The Company in-licenses intellectual property from third parties for technology and know-how used in its product candidates and development programs, some of which is further sublicensed to NAV Technology Licensees and collaboration partners. In-licenses may require the Company to make future payments relating to sublicense fees, milestone fees and royalties on future sales of licensed products. Additionally, the Company may be responsible for the cost of the maintenance of the intellectual property as incurred by its licensors. Up-front fees to obtain licensed technology are recorded as research and development expenses if the technology has no alternative future use. Sublicense fees are based on a specified percentage of license fees earned by the Company as a result of sublicensing the technology to third parties and are recorded as cost of revenues. Milestone fees are recorded as cost of revenues if the underlying milestone is achieved by a licensee, or as research and development expense if the underlying milestone is achieved by the Company as a result of the development of its product candidates and the technology has no alternative future use. Royalties due to licensors on sales of licensed products, including sales by NAV Technology Licensees, are recorded as cost of revenues. Patent maintenance costs are recorded as general and administrative expenses.

Please refer to Note 10 for information on licenses granted by the Company and collaboration agreements with third parties.

In February 2009, the Company entered into a license agreement, which has been amended from time to time, with The Trustees of the University of Pennsylvania (together with the University of Pennsylvania, Penn) for exclusive, worldwide rights to certain patents owned by Penn underlying the Company’s NAV Technology Platform, as well as exclusive rights to certain data, results and other information. Pursuant to the license agreement, the Company is obligated to pay Penn royalties on net sales of licensed products and sublicense fees. Additionally, the Company is obligated to reimburse Penn for certain costs incurred related to the maintenance of the licensed patents.

In April 2019, the Company amended its license from Penn to include exclusive license rights to certain patent rights and know-how, including research data and other information, relating to the treatment of late-infantile neuronal ceroid lipofuscinosis type 2 (CLN2) disease. In consideration for the additional licensed rights, and in addition to any consideration owed under the license prior to the amendment, the Company paid Penn an up-front fee and is obligated to pay milestone fees of up to $20.5 million upon the achievement of various development and sales-based milestones and additional royalties on net sales of licensed products for the treatment of CLN2 disease, none of which have been achieved or deemed probable of achievement as of December 31, 2021. Additionally, the amendment modified the percentage of sublicense fees the Company is obligated to pay Penn on amounts received by the Company from third parties for the sublicensing of the licensed rights for the treatment of CLN2 disease.

Expenses incurred by the Company related to the license from Penn were recorded as follows (in thousands):

	Years Ended December 31,
	2021		2020		2019
Cost of revenues	$	8,046	$	39	$	—
Research and development		—		—		200
General and administrative		706		821		905
	$	8,752	$	860	$	1,105

As of December 31, 2021 and 2020, the Company had recorded $8.2 million and $0.1 million, respectively, in expenses payable to Penn under the license agreement, which are included in accounts payable, accrued expenses and other current liabilities and other liabilities on the consolidated balance sheets.

In March 2009, the Company entered into a license agreement, which was amended in April 2009, with GlaxoSmithKline LLC (GSK) for exclusive, worldwide rights to certain patents underlying the Company’s NAV Technology Platform which are owned by Penn and exclusively licensed to GSK. Pursuant to the license agreement, the Company is obligated to pay GSK royalties on net sales of licensed products and sublicense fees. Additionally, the Company is obligated to reimburse GSK for certain costs incurred related to the maintenance of the licensed patents. The Company was also obligated to pay $1.5 million to GSK upon the achievement of various milestones, all of which have been achieved and paid as of December 31, 2021.

Expenses incurred by the Company related to the license from GSK were recorded as follows (in thousands):

	Years Ended December 31,
	2021		2020		2019
Cost of revenues:
Royalties on net sales of Zolgensma	$	43,161	$	26,278	$	5,822
Other cost of revenues		626		9,398		2,419
Total cost of revenues		43,787		35,676		8,241
General and administrative		889		1,046		928
	$	44,676	$	36,722	$	9,169

As of December 31, 2021 and 2020, the Company had recorded $16.3 million and $13.1 million, respectively, in expenses payable to GSK under the license agreement, which are included in accounts payable, accrued expenses and other current liabilities and other liabilities on the consolidated balance sheets.

In August 2019, the Company entered into an option and license agreement with Clearside Biomedical, Inc. (Clearside) pursuant to which the Company was granted an option to exclusively license the worldwide rights to certain patents related to Clearside’s proprietary, in-office SCS Microinjector™ for the delivery of RGX-314 to the suprachoroidal space to treat wet age-related macular degeneration (wet AMD), diabetic retinopathy (DR) and other diseases. The Company exercised its license option in October 2019, resulting in a payment of $1.6 million to Clearside which was recognized as research and development expense upon exercise. Additionally, the Company is obligated to pay milestone fees of up to $136.0 million upon the achievement of various development and sales-based milestones, as well as royalties on net sales of licensed products using the SCS Microinjector. Clearside is responsible for supplying the SCS Microinjector to the Company to support all preclinical, clinical and commercial needs. From the inception of the agreement through December 31, 2021, the Company had incurred $3.0 million for development milestones achieved, or deemed probable of achievement, under the agreement.

In November 2014, the Company entered into a license agreement, which has been amended from time to time, with Regents of the University of Minnesota (Minnesota), for an exclusive license under Minnesota’s interest in certain patent rights which are co-owned by Minnesota and the Company to commercialize products covered by the licensed patent rights in any country or territory in which a licensed patent has been issued and is unexpired, or a licensed patent application is pending. Pursuant to the license agreement, the Company is obligated to pay Minnesota annual maintenance fees, royalties on net sales, sublicense fees and fees upon the achievement of various milestones. Additionally, the Company is obligated to pay for certain costs incurred related to the maintenance of the licensed patents.

In August 2018, the Company entered into a license agreement with Emory University (Emory) for an exclusive license under Emory’s interest in certain patent rights which are co-owned by Emory and the Company to commercialize products covered by the licensed patent rights in any country or territory. Pursuant to the license agreement, the Company is obligated to reimburse Emory for patent prosecution and maintenance expenses and pay Emory annual maintenance fees under certain circumstances, royalties on net sales, sublicense fees and fees upon the achievement of various milestones for the first licensed product.

In the normal course of business, the Company enters into agreements with contract research organizations, contract manufacturing organizations and other third parties for services to be provided to the Company. Generally, these agreements provide for termination upon notice, with specified amounts due upon termination based on the timing of termination and the terms of the agreement. The actual amounts and timing of payments under these agreements are uncertain and contingent upon the initiation and completion of services to be provided to the Company.

In the normal course of business, the Company enters into agreements that contain a variety of representations and provide for general indemnification. The Company’s potential exposure under these agreements is unknown because it involves claims that may be made against the Company in the future. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. As of December 31, 2021 and 2020, the Company did not have any material indemnification claims that were probable or reasonably possible and consequently had not recorded any related liabilities.