8.         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 / U.S.

In February 2022, the Company entered into a lease for an office facility in Lexington, Massachusetts, U.S. of 12,716 square feet. The lease commenced in December 2022 and is set for a non-cancellable period ending March 2030. The lease is renewable for one five-year term.

In December 2021, the Company entered into a lease for a research and development facility in Lexington, Massachusetts, U.S. of 13,501 square feet. The lease commenced in May 2022 and is set for a non-cancellable period ending March 2029. Commencing August 2024, the Company subleased this facility for the residual term.

The fixed lease payments to be received during the remaining term under the agreement to sublease amount to $2.5 million as of December 31, 2025.

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 February 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. In May 2021, the Company leased an additional approximately 1,080 square meters of office space. The lease expires in October 2028.

As of December 31, 2025 the Company is sub-leasing two of the seven floors of its Amsterdam facility for a ten-year term ending on December 31, 2027.

The fixed lease payments to be received during the remaining term under the agreement to sub-lease amount to EUR 1.9 million ($2.2 million) as of December 31, 2025.

Operating lease liabilities

The components of lease cost for the years ended December 31, 2025, 2024 and 2023, respectively, were as follows:

  ​ ​ ​

Years ended December 31, 

  ​ ​ ​

2025

  ​ ​ ​

2024

  ​ ​ ​

2023

(in thousands)

Operating lease cost

$

7,152

$

6,486

$

7,018

Variable lease cost

871

1,137

1,238

Sublease income

(1,540)

(1,162)

(957)

Total lease cost

$

6,483

$

6,461

$

7,299

The table below presents the lease-related assets and liabilities recorded in the Consolidated Balance Sheets, as of December 31, 2025 and 2024, respectively:

December 31, 

December 31,

  ​ ​ ​

2025

  ​ ​ ​

2024

(in thousands)

Assets

Operating lease right-of-use assets

$

12,525

$

13,647

Liabilities

Current

Current operating lease liabilities

3,862

3,601

Non-current

Non-current operating lease liabilities

9,832

11,136

Total lease liabilities

$

13,694

$

14,737

Other information

The weighted-average remaining lease term as of December 31, 2025, is 5.1 years, compared to 5.9 years as of December 31, 2024, and the weighted-average discount rate as of December 31, 2025 is 11.5%, compared to 11.3% as of December 31, 2024. 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 for the years ended December 31, 2025, 2024 and 2023, respectively:

  ​ ​ ​

Year ended December 31, 

  ​ ​ ​

2025

  ​ ​ ​

2024

  ​ ​ ​

2023

(in thousands)

Cash paid for amounts included in the measurement of lease liabilities

Operating cash flows for operating leases

$

8,269

$

6,113

$

7,921

Undiscounted cash flows

The table below reconciles the undiscounted cash flows as of December 31, 2025, for each of the five following years and the total of the remaining years, to the operating lease liabilities recorded in the Consolidated Balance Sheet as of December 31, 2025.

  ​ ​ ​

Amsterdam(1)

  ​ ​ ​

Lexington

  ​ ​ ​

Other(2)

  ​ ​ ​

Total

(in thousands)

2026

$

2,188

1,431

247

3,866

2027

2,192

1,469

3,661

2028

2,112

1,508

3,620

2029

1,982

763

2,745

2030

1,982

130

2,112

Thereafter

1,817

1,817

Total lease payments

$

12,273

$

5,301

$

247

$

17,821

Less: amount of lease payments representing interest payments

(3,268)

(859)

(4,127)

Present value of lease payments

9,005

4,442

247

13,694

Less: current operating lease liabilities

(2,188)

(1,427)

(247)

(3,862)

Non-current operating lease liabilities

$

6,817

$

3,015

$

$

9,832

(1)Payments are due in EUR and have been translated at the foreign exchange rate as of December 31, 2025, of $1.18 / €1.00
(2)Payments are due in CHF and have been translated at the foreign exchange rate as of December 31, 2025, of $1.26 / CHF1.00

Historical Timeline

Fiscal YearFiled
2025Mar 2, 2026Showing above
2024Feb 27, 2025
2023Feb 28, 2024
2022Feb 27, 2023
2021Feb 25, 2022
2020Mar 1, 2021
2019Mar 2, 2020
2018Feb 28, 2019
2017Mar 14, 2018
2016Mar 15, 2017

About Leases Disclosures

Lease disclosures under ASC 842 provide a comprehensive view of a company's leased asset portfolio, including the split between operating and finance leases, discount rates used to present-value future payments, and the maturity schedule of lease obligations. This section reveals a significant source of off-balance-sheet commitments that were largely hidden before the current standard.

Key signals: the weighted-average discount rate affects the size of recorded lease liabilities — a higher rate reduces the reported obligation, so compare the chosen rate against the company's incremental borrowing rate. The operating versus finance lease mix affects both EBITDA and operating income presentation. Watch the maturity table for concentration risk: large payment cliffs in specific years may create cash flow pressure. Variable lease payments excluded from the liability measurement represent real obligations that do not appear on the balance sheet. Compare total lease costs against prior-year operating lease expense to assess the true economic burden.