Business Combination As set forth below, we completed two acquisitions from January 1, 2019 through June 30, 2020, and both were accounted for as business combinations. We applied the acquisition method of accounting. Accordingly, we record the tangible and intangible assets acquired and liabilities assumed at their estimated fair values as of the applicable date of acquisition. For each acquisition, we did not incur any material acquisition related costs. Icagen Acquisition On April 1, 2020, we acquired the core assets, including its partnered programs and ion channel technology from Icagen and certain of its affiliates. The purchase price of $19.9 million included $15.1 million cash consideration paid upon acquisition, and a contingent earn-out payment of up to $25.0 million of cash payments based on certain revenue milestones with an estimated fair value of $4.8 million. The fair value of the earn-out liability was determined using a probability weighted income approach incorporating the estimated future cash flows from expected future milestones. These cash flows were then discounted to present value using a discount rate based on the market participants' cost of debt reflective of Icagen. Refer to Note 2, Fair Value Measurement , for further discussion. The liability will be periodically assessed based on events and circumstances related to the underlying milestones, and any change in fair value will be recorded in our consolidated statements of operations. The carrying amount of the liability may fluctuate significantly and actual amount paid may be materially different than the carrying amount of the liability. There was no change in the fair value of the continent liabilities during the second quarter of 2020. As the acquisition is not considered significant, pro forma information has not been provided. The results of Icagen have been included in our results of operations since the date of acquisition. The preliminary allocation of the purchase price consisted of (1) $1.8 million of fair value of tangible assets acquired, (2) $(0.8) million of liabilities assumed, (3) $12.8 million of acquired intangibles, (4) $(3.7) million of deferred revenue in connection with assumed performance obligations under a collaboration agreement, (5) $0.8 million of deferred tax asset associated with the deferred revenue, and (6) $9.0 million of goodwill, the majority of which is deductible for tax purposes. Acquired intangibles include $11.1 million of customer relationships and $1.7 million of core technology. The fair values of the customer relationships were based on a discounted cash flow analysis incorporating the estimated future cash flows from these relationships during the contractual term. These cash flows were then discounted to present value using a discount rate of 17%. The fair value of the customer relationships is being amortized on a straight-line basis over the weighted average estimated useful life of 9.6 years The fair value of the core technology was based on the discounted cash flow method that estimated the present value of the potential royalties, milestones, and collaboration revenue streams derived from the licensing of the related technologies. These projected cash flows were discounted to present value using a discount rate of 17%. The fair value of the core technology is being amortized on a straight-line basis over the estimated useful life of 10 years. The total acquired intangibles are being amortized on a straight-line basis over the estimated useful life of 9.7 years. The estimated fair values of assets acquired and liabilities assumed, including deferred tax assets and liabilities, and purchased intangibles are provisional. The accounting for these amounts falls within the measurement period and therefore we may adjust these provisional amounts to reflect new information obtained about facts and circumstances that existed as of the acquisition date. Ab Initio Acquisition On July 23, 2019, we acquired privately-held Ab Initio Biotherapeutics, Inc., an antigen-discovery company located in South San Francisco, California. The purchase price of $12.0 million included $11.84 million cash consideration paid upon acquisition, net of cash acquired, and $0.15 million cash holdback for potential indemnification claims. As the acquisition is not considered significant, pro forma information has not been provided. The results of Ab Initio have been included in our results of operations since the date of acquisition. The preliminary allocation of the purchase price consisted of (1) $0.03 million of fair value of tangible assets acquired, (2) $(0.08) million of liabilities assumed, (3) $7.4 million of acquired technologies, (4) $(1.6) million of deferred tax liability in connection with the acquired intangibles, and (5) $6.3 million of goodwill, none of which is deductible for tax purposes. The fair value of the core technology was based on the discounted cash flow method that estimated the present value of the potential royalties, milestones, and collaboration revenue streams derived from the licensing of the related technologies. These projected cash flows were discounted to present value using a discount rate of 12%. The fair value of the core technology is being amortized on a straight-line basis over the weighted average estimated useful life of the approximately 20 years. The estimated fair values of deferred tax assets and liabilities are provisional. The accounting for these amounts falls within the measurement period and therefore we may adjust these provisional amounts to reflect new information obtained about facts and circumstances that existed as of the acquisition date.