On June 15, 2021, the Company entered into the first lease amendment (“First Lease Amendment”) and second lease amendment (“Second Lease Amendment” and, together with the First Lease Amendment, the “Lease Amendments”) with PPF Off 100 Cambridge Park Drive, LLC (the “Landlord”). The Lease Amendments amended the Company’s lease agreement for its corporate office and laboratory facilities with the Landlord in Cambridge, Massachusetts to add additional leased space in the same building (the “Amended Cambridgepark Lease”).

The First Lease Amendment expands the amount of space leased by the Company by an additional 10,262 square feet in exchange for aggregate total fixed rent payments of approximately $8.6 million with the annual fixed rental payments escalating from $0.9 million to $1.1 million during the term. The First Lease Amendment is estimated to commence during the fourth quarter of 2021.

The Second Lease Amendment expands the amount of space leased by the Company by an additional 30,175 square feet in exchange for aggregate total fixed rent payments of approximately $22.7 million with the annual fixed rental payments escalating from $1.2 million to $3.0 million during the term. The Second Lease Amendment’s term is estimated to commence during the first quarter of 2022.

Payments due associated with the Lease Amendments include fixed and variable payments. Variable payments relate to the Company’s share of the Landlord’s operating costs associated with the underlying assets and are recognized when the event on which those payments are assessed. The Amended Cambridgepark Lease does not contain a residual value guarantee. The Lease Amendments term end dates are coterminous with the existing lease agreement. In conjunction with the Lease Amendments, the Company was required to increase its irrevocable standby letter of credit to $2.4 million for the benefit of the Landlord, of which $1.6 million has been secured by money market investments and is presented as restricted cash equivalents.

For further information on terms and conditions of the Company’s Cambridgepark lease, please see Note 10 to the condensed consolidated financial statements included in the 2020 Annual Report.

	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands except weighted-average amounts)	2021		2020		2021		2020
Operating lease cost	$	757	$	285	$	1,504	$	285
Short-term lease cost		—		88		52		241
Variable lease cost		312		41		434		89
Total lease cost	$	1,069	$	414	$	1,990	$	615

The following table represents the weighted-average remaining lease term and discount rate information:

(in thousands)	June 30, 2021			December 31, 2020
Other Information
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$	1,141		$	703
Right-of-use assets obtained in exchange for lease obligations		35			17,899
Weighted-average remaining lease term (years)		9.1			9.6
Weighted-average discount rate		9.4	%		9.4	%

Right-of-use lease assets and lease liabilities are reported in the Company’s condensed consolidated balance sheets as follows:

(in thousands)	June 30, 2021		December 31, 2020
Assets
Operating right-of-use assets	$	16,356	$	17,117
Liabilities
Operating lease liabilities, current	$	1,164	$	863
Operating lease liabilities, non-current	$	16,731	$	17,430
Total lease liabilities	$	17,895	$	18,293