and received, and income taxes are included in net cash (used in) provided by operating activities. ​ 2.3.7 ​ Operating segments are identified as a component of an enterprise for which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision-making group, in making decisions on how to allocate resources and assess performance. The Company views its operations and manages its business as one operating segment, which comprises the discovery, development, and commercialization of innovative gene therapies. ​ 2.3.8 ​ The Company follows the provisions of ASC 260, Earnings Per Share ​ Diluted net (loss) / income per share reflects the dilution that would occur if share options or warrants to issue ordinary shares were exercised, performance or restricted share units were distributed, or shares under the employee share purchase plan were issued. However, potential ordinary shares are excluded if their effect is anti-dilutive. ​ Refer to Note 21 “ Basic and diluted earnings per share ​ 2.3.9 ​ Long-lived assets, which include property, plant, and equipment and finite-lived intangible assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of an asset or asset group may not be recoverable. Right-of-use assets are also reviewed for impairment in accordance with ASC 360, Property, Plant, and Equipment ​ Refer to Note 2.3.5 “ uniQure France SAS transaction ​ 2.3.10 ​ Investment securities consist of sovereign debt with residual maturities of less than 12 months (presented as current) and beyond (presented as non-current). The Company classifies these securities as held-to-maturity. Held-to-maturity securities are those securities in which the Company has the ability and intent to hold the security until maturity. Held-to-maturity securities are recorded at amortized cost, adjusted for applicable accrued interest and the amortization or accretion of premiums or discounts. Premiums and discounts are amortized or accreted over the term of the related held-to-maturity security as an adjustment to yield using the effective interest rate method. ​ Investments securities with original maturities of less than three months when purchased are presented within cash and cash equivalents (December 31, 2023: nil, December 31, 2022: $21.2 million). ​ A decline in the market value of any investment security below cost that is deemed to be other than temporary results in a reduction in the carrying amount to fair value. The impairment is charged to operations and a new cost base for the security is established. Other-than-temporary impairment charges are included in interest and other income (expense), net. Interest income is recognized when earned. ​ Refer to Note 6 “ Investment securities ​ 2.3.11 ​ ​ 2.3.12 ​ The Company started producing commercial materials in April 2022 to supply CSL Behring in accordance with the June 2020 Development and Commercial Supply Agreement between the Company and CSL Behring. From this date onwards, the Company presents the costs associated with the aforementioned activities as cost of contract manufacturing. Refer to Note 5 “Collaboration arrangements and concentration of credit risk” ​ Per ASC 330, Inventory, inventory is stated at the lower of cost or estimated net realizable value, on a first-in, first-out basis. The Company capitalizes raw materials to the extent these can be used in contract manufacturing for CSL Behring. The Company uses standard costs, approximating average costs to determine its cost basis for work in progress and finished goods. The Company’s assessment of recoverability value requires the use of estimates regarding the net realizable value of its inventory balances, including an assessment of excess or obsolete inventory. As applicable, write-downs resulting from adjustments to net realizable value will be recorded to cost of contract manufacturing. ​ 2.3.13 ​ Prepaid expenses are amounts paid in the period, for which the benefit has not been realized, and include payments made for insurance and research and clinical contracts. The related expense will be recognized in the subsequent period as incurred. ​ 2.3.14 ​ Deposits paid are either presented as other current assets or as other non-current assets based on duration of the underlying contractual arrangement. Deposits are classified as restricted cash and primarily relate to facility leases. ​ Contract assets are presented in current assets or as non-current assets based on the timing of the right to consideration. ​ 2.3.15 ​ Property, plant, and equipment is comprised mainly of laboratory equipment, leasehold improvements, construction-in-progress (“CIP”) and office equipment. All property, plant and equipment is stated at cost less accumulated depreciation. CIP consists of capitalized expenses associated with construction of assets not yet placed into service. Depreciation commences on CIP once the asset is placed into service based on its useful life determined at that time. ​ Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed as incurred. Upon disposal, the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss on the transaction is recognized in the consolidated statements of operations and comprehensive loss. ​ Depreciation is calculated using the straight-line method over the estimated useful lives of the assets (or in the case of leasehold improvements a shorter lease term), which are as follows: ​ ​ ​ ​ ​ ​ ​ · Leasehold improvements Between 10 – 15 years · Laboratory equipment ​ 5 years · Office equipment ​ Between 3 – 5 years ​ 2.3.16 ​ The Company records leases in accordance with ASC 842, Leases ​ ​ 2.3.17 Accounts payable and accrued expenses ​ Accounts payables are invoiced amounts related to obligations to pay for goods or services that have been acquired in the ordinary course of business from suppliers. Accounts payables are recognized at the amounts invoiced by suppliers. ​ Accrued expenses are recognized for goods or services that have been acquired in the ordinary course of business. ​ Contract liabilities, if any, are presented in accrued expenses. 2.3.18 ​ Long-term debt is initially recognized at cost and presented net of original issue discount or premium and debt issuance costs on the consolidated balance sheets. Amortization of debt discount and debt issuance costs is recognized as interest expense in profit and loss over the period of the debt, using the effective interest rate method. ​ 2.3.19 Pensions and other post-retirement benefit plans ​ The Company has a defined contribution pension plan for all employees at its Amsterdam facility in the Netherlands, which is funded by the Company through payments to an insurance company, with individual accounts for each participants’ assets. The Company has no legal or constructive obligation to pay further contributions if the plan does not hold sufficient assets to pay all employees the benefits relating to services rendered in the current and prior periods. The contributions are expensed as incurred. Prepaid contributions are recognized as an asset to the extent that a cash refund or a reduction in the future payments is available. ​ In 2016, the Company adopted a qualified 401(k) Plan for all employees located in the United States. The 401(k) Plan offers both a pre-tax and post-tax (Roth) component. Employees may contribute up to the IRS statutory limit each calendar year. The Company matches $0.50 for every $1.00 contributed to the plan by participants up to 6% of base compensation. Employer contributions are recognized as they are contributed, as long as the employee is rendering services in that period. If employer contributions are made in periods after an individual retires or terminates, the estimated cost is accrued during the employee’s service period. ​ The Company maintains defined benefit plans for its Swiss employees, including retirement benefit plans required by applicable local law. The Company accounts for pension assets and liabilities in accordance with ASC 715, Compensation - Retirement Benefits, which requires the recognition of the funded status of pension plans in the Company’s consolidated balance sheet. The liability in respect to defined benefit pension plans is the projected benefit obligation calculated annually by independent actuaries using the projected unit credit method. ​ The projected benefit obligation as of December 31, 2023 represents the actuarial present value of the estimated future payments required to settle the obligation that is attributable to employee services rendered before that date. Service cost is reported in research and development and general and administrative expenses. All other components of net period costs are reported in interest expense in the consolidated statement of operations and comprehensive loss. Plan assets are recorded at their fair value. Gains or losses arising from plan curtailments or settlements are accounted for at the time they occur. Actuarial gains and losses arising from differences between the actual and the expected return on plan assets are recognized in accumulated other comprehensive income (loss). ​ 2.3.20 Share-based compensation ​ The Company accounts for its share-based compensation awards in accordance with ASC 718, Compensation-Stock Compensation. ​ All the Company’s share-based compensation plans for employees are equity-classified. ASC 718 requires all share-based compensation to employees, including grants of employee options, restricted share units, performance share units and modifications to existing instruments, to be recognized in the consolidated statements of operations and comprehensive loss based on their grant-date fair values, net of an estimated forfeiture rate, over the requisite service period. Forfeitures of employee options are recognized as they occur. Compensation expense related to Performance Share Units is recognized when the Company considers achievement of the milestones to be probable. The requirements of ASC 718 are also applied to nonemployee share-based payment transactions except for specific guidance on certain inputs to an option-pricing model and the attribution of cost. ​ The Company uses a Hull & White option model to determine the fair value of option awards. The model captures early exercises by assuming that the likelihood of exercises will increase when the share-price reaches defined multiples of the strike price. This analysis is performed over the full contractual term. ​ ​ ​ 2.3.21 Revenue recognition ​ The Company primarily generates revenue from its commercialization and license agreement with CSL Behring. The Company generated revenue from services provided to Bristol-Myers Squibb (“BMS”) until February 21, 2023 (“Termination Date”). ​ CSL Behring collaboration ​ On June 24, 2020 (“Signing Date”), the Company entered into a commercialization and license agreement pursuant to which CSL Behring received exclusive global rights to etranacogene dezaparvovec (“Product”). On May 6, 2021, the CSL Behring Agreement became fully effective (“Closing”). The Company concluded that CSL Behring is a customer in accordance with ASC 606, Revenue from Contracts with Customers ​ (i) Sale of the exclusive global rights to etranacogene dezaparvovec, a gene therapy for patients with hemophilia B (the “Product”) (“License Sale”); and (ii) Generate information to support the regulatory approval of the current and next generation manufacturing process of the Product and to provide any such information generated to CSL Behring (“Manufacturing Development”). These performance obligations were considered distinct from one another, as CSL Behring can benefit from the identified service either on its own or together with other resources that are readily available to CSL Behring, and as the performance obligations are separately identifiable from other performance obligations in the CSL Behring Agreement. The Company continued to develop the Product between the Signing Date and Closing and performed certain reimbursable activities to fulfill the transfer of the global rights (“Additional Covenants” and together with the License the “License Sale”). The Additional Covenants are not considered distinct from the performance obligation to sell the license to CSL Behring as CSL Behring could not benefit from the Additional Covenants on their own, or have these activities be performed with readily available resources. ​ Refer to Note 5 “ Collaboration arrangements and concentration of credit risk ​ Bristol-Myers Squib collaboration ​ The Company initially entered into collaboration, research, and license agreements with BMS in 2015 (“BMS CLA”) and amended them in 2020 (“amended BMS CLA”). The agreement terminated on February 21, 2023. ​ The Company provided pre-clinical research activities ("Collaboration Revenue") under the amended BMS CLA. ​ 2.3.22 ​ The Company receives certain government and regional grants, which support its research efforts in defined projects, and include contributions towards the cost of research and development. These grants generally provide for reimbursement of approved costs incurred as defined in the respective grants and are deferred and recognized in the statements of operations and comprehensive loss over the period necessary to match them with the costs they are intended to compensate, when it is probable that the Company has complied with any conditions attached to the grant and will receive the reimbursement. ​ The Company’s other income also consists of employee retention credits received under the U.S. Coronavirus Aid, Relief, and Economic Security Act, income related to a settlement agreement that the Company and VectorY B.V. entered into in April 2021, as well as income from subleasing part of the Company’s Amsterdam facility. Other expense consists of expenses incurred in relation to the subleasing income. ​ ​ ​ ​ ​ 2.3.23 ​ Research and development costs are expensed as incurred. Research and development expenses generally consist of laboratory research, clinical trials, statistical analysis, and report writing, regulatory compliance costs incurred with clinical research organizations and other third-party vendors (including post-approval commitments to conduct consistency and comparability studies). In addition, research and development expenses consist of start-up and validation costs related to the Company’s Lexington facility and the development and improvement of the Company’s manufacturing processes and methods. Furthermore, research and development costs include costs of materials and costs of intangible assets purchased from others for use in research and development activities. The costs of intangibles that are purchased from others for a particular research and development project and that have no alternative future uses (in other research and development projects or otherwise) are expensed as research and development costs at the time the costs are incurred or at the time when no alternative future use is identified. ​ 2.3.24 ​ Income taxes are recorded in accordance with ASC 740, Income Taxes ​ The benefits of tax positions are recognized only if those positions are more likely than not, based on the technical merits, to be sustained upon examination. Recognized tax positions are measured at the largest amount of tax benefit that is greater than 50 percent likely of being realized upon settlement. 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 did not have any significant unrecognized tax benefits. ​ 2.3.25 Royalty Financing Agreement ​ In May 2023, uniQure biopharma B.V. (“uniQure biopharma”), a wholly-owned subsidiary of the Company entered into an agreement (the “Royalty Financing Agreement”) with the HemB SPV, L.P. (the “Purchaser”) to sell certain current and future royalties due to uniQure biopharma from CSL Behring under the CSL Behring Agreement by and between uniQure biopharma and CSL Behring from the net sales of HEMGENIX®. Refer to Note 14 “Royalty Financing Agreement” ​ In accordance with topic ASC 835, Interest, debt issuance costs incurred in relation to the Royalty Financing Agreement are presented as a reduction of carrying amount of the debt. Debt issuance cost is amortized together with the interest expense recorded. ​ 2.3.26 Restructuring expenses ​ Restructuring charges principally consist of one-time termination benefits. The Company records one-time termination benefits in accordance with ASC 420, Exit or Disposal Cost Obligations. One-time termination benefits are expensed at the date the Company notifies the employee, unless the employee must provide future service, in which case the benefits are expensed ratably over the future service period. ​ Other costs relate to the impairment of the Lexington facility that was closed as a result of a reorganization plan (the “Reorganization”). The Company has recognized an impairment loss of the right-of-use asset and corresponding leasehold improvements in accordance with ASC 360, Property, Plant and Equipment. ​ 2.3.27 Recently Adopted Accounting Pronouncements ​ None. ​ Recent Accounting Pronouncements Not Yet Effective ​ None. ​

uniQure France SAS transaction

uniQure France SAS transaction	12 Months Ended
	Dec. 31, 2023
uniQure France SAS transaction
uniQure France SAS transaction	3. uniQure France SAS transaction ​ At the Acquisition Date, the Company acquired uniQure France SAS (formerly Corlieve Therapeutics SAS). Following uniQure France SAS’s formation in November 2019, uniQure France SAS obtained exclusive licenses to certain patents from two French research institutions that continue to collaborate with the Company. uniQure France SAS also obtained an exclusive license from Regenxbio Inc. (“Regenxbio”). uniQure France SAS and Regenxbio simultaneously entered into a collaboration plan related to agreed joint preclinical research and development activities. At the Acquisition Date, uniQure France SAS and its Swiss subsidiary, Corlieve Therapeutics AG, employed seven employees. ​ The Company evaluated the uniQure France SAS transaction as to whether or not the transaction should be accounted for as a business combination or asset acquisition by first applying a screen test to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. Based on the fair values of the gross assets acquired, the Company determined the screen test was not met. The Company further analyzed whether or not the acquired inputs and processes that have the ability to create outputs would meet the definition of a business. Significant judgment is required in the application of the screen test to determine whether an acquisition is a business combination or an acquisition of assets. ​ Identifiable assets and liabilities of uniQure France SAS, including identifiable intangible assets, were recorded at their fair values as of the Acquisition Date, when the Company obtained control. The excess of the fair value of the consideration transferred over the fair value of the net assets acquired was recorded as goodwill. ​ Consideration ​ On the Acquisition Date, the Company acquired 97.7% of the outstanding ordinary shares of uniQure France SAS in return for EUR 44.9 million ($53.3 million as of the Acquisition Date). The Company acquired the remaining outstanding ordinary shares in February, July and September 2022 for a total of EUR 1.8 million ($1.9 million). ​ In addition to the payments to acquire 100% of the outstanding ordinary shares, uniQure France SAS’s former shareholders are eligible to receive up to EUR 40.0 million ($44.1 million as of December 31, 2023) upon achievement of certain development milestones through Phase I/II, of which EUR 10.0 million ($10.6 million) was paid in September 2023, and EUR 160.0 million ($176.6 million as of December 31, 2023) upon achievement of certain milestones associated with Phase III development and obtaining approval to commercialize uniQure France SAS’s target candidate for the treatment of mesial temporal lobe epilepsy (“AMT-260” or “MTLE”) in the United States of America and the European Union. The Company may elect to pay up to 25% of such milestone payments through the issuance of the Company’s ordinary shares. ​ As of the Acquisition Date, the Company recorded EUR 20.2 million ($24.0 million) as a contingent liability (presented as “Non-current liability”) for the fair value of these milestone payments. ​ Identified intangible assets ​ The Company identified various licenses that combined with the results of the research and development activities conducted in relation to AMT-260 since incorporation of uniQure France SAS in 2019 constitute an IPR&D Intangible Asset. ​ The Company determined the fair value of the IPR&D Intangible Asset using a present value model based on expected cash flows. Estimating the amounts and timing of cash flows required to complete the development of AMT-260 as well as net sales, cost of goods sold, and sales and marketing costs involved considerable judgment and uncertainty. The expected cash flows are materially impacted by the probability of successfully completing the various stages of development (i.e., dosing of first patient in clinical trial, advancing into late-stage clinical development and obtaining approval to commercialize a product candidate) as well as the weighted average cost of capital of 10.4% used to discount the expected cash flows. Based on all such information and its judgment the Company estimated the fair value of the IPR&D Intangible Asset at EUR 53.6 million ($63.6 million) as of the Acquisition Date. ​ Deferred tax liability, net ​ uniQure France SAS’s deferred tax assets at the time of acquisition amounted to EUR 1.5 million ($1.7 million). Recognition of the IPR&D Intangible Asset gave rise to a deferred tax liability of EUR 13.4 million ($15.9 million) at the enacted French corporate income tax rate of 25.0%. The Company consequently recorded a net deferred tax liability of EUR 11.9 million ($14.2 million as of the Acquisition Date). Changes in the net deferred tax liability after the Acquisition Date will be recorded in income tax expense in the Consolidated statements of operations and comprehensive income / (loss). ​ Goodwill ​ Goodwill represents the excess of total consideration over the estimated fair value of net assets acquired. The Company recorded EUR 23.9 million ($28.4 million) of goodwill in the consolidated balance sheet as of the Acquisition Date. The goodwill primarily relates to the recognition of a deferred tax liability recognized in association with the IPR&D Intangible asset of EUR 13.4 million ($15.9 million as of Acquisition Date) as well as the fair market value of the experienced workforce and potential synergies from the acquisition. The Company allocated the goodwill to its reporting unit. The Company does not expect any portion of this goodwill to be deductible for income tax purposes. ​ Debt As of the Acquisition Date, uniQure France SAS held a loan with outstanding amount equal to EUR 1.0 million ($1.2 million), which loan was repaid in its entirety in September 2021. As of the Acquisition Date, uniQure France SAS also held a loan with outstanding amount equal to EUR 0.4 million ($0.4 million), which was repaid in its entirety in December 2021. ​ Other As of the Acquisition Date, the Company also acquired other assets and assumed other liabilities, which included among others, EUR 2.9 million ($3.4 million) of current assets, which consisted of EUR 2.8 million ($3.3 million) of cash, and EUR 1.1 million ($1.3 million) of current liabilities. ​

Reorganization

Reorganization	12 Months Ended
	Dec. 31, 2023
Reorganization
Reorganization	4. Reorganization ​ On October 5, 2023, the Company announced the Reorganization. As a result, the Company recorded severance and other personnel related expenses for the impacted employees. ​ In 2023, as a part of the Reorganization, the Company decided to sublease one of its laboratories in Lexington. The carrying amount of the right-of-use asset was determined not to be recoverable. As a result, the Company recorded impairment charges for the related operating lease right-of-use assets and leasehold improvements. ​ ​ ​ ​ A summary of the restructuring charges for the year ended December 31, 2023 by major activity type is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Severance and Other Personnel Costs Impairment Charges Total ​ ​ ​ (in thousands) Research and development ​ $ 2,188 1,438 3,626 General and administrative ​ ​ 361 — 361 Total ​ $ 2,549 1,438 3,987 ​ A summary of the changes in the severance and other personnel liabilities, included within accrued expenses and other current liabilities on the consolidated balance sheets, related to the workforce reduction is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of liability ​ ​ ​ (in thousands) Balance as of January 1, 2023 ​ $ — Severance and other personnel costs ​ ​ 2,549 Cash payments during the period ​ ​ (1,522) Balance as of December 31, 2023 ​ $ 1,027 ​ ​

Collaboration arrangements and

Collaboration arrangements and concentration of credit risk	12 Months Ended
	Dec. 31, 2023
Collaboration arrangements and concentration of credit risk
Collaboration arrangements and concentration of credit risk	5. Collaboration arrangements and concentration of credit risk ​ CSL Behring collaboration ​ License Sale The Company determined that the fixed upfront payment of $450.0 million and the $12.4 million that the Company received in May 2021 in relation to the Additional Covenants should be allocated to the License Sale. In addition, the Company concluded that variable milestone payments, sales milestone payments and royalties should be allocated to the License Sale performance obligation as well. The Company determined that the License Sale was completed on May 6, 2021, when it transferred the license and CSL Behring assumed full responsibility for the development and commercialization of the Product. At Closing, the Company evaluated the amounts of potential payments and the likelihood that the payments will be received. The Company utilized the most likely amount method to estimate the variable consideration to be included in the transaction price. Since the Company cannot control the achievement of regulatory and first commercial sales milestones, the Company concluded that the potential payments were constrained as of Closing. The Company determined that it would recognize revenue related to these payments only to the extent that it becomes probable that no significant reversal of recognized cumulative revenue will occur thereafter. The Company determined that achievement of a total of $55.0 million of milestone payments related to the submissions of a biologics license application (“BLA”) and market authorization application (“MAA”) was probable as of February 25, 2022, the time of filing the 2021 financial statements, and hence recorded these as license revenue in the year ended December 31, 2021. In March and April 2022, the global regulatory submissions were submitted, and the Company received the $55.0 million owed to it from CSL Behring. The Company recorded $100.0 million in variable milestone revenue related to a first sale of HEMGENIX ® ® The Company is also eligible to receive up to $1.3 billion in additional payments based on the achievement of commercial milestones, which are not subject to the Royalty Financing Agreement. Royalties on the sale of HEMGENIX® are recorded once earned and are presented as license revenue. ​ The Company recognized $2.8 million (of which all related to royalty revenue), $100.0 million (nil related to royalty revenue) and $517.4 million (nil related to royalty revenue) of revenues related to the License Sale in the years ended December 31, 2023, 2022 and 2021, respectively. ​ The Company recorded expenses related to its existing license and other agreements as well as its financial advisor for a high single digit percentage of any such revenue recognized associated to meeting a milestone. Manufacturing Development ​ The Company determined that a $50.0 million variable milestone payment related to Manufacturing Development should be allocated to the Manufacturing Development performance obligation. The Company concluded that this milestone payment represents the stand-alone selling price (“SSP”) of the services based on the estimated cost of providing the services including a reasonable margin. Manufacturing Development includes providing information regarding a next generation manufacturing process of the Product to CSL Behring. CSL Behring did not request such services during the year ended December 31, 2023. The variable consideration will be reduced based on a formula linked to quantities supplied using the currently approved manufacturing process following the one year anniversaries of the BLA and MAA approvals. In conjunction with the ongoing technology transfer (see below), the Company is not actively generating information with respect to a next generation manufacturing process of the Product. The Company utilized the most likely amount method to estimate the variable consideration to be included in the transaction price. As of December 31, 2023, the Company has not recognized any revenue related to the Manufacturing Development milestone. Contract manufacturing ​ On the Signing Date, the Company and CSL Behring entered into a development and commercial supply agreement, pursuant to which, among other things, the Company will supply HEMGENIX ® The Company generated $10.8 million, $1.7 million and nil contract manufacturing revenue from sales to CSL Behring during the years ended December 31, 2023, 2022 and 2021. The Company recognizes contract manufacturing revenue when CSL Behring obtains control of ®. The Company incurred $13.6 million, $2.1 million and nil of cost in relation to its contract manufacturing activities during the years ended December 31, 2023, 2022 and 2021. Collaboration services ​ Following Closing, the Company was facilitating the completion of the HOPE-B clinical trial on behalf of CSL Behring until CSL Behring took over the execution of the clinical trials in December 2022. Activities related to on-demand development services and other services in accordance with the CSL Behring Agreement as well as activities related to the completing the HOPE-B clinical trial are reimbursed by CSL Behring at an agreed full-time-employee rate (“FTE-rate”) and CSL Behring also reimbursed agreed third-party expenses incurred in relation to performing these activities. The Company concluded that these rights at Closing did not represent material rights. The Company recognized $2.3 million of collaboration revenue in the year ended December 31, 2023, compared to $3.0 million and $2.4 million in the same periods in 2022 and 2021. Accounts eceivable and ontract asset As of December 31, 2023, the Company recorded accounts receivable of $4.0 million from CSL Behring related to collaboration services, contract manufacturing revenue and royalty revenue. As of December 31, 2022, the Company recorded accounts receivable of $2.2 million from CSL Behring related to collaboration services as well as a contract asset of $100.0 million for a milestone due from CSL Behring following the first sale of HEMGENIX ® As of December 31, 2021, the Company recorded accounts receivable of $2.9 million from CSL Behring related to collaboration services as well as a contract asset of $55.0 million associated with milestone payments due upon CSL Behring’s global regulatory submissions for HEMGENIX™ which were collected in March and April 2022. Bristol-Myers Squibb collaboration ​ On November 21, 2022, the Company received written notice that BMS is terminating the BMS CLA as amended effective February 21, 2023. ​ The Company recognized collaboration revenues associated with Collaboration Target-specific pre-clinical analytical development and process development activities that were reimbursable by BMS under the amended BMS CLA as well as other related agreements. Collaboration revenue related to these contracted services was recognized when performance obligations were satisfied. Total collaboration revenue generated with BMS are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 ​ ​ 2022 ​ ​ 2021 ​ ​ (in thousands) Bristol Myers Squibb $ — ​ $ 1,752 ​ $ 4,176 ​ $ — ​ $ 1,752 ​ $ 4,176 ​ ​ Amounts owed by BMS in relation to the collaboration revenue are as follows (presented as “Accounts receivable”) as of December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2023 2022 ​ ​ (in thousands) Bristol Myers Squibb ​ $ — ​ $ 136 Total ​ $ — ​ $ 136 ​

Investments securities

Investments securities	12 Months Ended
	Dec. 31, 2023
Investments securities
Investments securities	6. Investments securities ​ The following table summarizes the Company’s investments into sovereign debt as of December 31, 2023 and 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At December 31, 2023 ​ ​ Amortized cost ​ Gross unrealized holding gains ​ Gross unrealized holding losses ​ Estimated fair value ​ ​ (in thousands) Current investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Government debt securities (held-to-maturity) ​ $ 376,532 ​ $ 139 ​ $ — ​ $ 376,671 Total ​ $ 376,532 ​ $ 139 ​ $ — ​ $ 376,671 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At December 31, 2022 ​ ​ Amortized cost ​ Gross unrealized holding gains ​ Gross unrealized holding losses ​ Estimated fair value ​ ​ (in thousands) Current investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Government debt securities (held-to-maturity) ​ $ 124,831 ​ $ — ​ $ (283) ​ $ 124,548 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-current investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Government debt securities (held-to-maturity) ​ ​ 39,984 ​ ​ — ​ ​ (43) ​ ​ 39,941 Total ​ $ 164,815 ​ $ — ​ $ (326) ​ $ 164,489 ​ The Company invests in short-term U.S. and European government bonds with the highest investment credit rating. The U.S. and European government bonds are U.S. dollar and euro denominated, respectively. Inputs to the fair value of the investments are considered Level 2 inputs.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2023
Inventories
Inventories	​ 7. Inventories ​ The following table summarizes the inventory balances, net of reserves, as of December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2023 2022 ​ ​ (in thousands) Raw materials ​ $ 7,157 ​ $ 3,584 Work in progress ​ ​ 4,109 ​ ​ 1,874 Finished goods ​ ​ 758 ​ ​ 1,466 Inventories ​ $ 12,024 ​ $ 6,924 ​ The Company recorded write downs of $1.6 million and nil for the years ended December 31, 2023 and December 31, 2022. The costs are recognized as Cost of Contract Manufacturing Revenues.

Fair value measurement and Othe

Fair value measurement and Other non-operating (losses) / gains	12 Months Ended
	Dec. 31, 2023
Fair value measurement and Other non-operating (losses) / gains
Fair value measurement and Other non-operating (losses) / gains	8. Fair value measurement and Other non-operating (losses) / gains ​ The Company measures certain financial assets and liabilities at fair value, either upon initial recognition or for subsequent accounting or reporting. ​ The carrying amount of cash and cash equivalents, accounts receivable from licensing and collaboration partners, other assets, accounts payable, accrued expenses and other current liabilities reflected in the consolidated balance sheets approximate their fair values due to their short-term maturities. ​ The Company’s material financial assets include cash and cash equivalents, restricted cash and investment securities. Cash and cash equivalents and restricted cash are measured at fair value using Level 1 inputs. Restricted cash is included within “Other non-current assets” within the consolidated balance sheets. Investment securities are measured at amortized cost. ​ The following table sets forth the balances and changes in fair values of liabilities that are measured at fair value using Level 3 inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative ​ ​ ​ ​ ​ Contingent ​ financial ​ ​ ​ ​ consideration instruments Total ​ ​ (in thousands) Balance at December 31, 2020 ​ $ — ​ $ 2,645 ​ $ 2,645 Amount recorded for contingent consideration on Acquisition Date of uniQure France SAS ​ ​ 23,950 ​ ​ — ​ ​ 23,950 Net losses recognized in profit or loss ​ ​ 6,683 ​ ​ 160 ​ ​ 6,843 Currency translation effects ​ ​ (1,091) ​ ​ — ​ ​ (1,091) Balance at December 31, 2021 ​ $ 29,542 ​ $ 2,805 ​ $ 32,347 Net losses / (gains) recognized in profit or loss ​ ​ 7,080 ​ ​ (2,760) ​ ​ 4,320 Currency translation effects ​ ​ (1,306) ​ ​ (45) ​ ​ (1,351) Balance at December 31, 2022 ​ $ 35,316 ​ $ — ​ $ 35,316 Net losses recognized in profit or loss ​ ​ 15,895 ​ ​ — ​ ​ 15,895 Contingent consideration milestone payment ​ ​ (9,563) ​ ​ — ​ ​ (9,563) Currency translation effects ​ ​ 1,358 ​ ​ — ​ ​ 1,358 Balance at December 31, 2023 ​ $ 43,006 ​ $ — ​ $ 43,006 ​ Contingent consideration ​ The Company is required to pay up to EUR 178.8 million ($197.3 million at the December 31, 2023 foreign exchange rate) to the former shareholders of uniQure France SAS (formerly Corlieve Therapeutics SAS) upon the achievement of contractually defined milestones in connection with the Company’s acquisition of uniQure France (refer to Note 3 “uniQure France SAS transaction” ​ The fair value of the contingent consideration as of December 31, 2023 was $43.0 million (December 31, 2022: $35.3 million) using discount rates of approximately 15.3% to 15.6% (December 31, 2022: 14.0% to 14.4%). Following the clearance of an Investigational New Drug (“IND”) application for AMT-260 in August 2023, the Company increased the probability of achieving a EUR 30.0 million ($33.1 million) milestone payment following the dosing of the first patient in Phase I/II clinical trial from 66.0% to 100.0%. This also resulted in an increase of the probability that AMT-260 may advance to late-stage development and commercialization. ​ If as of December 31, 2023 the Company had assumed a 100% likelihood of AMT-260 advancing into a Phase III clinical study, then the fair value of the contingent consideration would have increased to $75.9 million. If as of December 31, 2023 the Company had assumed that it would discontinue development of the AMT-260 program, then the contingent consideration would have been released to income. ​ As of December 31, 2023, the Company classified $28.2 million of the total contingent consideration of $43.0 million as current liabilities. The balance sheet classification between current and non-current liabilities is based upon the Company’s best estimate of the timing of settlement of the remaining relevant milestones. ​ Derivative financial instruments ​ The Company recorded the following results in other non-operating (losses) / gains related to the changes in the fair value of derivative financial instruments. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ (in thousands) Other non-operating gains: ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative gains ​ $ — ​ $ 2,760 ​ $ — Total other non-operating gains: ​ ​ — ​ ​ 2,760 ​ ​ — Other non-operating losses: ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative losses ​ ​ — ​ ​ — ​ ​ (160) Other non-operating gains / (losses), net ​ $ — ​ $ 2,760 ​ $ (160) ​ Derivative financial instruments BMS ​ On December 1, 2020, as part of the amended BMS CLA, the Company and BMS agreed that upon the consummation of a change of control transaction of uniQure that occurs prior to December 1, 2026 or BMS’ delivery of a target cessation notice for all four Collaboration Targets, the Company (or its third party acquirer) shall pay to BMS a one-time, non-refundable, non-creditable cash payment of $70.0 million, provided that (x) if $70.0 million is greater than five percent (5.0%) of the net proceeds (as contractually defined) from such change of control transaction, the payment shall be an amount equal to five percent of such net proceeds, and (y) if $70.0 million is less than one percent of such net proceeds, the change of control payment shall be an amount equal to one percent of such net proceeds (“CoC-payment”). The amended BMS CLA was terminated on February 21, 2023. The Company had previously determined that the CoC-payment should be recorded as a derivative financial liability as of the December 1, 2020 initial recognition and that subsequent changes in the fair market value of this derivative financial liability should be recorded in profit and loss. ​ The Company determined the fair market value of the derivative financial liability to be nil as of December 31, 2022 as no change of control transaction had been consummated prior to the termination of the amended BMS CLA on February 21, 2023. This resulted in the derecognition of the derivative financial liability for the year ended December 31, 2022. ​ Accordingly, the Company recorded a $2.8 million gain within “Other non-operating (losses) / gains” in the year ended December 31, 2022 and no such gains or losses were recorded in the year ended December 31, 2023. ​ Other ​ As of December 31, 2023, the Company recorded $0.5 million liability related to consideration for post-acquisition services, presented within Other non-current liabilities in connection with the Company’s acquisition of uniQure France SAS (December 31, 2022: $0.3 million). ​ Investment securities ​ Refer to Note 6 “ Investment securities ​ Pension plan assets ​ Refer to Note 15 “ Retirement benefits ​ ​ Other

Property, plant, and equipment,

Property, plant, and equipment, net	12 Months Ended
	Dec. 31, 2023
Property, plant, and equipment, net
Property, plant, and equipment, net	9. Property, plant, and equipment, net ​ The following table presents the Company’s property, plant, and equipment as of December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2023 2022 ​ ​ (in thousands) Leasehold improvements ​ $ 46,512 ​ $ 44,871 Laboratory equipment ​ ​ 43,657 ​ ​ 39,393 Office equipment ​ ​ 6,383 ​ ​ 4,985 Construction-in-progress ​ ​ 5,668 ​ ​ 5,409 Total property, plant, and equipment ​ ​ 102,220 ​ ​ 94,658 Less accumulated depreciation ​ ​ (55,672) ​ ​ (44,126) Property, plant and equipment, net ​ $ 46,548 ​ $ 50,532 ​ Total depreciation expense was $10.3 million for the year ended December 31, 2023 (December 31, 2022: $8.2 million, December 31, 2021: $6.1 million). Depreciation expense is allocated to research and development expenses and cost of contract manufacturing to the extent it relates to the Company’s manufacturing facility and equipment and laboratory equipment. All other depreciation expenses are allocated to selling, general and administrative expense. ​ The following table summarizes property, plant, and equipment by geographic region. ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, ​ ​ 2023 ​ 2022 ​ ​ (in thousands) Lexington, Massachusetts (United States of America) ​ $ 19,437 ​ $ 20,258 Amsterdam (the Netherlands) ​ 27,095 ​ 30,252 Other ​ ​ 16 ​ ​ 22 Total ​ $ 46,548 ​ $ 50,532 ​

Right-of-use asset and lease li

Right-of-use asset and lease liabilities	12 Months Ended
	Dec. 31, 2023
Right-of-use asset and lease liabilities
Right-of-use asset and lease liabilities	10. Right-of-use asset and lease liabilities ​ The Company’s most significant leases relate to office and laboratory space under the following operating lease agreements: ​ Lexington, Massachusetts / United States ​ In July 2013, the Company entered into a lease for a facility in Lexington, Massachusetts, United States. The term of the lease commenced in November 2013, was set for 10 years starting from the 2014 rent commencement date and is non-cancellable. Originally, the lease for this facility had a termination date of 2024. In November 2018, the term was expanded by five years to June 2029. The lease continues to be renewable for two subsequent five-year terms. Additionally, the lease was expanded to include an additional 30,655 square feet within the same facility and for the same term. The lease of the expansion space commenced on June 1, 2019. ​ The contractually fixed annual increase of lease payments through 2029 for both the extension and expansion lease have been included in the lease payments. ​ In December 2021, the Company entered into a new lease for an additional facility in Lexington, Massachusetts, United States of approximately 13,501 square feet of space. The lease commenced in May 2022. Following the Company’s announcement of the Reorganization, the Company incurred costs amounting to $1.4 million associated with the impairment of the right-of-use asset and its associated leasehold improvements’ carrying value that was determined not be recoverable as of the cease-use date in late 2023. This facility is intended to be subleased in 2024. In February 2022, the Company also entered into a new lease for an additional facility in Lexington, Massachusetts, United States of approximately 12,716 square feet. The lease commenced in November 2022 and is set for a non-cancellable period of seven years and four months . The lease is renewable for one five-year term. Amsterdam / The Netherlands ​ In March 2016, the Company entered into a 16-year lease for a facility in Amsterdam, the Netherlands and amended this agreement in June 2016. The lease for the facility terminates in 2032, with an option to extend in increments of five-year periods. The lease contract includes variable lease payments related to annual increases in payments based on a consumer price index. ​ On December 1, 2017, the Company entered into an agreement to sub-lease three of the seven floors of its Amsterdam facility for a ten-year term ending on December 31, 2027, with an option for the sub-lessee to extend until December 31, 2031. In February 2020, the Company amended the agreement to sub-lease to take back one of the three floors effective March 1, 2020. The fixed lease payments to be received during the remaining term under the agreement to sub-lease amount to EUR 3.6 million ($4.0 million) as of December 31, 2023. ​ In May 2021, the Company entered into a sublease agreement to let an additional approximately 1,080 square meters of office space to accommodate the hiring of additional full-time employees. The lease expires in October 2028. ​ Operating lease liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) ​ ​ ​ Operating lease cost ​ $ 7,018 ​ $ 5,932 ​ $ 5,306 Variable lease cost ​ ​ 1,238 ​ ​ 785 ​ ​ 698 Sublease income ​ ​ (957) ​ ​ (849) ​ ​ (907) Total lease cost ​ $ 7,299 ​ $ 5,868 ​ $ 5,097 ​ The table below presents the lease-related assets and liabilities recorded on the Consolidated balance sheets. ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ ​ 2023 ​ 2022 ​ ​ (in thousands) Assets ​ ​ ​ ​ ​ ​ Operating lease right-of-use assets ​ $ 28,789 ​ ​ 32,726 Liabilities ​ ​ ​ ​ ​ ​ Current ​ ​ ​ ​ ​ ​ Current operating lease liabilities ​ ​ 8,344 ​ ​ 8,382 Non-current ​ ​ ​ ​ ​ ​ Non-current operating lease liabilities ​ ​ 28,316 ​ ​ 31,719 Total lease liabilities ​ $ 36,660 ​ ​ 40,101 ​ Other information The weighted-average remaining lease term as of December 31, 2023, is 6.1 years, compared to 7.2 years as of December 31, 2022, and the weighted-average discount rate as of December 31, 2023 is 11.2% , compared to 11.2% as of December 31, 2022. The Company uses an incremental borrowing rate applicable to the lease asset. The table below presents supplemental cash flow and non-cash information related to leases. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) Cash paid for amounts included in the measurement of lease liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows for operating leases ​ $ 7,921 ​ $ 7,532 ​ $ 5,738 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Right-of-use asset obtained in exchange for lease obligation ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating lease ​ $ 561 ​ $ 9,824 ​ $ 1,699 ​ Undiscounted cash flows The table below reconciles the undiscounted cash flows as of December 31, 2023, for each of the first five years and the total of the remaining years to the operating lease liabilities recorded on the Consolidated balance sheet as of December 31, 2023. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Lexington ​ Amsterdam (1) ​ Other ​ Total ​ (in thousands) 2024 $ 5,504 ​ $ 2,569 ​ $ 295 ​ $ 8,368 2025 ​ 5,859 ​ ​ 2,056 ​ ​ 295 ​ ​ 8,210 2026 ​ 6,031 ​ ​ 2,056 ​ ​ 246 ​ ​ 8,333 2027 ​ 6,207 ​ ​ 2,060 ​ ​ — ​ ​ 8,267 2028 ​ 6,388 ​ ​ 1,984 ​ ​ — ​ ​ 8,372 Thereafter ​ 2,956 ​ ​ 5,430 ​ ​ — ​ ​ 8,386 Total lease payments $ 32,945 ​ $ 16,155 ​ $ 836 ​ $ 49,936 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less: amount of lease payments representing interest payments ​ (7,920) ​ ​ (5,211) ​ ​ (145) ​ ​ (13,276) Present value of lease payments ​ 25,025 ​ ​ 10,944 ​ ​ 691 ​ ​ 36,660 Less: current operating lease liabilities ​ (5,504) ​ ​ (2,569) ​ ​ (271) ​ ​ (8,344) Non-current operating lease liabilities $ 19,521 ​ $ 8,375 ​ $ 420 ​ $ 28,316 (1) Payments are due in EUR and have been translated at the foreign exchange rate as of December 31, 2023, of $1.10 / €1.00

Intangible assets, net and Good

Intangible assets, net and Goodwill	12 Months Ended
	Dec. 31, 2023
Intangible assets, net and Goodwill
Intangible assets, net and Goodwill	​ 11. Intangible assets, net and Goodwill ​ The following table presents the Company’s acquired licenses and acquired IPR&D as of December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, ​ ​ 2023 ​ 2022 ​ ​ (in thousands) Acquired licenses ​ $ 2,419 ​ $ 2,346 Less accumulated amortization ​ ​ (1,057) ​ ​ (900) Acquired licenses, net ​ $ 1,362 ​ $ 1,446 Acquired IPR&D Intangible Asset ​ 59,119 ​ 57,332 Intangibles, net ​ $ 60,481 ​ $ 58,778 ​ a. Acquired licenses ​ All acquired licenses are owned by uniQure biopharma B.V, a subsidiary of the Company. The remaining weighted average life is 10.5 years as of December 31, 2023 (December 31, 2022 11.5 years). ​ ​ As of December 31, 2023, the estimated future amortization expense for each of the five succeeding years and the period thereafter is as follows: ​ ​ ​ ​ ​ Years Amount ​ ​ (in thousands) 2024 ​ $ 130 2025 ​ 130 2026 ​ 130 2027 ​ 130 2028 ​ 130 Thereafter ​ 712 Total ​ $ 1,362 ​ The amortization expense related to licenses for the year ended December 31, 2023 was $0.1 million (December 31, 2022: $0.4 million; December 31, 2021: $1.2 million). ​ b. Acquired in-process research and development ​ As part of its acquisition of uniQure France SAS as of July 30, 2021, the Company identified certain intangible assets related to an IPR&D Intangible Asset. Refer to Note 3 “uniQure France SAS transaction” ​ c. Goodwill ​ As part of its acquisition of uniQure France SAS as of July 30, 2021, the Company recorded goodwill. Refer to Note 3 “uniQure France SAS transaction”

Accrued expenses and other curr

Accrued expenses and other current liabilities	12 Months Ended
	Dec. 31, 2023
Accrued expenses and other current liabilities
Accrued expenses and other current liabilities	12. Accrued expenses and other current liabilities ​ Accrued expenses and other current liabilities include the following items: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2023 2022 ​ ​ (in thousands) Personnel related accruals and liabilities ​ $ 16,263 ​ $ 17,201 Accruals for goods received from and services provided by vendors-not yet billed ​ ​ 12,834 ​ ​ 11,120 Liability owed to the Purchaser pursuant to the Royalty Financing Agreement ​ ​ 1,437 ​ ​ — Accrued contract fulfillment costs and costs to obtain a contract ​ ​ — ​ ​ 2,250 Total ​ $ 30,534 ​ $ 30,571 ​ ​ ​ ​ ​

Long-term debt

Long-term debt	12 Months Ended
	Dec. 31, 2023
Long-term debt
Long-term debt	13. Long-term debt ​ On June 14, 2013, the Company entered into a venture debt loan facility with Hercules Capital, Inc. (formerly known as Hercules Technology Growth Capital, Inc.) (“Hercules”), which was amended and restated on June 26, 2014, on May 6, 2016 (“2016 Amended Facility”) and on December 6, 2018 (“2018 Amended Facility”). ​ On January 29, 2021, the Company and Hercules amended the 2018 Amended Facility (“2021 Amended Facility”). Pursuant to the 2021 Amended Facility, Hercules agreed to an additional Facility of $100.0 million (“Tranche B”) increasing the aggregate principal amount of the term loan facilities from $35.0 million to up to $135.0 million. On January 29, 2021, the Company drew down $35.0 million of the Tranche B. Advances under Tranche B bore interest at a rate equal to the greater of (i) 8.25% or (ii) 8.25% plus the prime rate, less 3.25% per annum. The principal balance of $70.0 million and all accrued but unpaid interest on advances under Tranche B was due on June 1, 2023, which date could have been extended by the Company by up to two twelve-month periods. In addition to Tranche B, the 2021 Amended Facility had also extended the interest only payment period of the previously funded $35.0 million term loan (“Tranche A”) from January 1, 2022 to June l, 2023. ​ On December 15, 2021, the Company and Hercules amended and restated the 2021 Amended Facility (“2021 Restated Facility”). Pursuant to the 2021 Restated Facility, Tranche A and Tranche B of the 2021 Amended Facility with a total outstanding balance of $70.0 million were consolidated into one tranche with a total commitment of $100.0 million. The Company drew down an additional $30.0 million, resulting in total principal outstanding as of December 31, 2021 of $100.0 million. The 2021 Restated Facility extended the loan’s maturity date from June 1, 2023 until December 1, 2025. The interest-only period was extended from January 1, 2023 to December 1, 2024, or December 1, 2025 if, prior to June 30, 2024, either (a) the BLA for AMT-061 had been approved by the U.S. Food and Drug Administration (“FDA”) or (b) AMT-130 had advanced into a pivotal trial. On November 22, 2022, the FDA approved the BLA for AMT-061 resulting in the extension of the interest-only period to December 1, 2025. ​ On May 12, 2023 the Company and Hercules amended the 2021 Restated Facility (the “2023 Amended Facility”). The total principal outstanding under the 2023 Amended Facility remained $100.0 million. The 2023 Amended Facility extended the maturity date and interest only period from December 1, 2025 to January 5, 2027 (the “Maturity Date”). The Company is required to repay the entire principal balance on the Maturity Date. The interest rate is adjustable and is the greater of (i) 7.95% and (ii) 7.95% plus the prime rate less 3.25% per annum. The Company paid a $2.5 million back-end fee in June 2023. Under the 2023 Amended Facility, the Company owes a back-end fee of $4.9 million on December 1, 2025 and a back-end fee of $1.3 million on the Maturity Date. ​ The amortized cost (including interest due presented as part of accrued expenses and other current liabilities) of the 2023 Amended Facility was $102.9 million as of December 31, 2023, compared to an amortized cost of $103.8 million as of December 31, 2022, and is recorded net of discount and debt issuance costs. The foreign currency gain on the loan was $3.0 million in 2023 (2022: loss of $5.8 million; 2021: loss of $5.3 million). The fair value of the loan approximates its carrying amount. Inputs to the fair value of the loan are considered Level 3 inputs. ​ Interest expense recorded during the years ended December 31 was as follows: ​ ​ ​ ​ ​ Years Amount ​ ​ (in millions) 2023 ​ $ 14.6 2022 ​ 11.5 2021 ​ ​ 7.2 ​ Under the 2023 Amended Facility the Company must remain current in its periodic reporting requirements and is required to keep a minimum cash balance deposited in bank accounts in the United States, equivalent to the lesser of (i) 65% of the outstanding balance of principal due or (ii) 100% of worldwide cash and cash equivalents. This restriction on cash and cash equivalents only relates to the location of the cash and cash equivalents, and such cash and cash equivalents can be used at the discretion of the Company. Beginning on April 1, 2024, the Company is required to keep a minimum of unrestricted cash of at least 30% of the loan amount outstanding. In combination with other covenants, the 2023 Amended Facility restricts the Company’s ability to, among other things, incur future indebtedness and obtain additional debt financing, to make investments in securities or in other companies, to transfer assets, to perform certain corporate changes, to make loans to employees, officers, and directors, and to make dividend payments and other distributions to its shareholders. The Company secured the facilities by directly or indirectly pledging its total assets of $831.7 million, less $9.3 million of cash and cash equivalents and other current assets held by the Company and $90.4 million of other current assets and investment held by uniQure France SAS as well as receivables sold to the Purchaser. ​ Under the 2023 Amended Facility, the occurrence of a material adverse effect, as defined therein, would entitle Hercules to declare all principal, interest and other amounts owed by the Company immediately due and payable. As of December 31, 2023, the Company was in material compliance with all covenants and provisions. ​ The aggregate maturities of the loans, including $47.6 million of coupon interest payments and financing fees, for each of the 37 months after December 31, 2023, are as follows: ​ ​ ​ ​ ​ Years Amount ​ ​ (in thousands) 2024 ​ $ 13,420 2025 ​ ​ 18,233 2026 ​ ​ 13,383 2027 ​ ​ 102,533 Total ​ $ 147,569 ​

Royalty Financing Agreement

Royalty Financing Agreement	12 Months Ended
	Dec. 31, 2023
Royalty Financing Agreement
Royalty Financing Agreement	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 14. Royalty Financing Agreement ​ On May 12, 2023, the Company entered into the Royalty Financing Agreement with the Purchaser. Under the terms of the Royalty Financing Agreement the Company received an upfront payment of $375.0 million in exchange for its rights to the lowest royalty tier on CSL Behring’s worldwide net sales of HEMGENIX® for certain current and future royalties due to the Company. The Company is also eligible to receive an additional $25.0 million milestone payment under the Royalty Financing Agreement if 2024 net sales of HEMGENIX® exceed a pre-specified threshold, as set forth in the Royalty Financing Agreement. The Purchaser will receive 1.85 times the upfront payment (or $693.8 million) and 1.85 times the $25.0 million milestone payment (if paid) until June 30, 2032 (“First Hard Cap Date”) if such thresholds are met or, if such cap is not met by June 30, 2032, up to 2.25 times of the upfront and milestone payment (if paid) through December 31, 2038. If 2024 net sales do not exceed a pre-specified threshold, the Company will be obligated to pay $25.0 million to the Purchaser but only to the extent that the Company achieves a future sales milestone under the CSL Behring Agreement. If such milestone payment is not due from CSL Behring, the Company is not obligated to pay any amounts to the Purchaser. ​ The Company has retained the rights to all other royalties, as well as commercial milestones totaling up to $1.3 billion, under the terms of the CSL Behring Agreement. ​ Net proceeds from the Royalty Financing Agreement, after deducting professional and financial advisory fees related to the transaction of $4.9 million, were $370.1 million. The Company initially recorded these net proceeds as “Liability from royalty financing agreement” at their fair market value on its balance sheet as of closing of the transaction on June 5, 2023. Following the initial recognition, the Company records the debt at amortized cost. ​ The Company expects to satisfy its commitment to the Purchaser prior to the First Hard Cap Date. The Company will record the difference of $323.7 million between the total expected payments of $693.8 million to the Purchaser and the $370.1 million net proceeds as interest expense using the effective interest rate method. The Company determined the effective interest rate based on the projected cash flows up to the First Hard Cap Date. Based on the Company’s projections the effective interest rate is expected to be within a range of 12.0% to 13.5% per annum. The Company would have recorded between $26.5 million and $29.9 million of interest expense during the year ended December 31, 2023 (nil for the year ended December 31, 2022 and 2021) if it had used effective interest rates of 12.0% or 13.5%, instead of the $26.9 million recorded in the during the year ended December 31, 2023 (nil for the year ended December 31, 2022 and 2021). The Company will prospectively update the effective interest rate at each reporting date based on updated projections. ​ The liability was initially recognized at fair value and inputs were considered Level 3 inputs. ​ The following table presents the movement in the liability related to the Royalty Financing Agreement between the closing of the transaction on June 5, 2023 and December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ Amount of liability ​ ​ ​ (in thousands) Gross proceeds from royalty financing agreement on June 5, 2023 ​ $ 375,000 Debt issuance costs paid ​ ​ (4,938) Royalty payments to Purchaser ​ ​ (1,317) Liability owed to the Purchaser (presented as "Accrued expense and other current liabilities") ​ ​ (1,437) Interest expense for the period June 5, 2023 to December 31, 2023 ​ ​ 26,933 Liability related to the royalty financing agreement ​ $ 394,241 ​

Retirement benefits

Retirement benefits	12 Months Ended
	Dec. 31, 2023
Retirement benefits
Retirement benefits	15. Retirement benefits ​ Defined benefit pension plan ​ The Company operates a defined benefit pension plan for its Swiss employees (the “Swiss Plan”) in accordance with local regulations and practices. The normal retirement age under the Swiss Plan is 65 for men and women. All benefits are immediately vested. Under the Swiss Plan, a percentage of pensionable salary is contributed as a retirement credit with additional contributions being made for death and disability benefits. Under Swiss pension law, participants who are covered by the pension plan of another employer are required to transfer the termination benefit of that pension plan into the plan of the Company. When employment at the Company ends before reaching retirement, the termination benefit is transferred out of the defined benefit pension plan. At time of retirement the accumulated retirement credit can be converted into a life-long annuity or be paid-out as a lump-sum. Participants are also permitted to withdraw a part of the accumulated termination benefit in special circumstances before reaching retirement age for example for payments related to obtain home ownership. ​ The Company recognized its net projected benefit obligation as of December 31, 2023 at a carrying amount of $2.5 million, presented within other non-current liabilities in the consolidated balance sheets. ​ The funded status of the Swiss Plan as of December 31, 2023 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2023 ​ ​ ​ (in thousands) Fair value of plan assets ​ ​ $ 8,946 Present value of projected benefit obligation ​ ​ ​ (11,499) Funded status: (net liability) ​ ​ $ (2,553) ​ ​ ​ ​ ​ Accumulated benefit obligation as of December 31, 2023 ​ ​ $ 10,739 ​ Actuarial losses of $2.1 million, net of $0.4 million deferred tax income, were recorded in other comprehensive income, net, during the year ended December 31, 2023. ​ The assumptions related to the Swiss Plan are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, Actuarial assumptions (% p.a.) 2023 Discount rate ​ ​ ​ 1.50% Expected return on plan assets ​ ​ ​ 2.60% Expected inflation rate ​ ​ ​ 1.60% Interest credit rate ​ ​ ​ 1.25% Long-term expected rate of salary increases ​ ​ ​ 1.60% Pension increase ​ ​ ​ 0.00% ​ Future benefits expected to be paid are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2023 Year 1 ​ ​ $ 533 Year 2 ​ ​ ​ 610 Year 3 ​ ​ ​ 528 Year 4 ​ ​ ​ 529 Year 5 ​ ​ ​ 540 Next 5 years ​ ​ ​ 4,992 ​ ​ ​ ​ ​ Other disclosure items: ​ ​ ​ ​ Next year's expected employer contribution ​ ​ $ 552 ​ ​ ​ ​ ​ ​ The Company's investment strategy for its pension plan is to optimize the long-term investment return on plan assets in relation to the liability structure to maintain an acceptable level of risk while minimizing the cost of providing pension benefits and maintaining adequate funding levels in accordance with the applicable rules in each jurisdiction. The Company does not manage any assets internally. The plan assets relate to assets being held by the Swiss pension foundations in which the Company's pension plan is set-up. ​ The allocation of plan assets is presented below: ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2023 Bonds ​ ​ 61% Equities ​ ​ 25% Real estate ​ ​ 10% Others ​ ​ 4% ​ The fair value of the plan assets is determined based on Level 2 inputs.

Shareholders' equity

Shareholders' equity	12 Months Ended
	Dec. 31, 2023
Shareholders' equity
Shareholders' equity	​ 16. Shareholders’ equity ​ As of December 31, 2023, the Company’s authorized share capital is €4.0 million (or $4.4 million when translated at an exchange rate as of December 31, 2023, of $1.10/ €1.00), divided into 80,000,000 ordinary shares, each with a nominal value of €0.05. The Company’s shareholders, at the 2021 Annual General Meeting of Stockholders held on June 16, 2021, approved an increase in the number of authorized ordinary shares by 20,000,000 to 80,000,000. ​ All ordinary shares issued by the Company were fully paid. Besides the minimum amount of share capital to be held under Dutch law, there are no distribution restrictions applicable to the equity of the Company. ​ As of December 31, 2023, and 2022 and 2021 the Company’s other comprehensive result was restricted for payment of dividends for an accumulated other comprehensive loss of $53.6 million in 2023, an accumulated other comprehensive loss of $58.3 million in 2022, and an accumulated other comprehensive loss of $28.9 million in 2021. ​ On March 1, 2021, the Company entered into a Sales Agreement with SVB Leerink LLC (“SVB Leerink”) with respect to an at-the-market (“ATM”) offering program, under which the Company may, from time to time in its sole discretion, offer and sell through SVB Leerink, acting as agent, its ordinary shares, up to an aggregate offering price of $200.0 million. The Company will pay SVB Leerink a commission equal to 3% of the gross proceeds of the sales price of all ordinary shares sold through it as sales agent under the Sales Agreement. In March and April 2021, the Company issued an aggregate of 921,730 ordinary shares at a weighted average price of $33.52 per ordinary share, with net proceeds of $29.6 million, after deducting underwriting discounts and net of offering expenses. The Company defers direct, incremental costs associated to this offering, except for the commission costs to SVB Leerink, which are a reduction to additional paid-in capital and will deduct these costs from additional paid-in capital in the consolidated balance sheets proportionately to the amount of proceeds raised. During the year ended December 31, 2021, $1.3 million of direct, incremental costs were deducted from additional paid-in capital (nil for the years ended December 31, 2022 and 2023). ​ Following the Closing of the CSL Behring transaction, the Company consumed its tax net operating loss carryforwards from the years 2011 to 2018. The Company allocated the tax benefit from the release of the valuation allowance related to net operating loss carryforwards generated by share issuance costs incurred in 2014, 2015, 2017 and 2018 to additional paid-in capital. This resulted is an increase of additional paid-in capital of $3.0 million in the year ended December 31, 2021. ​ The Company recorded a $0.8 million increase of additional paid-in capital in the year ended December 31, 2022 resulting from the release of valuation allowance for the tax benefit of share issuance costs incurred in 2018, 2019 and 2021 within the Netherlands. ​

Share-based compensation

Share-based compensation	12 Months Ended
	Dec. 31, 2023
Share-based compensation
Share-based compensation	​ 17. Share-based compensation ​ Share-based compensation expense recognized by classification included in the consolidated statements of operations and comprehensive (loss) / income was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ (in thousands) Cost of manufacturing services revenue ​ $ 826 ​ $ 323 ​ $ — Research and development ​ ​ 16,881 ​ ​ 18,402 ​ ​ 12,834 Selling, general and administrative ​ ​ 17,386 ​ ​ 15,479 ​ ​ 12,801 Total ​ $ 35,093 ​ $ 34,204 ​ $ 25,635 ​ Share-based compensation expense recognized by award type was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ (in thousands) Award type/ESPP ​ ​ ​ ​ ​ ​ ​ ​ ​ Share options ​ $ 13,302 ​ $ 13,425 ​ $ 12,477 Restricted share units ​ ​ 18,524 ​ ​ 15,486 ​ ​ 11,347 Performance share units ​ ​ 3,234 ​ ​ 5,267 ​ ​ 1,783 Employee share purchase plan ​ ​ 33 ​ ​ 26 ​ ​ 28 Total ​ $ 35,093 ​ $ 34,204 ​ $ 25,635 ​ As of December 31, 2023, the unrecognized compensation cost related to unvested awards under the various share-based compensation plans were: ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized Weighted average ​ share-based remaining ​ ​ compensation ​ period for ​ ​ expense ​ recognition ​ ​ (in thousands) ​ (in years) Award type ​ ​ ​ ​ ​ Share options ​ $ 21,708 ​ 2.47 Restricted share units ​ ​ 27,015 ​ 1.89 Performance share units ​ ​ 738 ​ 0.95 Total ​ $ 49,461 ​ 2.13 ​ The Company satisfies the exercise of share options and vesting of Restricted Share Units (“RSUs”) and Performance Share Units (“PSUs”) through newly issued ordinary shares. ​ The Company’s share-based compensation plans include the 2014 Amended and Restated Share Option Plan (the “2014 Plan”) and inducement grants under Rule 5653(c)(4) of The Nasdaq Global Select Market with terms similar to the 2014 Plan (together the “2014 Plans”). The Company previously had a 2012 Equity Incentive Plan (the “2012 Plan”). As of December 31, 2023, no fully vested share options are outstanding (December 31, 2022: nil) under the 2012 Plan. ​ At the general meeting of shareholders on January 9, 2014, the Company’s shareholders approved the adoption of the 2014 Plan. At the annual general meetings of shareholders in June 2015, 2016, 2018 and 2021, uniQure shareholders approved amendments of the 2014 Plan, increasing the shares authorized for issuance by 1,070,000 shares in 2015, 3,000,000 in 2016, 3,000,000 shares in 2018, 4,000,000 shares in 2021. At an extraordinary general meeting of shareholders in November 2023, an additional 1,750,000 shares were authorized for issuance, increasing the total to 14,351,471 shares. ​ ​ Share options Share options are priced on the date of grant and, except for certain grants made to non-executive directors, vest over a period of four years . The first 25% vests after one year from the initial grant date and the remainder vests in equal quarterly installments over years two, three and four. Certain grants to non-executive directors vest in full after one year . Any options that vest must be exercised by the tenth anniversary of the initial grant date. 2014 Plans The following tables summarize option activity under the Company’s 2014 Plans for the year ended December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options ​ ​ Number of ​ Weighted average ​ Weighted average ​ Aggregate intrinsic ​ ordinary shares exercise price remaining contractual life value ​ ​ ​ ​ ​ ​ ​ in years ​ ​ (in thousands) Outstanding at December 31, 2022 ​ 4,237,917 ​ $ 26.13 ​ 7.14 ​ $ 17,848 Granted ​ 1,650,030 ​ $ 18.16 ​ ​ ​ ​ ​ Forfeited ​ (543,481) ​ $ 22.04 ​ ​ ​ ​ ​ Expired ​ (356,366) ​ $ 36.26 ​ ​ ​ ​ ​ Exercised ​ (14,070) ​ $ 9.24 ​ ​ ​ ​ ​ Outstanding at December 31, 2023 ​ 4,974,030 ​ $ 23.25 ​ 6.71 ​ ​ 182 Thereof, fully vested, and exercisable on December 31, 2023 ​ 2,738,595 ​ $ 26.08 ​ 5.15 ​ ​ 182 Thereof, outstanding and expected to vest after December 31, 2023 ​ 2,235,435 ​ $ 19.78 ​ 8.77 ​ ​ — Outstanding and expected to vest after December 31, 2022 ​ 2,098,557 ​ $ 23.38 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total weighted average grant date fair value of options issued during the period (in $ millions) ​ ​ ​ $ 17.4 ​ ​ ​ ​ ​ Granted to directors and officers during the period (options, grant date fair value $ in millions) ​ 786,580 ​ $ 9.0 ​ ​ ​ ​ ​ Proceeds from option sales during the period (in $ millions) ​ ​ ​ $ 0.1 ​ ​ ​ ​ ​ ​ The following table summarizes information about the weighted average grant-date fair value of options during the years ended December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average ​ ​ Options ​ grant ‑ date fair value Granted, 2023 1,650,030 ​ $ 10.57 Granted, 2022 1,426,966 ​ ​ 9.04 Granted, 2021 1,174,893 ​ ​ 20.95 Vested, 2023 ​ 873,658 ​ ​ 13.50 Forfeited, 2023 ​ (543,481) ​ ​ 12.78 ​ The following table summarizes information about the weighted average grant-date fair value of options at December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average ​ ​ Options ​ grant ‑ date fair value Outstanding and expected to vest, 2023 2,235,435 ​ $ 11.50 Outstanding and expected to vest, 2022 2,098,557 ​ ​ 13.46 ​ ​ The fair value of each option issued is estimated at the respective grant date using the Hull & White option pricing model with the following weighted-average assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, Assumptions 2023 2022 ​ 2021 Expected volatility ​ 70% ​ 70% ​ 75% Expected terms ​ 10 years ​ 10 years ​ 10 years Risk free interest rate ​ 3.7% - 4.8% ​ 2.1% - 4.2% ​ 1.2 - 1.9% Expected dividend yield ​ 0% ​ 0% ​ 0% ​ The Hull & White option model captures early exercises by assuming that the likelihood of exercises will increase when the share price reaches defined multiples of the strike price. This analysis is performed over the full contractual term. ​ The following table summarizes information about options exercised during the years ended December 31: ​ ​ ​ ​ ​ ​ ​ ​ Exercised ​ ​ ​ ​ during the year ​ Intrinsic value ​ ​ ​ ​ (in thousands) 2023 14,070 ​ $ 154 2022 138,356 ​ 1,848 2021 241,496 ​ 5,046 ​ Restricted Share Units ​ The following table summarizes the RSU activity for the year ended December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ RSUs ​ ​ Weighted average ​ ​ Number of ​ grant-date fair ​ ​ ordinary shares ​ value Non-vested at December 31, 2022 ​ 1,818,774 ​ $ 20.46 Granted ​ 1,770,025 ​ $ 17.88 Vested ​ (738,447) ​ $ 22.65 Forfeited ​ (585,983) ​ $ 19.12 Non-vested at December 31, 2023 ​ 2,264,369 ​ $ 18.07 ​ ​ ​ ​ ​ ​ Total weighted average grant date fair value of RSUs granted during the period (in $ millions) ​ ​ ​ $ 31.6 Granted to directors and officers during the period (shares, $ in millions) ​ 419,200 ​ $ 8.3 ​ The following table summarizes information about the weighted average grant-date fair value of RSUs granted during the years ended December 31: ​ ​ ​ ​ ​ ​ ​ ​ Granted Weighted average ​ ​ during the year ​ grant ‑ date fair value 2023 1,770,025 ​ $ 17.88 2022 1,604,533 ​ ​ 16.10 2021 574,921 ​ ​ 36.14 ​ The following table summarizes information about the total fair value of RSUs that vested during the years ended December 31: ​ ​ ​ ​ ​ Total fair value ​ (in thousands) 2023 $ 13,729 2022 5,104 2021 8,063 ​ RSUs generally vest over one to three years . RSUs granted to non-executive directors will vest one year from the date of grant. ​ Performance Share Units ​ The following table summarizes the PSU activity for the year ended December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ PSUs ​ ​ Weighted average ​ ​ Number of ​ grant-date fair ​ ​ ordinary shares ​ value Non-vested at December 31, 2022 ​ 400,690 ​ $ 28.82 Vested ​ (94,510) ​ $ 30.65 Forfeited ​ (83,630) ​ $ 28.22 Non-vested at December 31, 2023 ​ 222,550 ​ $ 28.09 ​ ​ ​ ​ ​ ​ Total weighted average grant date fair value of PSUs granted during the period (in $ millions) ​ ​ ​ $ - ​ The Company granted shares to certain employees in September and December 2021 and various dates during the year ended December 31, 2022 that will be earned upon achievement of defined milestones. Earned shares will vest upon the later of a minimum service period of three years , or the achievement of defined milestones, subject to the grantee’s continued employment. In addition, portions of the December 2021 granted to executives and other members of senior management are subject to achieving a minimum total shareholder return relative to the Nasdaq biotechnology index. The Company recognizes the compensation cost related to these grants to the extent it considers achievement of the milestones to be probable. As of December 31, 2023, two milestones had been achieved and vested in either 2022 or 2023. Additionally, another two milestones are considered probable as of December 31, 2023. ​ In January 2018 and January and February 2019, the Company awarded PSUs to its executives and other members of senior management. These PSUs were earned in January 2019 and January 2020, based on the Board of Directors’ (the “Board”) assessment of the level of achievement of agreed upon performance targets through December 31, 2018, and December 31, 2019, respectively. The PSUs awarded for the year ended December 31, 2018 vested in February 2021 and the PSUs awarded for the year ended December 31, 2019 vested in January 2022. ​ The following table summarizes information about the weighted average grant-date fair value of the PSUs determined as of the date of the grant for the 2021 and 2022 PSUs: ​ ​ ​ ​ ​ ​ ​ ​ Granted Weighted average ​ ​ during the year ​ grant ‑ date fair value 2023 — ​ $ — 2022 34,700 ​ $ 15.11 2021 555,600 ​ $ 30.19 ​ The following table summarizes information about the total fair value of PSUs that vested during the years ended December 31: ​ ​ ​ ​ ​ Total fair value ​ (in thousands) 2023 $ 1,474 2022 4,450 2021 5,074 ​ Employee Share Purchase Plan (“ESPP”) ​ In June 2018, the Company’s shareholders adopted and approved an ESPP allowing the Company to issue up to 150,000 ordinary shares. The ESPP is intended to qualify under Section 423 of the Internal Revenue Code of 1986. Under the ESPP, employees are eligible to purchase ordinary shares through payroll deductions, subject to any plan limitations. The purchase price of the shares on each purchase date is equal to 85% of the lower of the closing market price on the offering date or the closing market price on the purchase date of each three-month offering period. During the year ended December 31, 2023, 19,198 ordinary shares have been issued (December 31, 2022: 11,242 and December 31, 2021: 4,724). As of December 31, 2023, a total of 96,862 ordinary shares remain available for issuance under the ESPP plan.

Expenses by nature

Expenses by nature	12 Months Ended
	Dec. 31, 2023
Expenses by nature
Expenses by nature	18. Expenses by nature ​ Operating expenses excluding expenses presented in other expenses included the following expenses by nature: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) Employee-related expenses ​ $ 135,728 ​ $ 119,903 ​ $ 96,161 Laboratory and development expenses ​ 63,065 ​ 65,964 ​ 36,014 Office and housing expenses ​ 22,960 ​ 17,612 ​ 14,638 Legal and advisory expenses ​ ​ 21,975 ​ 15,782 ​ 24,767 Fair value loss - uniQure France SAS contingent consideration ​ ​ 15,895 ​ 7,081 ​ 6,683 Other operating expenses ​ 11,236 ​ 8,510 ​ 10,528 Depreciation and amortization expenses ​ 10,046 ​ 8,250 ​ 7,299 Patent and license expenses ​ ​ 7,112 ​ ​ 9,548 ​ ​ 3,748 Impairment related to the Reorganization ​ ​ 1,438 ​ ​ — ​ ​ — Total ​ $ 289,455 ​ $ 252,650 ​ $ 199,838 ​ Details of employee-related expenses for the years ended December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) Wages and salaries ​ $ 71,852 ​ $ 63,704 ​ $ 53,078 Share-based compensation expenses ​ 34,267 ​ 33,881 ​ 25,635 Contractor expenses ​ 6,141 ​ 3,959 ​ 3,170 Social security costs ​ 5,900 ​ 5,179 ​ 4,496 Health insurance ​ 4,216 ​ 4,148 ​ 3,161 Costs related to pension plans ​ 3,611 ​ 2,667 ​ 2,051 Severance costs related to the Reorganization (refer to Note 4 " Reorganization ​ ​ 2,549 ​ ​ — ​ ​ — Other employee expenses ​ ​ 7,192 ​ ​ 6,365 ​ ​ 4,570 Total ​ $ 135,728 ​ $ 119,903 ​ $ 96,161 ​

Other income

Other income	12 Months Ended
	Dec. 31, 2023
Other income.
Other income	​ ​ 19. Other income ​ Other income during the year ended December 31, 2023 was $6.1 million compared to $7.2 million and $12.3 million during the same periods in 2022 and 2021, respectively. ​ Other income in 2023, 2022 and 2021 includes income from payments received from European authorities to subsidize the Company’s research and development efforts in the Netherlands. The amount recognized in the year ended December 31, 2023 was $5.0 million compared to $5.6 million in 2022 and $5.3 million in 2021. ​ In addition, other income included $2.6 million of employee retention credits received under the U.S. Coronavirus Aid, Relief, and Economic Security Act, during the year ended December 31, 2021. No such income was received in the years ended December 31, 2023 or December 31, 2022. ​ An additional $3.0 million of other income was recorded in the year ended December 31, 2021, related to the receipt by the Company of 69,899 shares of VectorY B.V. in conjunction with a settlement agreement that the Company and VectorY B.V. entered into in April 2021. In the year ended December 31, 2023 and 2022, the Company recognized nil and $0.3 million, respectively, of other income related to the equity stake received in VectorY. ​ In 2023, 2022 and 2021 the Company’s other income also consisted of income from the subleasing of a portion of the Amsterdam facility while other expense consists of expenses incurred in relation to the subleasing income. ​

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2023
Income taxes
Income taxes	20. Income taxes ​ a. Income tax (benefit) / expense ​ Due to the uncertainty surrounding the realization of favorable tax attributes in future tax returns, the Company has recorded a valuation allowance against the Company’s net deferred tax assets in the Netherlands and a partial valuation allowance against the Company’s net deferred tax assets in France. ​ In connection with the acquisition of uniQure France SAS, the Company recognized a deferred tax liability related to acquired identifiable intangible assets and a deferred tax asset for net operating tax loss carryforwards for a net of EUR 11.9 million ($14.2 million) as of the Acquisition Date. ​ There are no significant unrecognized tax benefits as of December 31, 2023 and 2022. ​ For the years ended December 31, 2023, 2022 and 2021, (loss) / income before income tax benefit / (expense) consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) Dutch operations ​ $ (282,530) ​ $ (96,872) ​ $ 348,400 U.S. operations ​ (6,903) ​ (14,934) ​ (12,737) Other ​ ​ (17,124) ​ ​ (16,453) ​ ​ (2,857) Total ​ $ (306,557) ​ $ (128,259) ​ $ 332,806 ​ The income tax (expense) / benefit for the years ended December 31, 2023, 2022 and 2021, consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) Current tax expense ​ ​ ​ ​ ​ ​ ​ ​ ​ Other ​ $ (110) ​ $ (24) ​ $ (7) Total current income tax expense ​ $ (110) ​ $ (24) ​ $ (7) Deferred tax (expense) / benefit ​ ​ ​ ​ ​ ​ Dutch operations ​ $ — ​ $ (808) ​ $ (3,047) U.S. operations ​ (2,708) ​ (1,075) ​ (771) Other ​ ​ 897 ​ ​ 3,377 ​ ​ 608 Total deferred tax (expense) / benefit ​ $ (1,811) ​ $ 1,494 ​ $ (3,210) Total income tax (expense) / benefit ​ $ (1,921) ​ $ 1,470 ​ $ (3,217) ​ b. Tax benefit recognized in other comprehensive income ​ The reconciliation of the amount of income tax benefit recognized in other comprehensive income for the year ended December 31, 2023 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2023 ​ Before tax Tax benefit Net of tax ​ ​ (in thousands) Unrecognized gain related to defined benefit pension plan liability ​ $ (2,553) ​ $ 417 ​ $ (2,136) Total ​ $ (2,553) ​ $ 417 ​ $ (2,136) ​ No income tax benefit or expense has been recognized in Other Comprehensive Income for the years ended December 31, 2022 and 2021. ​ c. Tax rate reconciliation ​ The reconciliation of the amount of income tax (expense) / benefit that would result from applying the Dutch statutory income tax rate to the Company’s reported amount of (loss) / income before income tax (expense) / benefit for the years ended December 31, 2023, 2022 and 2021, is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ (in thousands) (Loss) / income before income tax (expense) / benefit for the period ​ $ (306,557) ​ $ (128,259) ​ $ 332,806 Expected income tax benefit / (expense) at the tax rate enacted in the Netherlands (2023: 25.8%, 2022: 25.8%, 2021: 25.0%) ​ 79,092 ​ 33,091 ​ (83,201) Difference in tax rates between the Netherlands and the U.S. as well as other foreign countries ​ (124) ​ 99 ​ 309 Other net change in valuation allowance ​ (67,004) ​ (20,591) ​ 88,857 Non-deductible expenses ​ (13,885) ​ (11,129) ​ (9,182) Income tax (expense) / benefit ​ $ (1,921) ​ $ 1,470 ​ $ (3,217) ​ Non-deductible expenses predominantly relate to share-based compensation expenses. These expenses affected the effective tax rate by an amount of $9.0 million in 2023 (2022: $8.5 million; 2021: $6.7 million). The fair value loss on contingent consideration affected the effective tax rate by an amount of $4.1 million in 2023 ($1.9 million and $2.0 million in 2022 and 2021, respectively). ​ d. ​ The tax effects of temporary differences and carryforwards that give rise to significant portions of deferred tax assets and deferred tax liabilities as of December 31, 2023 and 2022 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ ​ 2023 ​ 2022 ​ ​ (in thousands) Deferred tax assets: ​ ​ Net operating loss carryforwards ​ $ 145,826 ​ $ 84,633 Operating lease liabilities ​ ​ 9,790 ​ ​ 10,612 Intangible assets ​ 6,417 ​ 3,826 Liability from Royalty Financing Agreement ​ ​ 6,155 ​ ​ — Interest carryforwards ​ ​ 3,711 ​ ​ 3,697 Accrued expenses and other current liabilities ​ ​ 1,435 ​ ​ 1,862 Inventory ​ ​ 497 ​ ​ — Defined benefit pension plan liability ​ ​ 406 ​ ​ — Property, plant and equipment ​ — ​ 510 Research and development tax credit carryforwards ​ ​ — ​ ​ 144 Total deferred tax assets ​ $ 174,237 ​ $ 105,284 Less valuation allowance ​ (145,191) ​ (74,547) Deferred tax assets, net of valuation allowance ​ $ 29,046 ​ $ 30,737 Acquired IPR&D intangible asset ​ ​ (15,242) ​ ​ (15,033) Operating lease right-of-use assets ​ ​ (8,159) ​ ​ (9,323) Property, plant and equipment ​ ​ (719) ​ ​ — Other current assets and receivables ​ ​ (193) ​ ​ (110) Deferred tax liability ​ $ (24,313) ​ $ (24,466) Net deferred tax asset ​ $ 4,733 ​ $ 6,271 ​ Changes in the valuation allowance were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) January 1, ​ $ 74,547 ​ $ 60,289 ​ $ 150,113 Changes recorded in the statement of operations ​ ​ 67,004 ​ ​ 20,593 ​ ​ (88,858) Changes recorded in equity ​ ​ — ​ ​ (972) ​ ​ — Increase related to 2021 Dutch tax reforms ​ — ​ — ​ 1,897 Valuation allowance assumed in uniQure France SAS acquisition ​ ​ — ​ ​ — ​ ​ 545 Other changes including currency translation adjustments ​ 3,640 ​ (5,363) ​ ​ (3,408) December 31, ​ $ 145,191 ​ $ 74,547 ​ $ 60,289 ​ The valuation allowance as of December 31, of $145.2 million as of December 31,2023 is primarily related to $142.4 million deferred tax assets in the Netherlands resulting from net operating loss carryforwards of $127.1 million, intangibles assets of $5.5 million, liability from Royalty Financing Agreement of $6.2 million and interest carryforwards of $3.7 million. ​ Netherlands ​ As of December 31, 2023, the total amount of net operating losses carried forward under the Dutch tax regime was $492.7 million (December 31, 2022: $264.0 million, 2021: $228.5 million). The Company has historically recorded a full valuation allowance. The Company evaluates all positive and negative evidence in assessing the need for a full valuation allowance. Management considers reversing taxable temporary differences, projected future taxable income and tax-planning strategies in making this assessment. The Company concluded that as of December 31, 2023, December 31, 2022 and December 31, 2021 it is more likely than not that the remaining deferred tax assets will not be realized. ​ As of December 31, 2023, the tax treatment of the Royalty Agreement has not yet been agreed with the Dutch tax authorities. A different tax treatment could result in a different categorization of temporary differences and an offsetting deferred tax asset. ​ The Company recorded $462.4 million of license revenue in May 2021 after the Closing of the CSL Behring transaction. The Company recorded such revenue in its Dutch tax return related to the 12-month period ended December 31, 2020, which it filed on February 10, 2022. As such, the Company filed a return showing a taxable profit in the Netherlands in 2020, which resulted in the consumption of substantially all of its Dutch net operating losses for the years 2011 to 2018. The Company’s remaining Dutch net operating tax losses carried forward relate to 2019, 2022 and 2023. The Company allocated the tax benefit from the release of the valuation allowance related to net operating loss carryforwards generated by share issuance cost incurred in 2014, 2015, 2017 and 2018 to additional paid-in capital. This resulted in an increase of additional paid-in capital as well as deferred tax expenses of $3.0 million during the year ended December 31, 2021. ​ The Company recorded $0.8 million increase of additional paid-in capital in the year ended December 31, 2022 resulting from the release of valuation allowance for the tax benefit of share issuance costs incurred in 2018, 2019 and 2021. ​ A portion of the valuation allowance for deferred tax assets recorded as of December 31, 2023 continues to relate to follow-on offering costs incurred in 2019. Any subsequently recognized tax benefits will be credited directly to contributed capital. As of December 31, 2023, that amount was $3.4 million ($3.3 million as of December 31, 2022). ​ The Dutch corporate tax rate for fiscal year 2021 was 25.0%. In December 2021, changes were enacted that raised the corporate income tax rate from 25.0% to 25.8% from 2022 onwards. ​ In June 2021 legislation was enacted allowing for an indefinite carryforward from fiscal year 2022 onwards of existing and future net operating loss carryforwards subject to a limit of offsetting taxable profit in excess of EUR 1.0 million to 50% of the taxable profit. ​ The fiscal periods from 2022 onwards are still open for inspection by the Dutch tax authorities. ​ United States of America ​ The federal corporate tax rate in the U.S. is 21.0%. In addition, the Company is subject to state income taxes resulting in a combined tax rate of 27.3% for its U.S. operation. As of December 31, 2023, an estimated $31.1 million of net operating losses remain to be carried forward. These net operating losses carried forward will expire in 2036 and 2037 except for $0.7 million which can be carried forward indefinitely with a deduction limited to 80% of taxable income in a given year. ​ The Company’s U.S. operations generated taxable income in the fiscal years 2018 to 2021 and 2023. The Company expects to continue to generate taxable income in the U.S. during the foreseeable future. ​ Under the provision of the Internal Revenue Code, the U.S. net operating losses carried forward may become subject to an annual limitation in the event of certain cumulative exchange in the ownership interest of significant shareholders over a three-year period in excess of 50 percent, as defined under Section 382 and 383 of the Internal Revenue Code. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation. ​ The fiscal periods from 2020 are still open for inspection by the Internal Revenue Service (“IRS”). To the extent the Company has tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the IRS or Massachusetts Department of Revenue to the extent utilized in a future period. The Company is currently not under examination by the IRS for any tax years. ​ France ​ The French corporate tax rate for fiscal year 2023 was 25.0%. In addition, the Company is subject to a surcharge of 3.3% of the 25.0% standard corporate tax rate resulting in a combined rate of 25.8%. ​ The Company’s French operations have incurred losses since incorporation and are expected to continue incurring tax losses for the foreseeable future. The French operations as of December 31, 2023 have an estimated $39.6 million ($23.3 million as of December 31, 2022) of net operating losses that are available for carry forward indefinitely. The Company recorded a partial valuation allowance during the year ended December 31, 2023. No such valuation allowance was recorded in the years ended December 31, 2022 and 2021. The Company evaluates all positive and negative evidence including future income from reversing taxable temporary differences (particularly from reversing the deferred tax liability related to the acquired IPR&D intangible asset), projected future taxable income and tax-planning strategies in making this assessment. ​

Basic and diluted earnings per

Basic and diluted earnings per share	12 Months Ended
	Dec. 31, 2023
Basic and diluted earnings per share
Basic and diluted earnings per share	​ 21. Basic and diluted earnings per share ​ Basic net (loss) / income per ordinary share is computed by dividing net (loss) / income for the period by the weighted average number of ordinary shares outstanding during the period. Diluted earnings per ordinary share are calculated by adjusting the weighted average number of ordinary shares outstanding, assuming conversion of all potentially dilutive ordinary shares. For the year ended December 31, 2021, dilutive net income / (loss) per ordinary share is computed using the treasury method. As the Company has incurred a loss in the years ended December 31, 2023 and December 31, 2022, all potentially dilutive ordinary shares for these years would have an antidilutive effect, if converted, and thus have been excluded from the computation of loss per share for the years ended December 31, 2023 and December 31, 2022. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ (in thousands, except share amounts) Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Net (loss) / income attributable to ordinary shares ​ $ (308,478) ​ $ (126,789) ​ $ 329,589 ​ ​ ​ (308,478) ​ ​ (126,789) ​ ​ 329,589 Denominator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average number of ordinary shares outstanding - basic ​ ​ 47,670,986 ​ ​ 46,735,045 ​ ​ 45,986,467 Stock options under 2014 Plans and previous plan ​ ​ — ​ ​ — ​ ​ 746,044 Non-vested RSUs and PSUs ​ ​ — ​ ​ — ​ ​ 107,162 Employee share purchase plan ​ ​ — ​ ​ — ​ ​ 1,299 Weighted-average number of ordinary shares outstanding - diluted ​ ​ 47,670,986 ​ ​ 46,735,045 ​ ​ 46,840,972 ​ The following table presents ordinary share equivalents that were excluded from the calculation of diluted net income / (loss) per ordinary share for the years ended December 31, 2023, 2022 and 2021 as the effect of their inclusion would have been anti-dilutive: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 Anti-dilutive ordinary share equivalents ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options under 2014 Plans and previous plan ​ ​ 4,974,030 ​ ​ 4,237,917 ​ ​ 2,576,281 Non-vested RSUs and PSUs ​ ​ 2,486,919 ​ ​ 2,219,464 ​ ​ 1,236,385 ESPP ​ ​ 3,640 ​ ​ 1,048 ​ ​ 1,842 Total anti-dilutive ordinary share equivalents ​ ​ 7,464,589 ​ ​ 6,458,429 ​ ​ 3,814,508 ​ The anti-dilutive ordinary shares are presented without giving effect to the application of the treasury method or exercise prices that exceeded the price of the Company’s ordinary shares as of December 31, 2023 and December 31, 2022.

Commitments and contingencies

Commitments and contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and contingencies
Commitments and contingencies	22. ​ In the course of its business, the Company enters as a licensee into contracts with other parties regarding the development and marketing of its pipeline products. Among other payment obligations, the Company is obligated to pay royalties to the licensors based on future sales levels and milestone payments whenever specified development, regulatory and commercial milestones are met. As both future sales levels and the timing and achievement of milestones are uncertain, the financial effect of these agreements cannot be estimated reliably. The Company also has obligations to make future payments that become due and payable upon the collection of milestone payments from CSL Behring. The achievement and timing of these milestones is not fixed and determinable. Relevant commitments and contingencies are further discussed in other sections of this form 10-K, such as, uniQure France SAS transaction and Note 5 “ Collaboration arrangements and concentration of credit risk ”, amongst others. ​

Related party transaction

Related party transaction	12 Months Ended
	Dec. 31, 2023
Related party transaction
Related party transaction	23. Related party transaction ​ None. ​ ​

Subsequent events

Subsequent events	12 Months Ended
	Dec. 31, 2023
Subsequent events
Subsequent events	24. Subsequent events ​ None. ​

Summary of significant accoun_2

Summary of significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2023
Summary of significant accounting policies
Basis of preparation	2.1 Basis of preparation ​ The Company prepared its consolidated financial statements in compliance with generally accepted accounting principles in the United States (“U.S. GAAP”). Any reference in these notes to applicable guidance is meant to refer to authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). ​ The consolidated financial statements have been prepared under the historical cost convention, except for derivative financial instruments and contingent consideration, which are recorded at fair value through profit or loss. ​ The consolidated financial statements are presented in United States (“U.S.”) dollars ($), except where otherwise indicated. Transactions denominated in currencies other than U.S. dollars are presented in the transaction currency with the U.S. dollar amount included in parenthesis, converted at the foreign exchange rate as of the transaction date. ​ The consolidated financial statements presented have been prepared on a going concern basis based on the Company’s cash and cash equivalents as of December 31, 2023 and the Company’s budgeted cash flows for the twelve months following the issuance date.
Use of estimates	2.2 ​ The preparation of consolidated financial statements, in conformity with U.S. GAAP and Securities and Exchange Commission (“SEC”) rules and regulations, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the consolidated financial statements and reported amounts of revenues and expenses during the reporting period. Estimates and assumptions are primarily made in relation to contingent consideration related to the acquisition of uniQure France SAS, the treatment of revenue to be recognized under the commercialization and license agreement entered into (“CSL Behring Agreement”) between the Company and CSL Behring LLC (“CSL Behring”), and the assessment of a valuation allowance on the Company’s deferred tax assets in the Netherlands. If actual results differ from the Company’s estimates, or to the extent these estimates are adjusted in future periods, the Company’s results of operations could either benefit from, or be adversely affected by, any such change in estimate.
Accounting policies	2.3 ​ The principal accounting policies applied in the preparation of these consolidated financial statements are set out below. These policies have been consistently applied to all the years presented, unless otherwise stated.
Consolidation	2.3.1 ​ The consolidated financial statements comprise the financial statements of the Company and its subsidiaries. Subsidiaries are all entities over which the Company has a controlling financial interest either through variable interest or through voting interest. Currently, the Company has no involvement with variable interest entities. ​ Inter-company transactions, balances, income, and expenses on transactions between uniQure entities are eliminated in consolidation. Profits and losses resulting from inter-company transactions that are recognized in assets are also eliminated. Accounting policies of subsidiaries have been changed where necessary to ensure consistency with the policies adopted by the Company.
Current versus non-current classification	2.3.2 ​ The Company presents assets and liabilities in the consolidated balance sheets based on current and non-current classification. ​ The term current assets is used to designate cash and other assets, or resources commonly identified as those that are reasonably expected to be realized in cash or sold or consumed during the normal operating cycle of the business. The Company’s normal operating cycle is twelve months. All other assets are classified as non-current. ​ The term current liabilities is used principally to designate obligations whose liquidation is reasonably expected to require the use of existing resources properly classifiable as current assets, or the creation of other current liabilities. Current liabilities are expected to be settled in the normal operating cycle. The Company classifies all other liabilities as non-current. ​ Deferred tax assets and liabilities are classified as non-current assets and liabilities, if any.
Foreign currency translation	2.3.3 ​ The functional currency of the Company and each of its entities (except for uniQure Inc. and Corlieve AG) is the euro (€). This represents the currency of the primary economic environment in which the entities operate. The functional currency of uniQure Inc. is the U.S. dollar ($) and the functional currency of Corlieve AG is the Swiss Franc (CHF). The consolidated financial statements are presented in U.S. dollars. ​ Foreign currency transactions are measured and recorded in the functional currency using the exchange rates prevailing at the dates of the transactions. Foreign exchange gains and losses resulting from the settlement of such transactions and from the re-measurement of monetary assets and liabilities denominated in foreign currencies at exchange rates prevailing at balance sheet date are recognized in profit and loss. ​ Upon consolidation, the assets and liabilities of foreign operations are translated into the functional currency of the shareholding entity at the exchange rates prevailing at the balance sheet date; items of income and expense are translated at monthly average exchange rates. The consolidated assets and liabilities are translated from uniQure N.V.’s functional currency, euro, into the reporting currency U.S. dollar at the exchange rates prevailing at the balance sheet date; items of income and expense are translated at monthly average exchange rates. Issued capital and additional paid-in capital are translated at historical rates with differences to the balance sheet date rate recorded as translation adjustments in other comprehensive income / loss. The exchange differences arising on translation for consolidation are recognized in “accumulated other comprehensive income / loss”. On disposal of a foreign operation, the component of other comprehensive income / loss relating to that foreign operation is recognized in profit or loss.
Fair value measurement	2.3.4 ​ The Company measures certain assets and liabilities at fair value, either upon initial recognition or for subsequent accounting or reporting. ASC 820, Fair Value Measurements and Disclosures ​ ● Level 1 - Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company can access at the measurement date. ​ ● Level 2 - Valuations based on quoted prices for similar assets or liabilities in markets that are not active or models for which the inputs are observable, either directly or indirectly. ​ ● Level 3 - Valuations that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and are unobservable. ​ To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. ​ Items measured at fair value on a recurring basis include financial instruments and contingent consideration (Note 7, “ Fair value measurement
uniQure France SAS transaction	2.3.5 uniQure France SAS transaction ​ On June 21, 2021, we entered into a share and purchase agreement (“SPA”) to acquire all of the outstanding ordinary shares of uniQure France SAS (formerly Corlieve Therapeutics SAS), a privately held French gene therapy company (“uniQure France SAS Transaction”). On July 30, 2021 (“Acquisition Date”), the Company acquired uniQure France SAS. The Company evaluated the uniQure France SAS transaction as to whether or not the transaction should be accounted for as a business combination or asset acquisition. Refer to Note 3 “ uniQure France SAS transaction ​ a. Goodwill ​ Goodwill represents the excess of the fair value of the consideration transferred over the fair value of the net assets assumed in a business combination. Goodwill is not amortized but is evaluated for impairment on an annual basis and between annual tests if the Company becomes aware of any events occurring or changes in circumstances that would more likely than not reduce the fair value of the reporting unit below its carrying amount. As of December 31, 2023, 2022 and 2021, the Company has not recognized any impairment charges related to goodwill. ​ Refer to Note 3 “ uniQure France SAS transaction ​ b. Acquired research and development ​ The Company identified various licenses that combined with the results of the research and development activities conducted in relation to its target candidate for the treatment of temporal lobe epilepsy (“AMT-260”) since incorporation of uniQure France SAS in 2019 constitute an In-process research and development intangible asset (“IPR&D Intangible Asset”). The IPR&D Intangible Asset is considered to be indefinite-lived until the completion or abandonment of the associated research and development efforts and is not amortized. If and when development is completed, which generally occurs when regulatory approval to market a product is obtained, the associated asset would be deemed finite-lived and would then be amortized based on its respective useful life at that point in time. For the years ended December 31, 2023, 2022 and 2021, the Company has not recognized any impairment charges related to the IPR&D Intangible Asset. In case of abandonment, the IPR&D Intangible Asset will be written-off. In accordance with ASC 350, Intangibles – Goodwill and Other, the Company tests indefinite-lived intangible assets for impairment on an annual basis and between annual tests if the Company becomes aware of any events occurring or changes in circumstances that would indicate the fair value of the IPR&D Intangible Asset is below its carrying amount. ​ Refer to Note 3 “ uniQure France SAS transaction ​ c. Contingent consideration ​ Each reporting period, the Company revalues the contingent consideration obligations associated with the uniQure France SAS transaction to their fair value and records changes in the fair value within research and development expenses. Changes in contingent consideration obligations result from changes in assumptions regarding the probabilities of achieving the relevant milestones, or probability of success (“POS”), the estimated timing of achieving such milestones, and the interest rate to discount the payments. Payments of portions of contingent consideration initially recorded as of the acquisition date are recorded as cash flows from financing activities, and payments, or the portion of the milestone payments representing changes in the fair value of contingent consideration subsequent to the initial recognition are recorded as cash flows from operating activities. ​ Refer to Note 3 “ uniQure France SAS transaction
Notes to the consolidated statements of cash flows	2.3.6 ​ The consolidated statements of cash flows have been prepared using the indirect method. The cash disclosed in the consolidated statements of cash flows is comprised of cash and cash equivalents and restricted cash. Cash and cash equivalents include bank balances, demand deposits and other short-term highly liquid investments (with maturities of less than three months at the time of purchase) that are readily convertible into a known amount of cash and are subject to an insignificant risk of fluctuation in value. ​ Cash flows denominated in foreign currencies have been translated at the average exchange rates. Exchange differences, if any, affecting cash and cash equivalents are shown separately in the consolidated statements of cash flows. Interest paid and received, and income taxes are included in net cash (used in) provided by operating activities.
Segment information	2.3.7 ​ Operating segments are identified as a component of an enterprise for which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision-making group, in making decisions on how to allocate resources and assess performance. The Company views its operations and manages its business as one operating segment, which comprises the discovery, development, and commercialization of innovative gene therapies.
Net (loss) / income per share	2.3.8 ​ The Company follows the provisions of ASC 260, Earnings Per Share ​ Diluted net (loss) / income per share reflects the dilution that would occur if share options or warrants to issue ordinary shares were exercised, performance or restricted share units were distributed, or shares under the employee share purchase plan were issued. However, potential ordinary shares are excluded if their effect is anti-dilutive. ​ Refer to Note 21 “ Basic and diluted earnings per share
Impairment of long-lived assets	2.3.9 ​ Long-lived assets, which include property, plant, and equipment and finite-lived intangible assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of an asset or asset group may not be recoverable. Right-of-use assets are also reviewed for impairment in accordance with ASC 360, Property, Plant, and Equipment ​ Refer to Note 2.3.5 “ uniQure France SAS transaction
Investment securities	2.3.10 ​ Investment securities consist of sovereign debt with residual maturities of less than 12 months (presented as current) and beyond (presented as non-current). The Company classifies these securities as held-to-maturity. Held-to-maturity securities are those securities in which the Company has the ability and intent to hold the security until maturity. Held-to-maturity securities are recorded at amortized cost, adjusted for applicable accrued interest and the amortization or accretion of premiums or discounts. Premiums and discounts are amortized or accreted over the term of the related held-to-maturity security as an adjustment to yield using the effective interest rate method. ​ Investments securities with original maturities of less than three months when purchased are presented within cash and cash equivalents (December 31, 2023: nil, December 31, 2022: $21.2 million). ​ A decline in the market value of any investment security below cost that is deemed to be other than temporary results in a reduction in the carrying amount to fair value. The impairment is charged to operations and a new cost base for the security is established. Other-than-temporary impairment charges are included in interest and other income (expense), net. Interest income is recognized when earned. ​ Refer to Note 6 “ Investment securities
Accounts receivable	2.3.11 ​
Inventories	2.3.12 ​ The Company started producing commercial materials in April 2022 to supply CSL Behring in accordance with the June 2020 Development and Commercial Supply Agreement between the Company and CSL Behring. From this date onwards, the Company presents the costs associated with the aforementioned activities as cost of contract manufacturing. Refer to Note 5 “Collaboration arrangements and concentration of credit risk” ​ Per ASC 330, Inventory, inventory is stated at the lower of cost or estimated net realizable value, on a first-in, first-out basis. The Company capitalizes raw materials to the extent these can be used in contract manufacturing for CSL Behring. The Company uses standard costs, approximating average costs to determine its cost basis for work in progress and finished goods. The Company’s assessment of recoverability value requires the use of estimates regarding the net realizable value of its inventory balances, including an assessment of excess or obsolete inventory. As applicable, write-downs resulting from adjustments to net realizable value will be recorded to cost of contract manufacturing.
Prepaid expenses	2.3.13 ​ Prepaid expenses are amounts paid in the period, for which the benefit has not been realized, and include payments made for insurance and research and clinical contracts. The related expense will be recognized in the subsequent period as incurred.
Other (non) current assets	2.3.14 ​ Deposits paid are either presented as other current assets or as other non-current assets based on duration of the underlying contractual arrangement. Deposits are classified as restricted cash and primarily relate to facility leases. ​ Contract assets are presented in current assets or as non-current assets based on the timing of the right to consideration.
Property, plant, and equipment	2.3.15 ​ Property, plant, and equipment is comprised mainly of laboratory equipment, leasehold improvements, construction-in-progress (“CIP”) and office equipment. All property, plant and equipment is stated at cost less accumulated depreciation. CIP consists of capitalized expenses associated with construction of assets not yet placed into service. Depreciation commences on CIP once the asset is placed into service based on its useful life determined at that time. ​ Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed as incurred. Upon disposal, the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss on the transaction is recognized in the consolidated statements of operations and comprehensive loss. ​ Depreciation is calculated using the straight-line method over the estimated useful lives of the assets (or in the case of leasehold improvements a shorter lease term), which are as follows: ​ ​ ​ ​ ​ ​ ​ · Leasehold improvements Between 10 – 15 years · Laboratory equipment ​ 5 years · Office equipment ​ Between 3 – 5 years
Leases	2.3.16 ​ The Company records leases in accordance with ASC 842, Leases ​
Accounts payable and accrued expenses	2.3.17 Accounts payable and accrued expenses ​ Accounts payables are invoiced amounts related to obligations to pay for goods or services that have been acquired in the ordinary course of business from suppliers. Accounts payables are recognized at the amounts invoiced by suppliers. ​ Accrued expenses are recognized for goods or services that have been acquired in the ordinary course of business. ​ Contract liabilities, if any, are presented in accrued expenses.
Long-term debt	2.3.18 ​ Long-term debt is initially recognized at cost and presented net of original issue discount or premium and debt issuance costs on the consolidated balance sheets. Amortization of debt discount and debt issuance costs is recognized as interest expense in profit and loss over the period of the debt, using the effective interest rate method.
Pensions and other post-retirement benefit plans	2.3.19 Pensions and other post-retirement benefit plans ​ The Company has a defined contribution pension plan for all employees at its Amsterdam facility in the Netherlands, which is funded by the Company through payments to an insurance company, with individual accounts for each participants’ assets. The Company has no legal or constructive obligation to pay further contributions if the plan does not hold sufficient assets to pay all employees the benefits relating to services rendered in the current and prior periods. The contributions are expensed as incurred. Prepaid contributions are recognized as an asset to the extent that a cash refund or a reduction in the future payments is available. ​ In 2016, the Company adopted a qualified 401(k) Plan for all employees located in the United States. The 401(k) Plan offers both a pre-tax and post-tax (Roth) component. Employees may contribute up to the IRS statutory limit each calendar year. The Company matches $0.50 for every $1.00 contributed to the plan by participants up to 6% of base compensation. Employer contributions are recognized as they are contributed, as long as the employee is rendering services in that period. If employer contributions are made in periods after an individual retires or terminates, the estimated cost is accrued during the employee’s service period. ​ The Company maintains defined benefit plans for its Swiss employees, including retirement benefit plans required by applicable local law. The Company accounts for pension assets and liabilities in accordance with ASC 715, Compensation - Retirement Benefits, which requires the recognition of the funded status of pension plans in the Company’s consolidated balance sheet. The liability in respect to defined benefit pension plans is the projected benefit obligation calculated annually by independent actuaries using the projected unit credit method. ​ The projected benefit obligation as of December 31, 2023 represents the actuarial present value of the estimated future payments required to settle the obligation that is attributable to employee services rendered before that date. Service cost is reported in research and development and general and administrative expenses. All other components of net period costs are reported in interest expense in the consolidated statement of operations and comprehensive loss. Plan assets are recorded at their fair value. Gains or losses arising from plan curtailments or settlements are accounted for at the time they occur. Actuarial gains and losses arising from differences between the actual and the expected return on plan assets are recognized in accumulated other comprehensive income (loss).
Share-based compensation	2.3.20 Share-based compensation ​ The Company accounts for its share-based compensation awards in accordance with ASC 718, Compensation-Stock Compensation. ​ All the Company’s share-based compensation plans for employees are equity-classified. ASC 718 requires all share-based compensation to employees, including grants of employee options, restricted share units, performance share units and modifications to existing instruments, to be recognized in the consolidated statements of operations and comprehensive loss based on their grant-date fair values, net of an estimated forfeiture rate, over the requisite service period. Forfeitures of employee options are recognized as they occur. Compensation expense related to Performance Share Units is recognized when the Company considers achievement of the milestones to be probable. The requirements of ASC 718 are also applied to nonemployee share-based payment transactions except for specific guidance on certain inputs to an option-pricing model and the attribution of cost. ​ The Company uses a Hull & White option model to determine the fair value of option awards. The model captures early exercises by assuming that the likelihood of exercises will increase when the share-price reaches defined multiples of the strike price. This analysis is performed over the full contractual term. ​
Revenue recognition	​
Other income, other expense	2.3.22 ​ The Company receives certain government and regional grants, which support its research efforts in defined projects, and include contributions towards the cost of research and development. These grants generally provide for reimbursement of approved costs incurred as defined in the respective grants and are deferred and recognized in the statements of operations and comprehensive loss over the period necessary to match them with the costs they are intended to compensate, when it is probable that the Company has complied with any conditions attached to the grant and will receive the reimbursement. ​ The Company’s other income also consists of employee retention credits received under the U.S. Coronavirus Aid, Relief, and Economic Security Act, income related to a settlement agreement that the Company and VectorY B.V. entered into in April 2021, as well as income from subleasing part of the Company’s Amsterdam facility. Other expense consists of expenses incurred in relation to the subleasing income.
Research and development expenses	2.3.23 ​ Research and development costs are expensed as incurred. Research and development expenses generally consist of laboratory research, clinical trials, statistical analysis, and report writing, regulatory compliance costs incurred with clinical research organizations and other third-party vendors (including post-approval commitments to conduct consistency and comparability studies). In addition, research and development expenses consist of start-up and validation costs related to the Company’s Lexington facility and the development and improvement of the Company’s manufacturing processes and methods. Furthermore, research and development costs include costs of materials and costs of intangible assets purchased from others for use in research and development activities. The costs of intangibles that are purchased from others for a particular research and development project and that have no alternative future uses (in other research and development projects or otherwise) are expensed as research and development costs at the time the costs are incurred or at the time when no alternative future use is identified.
Income taxes	2.3.24 ​ Income taxes are recorded in accordance with ASC 740, Income Taxes ​ The benefits of tax positions are recognized only if those positions are more likely than not, based on the technical merits, to be sustained upon examination. Recognized tax positions are measured at the largest amount of tax benefit that is greater than 50 percent likely of being realized upon settlement. 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 did not have any significant unrecognized tax benefits. ​
Royalty Financing Agreement	2.3.25 Royalty Financing Agreement ​ In May 2023, uniQure biopharma B.V. (“uniQure biopharma”), a wholly-owned subsidiary of the Company entered into an agreement (the “Royalty Financing Agreement”) with the HemB SPV, L.P. (the “Purchaser”) to sell certain current and future royalties due to uniQure biopharma from CSL Behring under the CSL Behring Agreement by and between uniQure biopharma and CSL Behring from the net sales of HEMGENIX®. Refer to Note 14 “Royalty Financing Agreement” ​ In accordance with topic ASC 835, Interest, debt issuance costs incurred in relation to the Royalty Financing Agreement are presented as a reduction of carrying amount of the debt. Debt issuance cost is amortized together with the interest expense recorded.
Restructuring expenses	2.3.26 Restructuring expenses ​ Restructuring charges principally consist of one-time termination benefits. The Company records one-time termination benefits in accordance with ASC 420, Exit or Disposal Cost Obligations. One-time termination benefits are expensed at the date the Company notifies the employee, unless the employee must provide future service, in which case the benefits are expensed ratably over the future service period. ​ Other costs relate to the impairment of the Lexington facility that was closed as a result of a reorganization plan (the “Reorganization”). The Company has recognized an impairment loss of the right-of-use asset and corresponding leasehold improvements in accordance with ASC 360, Property, Plant and Equipment.
Recently Adopted Accounting Pronouncements	2.3.27 Recently Adopted Accounting Pronouncements ​ None. ​ Recent Accounting Pronouncements Not Yet Effective ​ None.

Summary of significant accoun_3

Summary of significant accounting policies (Tables)	12 Months Ended
	Dec. 31, 2023
Summary of significant accounting policies
Schedule of estimated useful lives of depreciable property, plant and equipment	​ ​ ​ ​ ​ ​ ​ · Leasehold improvements Between 10 – 15 years · Laboratory equipment ​ 5 years · Office equipment ​ Between 3 – 5 years

Reorganization (Tables)

Reorganization (Tables)	12 Months Ended
	Dec. 31, 2023
Reorganization
Summary of the restructuring charges by major activity type	A summary of the restructuring charges for the year ended December 31, 2023 by major activity type is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Severance and Other Personnel Costs Impairment Charges Total ​ ​ ​ (in thousands) Research and development ​ $ 2,188 1,438 3,626 General and administrative ​ ​ 361 — 361 Total ​ $ 2,549 1,438 3,987
Summary of the changes in the severance and other personnel liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of liability ​ ​ ​ (in thousands) Balance as of January 1, 2023 ​ $ — Severance and other personnel costs ​ ​ 2,549 Cash payments during the period ​ ​ (1,522) Balance as of December 31, 2023 ​ $ 1,027

Collaboration arrangements an_2

Collaboration arrangements and concentration of credit risk (Tables)	12 Months Ended
	Dec. 31, 2023
Collaboration arrangements and concentration of credit risk
Schedule of collaboration and license revenue	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 ​ ​ 2022 ​ ​ 2021 ​ ​ (in thousands) Bristol Myers Squibb $ — ​ $ 1,752 ​ $ 4,176 ​ $ — ​ $ 1,752 ​ $ 4,176 ​
Schedule of amounts owed in relation to collaboration	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2023 2022 ​ ​ (in thousands) Bristol Myers Squibb ​ $ — ​ $ 136 Total ​ $ — ​ $ 136 ​

Investments securities (Tables)

Investments securities (Tables)	12 Months Ended
	Dec. 31, 2023
Investments securities
Schedule of investments into sovereign debt	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At December 31, 2023 ​ ​ Amortized cost ​ Gross unrealized holding gains ​ Gross unrealized holding losses ​ Estimated fair value ​ ​ (in thousands) Current investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Government debt securities (held-to-maturity) ​ $ 376,532 ​ $ 139 ​ $ — ​ $ 376,671 Total ​ $ 376,532 ​ $ 139 ​ $ — ​ $ 376,671 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At December 31, 2022 ​ ​ Amortized cost ​ Gross unrealized holding gains ​ Gross unrealized holding losses ​ Estimated fair value ​ ​ (in thousands) Current investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Government debt securities (held-to-maturity) ​ $ 124,831 ​ $ — ​ $ (283) ​ $ 124,548 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-current investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Government debt securities (held-to-maturity) ​ ​ 39,984 ​ ​ — ​ ​ (43) ​ ​ 39,941 Total ​ $ 164,815 ​ $ — ​ $ (326) ​ $ 164,489

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2023
Inventories
Schedule of inventory balances	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2023 2022 ​ ​ (in thousands) Raw materials ​ $ 7,157 ​ $ 3,584 Work in progress ​ ​ 4,109 ​ ​ 1,874 Finished goods ​ ​ 758 ​ ​ 1,466 Inventories ​ $ 12,024 ​ $ 6,924

Fair value measurement and Ot_2

Fair value measurement and Other non-operating (losses) / gains (Tables)	12 Months Ended
	Dec. 31, 2023
Fair value measurement and Other non-operating (losses) / gains
Schedule of changes in Level 3 items	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative ​ ​ ​ ​ ​ Contingent ​ financial ​ ​ ​ ​ consideration instruments Total ​ ​ (in thousands) Balance at December 31, 2020 ​ $ — ​ $ 2,645 ​ $ 2,645 Amount recorded for contingent consideration on Acquisition Date of uniQure France SAS ​ ​ 23,950 ​ ​ — ​ ​ 23,950 Net losses recognized in profit or loss ​ ​ 6,683 ​ ​ 160 ​ ​ 6,843 Currency translation effects ​ ​ (1,091) ​ ​ — ​ ​ (1,091) Balance at December 31, 2021 ​ $ 29,542 ​ $ 2,805 ​ $ 32,347 Net losses / (gains) recognized in profit or loss ​ ​ 7,080 ​ ​ (2,760) ​ ​ 4,320 Currency translation effects ​ ​ (1,306) ​ ​ (45) ​ ​ (1,351) Balance at December 31, 2022 ​ $ 35,316 ​ $ — ​ $ 35,316 Net losses recognized in profit or loss ​ ​ 15,895 ​ ​ — ​ ​ 15,895 Contingent consideration milestone payment ​ ​ (9,563) ​ ​ — ​ ​ (9,563) Currency translation effects ​ ​ 1,358 ​ ​ — ​ ​ 1,358 Balance at December 31, 2023 ​ $ 43,006 ​ $ — ​ $ 43,006
Schedule of other non-operating (losses) / gains	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ (in thousands) Other non-operating gains: ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative gains ​ $ — ​ $ 2,760 ​ $ — Total other non-operating gains: ​ ​ — ​ ​ 2,760 ​ ​ — Other non-operating losses: ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative losses ​ ​ — ​ ​ — ​ ​ (160) Other non-operating gains / (losses), net ​ $ — ​ $ 2,760 ​ $ (160)

Property, plant, and equipmen_2

Property, plant, and equipment, net (Tables)	12 Months Ended
	Dec. 31, 2023
Property, plant, and equipment, net
Schedule of property, plant, and equipment	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2023 2022 ​ ​ (in thousands) Leasehold improvements ​ $ 46,512 ​ $ 44,871 Laboratory equipment ​ ​ 43,657 ​ ​ 39,393 Office equipment ​ ​ 6,383 ​ ​ 4,985 Construction-in-progress ​ ​ 5,668 ​ ​ 5,409 Total property, plant, and equipment ​ ​ 102,220 ​ ​ 94,658 Less accumulated depreciation ​ ​ (55,672) ​ ​ (44,126) Property, plant and equipment, net ​ $ 46,548 ​ $ 50,532
Summary of long-lived assets by geographic region	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, ​ ​ 2023 ​ 2022 ​ ​ (in thousands) Lexington, Massachusetts (United States of America) ​ $ 19,437 ​ $ 20,258 Amsterdam (the Netherlands) ​ 27,095 ​ 30,252 Other ​ ​ 16 ​ ​ 22 Total ​ $ 46,548 ​ $ 50,532 ​

Right-of-use asset and lease _2

Right-of-use asset and lease liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Right-of-use asset and lease liabilities
Schedule of lease cost, balance sheet and cash flow information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) ​ ​ ​ Operating lease cost ​ $ 7,018 ​ $ 5,932 ​ $ 5,306 Variable lease cost ​ ​ 1,238 ​ ​ 785 ​ ​ 698 Sublease income ​ ​ (957) ​ ​ (849) ​ ​ (907) Total lease cost ​ $ 7,299 ​ $ 5,868 ​ $ 5,097 ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ ​ 2023 ​ 2022 ​ ​ (in thousands) Assets ​ ​ ​ ​ ​ ​ Operating lease right-of-use assets ​ $ 28,789 ​ ​ 32,726 Liabilities ​ ​ ​ ​ ​ ​ Current ​ ​ ​ ​ ​ ​ Current operating lease liabilities ​ ​ 8,344 ​ ​ 8,382 Non-current ​ ​ ​ ​ ​ ​ Non-current operating lease liabilities ​ ​ 28,316 ​ ​ 31,719 Total lease liabilities ​ $ 36,660 ​ ​ 40,101 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) Cash paid for amounts included in the measurement of lease liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows for operating leases ​ $ 7,921 ​ $ 7,532 ​ $ 5,738 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Right-of-use asset obtained in exchange for lease obligation ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating lease ​ $ 561 ​ $ 9,824 ​ $ 1,699 ​
Schedule of undiscounted cash flows and operating lease liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Lexington ​ Amsterdam (1) ​ Other ​ Total ​ (in thousands) 2024 $ 5,504 ​ $ 2,569 ​ $ 295 ​ $ 8,368 2025 ​ 5,859 ​ ​ 2,056 ​ ​ 295 ​ ​ 8,210 2026 ​ 6,031 ​ ​ 2,056 ​ ​ 246 ​ ​ 8,333 2027 ​ 6,207 ​ ​ 2,060 ​ ​ — ​ ​ 8,267 2028 ​ 6,388 ​ ​ 1,984 ​ ​ — ​ ​ 8,372 Thereafter ​ 2,956 ​ ​ 5,430 ​ ​ — ​ ​ 8,386 Total lease payments $ 32,945 ​ $ 16,155 ​ $ 836 ​ $ 49,936 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less: amount of lease payments representing interest payments ​ (7,920) ​ ​ (5,211) ​ ​ (145) ​ ​ (13,276) Present value of lease payments ​ 25,025 ​ ​ 10,944 ​ ​ 691 ​ ​ 36,660 Less: current operating lease liabilities ​ (5,504) ​ ​ (2,569) ​ ​ (271) ​ ​ (8,344) Non-current operating lease liabilities $ 19,521 ​ $ 8,375 ​ $ 420 ​ $ 28,316 (1) Payments are due in EUR and have been translated at the foreign exchange rate as of December 31, 2023, of $1.10 / €1.00

Intangible assets, net and Go_2

Intangible assets, net and Goodwill (Tables)	12 Months Ended
	Dec. 31, 2023
Intangible assets, net and Goodwill
Schedule of acquired licenses and acquired IPR&D	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, ​ ​ 2023 ​ 2022 ​ ​ (in thousands) Acquired licenses ​ $ 2,419 ​ $ 2,346 Less accumulated amortization ​ ​ (1,057) ​ ​ (900) Acquired licenses, net ​ $ 1,362 ​ $ 1,446 Acquired IPR&D Intangible Asset ​ 59,119 ​ 57,332 Intangibles, net ​ $ 60,481 ​ $ 58,778
Schedule of estimated future amortization expense	​ ​ ​ ​ ​ Years Amount ​ ​ (in thousands) 2024 ​ $ 130 2025 ​ 130 2026 ​ 130 2027 ​ 130 2028 ​ 130 Thereafter ​ 712 Total ​ $ 1,362

Accrued expenses and other cu_2

Accrued expenses and other current liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Accrued expenses and other current liabilities
Schedule of accrued expenses and other current liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2023 2022 ​ ​ (in thousands) Personnel related accruals and liabilities ​ $ 16,263 ​ $ 17,201 Accruals for goods received from and services provided by vendors-not yet billed ​ ​ 12,834 ​ ​ 11,120 Liability owed to the Purchaser pursuant to the Royalty Financing Agreement ​ ​ 1,437 ​ ​ — Accrued contract fulfillment costs and costs to obtain a contract ​ ​ — ​ ​ 2,250 Total ​ $ 30,534 ​ $ 30,571

Long-term debt (Tables)

Long-term debt (Tables)	12 Months Ended
	Dec. 31, 2023
Long-term debt
Schedule of interest expense	​ ​ ​ ​ ​ Years Amount ​ ​ (in millions) 2023 ​ $ 14.6 2022 ​ 11.5 2021 ​ ​ 7.2
Schedule of aggregate maturities of the loan	​ ​ ​ ​ ​ Years Amount ​ ​ (in thousands) 2024 ​ $ 13,420 2025 ​ ​ 18,233 2026 ​ ​ 13,383 2027 ​ ​ 102,533 Total ​ $ 147,569 ​

Royalty financing agreement (Ta

Royalty financing agreement (Tables)	12 Months Ended
	Dec. 31, 2023
Royalty Financing Agreement
Schedule of movement in the liability related to royalty financing agreement	​ ​ ​ ​ ​ ​ ​ ​ Amount of liability ​ ​ ​ (in thousands) Gross proceeds from royalty financing agreement on June 5, 2023 ​ $ 375,000 Debt issuance costs paid ​ ​ (4,938) Royalty payments to Purchaser ​ ​ (1,317) Liability owed to the Purchaser (presented as "Accrued expense and other current liabilities") ​ ​ (1,437) Interest expense for the period June 5, 2023 to December 31, 2023 ​ ​ 26,933 Liability related to the royalty financing agreement ​ $ 394,241 ​

Retirement benefits (Tables)

Retirement benefits (Tables)	12 Months Ended
	Dec. 31, 2023
Retirement benefits
Schedule of benefit obligation recognized in the consolidated balance sheets	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2023 ​ ​ ​ (in thousands) Fair value of plan assets ​ ​ $ 8,946 Present value of projected benefit obligation ​ ​ ​ (11,499) Funded status: (net liability) ​ ​ $ (2,553) ​ ​ ​ ​ ​ Accumulated benefit obligation as of December 31, 2023 ​ ​ $ 10,739
Schedule of weighted average assumptions related to the swiss plan	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, Actuarial assumptions (% p.a.) 2023 Discount rate ​ ​ ​ 1.50% Expected return on plan assets ​ ​ ​ 2.60% Expected inflation rate ​ ​ ​ 1.60% Interest credit rate ​ ​ ​ 1.25% Long-term expected rate of salary increases ​ ​ ​ 1.60% Pension increase ​ ​ ​ 0.00%
Schedule of future benefits expected to be paid	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2023 Year 1 ​ ​ $ 533 Year 2 ​ ​ ​ 610 Year 3 ​ ​ ​ 528 Year 4 ​ ​ ​ 529 Year 5 ​ ​ ​ 540 Next 5 years ​ ​ ​ 4,992 ​ ​ ​ ​ ​ Other disclosure items: ​ ​ ​ ​ Next year's expected employer contribution ​ ​ $ 552 ​ ​ ​ ​ ​
Schedule of allocation of plan assets	​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2023 Bonds ​ ​ 61% Equities ​ ​ 25% Real estate ​ ​ 10% Others ​ ​ 4%

Share-based compensation (Table

Share-based compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-based compensation
Schedule of share-based compensation expense by classification included in consolidated statements of operations and comprehensive loss	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ (in thousands) Cost of manufacturing services revenue ​ $ 826 ​ $ 323 ​ $ — Research and development ​ ​ 16,881 ​ ​ 18,402 ​ ​ 12,834 Selling, general and administrative ​ ​ 17,386 ​ ​ 15,479 ​ ​ 12,801 Total ​ $ 35,093 ​ $ 34,204 ​ $ 25,635
Schedule of share-based compensation expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ (in thousands) Award type/ESPP ​ ​ ​ ​ ​ ​ ​ ​ ​ Share options ​ $ 13,302 ​ $ 13,425 ​ $ 12,477 Restricted share units ​ ​ 18,524 ​ ​ 15,486 ​ ​ 11,347 Performance share units ​ ​ 3,234 ​ ​ 5,267 ​ ​ 1,783 Employee share purchase plan ​ ​ 33 ​ ​ 26 ​ ​ 28 Total ​ $ 35,093 ​ $ 34,204 ​ $ 25,635
Schedule of unrecognized compensation cost related to unvested awards	​ ​ ​ ​ ​ ​ ​ ​ Unrecognized Weighted average ​ share-based remaining ​ ​ compensation ​ period for ​ ​ expense ​ recognition ​ ​ (in thousands) ​ (in years) Award type ​ ​ ​ ​ ​ Share options ​ $ 21,708 ​ 2.47 Restricted share units ​ ​ 27,015 ​ 1.89 Performance share units ​ ​ 738 ​ 0.95 Total ​ $ 49,461 ​ 2.13
Schedule of weighted-average assumptions for fair value of option issued	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, Assumptions 2023 2022 ​ 2021 Expected volatility ​ 70% ​ 70% ​ 75% Expected terms ​ 10 years ​ 10 years ​ 10 years Risk free interest rate ​ 3.7% - 4.8% ​ 2.1% - 4.2% ​ 1.2 - 1.9% Expected dividend yield ​ 0% ​ 0% ​ 0%
Summary of RSUs activity	​ ​ ​ ​ ​ ​ ​ ​ ​ RSUs ​ ​ Weighted average ​ ​ Number of ​ grant-date fair ​ ​ ordinary shares ​ value Non-vested at December 31, 2022 ​ 1,818,774 ​ $ 20.46 Granted ​ 1,770,025 ​ $ 17.88 Vested ​ (738,447) ​ $ 22.65 Forfeited ​ (585,983) ​ $ 19.12 Non-vested at December 31, 2023 ​ 2,264,369 ​ $ 18.07 ​ ​ ​ ​ ​ ​ Total weighted average grant date fair value of RSUs granted during the period (in $ millions) ​ ​ ​ $ 31.6 Granted to directors and officers during the period (shares, $ in millions) ​ 419,200 ​ $ 8.3
Summary of PSUs activity	​ ​ ​ ​ ​ ​ ​ ​ ​ PSUs ​ ​ Weighted average ​ ​ Number of ​ grant-date fair ​ ​ ordinary shares ​ value Non-vested at December 31, 2022 ​ 400,690 ​ $ 28.82 Vested ​ (94,510) ​ $ 30.65 Forfeited ​ (83,630) ​ $ 28.22 Non-vested at December 31, 2023 ​ 222,550 ​ $ 28.09 ​ ​ ​ ​ ​ ​ Total weighted average grant date fair value of PSUs granted during the period (in $ millions) ​ ​ ​ $ -
2014 Plan
Share-based compensation
Summary of option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options ​ ​ Number of ​ Weighted average ​ Weighted average ​ Aggregate intrinsic ​ ordinary shares exercise price remaining contractual life value ​ ​ ​ ​ ​ ​ ​ in years ​ ​ (in thousands) Outstanding at December 31, 2022 ​ 4,237,917 ​ $ 26.13 ​ 7.14 ​ $ 17,848 Granted ​ 1,650,030 ​ $ 18.16 ​ ​ ​ ​ ​ Forfeited ​ (543,481) ​ $ 22.04 ​ ​ ​ ​ ​ Expired ​ (356,366) ​ $ 36.26 ​ ​ ​ ​ ​ Exercised ​ (14,070) ​ $ 9.24 ​ ​ ​ ​ ​ Outstanding at December 31, 2023 ​ 4,974,030 ​ $ 23.25 ​ 6.71 ​ ​ 182 Thereof, fully vested, and exercisable on December 31, 2023 ​ 2,738,595 ​ $ 26.08 ​ 5.15 ​ ​ 182 Thereof, outstanding and expected to vest after December 31, 2023 ​ 2,235,435 ​ $ 19.78 ​ 8.77 ​ ​ — Outstanding and expected to vest after December 31, 2022 ​ 2,098,557 ​ $ 23.38 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total weighted average grant date fair value of options issued during the period (in $ millions) ​ ​ ​ $ 17.4 ​ ​ ​ ​ ​ Granted to directors and officers during the period (options, grant date fair value $ in millions) ​ 786,580 ​ $ 9.0 ​ ​ ​ ​ ​ Proceeds from option sales during the period (in $ millions) ​ ​ ​ $ 0.1 ​ ​ ​ ​ ​
Summary of information about weighted average grant-date fair value of options granted	​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average ​ ​ Options ​ grant ‑ date fair value Granted, 2023 1,650,030 ​ $ 10.57 Granted, 2022 1,426,966 ​ ​ 9.04 Granted, 2021 1,174,893 ​ ​ 20.95 Vested, 2023 ​ 873,658 ​ ​ 13.50 Forfeited, 2023 ​ (543,481) ​ ​ 12.78
Summary of summarizes information about the weighted average grant-date fair value of options outstanding and expected to vest	​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average ​ ​ Options ​ grant ‑ date fair value Outstanding and expected to vest, 2023 2,235,435 ​ $ 11.50 Outstanding and expected to vest, 2022 2,098,557 ​ ​ 13.46
Summary of information about options exercised	​ ​ ​ ​ ​ ​ ​ ​ Exercised ​ ​ ​ ​ during the year ​ Intrinsic value ​ ​ ​ ​ (in thousands) 2023 14,070 ​ $ 154 2022 138,356 ​ 1,848 2021 241,496 ​ 5,046
Restricted share units ("RSUs")
Share-based compensation
Summary of information about weighted average grant-date fair value of options granted	​ ​ ​ ​ ​ ​ ​ ​ Granted Weighted average ​ ​ during the year ​ grant ‑ date fair value 2023 1,770,025 ​ $ 17.88 2022 1,604,533 ​ ​ 16.10 2021 574,921 ​ ​ 36.14
Summary of information about the total fair value of stock that vested	​ ​ ​ ​ ​ Total fair value ​ (in thousands) 2023 $ 13,729 2022 5,104 2021 8,063
Performance Share Awards
Share-based compensation
Summary of information about weighted average grant-date fair value of options granted	​ ​ ​ ​ ​ ​ ​ ​ Granted Weighted average ​ ​ during the year ​ grant ‑ date fair value 2023 — ​ $ — 2022 34,700 ​ $ 15.11 2021 555,600 ​ $ 30.19
Summary of information about the total fair value of stock that vested	​ ​ ​ ​ ​ Total fair value ​ (in thousands) 2023 $ 1,474 2022 4,450 2021 5,074

Expenses by nature (Tables)

Expenses by nature (Tables)	12 Months Ended
	Dec. 31, 2023
Expenses by nature
Schedule of operating expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) Employee-related expenses ​ $ 135,728 ​ $ 119,903 ​ $ 96,161 Laboratory and development expenses ​ 63,065 ​ 65,964 ​ 36,014 Office and housing expenses ​ 22,960 ​ 17,612 ​ 14,638 Legal and advisory expenses ​ ​ 21,975 ​ 15,782 ​ 24,767 Fair value loss - uniQure France SAS contingent consideration ​ ​ 15,895 ​ 7,081 ​ 6,683 Other operating expenses ​ 11,236 ​ 8,510 ​ 10,528 Depreciation and amortization expenses ​ 10,046 ​ 8,250 ​ 7,299 Patent and license expenses ​ ​ 7,112 ​ ​ 9,548 ​ ​ 3,748 Impairment related to the Reorganization ​ ​ 1,438 ​ ​ — ​ ​ — Total ​ $ 289,455 ​ $ 252,650 ​ $ 199,838
Schedule of employee-related expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) Wages and salaries ​ $ 71,852 ​ $ 63,704 ​ $ 53,078 Share-based compensation expenses ​ 34,267 ​ 33,881 ​ 25,635 Contractor expenses ​ 6,141 ​ 3,959 ​ 3,170 Social security costs ​ 5,900 ​ 5,179 ​ 4,496 Health insurance ​ 4,216 ​ 4,148 ​ 3,161 Costs related to pension plans ​ 3,611 ​ 2,667 ​ 2,051 Severance costs related to the Reorganization (refer to Note 4 " Reorganization ​ ​ 2,549 ​ ​ — ​ ​ — Other employee expenses ​ ​ 7,192 ​ ​ 6,365 ​ ​ 4,570 Total ​ $ 135,728 ​ $ 119,903 ​ $ 96,161 ​

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income taxes
Schedule of Income / (loss) before income tax (expense) / benefit	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) Dutch operations ​ $ (282,530) ​ $ (96,872) ​ $ 348,400 U.S. operations ​ (6,903) ​ (14,934) ​ (12,737) Other ​ ​ (17,124) ​ ​ (16,453) ​ ​ (2,857) Total ​ $ (306,557) ​ $ (128,259) ​ $ 332,806
Schedule of income tax benefit / (expense)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) Current tax expense ​ ​ ​ ​ ​ ​ ​ ​ ​ Other ​ $ (110) ​ $ (24) ​ $ (7) Total current income tax expense ​ $ (110) ​ $ (24) ​ $ (7) Deferred tax (expense) / benefit ​ ​ ​ ​ ​ ​ Dutch operations ​ $ — ​ $ (808) ​ $ (3,047) U.S. operations ​ (2,708) ​ (1,075) ​ (771) Other ​ ​ 897 ​ ​ 3,377 ​ ​ 608 Total deferred tax (expense) / benefit ​ $ (1,811) ​ $ 1,494 ​ $ (3,210) Total income tax (expense) / benefit ​ $ (1,921) ​ $ 1,470 ​ $ (3,217)
Schedule of reconciliation of income tax benefit recognized in other comprehensive income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2023 ​ Before tax Tax benefit Net of tax ​ ​ (in thousands) Unrecognized gain related to defined benefit pension plan liability ​ $ (2,553) ​ $ 417 ​ $ (2,136) Total ​ $ (2,553) ​ $ 417 ​ $ (2,136)
Schedule of reconciliation of statutory income tax rate to effective tax rate	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ (in thousands) (Loss) / income before income tax (expense) / benefit for the period ​ $ (306,557) ​ $ (128,259) ​ $ 332,806 Expected income tax benefit / (expense) at the tax rate enacted in the Netherlands (2023: 25.8%, 2022: 25.8%, 2021: 25.0%) ​ 79,092 ​ 33,091 ​ (83,201) Difference in tax rates between the Netherlands and the U.S. as well as other foreign countries ​ (124) ​ 99 ​ 309 Other net change in valuation allowance ​ (67,004) ​ (20,591) ​ 88,857 Non-deductible expenses ​ (13,885) ​ (11,129) ​ (9,182) Income tax (expense) / benefit ​ $ (1,921) ​ $ 1,470 ​ $ (3,217)
Schedule of significant portions of deferred tax assets and deferred tax liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ ​ 2023 ​ 2022 ​ ​ (in thousands) Deferred tax assets: ​ ​ Net operating loss carryforwards ​ $ 145,826 ​ $ 84,633 Operating lease liabilities ​ ​ 9,790 ​ ​ 10,612 Intangible assets ​ 6,417 ​ 3,826 Liability from Royalty Financing Agreement ​ ​ 6,155 ​ ​ — Interest carryforwards ​ ​ 3,711 ​ ​ 3,697 Accrued expenses and other current liabilities ​ ​ 1,435 ​ ​ 1,862 Inventory ​ ​ 497 ​ ​ — Defined benefit pension plan liability ​ ​ 406 ​ ​ — Property, plant and equipment ​ — ​ 510 Research and development tax credit carryforwards ​ ​ — ​ ​ 144 Total deferred tax assets ​ $ 174,237 ​ $ 105,284 Less valuation allowance ​ (145,191) ​ (74,547) Deferred tax assets, net of valuation allowance ​ $ 29,046 ​ $ 30,737 Acquired IPR&D intangible asset ​ ​ (15,242) ​ ​ (15,033) Operating lease right-of-use assets ​ ​ (8,159) ​ ​ (9,323) Property, plant and equipment ​ ​ (719) ​ ​ — Other current assets and receivables ​ ​ (193) ​ ​ (110) Deferred tax liability ​ $ (24,313) ​ $ (24,466) Net deferred tax asset ​ $ 4,733 ​ $ 6,271
Summary of Changes in the valuation allowance	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2023 2022 2021 ​ ​ (in thousands) January 1, ​ $ 74,547 ​ $ 60,289 ​ $ 150,113 Changes recorded in the statement of operations ​ ​ 67,004 ​ ​ 20,593 ​ ​ (88,858) Changes recorded in equity ​ ​ — ​ ​ (972) ​ ​ — Increase related to 2021 Dutch tax reforms ​ — ​ — ​ 1,897 Valuation allowance assumed in uniQure France SAS acquisition ​ ​ — ​ ​ — ​ ​ 545 Other changes including currency translation adjustments ​ 3,640 ​ (5,363) ​ ​ (3,408) December 31, ​ $ 145,191 ​ $ 74,547 ​ $ 60,289

Basic and diluted earnings pe_2

Basic and diluted earnings per share (Tables)	12 Months Ended
	Dec. 31, 2023
Basic and diluted earnings per share
Schedule of basic and diluted earnings per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 ​ ​ (in thousands, except share amounts) Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Net (loss) / income attributable to ordinary shares ​ $ (308,478) ​ $ (126,789) ​ $ 329,589 ​ ​ ​ (308,478) ​ ​ (126,789) ​ ​ 329,589 Denominator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average number of ordinary shares outstanding - basic ​ ​ 47,670,986 ​ ​ 46,735,045 ​ ​ 45,986,467 Stock options under 2014 Plans and previous plan ​ ​ — ​ ​ — ​ ​ 746,044 Non-vested RSUs and PSUs ​ ​ — ​ ​ — ​ ​ 107,162 Employee share purchase plan ​ ​ — ​ ​ — ​ ​ 1,299 Weighted-average number of ordinary shares outstanding - diluted ​ ​ 47,670,986 ​ ​ 46,735,045 ​ ​ 46,840,972
Schedule of potential dilutive common shares	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, ​ ​ 2023 ​ 2022 ​ 2021 Anti-dilutive ordinary share equivalents ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options under 2014 Plans and previous plan ​ ​ 4,974,030 ​ ​ 4,237,917 ​ ​ 2,576,281 Non-vested RSUs and PSUs ​ ​ 2,486,919 ​ ​ 2,219,464 ​ ​ 1,236,385 ESPP ​ ​ 3,640 ​ ​ 1,048 ​ ​ 1,842 Total anti-dilutive ordinary share equivalents ​ ​ 7,464,589 ​ ​ 6,458,429 ​ ​ 3,814,508

Summary of significant accoun_4

Summary of significant accounting policies (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) segment $ / shares	Dec. 31, 2022 USD ($)
Current and non-current classification
Operating cycle period	12 months
Segment information
Number of operating segments | segment	1
Pensions
Current investment securities	$ 376,532,000	$ 124,831,000
Pension benefits | Lexington
Pensions
Amount of employer matching contribution for every employee dollar contributed	$ 0.50
Lexington, Massachusetts (United States of America) | Pension benefits
Pensions
Amount contributed to plan (in dollars per share) | $ / shares	$ 1
Cash and Cash Equivalents
Pensions
Current investment securities	$ 0	$ 21,200,000
Maximum | Pension benefits | Lexington
Pensions
Percent of employee gross pay for which the employer makes a matching contribution	6%
Leasehold improvements | Minimum
Property, plant, and equipment, net
Estimated useful life (in years)	10 years
Leasehold improvements | Maximum
Property, plant, and equipment, net
Estimated useful life (in years)	15 years
Laboratory equipment
Property, plant, and equipment, net
Estimated useful life (in years)	5 years
Office equipment | Minimum
Property, plant, and equipment, net
Estimated useful life (in years)	3 years
Office equipment | Maximum
Property, plant, and equipment, net
Estimated useful life (in years)	5 years

uniQure France SAS transaction

uniQure France SAS transaction - Narrative (Details) $ in Thousands, € in Millions			1 Months Ended						12 Months Ended
	Jul. 30, 2021 USD ($) Institution employee	Jul. 30, 2021 EUR (€)	Sep. 30, 2023 USD ($)	Sep. 30, 2023 EUR (€)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 EUR (€)	Sep. 30, 2021 USD ($)	Sep. 30, 2021 EUR (€)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 EUR (€)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2023 EUR (€)	Jul. 30, 2021 EUR (€) Institution employee
Business Acquisition [Line Items]
Contingent consideration, net of current portion									$ 14,795		$ 9,334
Enacted tax rate									25.80%	25.80%	25.80%	25%
Goodwill									$ 26,379		$ 25,581
Repayment of debt acquired through acquisition of Corlieve												$ 1,572
uniQure France SAS
Business Acquisition [Line Items]
Number of institutions | Institution	2													2
Number of employees employed | employee	7													7
Percentage of outstanding ordinary shares	97.70%								100%				100%	97.70%
Value of shares issued	$ 53,300	€ 44.9
Contingent consideration, net of current portion	$ 24,000													€ 20.2
Weighted average cost of capital	10.40%													10.40%
Provisional fair value of IPR&D intangible asset	$ 63,600													€ 53.6
Deferred tax assets	1,700													1.5
Intangible assets	$ 15,900													13.4
Enacted tax rate	25%	25%
Deferred tax liability, net	$ 14,200													11.9
Goodwill	28,400													23.9
Repayment of debt acquired through acquisition of Corlieve					$ 400	€ 0.4	$ 1,200	€ 1
Current assets	3,400													2.9
Cash	3,300													2.8
Current liabilities	$ 1,300													€ 1.1
Acquisition of remaining outstanding ordinary shares									$ 1,900	€ 1.8
Contingent consideration paid on achievement of milestones			$ 10,600	€ 10
uniQure France SAS | Maximum
Business Acquisition [Line Items]
Consideration payable in development milestones through phase I or II									44,100				€ 40
Consideration payable in development milestones through phase III									$ 176,600				€ 160
Percentage of milestones payable through the issuance of shares									25%	25%

Reorganization - Restructuring

Reorganization - Restructuring charges (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Reorganization
Severance and Other Personnel Costs	$ 2,549
Impairment Charges	1,438
Total	3,987
Research and development
Reorganization
Severance and Other Personnel Costs	2,188
Impairment Charges	1,438
Total	3,626
General and administrative
Reorganization
Severance and Other Personnel Costs	361
Total	$ 361

Reorganization - Severance and

Reorganization - Severance and other personnel liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Restructuring Reserve [Roll Forward]
Severance and other personnel costs	$ 2,549
Cash payments during the period	(1,522)
Balance as of December 31, 2023	$ 1,027

Collaboration arrangements an_3

Collaboration arrangements and concentration of credit risk - CSL Behring and Bristol-Myers Squibb collaboration - Narrative (Details) $ in Thousands			1 Months Ended			12 Months Ended
	Dec. 01, 2020 item	Jun. 24, 2020 USD ($)	Apr. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	May 31, 2021 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jul. 31, 2023 USD ($)
Collaboration arrangements
Number of collaboration targets | item	4
Revenue						$ 15,843	$ 106,483	$ 524,002
Maximum
Collaboration arrangements
Collaboration agreement, additional payments receivable on achievement of commercial milestones							1,300,000
CLS
Collaboration arrangements
Upfront cash to receive upon the closing of the agreement		$ 450,000
Other payments received		12,400
Accounts receivable						4,000	2,200	2,900
Contract asset							100,000	55,000
Revenue							100,000
Sale amount received									$ 100,000
Milestone payments to be received upon achievement		$ 55,000
Collaboration revenues from related party			$ 55,000	$ 55,000
License revenues
Collaboration arrangements
Revenue					$ 462,400	2,758	100,000	517,400
License revenues | CLS
Collaboration arrangements
Revenue							0	0
Contract manufacturing revenues
Collaboration arrangements
Revenue						10,835	1,717	0
Contract manufacturing revenues | CLS
Collaboration arrangements
Revenue						13,600	2,100	0
Collaborative revenue | CLS
Collaboration arrangements
Revenue						2,300	3,000	2,400
License revenue | CLS
Collaboration arrangements
Revenue						2,800	$ 100,000	$ 517,400
Manufacturing Development [Member]
Collaboration arrangements
Revenue						$ 50,000

Collaboration arrangements an_4

Collaboration arrangements and concentration of credit risk - Amounts owed by BMS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenues	$ 15,843	$ 106,483	$ 524,002
BMS arrangement | Affiliated Entity [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amounts owed in relation to the collaboration services		136
Total revenues		1,752	4,176
BMS arrangement | Affiliated Entity [Member] | Bristol Myers Squibb
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amounts owed in relation to the collaboration services		136
Total revenues		$ 1,752	$ 4,176

Investments securities (Details

Investments securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Current investments:
Amortized cost, as adjusted	$ 376,532	$ 124,831
Gross unrealized holding gains	139
Estimated fair value	376,671
Non-current investments:
Amortized cost, as adjusted		39,984
Investments securities
Amortized cost, as adjusted		164,815
Gross unrealized holding losses		(326)
Estimated fair value		164,489
Investment purchased	366,439	163,146
Government debt securities
Current investments:
Amortized cost, as adjusted	376,532	124,831
Gross unrealized holding gains	139
Gross unrealized holding losses		(283)
Estimated fair value	$ 376,671	124,548
Non-current investments:
Amortized cost, as adjusted		39,984
Gross unrealized holding losses		(43)
Estimated fair value		$ 39,941

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Inventories
Raw materials	$ 7,157	$ 3,584
Work in progress	4,109	1,874
Finished goods	758	1,466
Inventories	12,024	6,924
Inventory write downs	$ 1,600	$ 0

Fair value measurement and Ot_3

Fair value measurement and Other non-operating (losses) / gains - Changes in Level 3 items (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Changes in Level 3 liabilities
Beginning Balance	$ 35,316	$ 32,347	$ 2,645
Amount recorded for contingent consideration on Acquisition Date of uniQure France SAS			23,950
Net (gains) losses recognized in profit or loss	$ 15,895	$ 4,320	$ 6,843
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense).	Other Nonoperating Income (Expense).	Other Nonoperating Income (Expense).
Contingent consideration milestone payment	$ (9,563)
Currency translation effects	1,358	$ (1,351)	$ (1,091)
Ending Balance	43,006	35,316	32,347
Contingent consideration.
Changes in Level 3 liabilities
Beginning Balance	35,316	29,542
Amount recorded for contingent consideration on Acquisition Date of uniQure France SAS			23,950
Net (gains) losses recognized in profit or loss	15,895	7,080	6,683
Contingent consideration milestone payment	(9,563)
Currency translation effects	1,358	(1,306)	(1,091)
Ending Balance	$ 43,006	35,316	29,542
Derivative financial instruments
Changes in Level 3 liabilities
Beginning Balance		2,805	2,645
Net (gains) losses recognized in profit or loss		(2,760)	160
Currency translation effects		$ (45)
Ending Balance			$ 2,805

Fair value measurement and Ot_4

Fair value measurement and Other non-operating (losses) / gains - Contingent Consideration (Details) $ in Thousands, € in Millions	1 Months Ended				12 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2023 EUR (€)	Aug. 31, 2023 USD ($)	Aug. 31, 2023 EUR (€)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2023 EUR (€)	Jul. 30, 2021 USD ($)	Jul. 30, 2021 EUR (€)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration, net of current portion					$ 14,795	$ 9,334
Milestone payment	$ 10,600	€ 10
Contingent consideration milestone payment	$ 9,600	€ 8.9
Change in fair value (presented within research and development expenses)					(9,563)
Contingent consideration					43,000
Current portion of contingent consideration					28,211	25,982
Liability related to post acquisition services					$ 500	300
One hundred percent likelihood of AMT-260 advancing into clinical development
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Percentage of increase in Probability of Success					100%
Change in fair value (presented within research and development expenses)					$ 75,900
Acquisition of Corlieve | Maximum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration payable upon achievement of contractually defined milestones					197,300		€ 178.8
uniQure France [S.A.S]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration, net of current portion					$ 43,000	$ 35,300		$ 24,000	€ 20.2
Milestone payment achieving due to increase In Probability Of Success In Clinical Development			$ 33,100	€ 30
uniQure France [S.A.S] | Maximum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration discount rate percentage					15.60%	14.40%
Percentage of increase in Probability of Success			100%	100%
uniQure France [S.A.S] | Minimum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration discount rate percentage					15.30%	14%
Percentage of increase in Probability of Success			66%	66%

Fair value measurement and Ot_5

Fair value measurement and Other non-operating (losses) / gains - Derivative financial instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Other non-operating gains
Derivative gains	$ 2,760
Total other non-operating gains:	2,760
Other non-operating losses
Derivative losses		$ (160)
Other non-operating gains / (losses), net	$ 2,760	$ (160)

Fair value measurement and Ot_6

Fair value measurement and Other non-operating (losses) / gains - BMS warrants (Details) $ in Thousands		12 Months Ended
	Dec. 01, 2020 USD ($) item	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Collaboration arrangements
Number of collaboration targets | item	4
Collaboration agreement, cash payable	$ 70,000
Fair value of derivative financial instruments		$ 43,006	$ 35,316	$ 32,347	$ 2,645
Fair value of the derivative financial liability			0
Other nonoperating (losses) / gains | CoC-payment
Collaboration arrangements
Gain (Loss) from the recognition of the derivative financial liability		$ 0	$ 2,800
Collaboration Agreement, If 70 Million Is Greater Than Five Percent Of Net Proceeds | Derecognition Of Warrants
Collaboration arrangements
Threshold percentage of net proceeds	5
Percentage Of net proceeds payable	5
Collaboration Agreement, If 70 Million Is Lesser Than One Percent Of Net Proceeds | Derecognition Of Warrants
Collaboration arrangements
Threshold percentage of net proceeds	1
Percentage Of net proceeds payable	1

Property, plant, and equipmen_3

Property, plant, and equipment, net - Summary of PP&E (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, plant and equipment
Total property, plant, and equipment, net	$ 102,220	$ 94,658
Less accumulated depreciation	(55,672)	(44,126)
Property, plant and equipment, net	46,548	50,532
Depreciation	10,300	8,200	$ 6,100
Leasehold improvements
Property, plant and equipment
Total property, plant, and equipment, net	46,512	44,871
Laboratory equipment
Property, plant and equipment
Total property, plant, and equipment, net	43,657	39,393
Office equipment
Property, plant and equipment
Total property, plant, and equipment, net	6,383	4,985
Construction-in-progress
Property, plant and equipment
Total property, plant, and equipment, net	$ 5,668	$ 5,409

Property, plant, and equipmen_4

Property, plant, and equipment, net - PP&E by geographic region (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, plant, and equipment, net
Property, plant, and equipment	$ 46,548	$ 50,532
Lexington, Massachusetts (United States of America)
Property, plant, and equipment, net
Property, plant, and equipment	19,437	20,258
Amsterdam (the Netherlands)
Property, plant, and equipment, net
Property, plant, and equipment	27,095	30,252
Other
Property, plant, and equipment, net
Property, plant, and equipment	$ 16	$ 22

Right-of-use asset and lease _3

Right-of-use asset and lease liabilities - Narrative (Details) € in Millions, $ in Millions	1 Months Ended			12 Months Ended
	Feb. 28, 2022 ft² item	Dec. 31, 2021 USD ($) ft²	Nov. 30, 2018 ft² item	Dec. 31, 2023 USD ($)	Dec. 31, 2023 EUR (€)	Dec. 31, 2022	May 31, 2021 m²	Dec. 01, 2017	Jun. 30, 2016	Mar. 31, 2016	Nov. 30, 2013
Leases
Area of facility (in square feet)			30,655				1,080
Weighted-average remaining lease term, Operating leases				6 years 1 month 6 days	6 years 1 month 6 days	7 years 2 months 12 days
Weighted-average discount rate, Operating leases				11.20%	11.20%	11.20%
Lexington, Massachusetts (United States of America)
Leases
Lease term (in years)	7 years 4 months		5 years								10 years
Number of subsequent renewals | item	1		2
Renewal term (in years)	5 years		5 years
Area of facility (in square feet) | ft²	12,716	13,501
Incurred costs | $		$ 1.4
Amsterdam (the Netherlands)
Leases
Lease term (in years)								10 years		16 years
Renewal term (in years)									5 years
Minimum rentals to be received				$ (4)	€ 3.6

Right-of-use asset and lease _4

Right-of-use asset and lease liabilities - Operating lease liabilities (Details) $ in Thousands		1 Months Ended	12 Months Ended
	Dec. 01, 2017 floor	Feb. 29, 2020 floor	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2023 $ / €	Dec. 31, 2023
Components of lease cost
Operating lease cost			$ 7,018	$ 5,932	$ 5,306
Variable lease cost			1,238	785	698
Sublease income			(957)	(849)	(907)
Total lease cost			7,299	5,868	5,097
Assets
Operating lease right-of-use assets			28,789	32,726
Current
Current operating lease liabilities			8,344	8,382
Non-current
Non-current operating lease liabilities			28,316	31,719
Total lease liabilities			36,660	40,101
Supplemental cash flow information related to leases
Cash paid for amounts included in the measurement of lease liabilities, Operating cash flows for operating leases			7,921	7,532	5,738
Right-of-use asset obtained in exchange for lease obligation
Operating lease			561	9,824	$ 1,699
Undiscounted Cash Flows
2024			8,368
2025			8,210
2026			8,333
2027			8,267
2028			8,372
Thereafter			8,386
Total lease payments			49,936
Less: amount of lease payments representing interest payments			(13,276)
Total lease liabilities			36,660	40,101
Less: current operating lease liabilities			(8,344)	(8,382)
Non-current operating lease liabilities			28,316	$ 31,719
Exchange rate (in USD per Euro)						1.10	1.10
Lexington, Massachusetts (United States of America)
Current
Current operating lease liabilities			5,504
Non-current
Non-current operating lease liabilities			19,521
Total lease liabilities			25,025
Undiscounted Cash Flows
2024			5,504
2025			5,859
2026			6,031
2027			6,207
2028			6,388
Thereafter			2,956
Total lease payments			32,945
Less: amount of lease payments representing interest payments			(7,920)
Total lease liabilities			25,025
Less: current operating lease liabilities			(5,504)
Non-current operating lease liabilities			19,521
Amsterdam (the Netherlands)
Components of lease cost
Number of floor of the facility | floor	7
Number of floors to sub-lease | floor	3	3
Number of floor to take back from the sub-lease | floor		1
Current
Current operating lease liabilities			2,569
Non-current
Non-current operating lease liabilities			8,375
Total lease liabilities			10,944
Undiscounted Cash Flows
2024			2,569
2025			2,056
2026			2,056
2027			2,060
2028			1,984
Thereafter			5,430
Total lease payments			16,155
Less: amount of lease payments representing interest payments			(5,211)
Total lease liabilities			10,944
Less: current operating lease liabilities			(2,569)
Non-current operating lease liabilities			8,375
Other
Current
Current operating lease liabilities			271
Non-current
Non-current operating lease liabilities			420
Total lease liabilities			691
Undiscounted Cash Flows
2024			295
2025			295
2026			246
Total lease payments			836
Less: amount of lease payments representing interest payments			(145)
Total lease liabilities			691
Less: current operating lease liabilities			(271)
Non-current operating lease liabilities			$ 420

Intangible assets, net and Go_3

Intangible assets, net and Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Acquired licenses, net	$ 60,481	$ 58,778
Intangibles, net	$ 60,481	$ 58,778
Weighted average remaining life	10 years 6 months	11 years 6 months
Licenses
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Acquired licenses	$ 2,419	$ 2,346
Less accumulated amortization	(1,057)	(900)
Acquired licenses, net	1,362	1,446
In-process research & development
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Acquired IPR&D Intangible Asset	$ 59,119	$ 57,332

Intangible assets, net and Go_4

Intangible assets, net and Goodwill - Future amortization expense (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Estimated amortization expense for the next five years
Acquired licenses, net	$ 60,481	$ 58,778
Licenses
Estimated amortization expense for the next five years
2024	130
2025	130
2026	130
2027	130
2028	130
Thereafter	712
Acquired licenses, net	$ 1,362	$ 1,446

Intangible assets, net and Go_5

Intangible assets, net and Goodwill - Carrying amount of Licenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Intangible assets
Impairment Of Intangible Asset Finite Lived Statement Of Income Or Comprehensive Income Extensible Enumeration Not Disclosed Flag	true	true	true
Licenses
Intangible assets
Amortization of Intangible Assets	$ 0.1	$ 0.4	$ 1.2

Accrued expenses and other cu_3

Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accrued expenses and other current liabilities
Personnel related accruals and liabilities	$ 16,263	$ 17,201
Accruals for goods received from and services provided by vendors-not yet billed	12,834	11,120
Liability owed to the Purchaser pursuant to the Royalty Financing Agreement	1,437
Accrued contract fulfillment costs and costs to obtain a contract		2,250
Total	$ 30,534	$ 30,571

Long-term debt (Details)

Long-term debt (Details) - USD ($) $ in Thousands				1 Months Ended	12 Months Ended
	Apr. 01, 2024	Dec. 15, 2021	Jan. 29, 2021	Jun. 30, 2033	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 05, 2027	Dec. 01, 2025	May 12, 2023
Long-term Debt
Investment, Variable Interest Rate, Type [Extensible Enumeration]					Prime Rate
Aggregate maturities of loan
Coupon interest payments and financing fees					$ 47,600
2024					13,420
2025					18,233
2026					13,383
2027					102,533
Total					$ 147,569
Prime Rate
Long-term Debt
Variable interest rate basis			8.25%
2021 Amended Facility
Long-term Debt
Outstanding debt			$ 35,000
Proceed from drew down			$ 35,000
Interest rate (as a percent)			8.25%
Maximum borrowing capacity			$ 135,000
Additional unconditional borrowing capacity			$ 100,000
2021 Amended Facility | Prime Rate
Long-term Debt
Discount rate (as a percent)			3.25%
2023 Amended Facility
Long-term Debt
Outstanding debt										$ 100,000
Interest rate (as a percent)					7.95%
Back-end fees paid				$ 2,500
Amortized cost net of discount and debt issuance costs					$ 102,900	$ 103,800
Foreign currency loss						$ 5,800	$ 5,300
Foreign currency gain					$ 3,000
2023 Amended Facility | Forecast
Long-term Debt
Back-end fees								$ 1,300	$ 4,900
2023 Amended Facility | Prime Rate
Long-term Debt
Variable interest rate basis					7.95%
Discount rate (as a percent)					3.25%
2018 and 2021 Amended Facility
Long-term Debt
Outstanding debt		$ 70,000	$ 70,000
Restated Facility 2021
Long-term Debt
Outstanding debt		100,000					100,000
Proceed from drew down		$ 30,000
Venture debt loan facility | 2023 Amended Facility
Long-term Debt
Minimum cash and cash equivalents in U.S. bank accounts					65%	100%
Assets pledged to secure facilities by directly or indirectly					$ 831,700
Assets not being pledged to secure facilities by directly or indirectly					9,300
Venture debt loan facility | 2023 Amended Facility | uniQure France
Long-term Debt
Assets not being pledged to secure facilities by directly or indirectly					90,400
Venture debt loan facility | 2018 and 2021 Amended Facility | Hercules
Long-term Debt
Interest expense recorded					$ 14,600	$ 11,500	$ 7,200
Subsequent events. | Venture debt loan facility | 2023 Amended Facility
Long-term Debt
Minimum cash and cash equivalents in U.S. bank accounts	30%

Royalty financing agreement (De

Royalty financing agreement (Details) $ in Thousands		7 Months Ended	12 Months Ended
	May 12, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2038	Jun. 30, 2032 USD ($)
Collaboration arrangements
Royalty financing agreement interest expense			$ 26,933
Net proceeds from the Royalty Financing Agreement			374,350
Payment of debt issuance costs			4,288
Interest Expense			41,557	$ 11,704	$ 7,474
CLS
Collaboration arrangements
Maximum rights to all other royalties, as well as contractual milestones retained		$ 1,300	1,300
Royalty financing agreement
Collaboration arrangements
Upfront payment received	$ 375,000
Additional milestone payment	$ 25,000
Ratio of upfront payment	1.85
Upfront payment payable to purchaser	$ 693,800	693,800	693,800
Royalty financing agreement interest expense		26,933	323,700
Net proceeds from the Royalty Financing Agreement			370,100
Payment of debt issuance costs		$ 4,938	4,900
Interest Expense			$ 26,900	$ 0	$ 0
Royalty financing agreement | Minimum
Collaboration arrangements
Effective interest rate (as a percent)		12%	12%
Interest Expense			$ 26,500
Royalty financing agreement | Maximum
Collaboration arrangements
Effective interest rate (as a percent)		13.50%	13.50%
Interest Expense			$ 29,900
Royalty financing agreement | First Hard Cap Date
Collaboration arrangements
Ratio of upfront payment							1.85
Upfront payment payable to purchaser							$ 25,000
Royalty financing agreement | If paid through December 31, 2038
Collaboration arrangements
Ratio of upfront payment						2.25
Royalty financing agreement | If 2024 net sales do not exceed a pre-specified threshold
Collaboration arrangements
Upfront payment payable to purchaser		$ 25,000	$ 25,000

Royalty financing agreement - M

Royalty financing agreement - Movement in the liability (Details) - USD ($) $ in Thousands		7 Months Ended	12 Months Ended
	Jun. 05, 2023	Dec. 31, 2023	Dec. 31, 2023
Collaboration arrangements
Debt issuance costs paid			$ 4,288
Liability owed to the Purchaser (presented as "Accrued expense and other current liabilities")		$ 1,437	1,437
Interest expense for the period			26,933
Liability related to the royalty financing agreement		394,241	394,241
Royalty financing agreement
Collaboration arrangements
Gross proceeds from royalty financing agreement	$ 375,000
Debt issuance costs paid		4,938	4,900
Royalty payments to Purchaser		(1,317)
Liability owed to the Purchaser (presented as "Accrued expense and other current liabilities")		1,437	1,437
Interest expense for the period		26,933	323,700
Liability related to the royalty financing agreement		$ 394,241	$ 394,241

Retirement benefits (Schedule o

Retirement benefits (Schedule of benefit obligations) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Retirement benefits
Fair value of plan assets	$ 8,946
Present value of projected benefit obligation	(11,499)
Funded status: (net liability)	(2,553)
Accumulated benefit obligation as of December 31, 2023	10,739
Defined benefit pension loss, net of taxes	(2,136)
Deferred tax income	417
Other non-current liabilities
Retirement benefits
Net projected benefit obligation	$ 2,500

Retirement benefits (Schedule_2

Retirement benefits (Schedule of Assumptions) (Details)	Dec. 31, 2023
Retirement benefits
Discount rate	1.50%
Expected return on plan assets	2.60%
Expected inflation rate	1.60%
Interest credit rate	1.25%
Long-term expected rate of salary increase	1.60%
Pension increase	0%

Retirement benefits (Schedule_3

Retirement benefits (Schedule of future benefits expected to be paid) (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Retirement benefits
Year 1	$ 533
Year 2	610
Year 3	528
Year 4	529
Year 5	540
Next 5 years	4,992
Other disclosure items:
Next year's expected employer contribution	$ 552

Retirement benefits (Schedule_4

Retirement benefits (Schedule of allocation of plan assets) (Details)	Dec. 31, 2023
Bonds
Retirement benefits
Percentage of allocation of plan assets	61%
Equities
Retirement benefits
Percentage of allocation of plan assets	25%
Real estate
Retirement benefits
Percentage of allocation of plan assets	10%
Others
Retirement benefits
Percentage of allocation of plan assets	4%

Shareholder's equity (Details)

Shareholder's equity (Details) € / shares in Units, $ / shares in Units, $ in Thousands, € in Millions		2 Months Ended	12 Months Ended
	Mar. 01, 2021 USD ($)	Apr. 30, 2021 USD ($) $ / shares shares	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) shares	Dec. 31, 2023 € / shares	Dec. 31, 2023 shares	Dec. 31, 2023 USD ($)	Dec. 31, 2023 $ / €	Dec. 31, 2023 EUR (€)	Dec. 31, 2023	Dec. 31, 2022 € / shares	Dec. 31, 2022 USD ($) shares	Jun. 16, 2021 shares
Authorized share capital								$ 4,400		€ 4
Exchange rate (in USD per Euro)									1.10		1.10
Ordinary shares, authorized | shares					80,000,000		80,000,000						80,000,000
Ordinary shares, par value (in euros per share) | € / shares						€ 0.05						€ 0.05
Common stock, additional shares authorized | shares														20,000,000
Accumulated other comprehensive loss					$ (28,900)			$ (53,553)					$ (58,291)
Aggregate offering price					29,564
Income tax benefit of past share issuance cost				$ 808	3,047
Increase of additional paid in capital				800
Sales Agreement with SVB Leerink LLC
Percentage of gross proceeds	3%
Sales Agreement with SVB Leerink LLC | Direct Incremental Labor
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs			$ 0	$ 0	$ 1,300
Sales Agreement with SVB Leerink LLC | Ordinary shares
Shares issued in connection with offering | shares		921,730
Share price (in dollars per share) | $ / shares		$ 33.52
Net proceeds		$ 29,600
Sales Agreement with SVB Leerink LLC | Maximum
Aggregate offering price	$ 200,000

Share-based compensation - Summ

Share-based compensation - Summary of share-based compensation expense and unrecognized costs (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2015
Share-based compensation
Authorized shares		14,351,471
Share-based compensation expense		$ 35,093	$ 34,204	$ 25,635
Unrecognized compensation costs		$ 49,461
Weighted-average remaining period for recognition (in years)		2 years 1 month 17 days
2014 Plan
Share-based compensation
Authorized shares		1,750,000
2014 Plan
Share-based compensation
Increase in authorized shares				4,000,000	3,000,000	3,000,000	1,070,000
Employee share purchase plan (ESPP)
Share-based compensation
Share-based compensation expense		$ 33	26	$ 28
Research and development expenses
Share-based compensation
Share-based compensation expense		16,881	18,402	12,834
Selling, general and administrative expense
Share-based compensation
Share-based compensation expense		17,386	15,479	12,801
Cost of manufacturing services revenues
Share-based compensation
Share-based compensation expense		826	323
Share options
Share-based compensation
Share-based compensation expense		13,302	13,425	12,477
Unrecognized compensation costs		$ 21,708
Weighted-average remaining period for recognition (in years)		2 years 5 months 19 days
Restricted share units ("RSUs")
Share-based compensation
Share-based compensation expense		$ 18,524	15,486	11,347
Unrecognized compensation costs		$ 27,015
Weighted-average remaining period for recognition (in years)		1 year 10 months 20 days
Performance Share Awards
Share-based compensation
Share-based compensation expense		$ 3,234	$ 5,267	$ 1,783
Unrecognized compensation costs		$ 738
Weighted-average remaining period for recognition (in years)		11 months 12 days
Employee share purchase plan | Employee share purchase plan (ESPP)
Share-based compensation
Ordinary shares available for issue	150,000	96,862
Discounted rate for purchase of shares	85%

Share-based compensation - Opti

Share-based compensation - Option activity and weighted-average assumptions (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Weighted average exercise price
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options	$ 308	$ 1,445	$ 2,798
Weighted-average assumptions used to estimate fair value of share options granted during year
Expected volatility (as a percent)			75%
Expected terms (in years)			10 years
Expected dividend (as a percent)			0%
The 2014 Plan [Member]
Options
Thereof, outstanding and expected to vest after at end of period (in shares)	2,235,435	2,098,557
Weighted average exercise price
Outstanding and expected to vest after at end of the period (in dollars per share)	$ 11.50	$ 13.46
Total weighted average grant date fair value of options issued during the period (in $ millions)	$ 17,400
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options	$ 100
Vesting period (in years)	4 years
Weighted-average assumptions used to estimate fair value of share options granted during year
Expected volatility (as a percent)	70%	70%
Expected terms (in years)	10 years	10 years
Risk free interest rate, minimum (as a percent)	3.70%	2.10%		1.20%
Risk free interest rate, maximum (as a percent)	4.80%	4.20%	1.90%
Expected dividend (as a percent)	0%	0%
Weighted average grant-date fair value
Forfeited (in dollar per share)	$ 12.78
The 2014 Plan [Member] | Share options
Options
Outstanding at beginning of the period (in shares)	4,237,917
Granted (in shares)	1,650,030	1,426,966	1,174,893
Forfeited (in shares)	(543,481)
Expired (in shares)	(356,366)
Exercised (in shares)	(14,070)	(138,356)	(241,496)
Outstanding at end of the period (in shares)	4,974,030	4,237,917
Thereof, fully vested and exercisable at end of period (in shares)	2,738,595
Thereof, outstanding and expected to vest after at end of period (in shares)	2,235,435	2,098,557
Weighted average exercise price
Outstanding at beginning of the period (in dollars per share)	$ 26.13
Granted (in dollars per share)	18.16
Forfeited (in dollars per share)	22.04
Expired (in dollars per share)	36.26
Exercised (in dollars per share)	9.24
Outstanding at end of period (in dollars per share)	23.25	$ 26.13
Thereof, fully vested and exercisable at end of period (in dollars per share)	26.08
Outstanding and expected to vest after at end of the period (in dollars per share)	$ 19.78	$ 23.38
Weighted average remaining contractual life (in years)
Outstanding	6 years 8 months 15 days	7 years 1 month 20 days
Thereof, fully vested and exercisable at end of year	5 years 1 month 24 days
Outstanding and expected to vest at end of year	8 years 9 months 7 days
Aggregate intrinsic value
Outstanding (in dollars)	$ 182	$ 17,848
Thereof, fully vested and exercisable	182
Exercised (in dollars)	$ 154	$ 1,848	$ 5,046
Weighted average grant-date fair value
Vested (in shares)	873,658
The 2014 Plan [Member] | Non-executive directors
Weighted average exercise price
Vesting period (in years)	1 year
The 2014 Plan [Member] | Directors and Officers
Options
Granted (in shares)	786,580
Weighted average exercise price
Granted (in dollars per share)	$ 9
The 2014 Plan [Member] | One year from grant date
Weighted average exercise price
Vesting percentage per year	25%
Vesting period (in years)	1 year
2012 Plan
Options
Outstanding at beginning of the period (in shares)	0
Outstanding at end of the period (in shares)	0	0

Share-based compensation - RSU

Share-based compensation - RSU activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
The 2014 Plan [Member]
Weighted average grant-date fair value
Granted (in dollars per share)	$ 10.57	$ 9.04	$ 20.95
Vested (in dollars per share)	$ 13.50
Other disclosure
Vesting period (in years)	4 years
The 2014 Plan [Member] | Non-executive directors
Other disclosure
Vesting period (in years)	1 year
Restricted share units ("RSUs")
Number of shares
Non-vested at beginning of period (in shares)	1,818,774
Granted (in shares)	1,770,025
Vested (in shares)	(738,447)
Forfeited (in shares)	(585,983)
Non-vested at end of period (in shares)	2,264,369	1,818,774
Weighted average grant-date fair value
Non-vested at beginning of period (in dollars per share)	$ 20.46
Granted (in dollars per share)	17.88
Vested (in dollars per share)	22.65
Forfeited (in dollars per share)	19.12
Non-vested at end of period (in dollars per share)	$ 18.07	$ 20.46
Other disclosure
Total weighted average grant date fair value of RSUs granted during the period (in millions)	$ 31,600
Restricted share units ("RSUs") | Non-executive directors
Other disclosure
Vesting period (in years)	1 year
Restricted share units ("RSUs") | Directors and Officers
Number of shares
Granted (in shares)	419,200
Weighted average grant-date fair value
Granted (in dollars per share)	$ 8.3
Restricted share units ("RSUs") | The 2014 Plan [Member]
Number of shares
Granted (in shares)	1,770,025	1,604,533	574,921
Weighted average grant-date fair value
Granted (in dollars per share)	$ 17.88	$ 16.10	$ 36.14
Other disclosure
Total weighted average grant date fair value of RSUs granted during the period (in millions)	$ 13,729	$ 5,104	$ 8,063
Minimum | Restricted share units ("RSUs")
Other disclosure
Vesting period (in years)	1 year
Maximum | Restricted share units ("RSUs")
Other disclosure
Vesting period (in years)	3 years

Share-based compensation - PSU

Share-based compensation - PSU activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) Milestone $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares
Other disclosure
Service period	3 years
Number of Milestones Achieved | Milestone	2
Number of Milestones Achievement Considered Probable | Milestone	2
2014 Plan
Weighted average grant-date fair value
Granted (in dollars per share)	$ 10.57	$ 9.04	$ 20.95
Vested (in dollars per share)	$ 13.50
Performance Share Awards
Number of shares
Non-vested at beginning of period (in shares) | shares	400,690
Vested (in shares) | shares	(94,510)
Forfeited (in shares) | shares	(83,630)
Non-vested at end of period (in shares) | shares	222,550	400,690
Weighted average grant-date fair value
Non-vested at beginning of period (in dollars per share)	$ 28.82
Vested (in dollars per share)	30.65
Forfeited (in dollars per share)	28.22
Non-vested at end of period (in dollars per share)	$ 28.09	$ 28.82
Performance Share Awards | 2014 Plan
Number of shares
Granted (in shares) | shares		34,700	555,600
Weighted average grant-date fair value
Granted (in dollars per share)		$ 15.11	$ 30.19
Other disclosure
Total weighted average grant date fair value of RSUs granted during the period (in millions) | $	$ 1,474	$ 4,450	$ 5,074

Share-based compensation - Empl

Share-based compensation - Employee Share Purchase Plan (Details) - Employee share purchase plan (ESPP) - Employee Stock - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jun. 30, 2018
Share-based compensation
Number of shares issued	19,198	11,242	4,724
Ordinary shares available for issue	96,862			150,000

Expenses by nature - Operating

Expenses by nature - Operating expenses excluding expenses presented in other expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating expenses:
Employee-related expenses	$ 135,728	$ 119,903	$ 96,161
Laboratory and development expenses	63,065	65,964	36,014
Office and housing expenses	22,960	17,612	14,638
Legal and advisory expenses	21,975	15,782	24,767
Fair value loss - uniQure France SAS contingent consideration	15,895	7,081	6,683
Other operating expenses	11,236	8,510	10,528
Depreciation and amortization expenses	10,046	8,250	7,299
Patent and license expenses	7,112	9,548	3,748
Impairment related to the Reorganization	1,438
Total	$ 289,455	$ 252,650	$ 199,838

Expenses by nature - Employee-r

Expenses by nature - Employee-related expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Employee-related expenses
Wages and salaries	$ 71,852	$ 63,704	$ 53,078
Share-based compensation expenses	34,267	33,881	25,635
Contractor expenses	6,141	3,959	3,170
Social security costs	5,900	5,179	4,496
Health insurance	4,216	4,148	3,161
Costs related to pension plans	3,611	2,667	2,051
Severance costs related to the Reorganization	2,549
Other employee expenses	7,192	6,365	4,570
Total	$ 135,728	$ 119,903	$ 96,161

Other income (Details)

Other income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Other income	$ 6,059	$ 7,171	$ 12,306
Income from payments received from European authorities	5,000	5,600	5,300
Employee retention income	0	$ 0	2,600
VectorY B.V
Schedule of Equity Method Investments [Line Items]
Settlement Income	$ 300		$ 3,000
Number of shares acquired in conjunction with settlement agreement			69,899

Income taxes - Income (loss) be

Income taxes - Income (loss) before income tax (expense) benefit (Details) $ in Thousands, € in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jul. 30, 2021 USD ($)	Jul. 30, 2021 EUR (€)
Loss before income taxes
Unrecognized Tax Benefits	$ 0	$ 0
Dutch operations	(282,530)	(96,872)	$ 348,400
(Loss) / income before income tax (expense) / benefit	(306,557)	(128,259)	332,806
Current tax expense
Other	(110)	(24)	(7)
Total current tax (expense)	(110)	(24)	(7)
Deferred tax benefit / (expense)
Dutch operations		(808)	(3,047)
Other	897	3,377	608
Total deferred tax benefit / (expense)	(1,811)	1,494	(3,210)
Total income tax benefit / (expense)	(1,921)	1,470	(3,217)
Acquisition of Corlieve
Loss before income taxes
Deferred tax liability, net				$ 14,200	€ 11.9
U.S. operations
Loss before income taxes
Loss before income tax benefit / (expense)	(6,903)	(14,934)	(12,737)
Deferred tax benefit / (expense)
Deferred tax benefit / (expense)	(2,708)	(1,075)	(771)
Other
Loss before income taxes
Loss before income tax benefit / (expense)	$ (17,124)	$ (16,453)	$ (2,857)

Income taxes - Tax benefit reco

Income taxes - Tax benefit recognized in other comprehensive income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income taxes
Unrecognized gain related to defined benefit pension plan liability before tax	$ (2,553)
Unrecognized gain related to defined benefit pension plan liability tax benefit	417
Defined benefit pension loss, net of taxes	$ (2,136)
Income tax benefit or expense		$ 0	$ 0

Income taxes - Tax rate reconci

Income taxes - Tax rate reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Tax rate reconciliation
(Loss) / income before income tax benefit / (expense) for the period	$ (306,557)	$ (128,259)	$ 332,806
Expected income tax benefit / (expense) at the tax rate enacted in the Netherlands (2022: 25.8%, 2021: 25.0%, 2020: 25.0%)	79,092	33,091	(83,201)
Difference in tax rates between the Netherlands and the U.S. as well as other foreign countries	(124)	99	309
Other net change in valuation allowance	(67,004)	(20,591)	88,857
Non-deductible expenses	(13,885)	(11,129)	(9,182)
Total income tax benefit / (expense)	$ (1,921)	$ 1,470	$ (3,217)
Enacted tax rate	25.80%	25.80%	25%
Non-deductible expenses, Share-based compensation	$ 9,000	$ 8,500	$ 6,700
Fair value loss on contingent consideration	$ 4,100	$ 1,900	$ 2,000
U.S. operations
Tax rate reconciliation
Enacted tax rate	21%

Income taxes - Significant comp

Income taxes - Significant components of deferred taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 145,826	$ 84,633
Liability from Royalty Financing Agreement	6,155
Operating lease liabilities	9,790	10,612
Intangible assets	6,417	3,826
Accrued expenses and other current liabilities	1,435	1,862
Property, plant and equipment		510
Inventory	497
Defined benefit pension plan liability	406
Research and development tax credit carryforwards		144
Interest carryforwards	3,711	3,697
Total deferred tax assets	174,237	105,284
Less valuation allowance	(145,191)	(74,547)	$ (60,289)	$ (150,113)
Deferred tax assets, net of valuation allowance	29,046	30,737
Deferred tax liabilities:
Acquired IPR&D intangible Asset	(15,242)	(15,033)
Operating lease right-of-use assets	(8,159)	(9,323)
Property, plant and equipment	(719)
Other current assets and receivables	(193)	(110)
Deferred tax liability	(24,313)	(24,466)
Net deferred tax asset	$ 4,733	$ 6,271

Income taxes - Changes in valua

Income taxes - Changes in valuation allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Opening balance	$ 74,547	$ 60,289	$ 150,113
Changes recorded in the statement of operations	67,004	20,593	(88,858)
Changes recorded in equity		(972)
Increase related to 2021 Dutch tax reforms			1,897
Valuation allowance assumed in uniQure France SAS acquisition			545
Other changes including currency translation adjustments	3,640	(5,363)	(3,408)
Ending balance	145,191	74,547	60,289
Net operating loss carryforwards	127,100
Intangibles assets	5,500
Royalty financing agreement	6,200
Interest carryforwards	3,700
Amount of valuation allowance for deferred tax assets within contributed capital as it relates to follow on offering costs.	3,400	3,300
U.S. operations
Operating Loss Carryforwards, Not Subject to Expiration	700
NETHERLANDS
Ending balance	142,400
France
Opening balance	0	0
Ending balance		0	$ 0
Operating Loss Carryforwards, Not Subject to Expiration	$ 39,600	$ 23,300

Income taxes - Tax losses expir

Income taxes - Tax losses expiring (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Tax loss carry-forwards
Tax loss carry-forwards	$ 492.7	$ 264	$ 228.5
U.S. operations | 2021
Tax loss carry-forwards
Tax loss carry-forwards	$ 31.1

Income taxes - Effective Tax Ra

Income taxes - Effective Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Enacted tax rate	25.80%	25.80%	25%
Income tax benefit of past share issuance cost		$ 808	$ 3,047
U.S. operations
Effective income tax rate	27.30%
Enacted tax rate	21%
Operating Loss Carryforwards, Not Subject to Expiration	$ 700
France
Effective income tax rate	25%
Operating Loss Carryforwards, Not Subject to Expiration	$ 39,600	$ 23,300
Percentage of corporate tax rate	3.30%
Effective income tax rate continuing operations	25.80%

Basic and diluted earnings pe_3

Basic and diluted earnings per share - Ordinary share (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net (loss) / income attributable to ordinary shares	$ (308,478)	$ (126,789)	$ 329,589
Weighted-average number of ordinary shares outstanding - basic	47,670,986	46,735,045	45,986,467
Weighted-average number of ordinary shares outstanding - diluted	47,670,986	46,735,045	46,840,972
Employee share purchase plan (ESPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment arrangements			1,299
Employee Stock Option [Member] | Previous plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment arrangements			746,044
Non-vested RSUs and PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment arrangements			107,162

Basic and diluted earnings pe_4

Basic and diluted earnings per share (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Basic and diluted earnings per share
Total potential dilutive ordinary shares	7,464,589	6,458,429	3,814,508
ESPP
Basic and diluted earnings per share
Total potential dilutive ordinary shares	3,640	1,048	1,842
Employee Stock Option [Member]
Basic and diluted earnings per share
Total potential dilutive ordinary shares	4,974,030	4,237,917	2,576,281
Non-vested RSUs and PSUs
Basic and diluted earnings per share
Total potential dilutive ordinary shares	2,486,919	2,219,464	1,236,385

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	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
Rule 10b5-1 Arr Modified Flag	false
Non-Rule 10b5-1 Arr Modified Flag	false