The Company’s product revenues have been primarily from sales of YUTIQ and DEXYCU in the U.S., which it began shipping to its 3PL in February 2019 and March 2019, respectively.

Net product revenues by product for the year ended December 31, 2019 were as follows (in thousands):

	Year Ended
	December 31, 2019
YUTIQ	$	12,046
DEXYCU		4,778
Total product sales, net	$	16,824

The following table summarizes activity in each of the product revenue allowance and reserve categories for the year ended December 31, 2019 (in thousands):

	Chargebacks, Discounts and Fees			Government and Other Rebates			Returns			Total
Beginning balance at January 1, 2019	$	—		$	—		$	—		$	—
Provision related to sales in the current year		2,301			429			732			3,462
Adjustments related to prior period sales		—			—			—			—
Deductions applied and payments made		(683	)		(158	)		(380	)		(1,221	)
Ending balance at December 31, 2019	$	1,618		$	271		$	352		$	2,241

Returns are recorded as a reduction of accounts receivable on the condensed consolidated balance sheets. Chargebacks, discounts and fees and rebates are recorded as a component of accrued expenses on the condensed consolidated balance sheets (See Note 8).

Under a collaboration agreement with Alimera, as amended in March 2008 (the “Prior Alimera Agreement”), the Company licensed to Alimera the rights to develop, market and sell certain product candidates, including ILUVIEN for DME, and Alimera assumed all financial responsibility for the development of the licensed products. The Company was entitled to receive a share of any net profits (as defined) on sales of each licensed product (including ILUVIEN) by Alimera, measured on a quarter-by-quarter and country-by-country basis, and Alimera was entitled to recover a share of previously incurred and unapplied net losses (as defined) for commercialization of each product in a country. The Company was also entitled to reimbursement of certain patent maintenance costs with respect to the patents licensed to Alimera.

On July 10, 2017, the Company entered into a further amended and restated collaboration agreement (the “Amended Alimera Agreement”), pursuant to which the Company (i) licensed its then Durasert three-year uveitis product candidate (currently marketed by the Company as YUTIQ in the U.S.) to Alimera for regulatory approval and distribution under its ILUVIEN trade name in EMEA and (ii) converted the net profit share arrangement for each licensed product (including ILUVIEN) under the Prior Alimera Agreement to a sales-based royalty on a calendar quarter basis commencing July 1, 2017, with payments from Alimera due 60 days following the end of each quarter.

Following the completion of the Amended Alimera Agreement, Alimera filed a Type II variation in December 2017 for ILUVIEN for the treatment of non-infectious uveitis affecting the posterior segment of the eye in all seventeen European countries in which it previously received regulatory approval for ILUVIEN for DME. In March 2019, Alimera received regulatory approval for the uveitis indication. After the label for this new indication is finalized consistent with each such country’s local requirements, Alimera has indicated that it plans to commercialize the product for this indication under its ILUVIEN trademark.

Under the Amended Alimera Agreement, sales-based royalties started at the rate of 2%. Commencing December 12, 2018, the royalty rate increased to 6% on aggregate calendar year net sales up to $75.0 million and to 8% on any calendar year net sales in excess of $75.0 million. Alimera’s share of contingently recoverable accumulated ILUVIEN commercialization losses under the Prior Alimera Agreement, capped at $25.0 million, are being reduced as follows: (i) $10.0 million was cancelled in lieu of an upfront license fee on the effective date of the Amended Alimera Agreement; (ii) for the period from December 12, 2018 through calendar year 2020, 50% of earned sales-based royalties in excess of 2% will be offset against quarterly royalty payments otherwise due from Alimera; (iii) in March 2019, another $5.0 million was cancelled upon Alimera’s receipt of regulatory approval for ILUVIEN for the uveitis indication; and (iv) commencing in calendar year 2021, 20% of earned sales-based royalties in excess of 2% will be offset against quarterly royalty payments otherwise due from Alimera until such time as the balance of the original $25 million of recoverable commercialization losses has been fully recouped. At December 31, 2019, the remaining recoverable balance of these commercialization losses was approximately $8.9 million.

Revenue recognized under the Amended Alimera Agreement totaled $2.1 million in the year ended December 31, 2019, $627,000 in the six months ended December 31, 2018 and $723,000 in fiscal 2018. In addition to patent fee reimbursements in those periods, the Company recorded sales-based royalty income totaled $2.0 million in the year ended December 31, 2019, $588,000 in the six months ended December 31, 2018 and $575,000 in fiscal 2018.

Pursuant to a licensing and development agreement, as amended, Bausch & Lomb has a worldwide exclusive license to make and sell Retisert in return for royalties based on sales. Royalty income was $204,000 in the year ended December 31, 2019, $456,000 in the six months ended December 31, 2018, approximately $1.0 million in fiscal 2018 and $970,000 in fiscal 2017. The patent with which Retisert is marketed expired in March 2019. As such, pursuant to our agreement with Bausch & Lomb, payment of sales-based royalties concluded at the end of March 2019. Accounts receivable from Bausch & Lomb was $0 at December 31, 2019 and $253,000 at December 31, 2018.

The Company entered into an exclusive, worldwide royalty-bearing license agreement in December 2012, amended and restated in March 2013, with OncoSil Medical UK Limited (f/k/a Enigma Therapeutics Limited), a wholly-owned subsidiary of OncoSil Medical Ltd (“OncoSil”) for the development of BrachySil, the Company’s previous product candidate for the treatment of pancreatic and other types of cancer. The Company received an upfront fee of $100,000 and is entitled to 8% sales-based royalties, 20% of sublicense consideration and milestone payments based on aggregate product sales. OncoSil is obligated to pay an annual license maintenance fee of $100,000 by the end of each calendar year, the most recent of which was received in December 2019. For each calendar year commencing with 2014, the Company is entitled to receive reimbursement of any patent maintenance costs, sales-based royalties and sub-licensee sales-based royalties earned, but only to the extent such amounts, in the aggregate, exceed the $100,000 annual license maintenance fee. As of December 31, 2019, OncoSil has not received regulatory approval in any jurisdiction. In March 2019 the Clinical Oversight Committee of the British Standards Institute (“BSI”) advised OncoSil that insufficient clinical benefit had been demonstrated to recommend approval of its longstanding CE Mark application. In October 2019, Oncosil announced that it had completed its follow up meeting with BSI and is focused on submitting an updated Clinical Evaluation Report for CE Mark approval. The Company has no consequential performance obligations under the OncoSil license agreement. As of December 31, 2019, no deferred revenue was recorded for this agreement.

In November 2018, the Company entered into an exclusive license agreement with Ocumension Therapeutics (“Ocumension”) for the development and commercialization of its three-year micro insert using the Durasert technology for the treatment of chronic non-infectious uveitis affecting the posterior segment of the eye (YUTIQ in the U.S.) in Mainland China, Hong Kong, Macau and Taiwan. The Company received a one-time upfront payment of $1.75 million from Ocumension and is eligible to receive up to (i) $7.25 million upon the achievement by Ocumension of certain prescribed development and regulatory milestones, and (ii) $3.0 million commercial sales-based milestones. In addition, the Company is entitled to receive mid-single digit sales-based royalties. Ocumension has also received a special approval by the Hainan Province People's Government to market this product for chronic, non-infectious posterior segment uveitis in the Hainan Bo Ao Lecheng International Medical Tourism Pilot Zone (“Hainan Pilot Zone”). In March 2019, the Company entered into a Memorandum of Understanding (“MOU”), pursuant to which, the Company will supply product for the clinical trials and Hainan Pilot Zone use. Paralleling to Ocumension’s normal registration process of the product with the Chinese Regulatory Authorities, the MOU modified the Company’s entitlement to the development and regulatory milestones of up to $7.25 million under the license agreement to product supply milestones or development milestones, whichever comes first, totaling up to $7.25 million. In August 2019, the Company began shipping this product to Ocumension.

The Company was required to provide a fixed number of hours of technical assistance support to Ocumension at no cost, which was completed already and no future performance obligation exists. Ocumension is responsible for all development, regulatory and commercial costs, including any additional technical assistance requested. Ocumension has a first right of negotiation for an additional exclusive license to the Company’s shorter-duration line extension candidate for this indication.

In August 2019, the Company received a $1.0 million development milestone payment from Ocumension triggered by the approval of its Investigational New Drug (“IND”) in China for this program. The IND allows the importation of finished product into China for use in a clinical trial to support regulatory filing.

In January 2020, the Company entered into an exclusive license agreement with Ocumension for the development and commercialization in Mainland China, Hong Kong, Macau and Taiwan of DEXYCU for the treatment of post-operative inflammation following ocular surgery. Pursuant to the terms of the license agreement, the Company received upfront payments of $2.0 million from Ocumension in February 2020 and will be eligible to receive up to (i) 6.0 million upon the achievement by Ocumension of certain prescribed development and regulatory milestones, and (ii) 6.0 million commercial sales-based milestones. In addition, the Company is entitled to receive mid-single digit sales-based royalties. In exchange, Ocumension will receive exclusive rights to develop and commercialize DEXYCU in Mainland China, Hong Kong, Macau and Taiwan, at its own cost and expense with the Company supplying product for clinical trials and commercial sale. In addition, Ocumension will receive a fixed number of hours of technical assistance support from the Company at no cost.

In the year ended December 31, 2019, revenue recognized under the license agreement and MOU with Ocumension totaled $1.1 million. In addition to $91,000 of revenue from product sales, $1.0 million was recognized as license and collaboration agreement revenue. In the six months ended December 31, 2018, $1.7 million was recognized as license and collaboration agreement revenue. As of December 31, 2019 and 2018, $0 and $30,000 of deferred revenue was recorded for this agreement, respectively.

In February 2020, the Company entered into an Exclusive License Agreement with Equinox Science, LLC (“Equinox”), pursuant to which Equinox granted us an exclusive, sublicensable, royalty-bearing right and license to certain patents and other Equinox intellectual property to research, develop, make, have made, use, sell, offer for sale and import the compound vorolanib and any pharmaceutical products comprising the compound for the prevention or treatment of age-related macular degeneration, diabetic retinopathy and retinal vein occlusion using our proprietary localized delivery technologies, in each case, throughout the world except China, Hong Kong, Taiwan and Macau.

In consideration for the rights granted by Equinox, the Company (i) made a one time, non-refundable, non-creditable upfront cash payment of $1.0 million to Equinox in February 2020, and (ii) agreed to pay milestone payments totaling up to $50 million upon the achievement of certain development and regulatory milestones, consisting of (a) completion of a Phase II clinical trial for the Compound or a Licensed Product, (b) the filing of a new drug application or foreign equivalent for the Compound or a Licensed Product in the United States, European Union or United Kingdom and (c) regulatory approval of the Compound or a Licensed Product in the United States, European Union or United Kingdom.

The Company also agreed to pay Equinox tiered royalties based upon annual net sales of Licensed Products in the Territory. The royalties are payable with respect to a Licensed Product in a particular country in the Territory on a country-by-country and Licensed Product-by-Licensed Product basis until the later of (i) twelve years after the first commercial sale of such Licensed Product in such country and (ii) the first day of the month following the month in which a generic product corresponding to such Licensed Product is launched in such country (collectively, the “Royalty Term”). The royalty rates range from the high-single digits to low-double digits depending on the level of annual net sales. The royalty rates are subject to reduction during certain periods when there is no valid patent claim that covers a Licensed Product in a particular country.

The Company from time to time enters into funded agreements to evaluate the potential use of its technology systems for sustained release of third-party drug candidates in the treatment of various diseases. Consideration received is generally recognized as revenue over the term of the feasibility study agreement. Revenue recognition for consideration, if any, related to a license option right is assessed based on the terms of any such future license agreement or is otherwise recognized at the completion of the feasibility study agreement. Revenues under feasibility study agreements totaled $135,000 for the year ended December 31, 2019, $15,000 in the six months ended December 31, 2018, $1.1 million in fiscal 2018 and $211,000 in fiscal 2017, respectively. At December 31, 2019, $15,000 deferred revenue was recorded for the feasibility study agreements.