The Company has real estate operating leases in Cambridge, Andover and Burlington, Massachusetts and Dublin and Columbus, Ohio that provide for scheduled annual rent increases throughout each lease’s term. The Company has also identified leases embedded in certain of its manufacturing and supply agreements as the Company determined that it controls the use of the facilities and related equipment therein. For more information related to manufacturing and supply agreements with Thermo Fisher Scientific, Inc. (“Thermo”) and Catalent, Inc. (“Catalent”), please refer to Note 21, Commitments.

The lease on all four dedicated clean room suites at Catalent and four of the eight dedicated clean room suites at Thermo commenced during 2020, which is when the dedicated clean room suites became available for use by the Company. Accordingly, the fixed and in-substance fixed contract consideration associated with the dedicated clean room suites was allocated to the lease and non-lease components. The lease component was determined based on the estimated standalone price of the leased clean rooms and the associated equipment based on available market and specific cost information. The non-lease component was determined using the residual estimation approach as the standalone price of the gene therapy manufacturing and supply services provided by both Catalent and Thermo is highly variable. Lease expense recognized prior to regulatory approval of the related product will be classified to research and development expense. Upon regulatory approval, lease expense will be classified to cost of inventory with the recognition in cost of sales as the sales of product occur.

The leases on the remaining four clean room suites at Thermo have not commenced as of December 31, 2020 because these clean room suites are not yet available for use by the Company. Accordingly, cumulative payments totaling $52.7 million made to Thermo as of December 31, 2020 have been recorded as other assets in the accompanying consolidated balance sheets, a portion of which will be considered in the initial measurement of the cost of the ROU asset at the lease commencement date, currently anticipated to occur in the first half of 2021.

As of December 31, 2020, ROU assets for operating leases were $91.8 million and operating lease liabilities were $101.3 million. The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases for the year ended December 31, 2020:

	For the Year Ended December 31, 2020
	(in thousands)
Lease cost
Operating lease cost	$	18,978
Variable lease cost		17,065
Total lease cost	$	36,043

Other information
Operating lease payments	$	19,344
Operating lease liabilities arising from obtaining ROU assets		59,327
Weighted average remaining lease term	4.6 years
Weighted average discount rate		7.6	%

The following table summarizes maturities of lease liabilities and the reconciliation of lease liabilities as of December 31, 2020:

	As of December 31, 2020
	(in thousands)
2021	$	27,846
2022		25,513
2023		25,615
2024		25,430
2025		10,910
Thereafter		4,131
Total minimum lease payments		119,445
Less: imputed interest		(18,148	)
Total operating lease liabilities	$	101,297
Included in the consolidated balance sheet:
Current portion of lease liabilities within other current liabilities	$	20,930
Lease liabilities		80,367
Total operating lease liabilities	$	101,297