3. Acquisition of Icon Bioscience, Inc. On March 28, 2018, the Company and its newly-created wholly-owned subsidiary, Oculus Merger Sub, Inc., acquired Icon, a specialty biopharmaceutical company, through a reverse triangular merger (the Icon Acquisition) pursuant to an Agreement and Plan of Merger (the Merger Agreement) between the Company, Icon, and Shareholder Representative Services LLC (SRS), solely in its capacity as representative of Icons securityholders. The Icon Acquisition was accounted for as an asset acquisition because substantially all of the fair value of the gross assets acquired were deemed to be concentrated in a group of similar identifiable assets related to Icons lead product, DEXYCU. A portion of the Icon Acquisition was funded by a debt financing and an equity financing, both of which closed concurrently with the Icon Acquisition (see Notes 9 and 10). Pursuant to the Merger Agreement, the Company made a closing payment of $15.0 million to SRS, net of an estimated $127,000 working capital adjustment, and is obligated to pay certain post-closing contingent cash payments upon the achievement of specified milestones and based upon certain net sales and partnering revenue standards, in each case subject to the terms and conditions set forth in the Merger Agreement. These include but are not limited to (i) a one-time development milestone of $15.0 million payable in cash upon the first commercial sale of DEXYCU in the U.S., (ii) sales milestone payments totaling up to $95.0 million upon the achievement of certain sales thresholds and subject to certain Centers for Medicare &amp; Medicaid Services (CMS) reimbursement conditions set forth in the Merger Agreement, (iii) quarterly earn-out payments equal to 12% on net sales of DEXYCU in a given year, which earn-out payments will increase to 16% of net sales of DEXYCU in such year beginning in the calendar quarter for such year to the extent aggregate annual DEXYCU consideration exceeds $200.0 million in such year, (iv) quarterly earn-out payments equal to 20% of partnering revenue received by the Company for DEXYCU outside of the U.S., and (v) single-digit percentage quarterly earn-out payments with respect to net sales and/or partnering income, if any, resulting from future clinical development, regulatory approval and commercialization of any other product candidates the Company acquired in the Icon Acquisition. Following the first commercial sale of DEXYCU, the Company paid the $15.0 million one-time development milestone to SRS in April 2019. The purchase price on the date of the Icon Acquisition was $32.0 million, and was comprised of the closing consideration of $15.0 million, including the assumption of an estimated $127,000 of net current liabilities of Icon, the contingent development milestone payment of $15.0 million and transaction costs of approximately $2.0 million. Given the stage of development of DEXYCU, the Company determined these payments did not represent research and development costs. The contingent consideration in the form of sales milestones will be capitalized as additional intangible assets when any such consideration becomes probable and can be reasonably estimated. Sales-based royalty payments will be expensed as incurred. The purchase price was allocated to a single finite-lived intangible asset with an expected amortization life of approximately 13 years. The intangible asset is being amortized on a straight-line basis over that period. The acquisition did not have a net tax impact due to a full valuation allowance against the acquired net deferred tax assets. For the three and six months ended June 30, 2019, the Company accrued sales-based royalty expense of $0 and $99,000 respectively, as a component of cost of sales.