Summary of Significant Accounting Policies and New Accounting Guidance (Policies)	12 Months Ended
Dec. 31, 2022
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include all of our accounts and all entities in which we have a controlling interest and/or are required to be consolidated in accordance with the Generally Accepted Accounting Principles in the United States (“GAAP”). All significant intercompany accounts and transactions have been eliminated in consolidation. In determining whether we are the primary beneficiary of a variable interest entity and therefore required to consolidate, we apply a qualitative approach that determines whether we have both the power to direct the economically significant activities of the entity and the obligation to absorb losses of, or the right to receive benefits from, the entity that could potentially be significant to that entity. These considerations impact the way we account for our existing collaborative relationships and other arrangements. We continuously assess whether we are the primary beneficiary of a variable interest entity as changes to existing relationships or future transactions may result in us consolidating or deconsolidating our partner(s) to collaborations and other arrangements.
Use of Estimates	Use of EstimatesThe preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates. If different assumptions were made or different conditions had existed, our financial results could have been materially different.
Reclassifications	Reclassifications Certain reclassifications have been made to prior year amounts to conform to the current year presentation. During 2022, the Company made reclassifications between the operating expenses lines on the consolidated income statement in order to more clearly reflect the Company’s investments to create and protect the value of our innovations. The Company grouped research and portfolio related costs within the line "Research and portfolio development", previously referred to as "Development", which resulted in reclassifying certain portfolio related costs out of the "Licensing" line, previously referred to as "Patent administration and licensing", and into "Research and portfolio development." The impact of this reclassification was $110.9 million, $111.1 million, and $119.7 million for the twelve months ended December 31, 2022, 2021, and 2020, respectively. Additionally, the previous "Selling, general, and administrative" line is now referred to as "General and administrative".
Foreign Currency Transaction	Foreign Currency Translation 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.
Cash, Cash Equivalents, Restricted Cash and Marketable Securities	Cash, Cash Equivalents, Restricted Cash and Marketable Securities 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. As of December 31, 2022 and 2021, the majority of our marketable securities have been classified as available-for-sale and are carried at fair value, with unrealized gains and losses reported net-of-tax as a separate component of shareholders’ equity. Substantially all of our investments are investment grade government and corporate debt securities that have maturities of less than two years, and we have both the ability and intent to hold the investments until maturity.
Other-than-Temporary Impairments and Impairment of Long-Lived Assets	Other-than-Temporary Impairments 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 (expense) income, net" line of our consolidated statements of income. Impairment of Long-Lived Assets 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. In 2022, we recognized a $2.4 million impairment, comprised of $0.4 million of property and equipment and $2.0 million of right of use assets, related to the abandonment of portions of three of our leased properties, which was included within “Restructuring activities” in the consolidated statement of income. In 2021, a non-controlled subsidiary that we consolidate for financial statement purposes approved a plan to sell certain patents, which resulted in the Company recognizing a $13.2 million impairment, as discussed further in Note 20, "Restructuring Activities". In 2020, we recognized a $1.1 million impairment, comprised of $0.8 million of Property, Plant, and Equipment, and $0.3 million of Operating lease right-of-use asset related to the abandonment of one of our leased properties, which was included within “Operating Expenses” in the consolidated statement of income.
Patents	Intangible Assets Patents 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 9.7 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 and Other Intangible Assets	Goodwill 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 or if circumstances indicate a triggering event has occurred. We first assess qualitative factors to determine whether it is more likely than not that the fair value of our one 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 the 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 the 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 our 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 our 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. The carrying value of goodwill was $22.4 million as of December 31, 2022 and December 31, 2021, which was included within "Other non-current assets, net" in the consolidated balance sheets. No impairments were recorded during 2022, 2021 or 2020 as a result of our annual goodwill impairment assessment.
Property and Equipment	Property and Equipment Property and equipment are stated at cost, less depreciation, amortization and impairments. 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.
Leases	LeasesWe determine if an arrangement is a lease at inception. Operating lease right-of-use assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at commencement date, except short-term leases with an original term of 12 months or less, based on the present value of lease payments over the lease term. As most of our leases do not provide an implicit rate, we generally use an incremental borrowing rate based on the estimated rate of interest for collateralized borrowing over a similar term of the lease payments at commencement date. The operating lease right-of-use assets also includes any lease payments made and excludes lease incentives. Lease expense is recognized over the expected term on a straight-line basis. Leases with a lease term of 12 months or less are accounted for using the practical expedient which allows for straight-line rent expense over the remaining term of the lease.
Internal-Use Software Costs	Internal-Use Software Costs 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. All computer software costs capitalized to date relate to the purchase, development and implementation of engineering, accounting and other enterprise software.
Revenue Recognition	Revenue Recognition We derive the vast majority of our revenue from patent licensing. The timing and amount of revenue recognized from each licensee depend 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 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. For certain patent license agreements or other contractual arrangements, the amount of consideration that we will receive is uncertain. In such cases, we estimate and recognize licensing revenues only when we have a contract, as defined in the revenue recognition guidance. Such estimates are only recognized to the extent it is probable that a significant reversal of cumulative revenues recognized will not occur. We analyze the risk of a significant revenue reversal considering both the likelihood and magnitude of the reversal and, if necessary, constrain the amount of estimated revenues recognized in order to mitigate this risk, which may result in recognizing revenues less than amounts we expect we are most likely to receive. These aforementioned estimates may require significant judgment. Patent License Agreements 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 for Past Patent Royalties 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 Agreements 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. Variable Agreements 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 and recognize sales-based royalties on such licensed products in the period in which the associated sales occur, considering all relevant information (historical, current and forecasted) that is reasonably available to us. Estimating licensees’ quarterly royalties prior to receiving the royalty reports requires us to make assumptions and judgments related to forecasted trends and growth rates used to estimate our licensees’ sales, which could have an impact on the amount of revenue we report on a quarterly basis. As a result of recognizing revenues in the period in which the licensees’ sales occur using estimates, adjustments to revenues are required in subsequent periods to reflect changes in estimates as new information becomes available, primarily resulting from actual amounts reported by our licensees. Technology Solutions Technology solutions revenue consists primarily of revenue from royalty payments, software licenses, and engineering services. 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 the percentage of completion method. Patent SalesDuring 2022, we determined patent sales are no longer a part of the company’s on-going central operations and therefore will no longer be accounted for as revenue.
Accounts Receivable	Accounts ReceivableAccounts receivable is presented net of allowance for doubtful accounts. Our accounts receivable consists mainly of trade receivables derived from fixed-fee license arrangements with contractual payment terms. The remaining material amounts of our accounts receivable are from variable patent license agreements, which primarily are paid on a quarterly basis. The provision for doubtful accounts reflects the current estimate of credit losses expected to be incurred over the life of the financial asset, based on historical experience, current conditions and reasonable forecasts of future economic conditions. Further, we evaluate the collectability of our accounts receivable and if there is doubt that we will collect the full amount, we will record a reserve specific to that customer’s receivable balance.
Investments in Other Entities	Investments in Other Entities 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. Additionally, other investments may be accounted for under the equity method of accounting. Under this method, we initially record our investment in the stock of an investee at cost, and adjust the carrying amount of the investment to recognize our share of the earnings or losses of the investee after the date of acquisition. The amount of the adjustment is included in the 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 is included within "Other non-current assets, net" on our consolidated balance sheets.
Collaborative Arrangements	Collaborative Arrangements 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.
Deferred Charges	Deferred Charges 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 "Licensing" line of our consolidated statements of income and was immaterial for the years presented. There were $0.7 million of new direct contract costs in 2022 and no new direct contract costs incurred during 2021 or 2020. Incremental direct costs incurred related to a debt financing transaction may be capitalized. In connection with our offering of the 2027 Notes, 2024 Notes, and 2020 Notes, defined and discussed in detail within Note 9, "Obligations", we incurred directly related costs. The debt issuance costs 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.
Research and Portfolio Development	Research and Portfolio DevelopmentResearch and portfolio 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.
Compensation Programs	Compensation Programs We use a variety of compensation programs to attract, retain and motivate our employees, and to align employee compensation more closely 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 RSU awards and cash awards, noting equity awards are granted pursuant to the terms and conditions of our Equity Plans (as defined in Note 12, "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. For stock options considered to be “plain vanilla” options, the Company estimates the expected term based on the simplified method as prescribed by Staff Accounting Bulletin Topic 14. The simplified method was used because the Company does not believe it has sufficient historical exercise data to provide a reasonable basis for the expected term of its grants. In all periods, our policy has been to set the value of RSUs 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. In the event of canceled awards, we adjust compensation expense recognized to date as they occur. Tax windfalls and shortfalls related to the tax effects of employee share-based compensation are included in our tax provision. On the consolidated statements of cash flows, tax windfalls and shortfalls related to employee share-based compensation awards are included within operating activities and cash paid to tax authorities for shares withheld are included within financing activities. The inclusion of windfalls and shortfalls in the tax provision could increase our earnings volatility between periods. Tax windfalls and shortfalls related to share-based compensation was shortfalls of $0.4 million for the year ended 2022, and windfalls for the years ended 2021 and 2020 of $0.8 million and $0.2 million, respectively.
Restructuring	Restructuring Restructuring activities include, but are not limited to, costs associated with termination benefits such as severance costs and retention bonuses, contract termination costs, and other costs associated with an exit or disposal activity. The termination benefits included within restructuring activities are recognized in accordance with either ASC 420, Exit or Disposal Cost Obligations ("ASC 420") or ASC 712, Compensation – Nonretirement Postemployment Benefits ("ASC 712"), as applicable. Liabilities are recognized in accordance with ASC 420 when management commits to a plan of termination, the employees to be terminated are identified, the terms of the benefit arrangement are established, it was determined that either changes to the plan or withdrawal are unlikely, and the arrangements were communicated to employees. Liabilities that fall under ASC 712 are recognized when the liability was determined to be probable of being paid and reasonably estimable. The current liabilities are recorded within "Other accrued expenses" and long-term liabilities are included in "Other long-term liabilities" in the consolidated balance sheets. The restructuring expenses are included in "Restructuring activities" in the consolidated statements of income.
Income Taxes	Income Taxes 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 an uncertain 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.
Treasury Stock	Treasury Stock We record the repurchase of our shares of common stock at cost based on the settlement date of the transaction. These shares are classified as treasury stock, which is a reduction to shareholders’ equity. Treasury shares are included in authorized and issued shares, but excluded from outstanding shares. In August 2022, the Inflation Reduction Act was enacted in the United States, which included, among other items, a 1% excise tax on certain net stock repurchases after December 31, 2022. Any such excise tax on our stock repurchases will be recorded as a component of stockholders’ equity, as Treasury Stock.
New Accounting Guidance	New Accounting Guidance Accounting Standards Update: Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity Classified Written Call Options In May 2021, the FASB issued ASU No. 2021-04. The amendments in this ASU are intended to clarify and reduce diversity in an issuer’s accounting for modifications or exchanges of freestanding equity-classified written call options, including warrants, that remain equity classified after modification or exchange. ASU 2021-04 is effective for fiscal years beginning after December 15, 2021, with early adoption allowed. We adopted this guidance as of January 1, 2022 and the adoption did not have a material impact on our consolidated financial statements. Accounting Standards Update: Simplifying the Accounting for Convertible Instruments In August 2020, the FASB issued ASU No. 2020-06, “Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity” (“ASU 2020-06”). The amendments in this ASU are intended to simplify accounting for convertible debt instruments and convertible preferred stock by removing certain accounting models which separate the embedded conversion features from the host contract. ASU 2020-06 also amends certain guidance in ASC 260 on the computation of earnings per share for convertible instruments and contracts on an entity’s own equity. ASU 2020-06 is effective for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years, and early adoption was permitted for fiscal years beginning after December 15, 2020. The ASU permits the use of either the modified retrospective or fully retrospective methods of transition. We elected to early adopt this standard on a modified retrospective approach as of January 1, 2021, which resulted in a $10.4 million, $50.2 million and $15.6 million increase to net deferred tax assets, long-term debt and retained earnings, respectively, and a $55.4 million decrease to additional paid-in capital. This $50.2 million increase to long-term debt, net was comprised of $51.6 million of unamortized interest discount partially offset by a net increase of $1.4 million in unamortized debt issuance costs following the reversal of the initially established equity component of deferred financing costs. This was due to the standard no longer requiring bifurcation of the embedded conversion feature from the host contract on the 2024 Notes, as defined in Note 9, "Obligations". This adoption also reduced non-cash interest expense starting in 2021 due to the removal of the accretion of the debt discount on the 2024 Notes. In addition, the adoption requires the use of the if-converted method of calculating diluted earnings per share rather than the treasury stock method for convertible instruments and requires the inclusion of the potential effect of shares settled in cash or shares in the diluted earnings per share calculation.
Fair Value Measurements	Fair Value Measurements 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 1 Inputs — Level 1 includes financial instruments for which quoted market prices for identical instruments are available in active markets. 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. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of financial assets and financial liabilities and their placement within the fair value hierarchy. We use quoted market prices for similar assets to estimate the fair value of our Level 2 investments.
Net Income Per Share	Basic Earnings Per Share ("EPS") is calculated by dividing net income available to common shareholders by the weighted-average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if options or other securities with features that could result in the issuance of common stock were exercised or converted to common stock.

Summary of Significant Accounting Policies and New Accounting Guidance (Policies)

12 Months Ended

Dec. 31, 2022

The accompanying consolidated financial statements include all of our accounts and all entities in which we have a controlling interest and/or are required to be consolidated in accordance with the Generally Accepted Accounting Principles in the United States (“GAAP”). All significant intercompany accounts and transactions have been eliminated in consolidation.

In determining whether we are the primary beneficiary of a variable interest entity and therefore required to consolidate, we apply a qualitative approach that determines whether we have both the power to direct the economically significant activities of the entity and the obligation to absorb losses of, or the right to receive benefits from, the entity that could potentially be significant to that entity. These considerations impact the way we account for our existing collaborative relationships and other arrangements. We continuously assess whether we are the primary beneficiary of a variable interest entity as changes to existing relationships or future transactions may result in us consolidating or deconsolidating our partner(s) to collaborations and other arrangements.

Use of Estimates

Use of EstimatesThe preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates. If different assumptions were made or different conditions had existed, our financial results could have been materially different.

Reclassifications

Certain reclassifications have been made to prior year amounts to conform to the current year presentation.

During 2022, the Company made reclassifications between the operating expenses lines on the consolidated income statement in order to more clearly reflect the Company’s investments to create and protect the value of our innovations. The Company grouped research and portfolio related costs within the line "Research and portfolio development", previously referred to as "Development", which resulted in reclassifying certain portfolio related costs out of the "Licensing" line, previously referred to as "Patent administration and licensing", and into "Research and portfolio development." The impact of this reclassification was $110.9 million, $111.1 million, and $119.7 million for the twelve months ended December 31, 2022, 2021, and 2020, respectively. Additionally, the previous "Selling, general, and administrative" line is now referred to as "General and administrative".

Foreign Currency Transaction

Foreign Currency Translation

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.

Cash, Cash Equivalents, Restricted Cash and Marketable Securities

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.

As of December 31, 2022 and 2021, the majority of our marketable securities have been classified as available-for-sale and are carried at fair value, with unrealized gains and losses reported net-of-tax as a separate component of shareholders’ equity. Substantially all of our investments are investment grade government and corporate debt securities that have maturities of less than two years, and we have both the ability and intent to hold the investments until maturity.

Other-than-Temporary Impairments and Impairment of Long-Lived Assets

Other-than-Temporary Impairments

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 (expense) income, net" line of our consolidated statements of income.

Impairment of Long-Lived Assets

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. In 2022, we recognized a $2.4 million impairment, comprised of $0.4 million of property and equipment and $2.0 million of right of use assets, related to the abandonment of portions of three of our leased properties, which was included within “Restructuring activities” in the consolidated statement of income. In 2021, a non-controlled subsidiary that we consolidate for financial statement purposes approved a plan to sell certain patents, which resulted in the Company recognizing a $13.2 million impairment, as discussed further in Note 20, "Restructuring Activities". In 2020, we recognized a $1.1 million impairment, comprised of $0.8 million of Property, Plant, and Equipment, and $0.3 million of Operating lease right-of-use asset related to the abandonment of one of our leased properties, which was included within “Operating Expenses” in the consolidated statement of income.

Patents

Intangible Assets

Patents

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 9.7 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 and Other Intangible Assets

Goodwill

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 or if circumstances indicate a triggering event has occurred. We first assess qualitative factors to determine whether it is more likely than not that the fair value of our one 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 the 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 the 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 our 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 our 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.

The carrying value of goodwill was $22.4 million as of December 31, 2022 and December 31, 2021, which was included within "Other non-current assets, net" in the consolidated balance sheets. No impairments were recorded during 2022, 2021 or 2020 as a result of our annual goodwill impairment assessment.

Property and Equipment

Property and equipment are stated at cost, less depreciation, amortization and impairments. 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.

Leases

LeasesWe determine if an arrangement is a lease at inception. Operating lease right-of-use assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at commencement date, except short-term leases with an original term of 12 months or less, based on the present value of lease payments over the lease term. As most of our leases do not provide an implicit rate, we generally use an incremental borrowing rate based on the estimated rate of interest for collateralized borrowing over a similar term of the lease payments at commencement date. The operating lease right-of-use assets also includes any lease payments made and excludes lease incentives. Lease expense is recognized over the expected term on a straight-line basis. Leases with a lease term of 12 months or less are accounted for using the practical expedient which allows for straight-line rent expense over the remaining term of the lease.

Internal-Use Software Costs

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.

All computer software costs capitalized to date relate to the purchase, development and implementation of engineering, accounting and other enterprise software.

Revenue Recognition

We derive the vast majority of our revenue from patent licensing. The timing and amount of revenue recognized from each licensee depend 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 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.

For certain patent license agreements or other contractual arrangements, the amount of consideration that we will receive is uncertain. In such cases, we estimate and recognize licensing revenues only when we have a contract, as defined in the revenue recognition guidance. Such estimates are only recognized to the extent it is probable that a significant reversal of cumulative revenues recognized will not occur. We analyze the risk of a significant revenue reversal considering both the likelihood and magnitude of the reversal and, if necessary, constrain the amount of estimated revenues recognized in order to mitigate this risk, which may result in recognizing revenues less than amounts we expect we are most likely to receive. These aforementioned estimates may require significant judgment.

Patent License Agreements

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 for Past Patent Royalties

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 Agreements

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.

Variable Agreements

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 and recognize sales-based royalties on such licensed products in the period in which the associated sales occur, considering all relevant information (historical, current and forecasted) that is reasonably available to us. Estimating licensees’ quarterly royalties prior to receiving the royalty reports requires us to make assumptions and judgments related to forecasted trends and growth rates used to estimate our licensees’ sales, which could have an impact on the amount of revenue we report on a quarterly basis. As a result of recognizing revenues in the period in which the licensees’ sales occur using estimates, adjustments to revenues are required in subsequent periods to reflect changes in estimates as new information becomes available, primarily resulting from actual amounts reported by our licensees.

Technology Solutions

Technology solutions revenue consists primarily of revenue from royalty payments, software licenses, and engineering services. 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 the percentage of completion method.

Patent SalesDuring 2022, we determined patent sales are no longer a part of the company’s on-going central operations and therefore will no longer be accounted for as revenue.

Accounts Receivable

Accounts ReceivableAccounts receivable is presented net of allowance for doubtful accounts. Our accounts receivable consists mainly of trade receivables derived from fixed-fee license arrangements with contractual payment terms. The remaining material amounts of our accounts receivable are from variable patent license agreements, which primarily are paid on a quarterly basis. The provision for doubtful accounts reflects the current estimate of credit losses expected to be incurred over the life of the financial asset, based on historical experience, current conditions and reasonable forecasts of future economic conditions. Further, we evaluate the collectability of our accounts receivable and if there is doubt that we will collect the full amount, we will record a reserve specific to that customer’s receivable balance.

Investments in Other Entities

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.

Additionally, other investments may be accounted for under the equity method of accounting. Under this method, we initially record our investment in the stock of an investee at cost, and adjust the carrying amount of the investment to recognize our share of the earnings or losses of the investee after the date of acquisition. The amount of the adjustment is included in the 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 is included within "Other non-current assets, net" on our consolidated balance sheets.

Collaborative Arrangements

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.

Deferred Charges

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 "Licensing" line of our consolidated statements of income and was immaterial for the years presented. There were $0.7 million of new direct contract costs in 2022 and no new direct contract costs incurred during 2021 or 2020.

Incremental direct costs incurred related to a debt financing transaction may be capitalized. In connection with our offering of the 2027 Notes, 2024 Notes, and 2020 Notes, defined and discussed in detail within Note 9, "Obligations", we incurred directly related costs. The debt issuance costs 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.

Research and Portfolio Development

Research and Portfolio DevelopmentResearch and portfolio 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.

Compensation Programs

We use a variety of compensation programs to attract, retain and motivate our employees, and to align employee compensation more closely 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 RSU awards and cash awards, noting equity awards are granted pursuant to the terms and conditions of our Equity Plans (as defined in Note 12, "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. For stock options considered to be “plain vanilla” options, the Company estimates the expected term based on the simplified method as prescribed by Staff Accounting Bulletin Topic 14. The simplified method was used because the Company does not believe it has sufficient historical exercise data to provide a reasonable basis for the expected term of its grants. In all periods, our policy has been to set the value of RSUs 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.

In the event of canceled awards, we adjust compensation expense recognized to date as they occur. Tax windfalls and shortfalls related to the tax effects of employee share-based compensation are included in our tax provision. On the consolidated statements of cash flows, tax windfalls and shortfalls related to employee share-based compensation awards are included within operating activities and cash paid to tax authorities for shares withheld are included within financing activities. The inclusion of windfalls and shortfalls in the tax provision could increase our earnings volatility between periods. Tax windfalls and shortfalls related to share-based compensation was shortfalls of $0.4 million for the year ended 2022, and windfalls for the years ended 2021 and 2020 of $0.8 million and $0.2 million, respectively.

Restructuring

Restructuring activities include, but are not limited to, costs associated with termination benefits such as severance costs and retention bonuses, contract termination costs, and other costs associated with an exit or disposal activity. The termination benefits included within restructuring activities are recognized in accordance with either ASC 420, Exit or Disposal Cost Obligations ("ASC 420") or ASC 712, Compensation – Nonretirement Postemployment Benefits ("ASC 712"), as applicable. Liabilities are recognized in accordance with ASC 420 when management commits to a plan of termination, the employees to be terminated are identified, the terms of the benefit arrangement are established, it was determined that either changes to the plan or withdrawal are unlikely, and the arrangements were communicated to employees. Liabilities that fall under ASC 712 are recognized when the liability was determined to be probable of being paid and reasonably estimable. The current liabilities are recorded within "Other accrued expenses" and long-term liabilities are included in "Other long-term liabilities" in the consolidated balance sheets. The restructuring expenses are included in "Restructuring activities" in the consolidated statements of income.

Income Taxes

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 an uncertain 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.

Treasury Stock

We record the repurchase of our shares of common stock at cost based on the settlement date of the transaction. These shares are classified as treasury stock, which is a reduction to shareholders’ equity. Treasury shares are included in authorized and issued shares, but excluded from outstanding shares.

In August 2022, the Inflation Reduction Act was enacted in the United States, which included, among other items, a 1% excise tax on certain net stock repurchases after December 31, 2022. Any such excise tax on our stock repurchases will be recorded as a component of stockholders’ equity, as Treasury Stock.

New Accounting Guidance

Accounting Standards Update: Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity Classified Written Call Options

In May 2021, the FASB issued ASU No. 2021-04. The amendments in this ASU are intended to clarify and reduce diversity in an issuer’s accounting for modifications or exchanges of freestanding equity-classified written call options, including warrants, that remain equity classified after modification or exchange. ASU 2021-04 is effective for fiscal years beginning after December 15, 2021, with early adoption allowed. We adopted this guidance as of January 1, 2022 and the adoption did not have a material impact on our consolidated financial statements.

Accounting Standards Update: Simplifying the Accounting for Convertible Instruments

In August 2020, the FASB issued ASU No. 2020-06, “Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity” (“ASU 2020-06”). The amendments in this ASU are intended to simplify accounting for convertible debt instruments and convertible preferred stock by removing certain accounting models which separate the embedded conversion features from the host contract. ASU 2020-06 also amends certain guidance in ASC 260 on the computation of earnings per share for convertible instruments and contracts on an entity’s own equity. ASU 2020-06 is effective for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years, and early adoption was permitted for fiscal years beginning after December 15, 2020. The ASU permits the use of either the modified retrospective or fully retrospective methods of transition. We elected to early adopt this standard on a modified retrospective approach as of January 1, 2021, which resulted in a $10.4 million, $50.2 million and $15.6 million increase to net deferred tax assets, long-term debt and retained earnings, respectively, and a $55.4 million decrease to additional paid-in capital. This $50.2 million increase to long-term debt, net was comprised of $51.6 million of unamortized interest discount partially offset by a net increase of $1.4 million in unamortized debt issuance costs following the reversal of the initially established equity component of deferred financing costs. This was due to the standard no longer requiring bifurcation of the embedded conversion feature from the host contract on the 2024 Notes, as defined in Note 9, "Obligations". This adoption also reduced non-cash interest expense starting in 2021 due to the removal of the accretion of the debt discount on the 2024 Notes. In addition, the adoption requires the use of the if-converted method of calculating diluted earnings per share rather than the treasury stock method for convertible instruments and requires the inclusion of the potential effect of shares settled in cash or shares in the diluted earnings per share calculation.

Fair Value Measurements

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 1 Inputs — Level 1 includes financial instruments for which quoted market prices for identical instruments are available in active markets.

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.

Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of financial assets and financial liabilities and their placement within the fair value hierarchy. We use quoted market prices for similar assets to estimate the fair value of our Level 2 investments.

Net Income Per Share

Basic Earnings Per Share ("EPS") is calculated by dividing net income available to common shareholders by the weighted-average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if options or other securities with features that could result in the issuance of common stock were exercised or converted to common stock.