5. Acquisition of Kairos Description of the Transaction On March 18, 2016, the Company completed the acquisition of all remaining issued and outstanding shares of Kairos Therapeutics Inc. (Kairos), for $24,778 (C$32,257). This consideration was comprised of $23,043 (C$30,000) in common shares of the Company, and $1,733 (C$2,257) in cash, pursuant to a net working capital adjustment determined at closing. Prior to this acquisition the Company had a 19.99% equity interest in Kairos. The Company recognized IPR&amp;D and Goodwill as part of the purchase price allocation. Impairment Evaluation for Intangible Assets and Goodwill All IPR&amp;D acquired in the Kairos business combination is classified as indefinite-lived and is not currently being amortized. IPR&amp;D becomes definite-lived upon the completion of the associated research and development efforts, and will be amortized from that time over an estimated useful life based on respective patent terms. The Company evaluates the recoverable amount of intangible assets on an annual basis and performs an annual evaluation of goodwill as of December 31 each year, unless there is an event or change in the business that could indicate impairment, in which case earlier testing is performed. For the year ended December 31, 2016, the Company recorded an impairment charge of $768 for the discontinuance of the Co-Development program with Oxford BioTherapeutics (OBT Co-Development). Furthermore, for the three months ended March 31, 2017, the Company recorded an impairment charge of $1,536 related to the fair value of IPR&amp;D recognized in relation to the Research Collaboration Agreement with OBT (OBT Technology Swap Agreement) as the Company chose not to advance the associated research and development projects within the research term which expired on February 11, 2017. The Company performed its annual impairment test for IPR&amp;D as of December 31, 2018 and concluded that there were no impairment indicators related to IPR&amp;D for the twelve months ended December 31, 2018. The following table summarizes the carrying value of IPR&amp;D, net of impairment: Acquired IPR&amp;D Accumulated Impairment Net Balance at December 31, 2016 $ 20,700 $ (768 ) $ 19,932 Change during the year  (1,536 ) (1,536 ) Balance at December 31, 2017 $ 20,700 $ (2,304 ) $ 18,396 Change during the period    Balance at December 31, 2018 $ 20,700 $ (2,304 ) $ 18,396 The Company also performed its annual impairment test for goodwill as of December 31, 2018. As part of the evaluation of the recoverability of goodwill, the Company identified only one reporting unit to which the total carrying amount of goodwill has been assigned. As at December 31, 2018, the Company performed a qualitative assessment for impairment of goodwill, considering factors including industry and market conditions, macro-economic conditions, and the excess of market capitalization over the carrying value of the net assets at December 31, 2018, and concluded that it was not more likely than not that the fair value of the reporting unit was less than its carrying value. Consequently, the step 1 quantitative test was not required.