We have operating leases for office space, laboratory operations, research and development facilities, manufacturing locations, warehouses and certain equipment. We determine if a contract contains a lease at inception or modification of a contract. Our leases generally do not provide an implicit interest rate, and we therefore use our incremental borrowing rate as the discount rate when measuring operating lease liabilities. The incremental borrowing rate represents an estimate of the interest rate we would incur at lease commencement to borrow an amount equal to the lease payments on a collateralized basis over the term of the lease within a particular currency environment. We used the incremental borrowing rates as of January 1, 2019, for operating leases that commenced prior to that date. Many of our leases contain rental escalation, renewal options and/or termination options that are factored into our determination of lease payments as appropriate. Variable lease payment amounts that cannot be determined at the commencement of the lease are not included in the right-to-use assets or liabilities.

We elected the use of permitted practical expedients of not recording leases on our Condensed Consolidated Balance Sheet when the leases have terms of 12 months or less, and we elected not to separate nonlease components from lease components and instead account for each separate lease component and the nonlease components associated with that lease component as a single lease component.

On January 2, 2023, ModeX entered into a 10-year office lease agreement that commenced in October 2023. ModeX was previously located in Natick, Massachusetts and relocated to Weston, Massachusetts, upon lease commencement. The new location is approximately 33,056 square feet of office space. ModeX has two options to extend the lease term for an additional five years per extension, which could commence upon the expiration of the term in October 2033. Straight-line monthly expense for the lease is $243.5 thousand.

The following table presents the lease balances within the Condensed Consolidated Balance Sheet as of June 30, 2025 and December 31, 2024:


(in thousands)	Classification on the Balance Sheet	June 30, 2025			December 31, 2024
Assets
Operating lease assets	Operating lease right-of-use assets	$	46,627		$	54,003
Finance lease assets	Property, plant and equipment, net		5,255			5,743

Liabilities
Current
Operating lease liabilities	Current maturities of operating leases		9,919			12,649
Accrued expenses	Current maturities of finance leases		1,566			1,679
Long-term
Operating lease liabilities	Operating lease liabilities		37,291			48,849
Other long-term liabilities	Finance lease liabilities	$	3,689		$	4,064

Weighted average remaining lease term
Operating leases (in years)			6.6			6.4
Finance leases (in years)			7.6			7.1
Weighted average discount rate
Operating leases			6.8	%		6.6	%
Finance leases			5.0	%		5.3	%

The following table reconciles the undiscounted future minimum lease payments (displayed by year and in the aggregate) under noncancelable operating leases with terms of more than one year to the total operating lease liabilities recognized on our Condensed Consolidated Balance Sheet as of June 30, 2025:


(in thousands)	Operating		Finance
July 1, 2025 through December 31, 2025	$	5,388	$	920
2026		9,716		1,401
2027		8,541		894
2028		8,008		264
2029		7,283		257
Thereafter		19,071		2,029
Total undiscounted future minimum lease payments		58,007		5,765
Less: Difference between lease payments and discounted lease liabilities		10,797		510
Total lease liabilities	$	47,210	$	5,255

Expense under operating leases and finance leases was $13.0 million and $0.6 million, respectively, for the six months ended June 30, 2025, which included $0.7 million of variable lease costs. Expense under operating leases and finance leases was $9.2 million and $1.3 million, respectively, for the six months ended June 30, 2024, which included $1.0 million of variable lease costs. Operating lease costs and finance lease costs are included within Operating loss in the Condensed Consolidated Statement of Operations. Short-term lease costs were not material.


	For the six months ended June 30,
(in thousands)	2025		2024
Operating cash out flows from operating leases	$	7,711	$	9,113
Operating cash out flows from finance leases		111		238
Financing cash out flows from finance leases		566		1,268
Total	$	8,388	$	10,619