The functional currency of substantially all of the Company's wholly-owned subsidiaries is the U.S. dollar. Certain subsidiaries have monetary assets and liabilities that are denominated in a currency that is different than the functional currency. The gains and losses resulting from this remeasurement and translation of monetary assets denominated in a currency that is different than the functional currency are reflected in the determination of net income (loss).

We classify all highly liquid investment securities with original maturities of three months or less at date of purchase as cash equivalents. Cash that is held for a specific purpose and therefore not available to the Company for immediate or general business use is classified as restricted cash. Our investments are comprised of mutual and exchange traded funds, commercial paper, United States and municipal government obligations and corporate securities. Management determines the appropriate classification of our investments at the time of acquisition and re-evaluates such determination at each balance sheet date.

We review our investment portfolio during each reporting period to determine whether there are identified events or circumstances that would indicate there is a decline in the fair value that is considered to be other-than-temporary. For non-public investments, if there are no identified events or circumstances that would have a significant adverse effect on the fair value of the investment, then the fair value is not estimated. If an investment is deemed to have experienced an other-than-temporary decline below its cost basis, we reduce the carrying amount of the investment to its quoted or estimated fair value, as applicable, and establish a new cost basis for the investment. We charge the impairment to the "Other Income (Expense), Net" line of our consolidated statements of income.

We capitalize external costs, such as filing fees and associated attorney fees, incurred to obtain issued patents and patent license rights. We expense costs associated with maintaining and defending patents subsequent to their issuance in the period incurred. We amortize capitalized patent costs for internally generated patents on a straight-line basis over 10 years, which represents the estimated useful lives of the patents. The ten-year estimated useful life for internally generated patents is based on our assessment of such factors as: the integrated nature of the portfolios being licensed, the overall makeup of the portfolio over time, and the length of license agreements for such patents. The estimated useful lives of acquired patents and patent rights, however, have been and will continue to be based on a separate analysis related to each acquisition and may differ from the estimated useful lives of internally generated patents. The average estimated useful life of acquired patents is 9.6 years. We assess the potential impairment to all capitalized net patent costs when events or changes in circumstances indicate that the carrying amount of our patent portfolio may not be recoverable.

Goodwill is recorded as the difference, if any, between the aggregate consideration paid for an acquisition and the fair value of the net tangible and identified intangible assets acquired under a business combination. We review impairment of goodwill annually on the first day of the fourth quarter. We first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether a quantitative goodwill impairment test is necessary. If we conclude it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, we need not perform the quantitative assessment.

If based on the qualitative assessment we believe it is more likely than not that the fair value of a reporting unit is less than its carrying value, a quantitative assessment test is required to be performed. This assessment requires us to compare the fair value of each reporting unit to its carrying value including allocated goodwill. We determine the fair value of our reporting units generally using a combination of the income and market approaches. The income approach is estimated through the discounted cash flow method based on assumptions about future conditions such as future revenue growth rates, new product and technology introductions, gross margins, operating expenses, discount rates, future economic and market conditions, and other assumptions. The market approach estimates the fair value of our equity by utilizing the market comparable method which is based on revenue multiples from comparable companies in similar lines of business. If the carrying value of a reporting unit exceeds the reporting unit’s fair value, a goodwill impairment charge will be recorded for the difference up to the carrying value of goodwill.

Property and equipment are stated at cost. Depreciation and amortization of property and equipment are provided using the straight-line method. The estimated useful lives for computer equipment, computer software, engineering and test equipment and furniture and fixtures are generally three to five years. Leasehold improvements are amortized over the lesser of their estimated useful lives or their respective lease terms, which are generally five to ten years. Buildings are being depreciated over twenty-five years. Expenditures for major improvements and betterments are capitalized, while minor repairs and maintenance are charged to expense as incurred. Upon the retirement or disposition of property, plant and equipment, the related cost and accumulated depreciation or amortization are removed, and a gain or loss is recorded.

In February 2016, the Financial Accounting Standards Board ("FASB") issued ASU 2016-02, "Leases (Topic 842)" or ("ASC 842"), which outlines a comprehensive change to the lease accounting model and supersedes prior lease guidance. The new guidance requires lessees to recognize lease liabilities and corresponding right-of-use assets for all leases with lease terms of greater than 12 months, and also changes the definition of a lease and expands the disclosure requirements of lease arrangements.

The Company adopted this guidance on January 1, 2019 using the modified retrospective transition effective date method. As part of that adoption, we have elected the package of three practical expedients, which includes the following: an entity may elect not to reassess whether expired or existing contracts contain a lease under the revised definition of a lease; an entity may elect not to reassess the lease classification for expired or existing leases; and an entity may elect not to reassess whether previously capitalized initial direct costs would qualify for capitalization. The Company has elected not to utilize the hindsight expedient in determining the lease term, and to not record leases with an initial term of 12 months or less on our balance sheet. Additionally, the Company has elected to account for lease components and non-lease components as a single lease component for all asset classes. Lease expense is recognized over the expected term on a straight-line basis.

We capitalize costs associated with software developed for internal use that are incurred during the software development stage. Such costs are limited to expenses incurred after management authorizes and commits to a computer software project, believes that it is more likely than not that the project will be completed, the software will be used to perform the intended function with an estimated service life of two years or more, and the completion of conceptual formulation, design and testing of possible software project alternatives (the preliminary design stage). Costs incurred after final acceptance testing has been successfully completed are expensed. Capitalized computer software costs are amortized over their estimated useful life of three years.

We evaluate long-lived assets for impairment when factors indicate that the carrying value of an asset may not be recoverable. When factors indicate that such assets should be evaluated for possible impairment, we review whether we will be able to realize our long-lived assets by analyzing the projected undiscounted cash flows in measuring whether the asset is recoverable. We did not have any long-lived asset impairments in 2019, 2018 or 2017.

We may make strategic investments in companies that have developed or are developing technologies that are complementary to our business. We made an accounting policy election for a measurement alternative for our equity investments that do not have readily determinable fair values, specifically related to our strategic investments in other entities. Under the alternative, our strategic investments in other entities without readily determinable fair values are measured at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for an identical or similar investment of the same issuer, if any. On a quarterly basis, we monitor items such as our investment’s financial position and liquidity, performance targets, business plans, and cost trends to assess whether there are any triggering events or indicators present that would be indicative of an impairment, or any other observable price changes as indicated above. We do not adjust our investment balance when the investee reports profit or loss.

determination of net income, and such amount reflects adjustments similar to those made in preparing consolidated statements including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between our cost and underlying equity in net assets of the investee at the date of investment. The investment is also adjusted to reflect our share of changes in the investee’s capital. Dividends received from an investee reduce the carrying amount of the investment. When there are a series of operating losses by the investee or when other factors indicate that a decrease in value of the investment has occurred which is other than temporary, we recognize an impairment equal to the difference between the fair value and the carrying amount of our investment.

The carrying value of our investments in other entities are included within "Other Non-Current Assets" on our consolidated balance sheets. During 2019, 2018 and 2017, we made investments in other entities of 0.4 million, 6.7 million and 4.6 million, respectively. The carrying value of our investments in other entities as of December 31, 2019 and 2018 was $14.2 million and $17.4 million, respectively, the majority of which are accounted for under the measurement alternative for equity investments described above.

We derive the vast majority of our revenue from patent licensing. The timing and amount of revenue recognized from each licensee depends upon a variety of factors, including the specific terms of each agreement and the nature of the deliverables and obligations. Such agreements are often complex and include multiple performance obligations. These agreements can include, without limitation, performance obligations related to the settlement of past patent infringement liabilities, patent and/or know-how licensing royalties on covered products sold by licensees, access to a portfolio of technology as it exists at a point in time, and access to a portfolio of technology at a point in time along with a promises to provide any technology updates to the portfolio during the term.

In accordance with US GAAP, we use a five-step model to achieve the core underlying principle that an entity should recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. These steps include (1) identifying the contract with the customer, (2) identifying the performance obligations, (3) determining the transaction price, (4) allocating the transaction price to the performance obligations, and (5) recognizing revenue as the entity satisfies the performance obligation(s). Additionally, we have elected to utilize certain practical expedients in the application of ASC 606. In evaluating the presence of a significant financing component in our agreements, we utilize the practical expedient to exclude any contracts wherein the gap between payment by our customers and the delivery of our performance obligation is less than one year. We have also elected to utilize the practical expedient related to costs of obtaining a contract where an entity may recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that the entity otherwise would have recognized is one year or less. Timing of revenue recognition may differ significantly from the timing of invoicing to customers. Contract assets are included in accounts receivable and represent unbilled amounts expected to be received from customers in future periods, where the revenue recognized to date exceeds the amount billed, and right to payment is subject to the underlying contractual terms. Contract assets are classified as long-term assets if the payments are expected to be received more than one year from the reporting date. Contract assets due within less than twelve months of the balance sheet date are included within accounts receivable in our consolidated balance sheets. Contract assets due more than twelve months after the balance sheet date are included within other non-current assets.

Upon signing a patent license agreement, we provide the licensee permission to use our patented inventions in specific applications. We account for patent license agreements in accordance with the guidance indicated above. Certain patent license agreements contain revenue from non-financial sources in the form of patents received from the customer. Under our patent license agreements, we typically receive one or a combination of the following forms of payment as consideration for permitting our licensees to use our patented inventions in their applications and products:

Consideration related to a licensee’s product sales from prior periods may result from a negotiated agreement with a licensee that utilized our patented inventions prior to signing a patent license agreement with us or from the resolution of a disagreement or arbitration with a licensee over the specific terms of an existing license agreement. We may also receive consideration for past patent royalties in connection with the settlement of patent litigation where there was no prior patent license agreement. In each of these cases, we record the consideration as revenue as prescribed by the five-step model.

Fixed-fee license agreements include fixed, non-refundable royalty payments that fulfill the licensee’s obligations to us under a patent license agreement for a specified time period or for the term of the agreement for specified products, under certain patents or patent claims, for sales in certain countries, or a combination thereof - in each case for a specified time period (including for the life of the patents licensed under the agreement).

Dynamic fixed-fee license agreements contain a single performance obligation that represents ongoing access to a portfolio of technology over the license term, since our promise to transfer to the licensee access to the portfolio as it exists at inception of the license, along with promises to provide any technology updates to the portfolio during the term, are not separately identifiable. Upon entering a new agreement, we allocate the transaction price to the performance obligations delivered at signing (e.g. our existing patent portfolio) and future performance obligations (e.g. the technology updates). We use a time-based input method of progress to determine the timing of revenue recognition, and as such we recognize the future deliverables on a straight-line basis over the term of the agreement. We utilize the straight-line method as we believe that it best depicts efforts expended to develop and transfer updates to the customer evenly throughout the term of the agreement.

Static fixed-fee license agreements are fixed-price contracts that generally do not include updates to technology we create after the inception of the license agreement or in which the customer does not stand to substantively benefit from those updates during the term. Although we have few static fixed-fee license agreements, we generally satisfy our performance obligations under such agreements at contract signing, and as such revenue is recognized at that time.

Upon entering a new variable patent license agreement, the licensee typically agrees to pay royalties or license fees on licensed products sold during the term of the agreement. We utilize the sales- or usage- based royalty exception for these agreements and recognize revenues during the contract term when the underlying sale or usage occurs. Our licensees under variable agreements provide us with quarterly royalty reports that summarize their sales of covered products and their related royalty obligations to us. We typically receive these royalty reports subsequent to the period in which our licensees’ underlying sales occurred. As a result, we are required to estimate revenues, subject to the constraint on our ability to estimate such amounts.

Technology solutions revenue consists of revenue from royalty payments, software licenses, engineering services and product sales. The nature of these contracts and timing of payments vary. We recognize revenue from royalty payments and license agreements using the same methods described above under our policy for recognizing revenue from patent license agreements. We recognize revenue from engineering services using percentage of completion method.

We record the elements of our collaboration agreements that represent joint operating activities in accordance with ASC 808, Collaborative Arrangements (“ASC 808”). Accordingly, the elements of our collaboration agreements that represent activities in which both parties are active participants, and to which both parties are exposed to the significant risks and rewards that are dependent on the commercial success of the activities, are recorded as collaborative arrangements. Generally, the classification of a transaction under a collaborative arrangement is determined based on the nature and contractual terms of the arrangement along with the nature of the operations of the participants. For transactions that are deemed to be a collaborative arrangement under ASC 808, costs incurred and revenues generated on sales to third parties will be reported in our consolidated statement of operations on a gross basis if the Company is deemed to be the principal in the transaction, or on a net basis if the Company is instead deemed to be the agent in the transaction, consistent with the guidance in ASC 606-10-55-36, Revenue From Contracts with Customers - Principal Agent Considerations.

Direct costs of obtaining a contract or fulfilling a contract in a transaction that results in the deferral of revenue may be either expensed as incurred or capitalized, depending on certain criteria. In conjunction with our adoption of ASC 606 effective January 1, 2018, we made a policy election to utilize the practical expedient related to costs of obtaining a contract where an entity may recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that the entity otherwise would have recognized is one year or less. If the amortization period is greater than one year, we capitalize direct costs incurred for the acquisition or fulfillment of a contract through the date of signing if they are directly related to a particular revenue arrangement and are expected to be recovered. The costs are amortized on a straight-line basis over the life of the patent license agreement.

For example, from time to time, we use sales agents to assist us in our licensing and/or patent sale activities. In such cases, we may pay a commission. The commission rate varies from agreement to agreement. Commissions are normally paid shortly after our receipt of cash payments associated with the patent license or patent sale agreements. We defer recognition of commission expense and amortize these expenses in proportion to our recognition of the related revenue. Commission expense is included within the "Patent administration and licensing" line of our consolidated statements of income and was immaterial for the years presented. There were no new direct contract costs incurred during 2019, 2018 or 2017.

Incremental direct costs incurred related to a debt financing transaction may be capitalized. In connection with our offering of the 2024 Notes and 2020 Notes, defined and discussed in detail within Note 10, "Obligations", we incurred directly related costs. The initial purchasers' transaction fees and related offering expenses were allocated to the liability and equity components of the debt in proportion to the allocation of proceeds and accounted for as debt issuance costs. The debt issuance costs allocated to the liability component of the debt were capitalized as deferred financing costs and recorded as a direct reduction of the debt. These costs are being amortized over the term of the debt using the effective interest method and are included within the "Interest expense" line of our consolidated statements of income. The costs allocated to the equity component of the debt were recorded as a reduction of the equity component of the debt. The balance of unamortized deferred financing costs as of December 31, 2019 and 2018 was $5.9 million and $1.6 million, respectively. The Company incurred $6.4 million of new debt issuance costs during 2019 in conjunction with the issuance of the 2024 Notes, noting no new debt issuance costs were incurred in 2018 or 2017. Deferred financing expense was $1.5 million, $1.4 million and $1.4 million in 2019, 2018 and 2017, respectively.

Research and development expenditures are expensed in the period incurred, except certain software development costs that are capitalized between the point in time that technological feasibility of the software is established and when the product is available for general release to customers. We did not have any capitalized software costs related to research and development in any period presented. Research, development and other related costs were approximately $74.9 million, $69.7 million and $75.7 million in 2019, 2018 and 2017, respectively.

We use a variety of compensation programs to attract, retain and motivate our employees, and to more closely align employee compensation with company performance. These programs include, but are not limited to, short-term incentives tied to performance goals, cash awards to inventors for filed patent applications and patent issuances, and long-term incentives in the form of stock option awards, time-based restricted stock unit (“RSU”) awards, performance-based awards and cash awards, noting equity awards are granted pursuant to the terms and conditions of our Equity Plans (as defined in Note 13, "Compensation Plans and Programs"). Our long-term incentives, including equity awards, typically include annual equity and cash award grants with three- to five-year vesting periods; as a result, in any one year, we are typically accounting for at least three active cycles.

We account for compensation costs associated with share-based compensation based on the fair value of the instruments issued. The estimated value of stock options includes assumptions around expected life, stock volatility and dividends. The expected life of our stock option awards is based on the simplified method as prescribed by Staff Accounting Bulletin Topic 14. In all periods, our policy has been to set the value of RSUs and restricted stock awards equal to the value of our underlying common stock on the date of measurement. For grants with graded vesting, we amortize the associated unrecognized compensation cost using an accelerated method. For grants that cliff vest, we amortize the associated unrecognized compensation cost on a straight-line basis over their vesting term.

Income taxes are accounted for under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, and operating loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the Consolidated Statement of Income in the period in which the change was enacted. A valuation allowance is recorded to reduce the carrying amounts of deferred tax assets if management has determined that it is more likely than not that such assets will not be realized.

In addition, the calculation of tax liabilities involves significant judgment in estimating the impact of uncertainties in the application of complex tax laws. We are subject to examinations by the U.S. IRS and other taxing jurisdictions on various tax matters, including challenges to various positions we assert in our filings. In the event that the IRS or another taxing jurisdiction levies an assessment in the future, it is possible the assessment could have a material adverse effect on our consolidated financial condition or results of operations.

The financial statement recognition of the benefit for a tax position is dependent upon the benefit being more likely than not to be sustainable upon audit by the applicable tax authority. If this threshold is met, the tax benefit is then measured and recognized at the largest amount that is greater than 50 percent likely of being realized upon ultimate settlement. In the event that the IRS or another taxing jurisdiction levies an assessment in the future, it is possible the assessment could have a material adverse effect on our consolidated financial condition or results of operations.

In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)", or ASC 842, which outlines a comprehensive change to the lease accounting model and supersedes prior lease guidance. Refer to Note 17, "Leases," for information regarding our adoption of this guidance effective January 1, 2019 and a discussion of the impact to information presented herein, as well as additional required disclosures under the new guidance.

In June 2018, the FASB issued ASU No. 2018-07, "Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting," which is intended to reduce cost and complexity and to improve financial reporting for share-based payments issued to nonemployees. The guidance is effective for fiscal years beginning after December 15, 2018 and early adoption is permitted. We adopted this guidance in first quarter 2019 and it did not have a material impact on our consolidated financial statements.

In June 2016, the FASB issued ASU No. 2016-13, "Financial Instruments - Credit Losses". This ASU introduces a new accounting model for recognizing credit losses on certain financial instruments and financial assets, including trade receivables, based upon an estimate of current expected credit losses, otherwise known as CECL. The new guidance requires the recognition of an allowance that reflects the current estimate of credit losses expected to be incurred over the life of the financial asset, based not only on historical experience and current conditions, but also on reasonable forecasts. Additionally, ASU No. 2016-13 made several changes to the available-for-sale impairment model. The guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, and early adoption is permitted. We have concluded that this guidance will not have a material impact on our consolidated financial statements.

In August 2018, the FASB issued ASU No. 2018-15 “Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract”. The amendments in this ASU align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The guidance is effective for fiscal years beginning after December 15, 2019, including interim

In November 2018, the FASB issued ASU No. 2018-18, "Collaborative Arrangements (Topic 808): Clarifying the Interaction Between Topic 808 and Topic 606". The amendments in this ASU provide guidance on how to assess whether certain transactions between collaborative arrangement participants should be accounted for within the revenue recognition standard. The amendments in this update are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, and early adoption is permitted for entities who have previously adopted the new revenue recognition guidance. We have concluded that this guidance will not have a material impact on our consolidated financial statements.

In December 2019, the FASB issued ASU No. 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes" ("ASU 2019-12"). The amendments in this ASU are intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. ASU 2019-12 is effective for fiscal years beginning after December 15, 2020 with early adoption allowed. The Company is currently evaluating the impact of the adoption of ASU 2019-12 on its consolidated financial statements.

Our accounts receivable are derived principally from patent license and technology solutions agreements. As of December 31, 2019 and 2018, seven and five licensees comprised 73% and 76%, respectively, of our accounts receivable balance. We perform ongoing credit evaluations of our licensees, who generally include large, multinational, wireless telecommunications equipment manufacturers. We believe that the book values of our financial instruments approximate their fair values.

We use various valuation techniques and assumptions when measuring the fair value of our assets and liabilities. We utilize market data or assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. This guidance established a hierarchy that prioritizes fair value measurements based on the types of input used for the various valuation techniques (market approach, income approach and cost approach). The levels of the hierarchy are described below:

Level 2 Inputs — Level 2 includes financial instruments for which there are inputs other than quoted prices included within Level 1 that are observable for the instrument such as quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets with insufficient volume or infrequent transactions (less active markets) or model-driven valuations in which significant inputs are observable or can be derived principally from, or corroborated by, observable market data, including market interest rate curves, referenced credit spreads and pre-payment rates.

Level 3 Inputs — Level 3 includes financial instruments for which fair value is derived from valuation techniques including pricing models and discounted cash flow models in which one or more significant inputs are unobservable, including the company’s own assumptions. The pricing models incorporate transaction details such as contractual terms, maturity and, in certain instances, timing and amount of future cash flows, as well as assumptions related to liquidity and credit valuation adjustments of marketplace participants.



	Fair Value as of December 31, 2018
	Level 1		Level 2		Level 3		Total
Assets:
Money market and demand accounts (a)	$	488,733	$	—	$	—	$	488,733
Commercial paper	—		14,548		—		14,548
U.S. government securities	—		289,576		—		289,576
Corporate bonds and asset backed securities	—		166,600		—		166,600
	$	488,733	$	470,724	$	—	$	959,457
Liabilities:
Contingent consideration resulting from the Technicolor Patent Acquisition	$	—	$	—	$	19,800	$	19,800
	$	—	$	—	$	19,800	$	19,800

As discussed further in Note 5, we completed the Technicolor Patent Acquisition during third quarter 2018. In conjunction with the Technicolor Patent Acquisition, we initially recognized a contingent consideration liability which was measured at fair value on a recurring basis using significant unobservable inputs classified as Level 3 measurements within the fair value hierarchy. We utilized a Monte Carlo simulation model to determine the estimated fair value of the contingent consideration liability through first quarter 2019. A Monte Carlo simulation uses random numbers together with volatility assumptions to generate individual paths, or trials, for variables of interest governed by a Geometric Brownian Motion in a risk-neutral framework.

During second quarter 2019, we completed the R&I Acquisition. The transaction met the definition of an asset acquisition and was accounted for using the cost accumulation and allocation model. As discussed in Note 5, "Business Combinations and Other Transactions," as part of this acquisition, Technicolor reduced its rights to the revenue-sharing arrangement that created the initial contingent consideration liability from the Technicolor Patent Acquisition. We determined that the initial contingent consideration liability from the Technicolor Patent Acquisition was significantly modified in conjunction with the R&I Acquisition, and, as such, the contingent consideration liability will now be accounted for under ASC 450 - Contingencies under the asset acquisition framework when the liability is deemed probable and estimable. Since the contingent consideration liability arising from the amended revenue-sharing arrangement was not probable and estimable as of the acquisition date, the carrying value of the previous contingent consideration liability was derecognized, which resulted in a $20.5 million gain which is included within "Other Income (Expense), Net" in the consolidated statement of income for the

year ended December 31, 2019. Therefore, effective as of the acquisition date of May 31, 2019, the contingent consideration liability was no longer a Level 3 fair value recurring measurement. As of December 31, 2019, the contingent consideration liability from the amended revenue-sharing arrangement was deemed not probable and estimable and is therefore not reflected within the consolidated financial statements.

The following table provides a reconciliation of the beginning and ending balances of our Level 3 fair value measurements from December 31, 2018 to December 31, 2019, which includes the contingent consideration liability resulting from the Technicolor Patent Acquisition discussed further above and within Note 5 (in thousands). The Level 3 contingent consideration liability was historically included within "Other long-term liabilities" in the consolidated balance sheet prior to its derecognition in second quarter 2019.

As more fully disclosed in Note 5, we recognized long-term debt in conjunction with the Technicolor Patent Acquisition. The carrying value and related estimated fair value of the Technicolor Patent Acquisition long-term debt reported in the consolidated balance sheet as of December 31, 2019 and December 31, 2018 was as follows (in thousands). The aggregate fair value of the Technicolor Patent Acquisition long-term debt is a Level 3 fair value measurement.

As disclosed in Note 2, we made an accounting policy election to utilize a measurement alternative for equity investments that do not have readily determinable fair values, which applies to our long-term strategic investments in other entities. Under the alternative, our long-term strategic investments in other entities that do not have readily determinable fair values are measured at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for an identical or similar investment of the same issuer. Any adjustments to the carrying value of those investments are considered non-recurring fair value measurements.

During the year ended December 31, 2019, we recognized a net loss of $2.6 million resulting from the partial impairment of one of our strategic investments partially offset by a gain on sale of a separate strategic investment, which is included within "Other Income (Expense), Net" in the consolidated statement of income. During the year ended December 31, 2018, we recognized an aggregate $8.4 million loss resulting from the sale of our entire ownership interest in one of our strategic investments and the impairment of a separate strategic investment. Certain of our investments in other entities may be seeking additional financing in the next twelve months or potential exit strategies. We will continue to review and monitor our investments in other entities for any indications of an increase in fair value or impairment.

During fourth quarter 2019, we entered into a multi-year, worldwide, non-exclusive, royalty-bearing patent license and settlement agreement with ZTE Corporation. A portion of the future consideration for the agreement was in the form of patents. We have yet to record these patents on our balance sheet as of December 31, 2019 as they have not yet been transferred. However, we have determined the estimated fair value of the patents for determining the transaction price for revenue recognition purposes, which was estimated to be $14.0 million utilizing the market approach. The value will be amortized as a non-cash expense over the patents' estimated useful lives once transferred. Additionally, as previously disclosed, during 2018 and 2017, we entered into patent license agreements with Sony and LG, respectively, for which a portion of the consideration was patents. The estimated fair value of the Sony patents was $22.5 million, and the estimated fair value of the LG patents was $19.7 million, which are being amortized as a non-cash expense over their estimated useful lives. We estimated the fair value of the patents in the Sony and LG transactions through a combination of the income approach, the market approach, and the cost approach.

As noted above, we estimated the fair value of the patents in these transactions using one of, or a combination of, an analysis of comparable market transactions (the market approach), a discounted cash flow analysis (the income approach) and/or by quantifying the amount of money required to replace the future service capability of the assets (the cost approach). For the market approach, judgment was applied as to which market transactions were most comparable to the transaction. For the income approach, the inputs and assumptions used to develop these estimates were based on a market participant perspective and included estimates of projected royalties, discount rates, economic lives and income tax rates, among others. For the cost approach, we utilized the historical cost of assets of similar technologies to determine the estimated replacement cost, including research, development, testing and patent application fees.