Summary of Significant Accounting Policies	12 Months Ended
Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	1. Summary of Significant Accounting Policies Background - Knowles Corporation (NYSE:KN) is a market leader and global provider of advanced micro-acoustic, audio processing, and precision device solutions, serving the mobile consumer electronics, communications, medical, defense, aerospace, and industrial markets. The Company uses its leading position in micro-electro-mechanical systems ("MEMS") microphones and strong capabilities in audio processing technologies to optimize audio systems and improve the user experience in mobile, ear, and Internet of Things ("IoT") applications. Knowles is also the leader in acoustics components used in hearing aids and has a strong position in high-end capacitors. The Company's focus on its customers, combined with its unique technology, proprietary manufacturing techniques, rigorous testing, and global scale, enable the Company to deliver innovative solutions that optimize the user experience. References to "Knowles," "the Company," "we," "our," and "us" refer to Knowles Corporation and its consolidated subsidiaries. Our common stock began trading under the ticker symbol “KN” on the New York Stock Exchange (the “NYSE”) on March 3, 2014. On January 19, 2018, the Company acquired substantially all of the assets of Compex Corporation ("Compex"), a capacitors manufacturer. See Note 3. Acquisitions for additional information related to the transaction. On November 28, 2017, the Company completed the sale of its high-end oscillators business ("Timing Device Business"). On July 7, 2016, the Company completed the sale of its speaker and receiver product line (“Speaker and Receiver Product Line”). In accordance with Accounting Standards Codification ("ASC") 205-20, Presentation of Financial Statements - Discontinued Operations, the results of operations and related assets and liabilities for the Timing Device Business and Speaker and Receiver Product Line have been reclassified as discontinued operations for all periods presented. See Note 2. Disposed and Discontinued Operations for additional information related to the transactions. In January 2017, the Company changed its allocation of resources and internal reporting structure to facilitate delivering growth in its core business. Following these changes, the Company's two reportable segments are Audio and Precision Devices ("PD"). See Note 17. Segment Information for additional information related to the Company’s segments. Financial Statement Presentation - The Consolidated Financial Statements included in this Annual Report on Form 10-K are presented in conformity with U.S. generally accepted accounting principles ("U.S. GAAP"). Use of Estimates - The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the accompanying financial statements and disclosures. These estimates may be adjusted due to changes in future economic, industry, or customer financial conditions, as well as changes in technology or demand. Estimates are used in accounting for, among other items, allowances for doubtful accounts receivable, inventory reserves, restructuring reserves, warranty reserves, pension and post-retirement plans, stock-based compensation, corporate allocations, useful lives for depreciation and amortization of long-lived assets, future cash flows associated with impairment testing for goodwill, indefinite-lived intangible assets and other long-lived assets, deferred tax assets, uncertain income tax positions, changes in tax laws, and contingencies. Actual results may ultimately differ from estimates, although management does not believe such differences would materially affect the financial statements in any individual year. Estimates and assumptions are periodically reviewed and the effects of revisions are reflected in the Consolidated Financial Statements in the period that they are determined. Cash and Cash Equivalents - Cash and cash equivalents include cash on hand, demand deposits, and temporary cash investments with original maturities less than three months. Allowance for Doubtful Accounts – The Company maintains allowances for estimated losses as a result of customers' inability to make required payments. Management evaluates the aging of the accounts receivable balances, the financial condition of its customers, historical trends, and the time outstanding of specific balances to estimate the amount of accounts receivable that may not be collected in the future and records the appropriate provision. Inventories – Inventories are stated at the lower of cost or net realizable value, determined on the first-in, first-out ("FIFO") basis. The value of inventory may decline as a result of surplus inventory, price reductions, or technological obsolescence. It is the Company’s policy to carry reserves against the carrying value of inventory when items have no future demand (obsolete inventory) and additionally, where inventory items on hand have demand, yet have insufficient forecasted activity to consume the entire stock within a reasonable period. It is the Company’s policy to carry reserves against the carrying value of such at-risk inventory items after considering the nature of the risk and any mitigating factors. Prepaid and Other Current Assets – Prepaid and other current assets at December 31, 2017 includes $10.0 million held in escrow related to the sale of the Timing Device Business that was received during the third quarter of 2018. The remaining balance at December 31, 2018 and 2017 is made up of prepaid insurance, supplier prepayments, prepaid licensing fees, and other miscellaneous prepaid assets, none of which are individually significant. Property, Plant, and Equipment - Property, plant, and equipment includes the historic cost of land, buildings, equipment, and significant improvements to existing plant and equipment or, in the case of acquisitions, a fair market value appraisal of such assets completed at the time of acquisition. Property, plant, and equipment also includes the cost of purchased software. Expenditures for maintenance, repairs, and minor renewals are expensed as incurred. When property or equipment is sold or otherwise disposed of, the related cost and accumulated depreciation is removed from the respective accounts, and the gain or loss realized on disposition is reflected in earnings. The Company historically depreciates its assets on a straight-line basis over their estimated useful lives as follows: buildings and improvements 5 to 31.5 years; machinery and equipment 1.5 to 7 years; furniture and fixtures 2 to 5 years; vehicles 3 to 5 years; and software 3 to 5 years. Derivative Instruments - The Company uses derivative financial instruments to hedge its exposures to various risks, including interest rate and foreign currency exchange rate risk. The Company does not enter into derivative financial instruments for speculative purposes and does not have a material portfolio of derivative financial instruments. Derivative financial instruments used for hedging purposes must be designated and effective as a hedge of the identified risk exposure at inception of the contract. The Company recognizes all derivatives as either assets or liabilities on the Consolidated Balance Sheets and measures those instruments at fair value. For derivatives designated as cash flow hedges, the effective portion of changes in the fair value of the derivatives is recorded as a component of other comprehensive earnings and subsequently recognized in net earnings when the hedged items impact earnings. Goodwill and Indefinite-Lived Intangible Assets - Goodwill represents the excess of purchase consideration over the fair value of the net assets of businesses acquired. Goodwill and certain other intangible assets deemed to have indefinite lives (primarily trademarks) are not amortized. Instead, goodwill and indefinite-lived intangible assets are tested for impairment at least annually, or more frequently if there are events or circumstances indicating the carrying value of individual reporting units or assets may exceed their respective fair values on a more likely than not basis. The Company performs its annual impairment assessment in the fourth quarter of each year on October 1. Recoverability of goodwill is measured at the reporting unit level. Following the sale of the Timing Device Business on November 28, 2017, the Company has three reporting units. The goodwill balances associated with the Mobile Consumer Electronics ("MCE"), Hearing Health Technologies ("HHT"), and Capacitors reporting units were $722.1 million, $137.8 million, and $28.0 million, respectively, as of December 31, 2018. The impairment assessment compares the fair value of each reporting unit to its carrying value. Impairment is measured as the amount by which the carrying value of a reporting unit exceeds its fair value. Fair value is estimated using a discounted cash flow approach that includes the Company’s market participant assumptions, projections of future cash flows based on historical performance and future estimated results, determinations of appropriate discount rates, and other assumptions which are considered reasonable and inherent in the discounted cash flow analysis. Significant assumptions used in the assessment include forecasted revenue and terminal growth rates, profit margins, income taxes, and the Company's weighted average cost of capital. These assumptions require significant judgment and actual results may differ from estimated amounts. The fair value of all of the Company’s reporting units exceeded the carrying values by at least 50%, resulting in no goodwill impairment charges. Potential circumstances that could have a negative effect on the fair value of our reporting units include, but are not limited to, lower than forecasted growth rates or profit margins and changes in the weighted average cost of capital. A reduction in the estimated fair value of the reporting units could trigger an impairment in the future. The Company cannot predict the occurrence of certain events or changes in circumstances that might adversely affect the carrying value of goodwill and intangible assets. In testing its other indefinite-lived intangible assets for impairment, the Company uses a relief from royalty method to calculate and compare the fair value of the intangible asset to its carrying value. This method estimates the fair value of trademarks by calculating the present value of royalty income that could hypothetically be earned by licensing the trademark to a third party. Any excess of carrying value over the estimated fair value is recognized as an impairment loss. No impairment of indefinite-lived intangibles was indicated for the years ended December 31, 2018, 2017, or 2016. See Note 7. Goodwill and Other Intangible Assets for additional information on goodwill and indefinite-lived intangible assets. Other Intangible and Long-Lived Assets - Other intangible assets with determinable lives consist primarily of customer relationships, unpatented technology, patents, and trademarks and are amortized over their estimated useful lives, historically ranging from 5 to 15 years. The Company relies on patents and proprietary technology, and seeks patent protection for products and production methods. The Company capitalizes external legal costs incurred in the defense of its patents when it believes that a significant, discernible increase in value will result from the defense and a successful outcome of the legal action is probable. These costs are amortized over the remaining estimated useful life of the patent, which is typically 7 to 10 years. The Company’s assessment of future economic benefit and/or the successful outcome of legal action related to patent defense involves considerable management judgment and a different outcome could result in material write-offs of the carrying value of these assets. The Company capitalized no legal costs related to the defense of its patents during the years ended December 31, 2018, 2017, and 2016. Long-lived assets (including intangible assets with determinable lives) are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If an indicator of impairment exists for any grouping of assets, an estimate of undiscounted future cash flows is produced and compared to its carrying value. If an asset is determined to be impaired, the loss is measured by the excess of the carrying amount of the asset over its fair value as determined by an estimate of discounted future cash flows. The Company recorded no impairments during the year ended December 31, 2018. During the years ended December 31, 2017 and 2016, the Company recorded impairments and other charges related to its continuing operations of $21.3 million and $0.5 million, respectively. See Note 4. Impairments for additional details. Foreign Currency - Assets and liabilities of non-U.S. subsidiaries, where the functional currency is not the U.S. dollar, are translated into U.S. dollars at year-end exchange rates. Revenue and expense items are translated using weighted-average yearly exchange rates. Foreign currency translation gains and losses are included as a component of Accumulated other comprehensive loss. Assets and liabilities of an entity that are denominated in currencies other than an entity’s functional currency are re-measured into the functional currency using end of period exchange rates or historical rates where applicable to certain balances. Gains and losses related to these re-measurements are recorded within the Consolidated Statements of Earnings as a component of Other expense (income), net. Revenue Recognition - The Company adopted ASC 606, Revenue from Contracts with Customers, on January 1, 2018 using the modified retrospective (cumulative effect) transition method. Refer to the Recently Adopted Accounting Standards section below for additional information. Stock-Based Compensation – The principal awards issued under the stock-based compensation plans include stock options, restricted stock units ("RSUs"), and performance share units ("PSUs"). The cost for such awards is measured at the grant date based on the fair value of the award. The value of the portion of the award that is expected to ultimately vest is generally recognized as expense on a straight-line basis, generally over the explicit service period and is included in Cost of goods sold, Research and development expenses, and Selling and administrative expenses in the Consolidated Statements of Earnings, depending on the functional area of the underlying employees. The cost related to PSUs is recognized based on the expected attainment of performance targets. Changes in estimates that impact the number of shares expected to vest are recognized prospectively through cumulative adjustments. The Company uses the Black-Scholes valuation model to estimate the fair value of stock options granted to employees. The fair value of each RSU granted is equal to the share price at the date of the grant. The fair value of each PSU is determined using a binomial model simulation. At the time of grant, the Company estimates forfeitures, based on historical experience, in order to estimate the portion of the award that will ultimately vest. See Note 13. Equity Incentive Program for additional information related to the Company’s stock-based compensation. Income Taxes - The Company records a provision for income taxes for the anticipated tax consequences of the reported results of operations using the asset and liability method. Under this method, the Company recognizes deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities, as well as for operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using the tax rates that are expected to apply to taxable income for the years in which those tax assets and liabilities are expected to be realized or settled. The Company offsets and presents deferred tax liabilities and assets, as well as any related valuation allowance, as a single non-current amount on the Consolidated Balance Sheets on a jurisdictional basis. The Company establishes valuation allowances for its deferred tax assets if, based on all available positive and negative evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. In making such assessments, significant weight is given to evidence that can be objectively verified. The assessment of the need for a valuation allowance requires considerable judgment on the part of management with respect to the benefits that could be realized from future taxable income, as well as other positive and negative factors. Management considers the scheduled reversal of deferred tax liabilities, projected future taxable income, and tax-planning strategies in making this assessment. The Company recognizes tax benefits from uncertain tax positions only if it believes that it is more likely than not that the tax position will be sustained on examination by the taxing authorities based on the technical merits of the position. Adjustments are made to these reserves when facts and circumstances change, such as the closing of a tax audit or the refinement of an estimate. To the extent that the final tax outcome of these matters is different than the amounts recorded, such differences will affect the provision for income taxes in the period in which such determination is made and could have a material impact on the Company's financial condition and operating results. The provision for income taxes includes the effects of any reserves that are believed to be appropriate, as well as the related net interest and penalties. On December 22, 2017, the U.S. bill commonly referred to as the Tax Cuts and Jobs Act ("Tax Reform Act") was enacted, which significantly changed U.S. tax law by, among other things, lowering corporate income tax rates, implementing a territorial tax system, and imposing a repatriation tax on deemed repatriated earnings of foreign subsidiaries. The Tax Reform Act permanently reduces the U.S. corporate income tax rate from a maximum of 35% to a flat 21% rate, effective January 1, 2018. The Tax Reform Act also provided for a one-time deemed repatriation of post-1986 undistributed foreign subsidiary earnings and profits ("E&P") through the year ended December 31, 2017. The Global Intangible Low-Taxed Income ("GILTI") provisions of the Tax Reform Act also require the Company to include in its U.S. income tax return foreign subsidiary earnings in excess of an allowable return on the foreign subsidiary’s tangible assets. The Company was subject to the GILTI provisions beginning in 2018. The Company has elected to account for GILTI tax in the period in which it is incurred, and therefore has not provided any deferred tax impacts of GILTI in its Consolidated Financial Statements. On December 22, 2017, the Securities and Exchange Commission ("SEC") staff issued Staff Accounting Bulletin No. 118 (“SAB 118”) to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Reform Act. The Company recognized provisional tax impacts related to deemed repatriated earnings, the change in beginning of year valuation allowance, and the benefit for the remeasurement of deferred tax assets and liabilities as of December 31, 2017. During the fourth quarter of 2018, the Company finalized its accounting for the effects of the Tax Reform Act under SAB 118. The Company recorded a $17.8 million reduction to the net transition tax liability due to the impact of an Internal Revenue Service ("IRS") approval for an entity classification received during the fourth quarter of 2018. During the third quarter of 2018, the Company recorded an uncertain tax position of $36.0 million related to consequences of the Tax Reform Act. As a result of the IRS approval for an entity classification received during the fourth quarter of 2018, the Company recognized a $36.0 million benefit related to the release of the uncertain tax position. Although the Company’s accounting for the effects of the Tax Reform Act is finalized under SAB 118, there may be future adjustments based on potential changes in the interpretation of the Tax Reform Act, its supporting regulations, and subsequent guidance that may be issued. The impact of any such adjustments, which could have a material impact on the Consolidated Financial Statements, will be recognized in the period the changes arise or the related regulations are enacted. The Company is in the process of evaluating the final regulations on Section 965, which were released by the IRS on January 15, 2019, and will recognize any related impact in the first quarter of 2019. Research and Development Costs – Research and development costs, including qualifying engineering costs, are expensed when incurred. Non-cash Investing Activities - Purchases of property, plant, and equipment included in accounts payable at December 31, 2018, 2017, and 2016 were $7.1 million, $8.5 million, and $1.5 million, respectively. These non-cash amounts are not reflected as outflows to Additions to property, plant, and equipment within investing activities of the Consolidated Statements of Cash Flows for the respective periods. Reclassifications - Certain amounts in prior years have been reclassified to conform to the current year presentation. Refer to the Recently Adopted Accounting Standards section below for additional information. Recently Issued Accounting Standards In August 2018, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2018-14 to amend disclosure requirements related to defined benefit pension and other postretirement plans. The standard is effective for public business entities for fiscal years beginning after December 15, 2020. Early adoption is permitted and retrospective application of the guidance is required. The Company has not yet determined the impact of the standard on its disclosures or its adoption date. In February 2018, the FASB issued ASU 2018-02, which allows the reclassification from accumulated other comprehensive income to retained earnings of stranded tax effects resulting from the Tax Reform Act. The standard also requires certain disclosures concerning stranded tax effects regardless of the election with respect to stranded tax effects resulting from the Tax Reform Act. The standard is effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. The standard should be applied either in the period of adoption or retrospectively to each period (or periods) in which the effects of the Tax Reform Act were recognized. The Company has elected to reclassify the stranded tax effects resulting from the Tax Reform Act upon adoption of the standard on January 1, 2019, the impact of which will not be significant. In February 2016, the FASB issued ASU 2016-02 and issued subsequent amendments to the initial guidance within ASU 2018-01, ASU 2018-10, ASU 2018-11, and ASU 2018-20, which are collectively referred to as "ASC 842." This guidance requires a lessee to recognize a lease liability and right-of-use asset for all leases, including operating leases, with a term greater than 12 months. The guidance also provides clarification surrounding the presentation of the effects of leases in the statement of earnings. This standard is effective for public business entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Prior to the issuance of ASU 2018-11 in July 2018, the standard required a modified retrospective transition method under which the guidance would be applied at the beginning of the earliest comparative period presented in the financial statements. ASU 2018-11 allows entities to elect an additional transition method under which the guidance would be applied as of the adoption date. The Company will adopt the standard under this new transition method that will not require comparative period financial statements to be recast. The standard includes a number of optional practical expedients that entities may elect to apply. The Company will elect the transition package of practical expedients for leases that commenced before the adoption date, which among other things, allows the Company to carry forward historical lease classifications. The Company will also elect the practical expedient to not separate nonlease components from lease components, which may increase lease liabilities and right-of-use assets through the inclusion of payments for nonlease components such as maintenance. The Company is finalizing its evaluation of the impact of the standard on its Consolidated Financial Statements, accounting processes, internal controls, and disclosures. The impact of adoption will depend on the lease portfolio as of the transition date and the Company's accounting policy elections. The Company expects to recognize $40 million to $45 million of operating lease liabilities and $37 million to $42 million of operating lease right-of-use assets on its Consolidated Balance Sheets upon adoption of the standard. The standard is not expected to have any other material impacts on the Consolidated Financial Statements. The adoption date for the standard is January 1, 2019. Recently Adopted Accounting Standards In August 2017, the FASB issued ASU 2017-12 with the objective of improving the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements and simplify the application of hedge accounting guidance. The standard is effective for public business entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. The standard requires adoption on a modified retrospective basis for hedging relationships existing as of the adoption date and on a prospective basis for the amended presentation and disclosure requirements. The Company elected to early adopt the standard as of January 1, 2018. Adoption of the standard did not result in a cumulative effect adjustment to retained earnings as of January 1, 2018 as the Company had no cumulative ineffectiveness recognized under its hedging relationships existing as of the adoption date. See Note 10. Hedging Transactions and Derivative Instruments for detail on the Company's prospective adoption of the amended presentation and disclosure requirements. The adoption of this standard had no other impact on the Consolidated Financial Statements. In May 2017, the FASB issued ASU 2017-09 that provides guidance about when a change to the terms or conditions of a share based payment award must be accounted for as a modification. The new guidance requires modification accounting if the fair value, vesting condition, or classification of an award is not the same immediately before and after a change to the terms and conditions of the award. This standard is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company prospectively adopted this guidance on January 1, 2018, which had no impact on the Consolidated Financial Statements. In March 2017, the FASB issued ASU 2017-07 primarily to improve the presentation of net periodic pension and post-retirement benefit cost. The new guidance requires that an employer report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be presented in the statement of earnings separately from the service cost component and outside of any subtotal of operating income. This standard is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company adopted this guidance on January 1, 2018 using a retrospective approach for the presentation of net benefit cost components. For the year ended December 31, 2017, net benefit income other than service cost of $0.3 million previously presented in both the Cost of goods sold and Selling and administrative expenses lines on the Consolidated Statements of Earnings has been reclassified to the Other expense (income), net line. For the year ended December 31, 2016, net benefit income other than service cost of $0.2 million previously presented in the Cost of goods sold line on the Consolidated Statements of Earnings has been reclassified to the Other expense (income), net line. The adoption of this standard had no other impact on the Consolidated Financial Statements. See Note 15. Employee Benefit Plans for additional information related to the Company’s pension and post-retirement plans. In January 2017, the FASB issued ASU 2017-01, which requires a reporting entity to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or liabilities. This standard is effective for public business entities for annual periods beginning after December 15, 2017, including interim periods within those periods. The Company prospectively adopted this guidance on January 1, 2018, which had no impact on the Consolidated Financial Statements. In August 2016, the FASB issued ASU 2016-15 with the objective of reducing the existing diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The new guidance requires evaluation of cash receipts and payments on the basis of the nature of the underlying cash flows and provides clarity for categorization for specific transactions. This standard is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company retrospectively adopted this guidance on January 1, 2018, which had no impact on the Consolidated Financial Statements. In January 2016, the FASB issued ASU 2016-01, which requires a company to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk if the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. This standard is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company adopted this guidance on a modified retrospective basis as of January 1, 2018, which had no impact on the Consolidated Financial Statements. In May 2014, the FASB issued ASU 2014-09 and issued subsequent amendments to the initial guidance within ASU 2015-14, ASU 2016-08, ASU 2016-10, ASU 2016-12, and ASU 2016-20, which are collectively referred to as "ASC 606." The core principal of the guidance is to provide a comprehensive revenue recognition model that requires a company to recognize revenue to depict the transfer of goods or services to a customer at an amount that reflects the consideration it expects to receive in exchange for those goods or services. The guidance also requires additional disclosure about the nature, amount, timing, and uncertainty of revenue and cash flows arising from customer contracts. The standard is effective for annual and interim periods beginning after December 15, 2017. On January 1, 2018, the Company adopted ASC 606 using the modified retrospective (cumulative effect) transition method. Under this transition method, results for reporting periods beginning January 1, 2018 or later are presented under ASC 606, while prior period results continue to be reported in accordance with previous guidance. The Company did not recognize a cumulative effect adjustment to retained earnings as of January 1, 2018 as the impact of the standard on the Consolidated Financial Statements was not material. As described below, the analysis of contracts under ASC 606 supports the recognition of revenue at a point in time, resulting in revenue recognition timing that is materially consistent with our historical practice of recognizing revenue when title and risk of loss pass to the customer. Revenue is recognized when control of the promised goods or services is transferred to the customer in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The majority of the Company’s revenue is generated through the manufacture and sale of a broad range of specialized products and components. For product and component sales, each good sold to a customer typically represents a distinct performance obligation. The Company’s performance obligation to provide goods to a customer is typically satisfied at a point in time upon completion of the shipping process as indicated by the terms of the contract, at which point control is transferred to the customer and revenue is recognized. The Company has no significant arrangements with multiple performance obligations. Remaining performance obligations consist of the aggregate amount of the total transaction price that is unsatisfied or partially satisfied. As of December 31, 2018, our total remaining performance obligations are immaterial. The Company recognizes sales-based royalty revenue under third-party license agreements as the related sales are made by licensees. The terms of a contract or historical business practice can give rise to variable consideration, including customer discounts, rebates, and returns. The Company estimates variable consideration using either the expected value or most likely amount method. We include estimated amounts in the transaction price to the extent it is probable that a significant reversal of revenue will not occur in a subsequent reporting period. Our estimates of variable consideration are based on all reasonably available information (historical, current, and forecasted). Rebates are recognized over the contract period based on expected revenue levels. Sales discounts and rebates totaled $8.1 million, $9.1 million, and $8.7 million for the years ended December 31, 2018, 2017, and 2016, respectively. Returns and allowances totaled $7.7 million, $8.5 million, and $5.1 million for the years ended December 31, 2018, 2017, and 2016, respectively. The Company elected to account for shipping and handling activities that occur after control of the related good transfers to the customer as fulfillment activities rather than evaluating such activities as performance obligations. As a result, all shipping and handling costs related to contracts with customers are recognized in the Cost of goods sold line on the Consolidated Statements of Earnings, which is consistent with our historical practice. Additionally, the Company elected to apply the practical expedient allowing incremental costs of obtaining a contract to be expensed as incurred if the amortization period of the resulting asset would have been less than one year. These costs primarily consist of sales commissions and the Company has no such significant costs exceeding the one year limit for applying the practical expedient. Receivables, net from contracts with customers were $128.6 million and $127.0 million as of December 31, 2018 and January 1, 2018, respectively. See Note 17. Segment Information for disclosures regarding the disaggregation of revenues.

Background - Knowles Corporation (NYSE:KN) is a market leader and global provider of advanced micro-acoustic, audio processing, and precision device solutions, serving the mobile consumer electronics, communications, medical, defense, aerospace, and industrial markets. The Company uses its leading position in micro-electro-mechanical systems ("MEMS") microphones and strong capabilities in audio processing technologies to optimize audio systems and improve the user experience in mobile, ear, and Internet of Things ("IoT") applications. Knowles is also the leader in acoustics components used in hearing aids and has a strong position in high-end capacitors. The Company's focus on its customers, combined with its unique technology, proprietary manufacturing techniques, rigorous testing, and global scale, enable the Company to deliver innovative solutions that optimize the user experience. References to "Knowles," "the Company," "we," "our," and "us" refer to Knowles Corporation and its consolidated subsidiaries. Our common stock began trading under the ticker symbol “KN” on the New York Stock Exchange (the “NYSE”) on March 3, 2014.

On November 28, 2017, the Company completed the sale of its high-end oscillators business ("Timing Device Business"). On July 7, 2016, the Company completed the sale of its speaker and receiver product line (“Speaker and Receiver Product Line”). In accordance with Accounting Standards Codification ("ASC") 205-20, Presentation of Financial Statements - Discontinued Operations, the results of operations and related assets and liabilities for the Timing Device Business and Speaker and Receiver Product Line have been reclassified as discontinued operations for all periods presented. See Note 2. Disposed and Discontinued Operations for additional information related to the transactions.

In January 2017, the Company changed its allocation of resources and internal reporting structure to facilitate delivering growth in its core business. Following these changes, the Company's two reportable segments are Audio and Precision Devices ("PD"). See Note 17. Segment Information for additional information related to the Company’s segments.

Use of Estimates - The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the accompanying financial statements and disclosures. These estimates may be adjusted due to changes in future economic, industry, or customer financial conditions, as well as changes in technology or demand. Estimates are used in accounting for, among other items, allowances for doubtful accounts receivable, inventory reserves, restructuring reserves, warranty reserves, pension and post-retirement plans, stock-based compensation, corporate allocations, useful lives for depreciation and amortization of long-lived assets, future cash flows associated with impairment testing for goodwill, indefinite-lived intangible assets and other long-lived assets, deferred tax assets, uncertain income tax positions, changes in tax laws, and contingencies. Actual results may ultimately differ from estimates, although management does not believe such differences would materially affect the financial statements in any individual year. Estimates and assumptions are periodically reviewed and the effects of revisions are reflected in the Consolidated Financial Statements in the period that they are determined.

Allowance for Doubtful Accounts – The Company maintains allowances for estimated losses as a result of customers' inability to make required payments. Management evaluates the aging of the accounts receivable balances, the financial condition of its customers, historical trends, and the time outstanding of specific balances to estimate the amount of accounts receivable that may not be collected in the future and records the appropriate provision.

Inventories – Inventories are stated at the lower of cost or net realizable value, determined on the first-in, first-out ("FIFO") basis. The value of inventory may decline as a result of surplus inventory, price reductions, or technological obsolescence. It is the Company’s policy to carry reserves against the carrying value of inventory when items have no future demand (obsolete inventory) and additionally, where inventory items on hand have demand, yet have insufficient forecasted activity to consume the entire stock within a reasonable period. It is the Company’s policy to carry reserves against the carrying value of such at-risk inventory items after considering the nature of the risk and any mitigating factors.

Prepaid and Other Current Assets – Prepaid and other current assets at December 31, 2017 includes $10.0 million held in escrow related to the sale of the Timing Device Business that was received during the third quarter of 2018. The remaining balance at December 31, 2018 and 2017 is made up of prepaid insurance, supplier prepayments, prepaid licensing fees, and other miscellaneous prepaid assets, none of which are individually significant.

Property, Plant, and Equipment - Property, plant, and equipment includes the historic cost of land, buildings, equipment, and significant improvements to existing plant and equipment or, in the case of acquisitions, a fair market value appraisal of such assets completed at the time of acquisition. Property, plant, and equipment also includes the cost of purchased software. Expenditures for maintenance, repairs, and minor renewals are expensed as incurred. When property or equipment is sold or otherwise disposed of, the related cost and accumulated depreciation is removed from the respective accounts, and the gain or loss realized on disposition is reflected in earnings. The Company historically depreciates its assets on a straight-line basis over their estimated useful lives as follows: buildings and improvements 5 to 31.5 years; machinery and equipment 1.5 to 7 years; furniture and fixtures 2 to 5 years; vehicles 3 to 5 years; and software 3 to 5 years.

Derivative Instruments - The Company uses derivative financial instruments to hedge its exposures to various risks, including interest rate and foreign currency exchange rate risk. The Company does not enter into derivative financial instruments for speculative purposes and does not have a material portfolio of derivative financial instruments. Derivative financial instruments used for hedging purposes must be designated and effective as a hedge of the identified risk exposure at inception of the contract. The Company recognizes all derivatives as either assets or liabilities on the Consolidated Balance Sheets and measures those instruments at fair value. For derivatives designated as cash flow hedges, the effective portion of changes in the fair value of the derivatives is recorded as a component of other comprehensive earnings and subsequently recognized in net earnings when the hedged items impact earnings.

Goodwill and Indefinite-Lived Intangible Assets - Goodwill represents the excess of purchase consideration over the fair value of the net assets of businesses acquired. Goodwill and certain other intangible assets deemed to have indefinite lives (primarily trademarks) are not amortized. Instead, goodwill and indefinite-lived intangible assets are tested for impairment at least annually, or more frequently if there are events or circumstances indicating the carrying value of individual reporting units or assets may exceed their respective fair values on a more likely than not basis. The Company performs its annual impairment assessment in the fourth quarter of each year on October 1. Recoverability of goodwill is measured at the reporting unit level. Following the sale of the Timing Device Business on November 28, 2017, the Company has three reporting units. The goodwill balances associated with the Mobile Consumer Electronics ("MCE"), Hearing Health Technologies ("HHT"), and Capacitors reporting units were $722.1 million, $137.8 million, and $28.0 million, respectively, as of December 31, 2018.

The impairment assessment compares the fair value of each reporting unit to its carrying value. Impairment is measured as the amount by which the carrying value of a reporting unit exceeds its fair value. Fair value is estimated using a discounted cash flow approach that includes the Company’s market participant assumptions, projections of future cash flows based on historical performance and future estimated results, determinations of appropriate discount rates, and other assumptions which are considered reasonable and inherent in the discounted cash flow analysis. Significant assumptions used in the assessment include forecasted revenue and terminal growth rates, profit margins, income taxes, and the Company's weighted average cost of capital. These assumptions require significant judgment and actual results may differ from estimated amounts. The fair value of all of the Company’s reporting units exceeded the carrying values by at least 50%, resulting in no goodwill impairment charges. Potential circumstances that could have a negative effect on the fair value of our reporting units include, but are not limited to, lower than forecasted growth rates or profit margins and changes in the weighted average cost of capital. A reduction in the estimated fair value of the reporting units could trigger an impairment in the future. The Company cannot predict the occurrence of certain events or changes in circumstances that might adversely affect the carrying value of goodwill and intangible assets.

In testing its other indefinite-lived intangible assets for impairment, the Company uses a relief from royalty method to calculate and compare the fair value of the intangible asset to its carrying value. This method estimates the fair value of trademarks by calculating the present value of royalty income that could hypothetically be earned by licensing the trademark to a third party. Any excess of carrying value over the estimated fair value is recognized as an impairment loss. No impairment of indefinite-lived intangibles was indicated for the years ended December 31, 2018, 2017, or 2016.

Other Intangible and Long-Lived Assets - Other intangible assets with determinable lives consist primarily of customer relationships, unpatented technology, patents, and trademarks and are amortized over their estimated useful lives, historically ranging from 5 to 15 years. The Company relies on patents and proprietary technology, and seeks patent protection for products and production methods. The Company capitalizes external legal costs incurred in the defense of its patents when it believes that a significant, discernible increase in value will result from the defense and a successful outcome of the legal action is probable. These costs are amortized over the remaining estimated useful life of the patent, which is typically 7 to 10 years. The Company’s assessment of future economic benefit and/or the successful outcome of legal action related to patent defense involves considerable management judgment and a different outcome could result in material write-offs of the carrying value of these assets. The Company capitalized no legal costs related to the defense of its patents during the years ended December 31, 2018, 2017, and 2016.

Long-lived assets (including intangible assets with determinable lives) are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If an indicator of impairment exists for any grouping of assets, an estimate of undiscounted future cash flows is produced and compared to its carrying value. If an asset is determined to be impaired, the loss is measured by the excess of the carrying amount of the asset over its fair value as determined by an estimate of discounted future cash flows.

Foreign Currency - Assets and liabilities of non-U.S. subsidiaries, where the functional currency is not the U.S. dollar, are translated into U.S. dollars at year-end exchange rates. Revenue and expense items are translated using weighted-average yearly exchange rates. Foreign currency translation gains and losses are included as a component of Accumulated other comprehensive loss. Assets and liabilities of an entity that are denominated in currencies other than an entity’s functional currency are re-measured into the functional currency using end of period exchange rates or historical rates where applicable to certain balances. Gains and losses related to these re-measurements are recorded within the Consolidated Statements of Earnings as a component of Other expense (income), net.

Stock-Based Compensation – The principal awards issued under the stock-based compensation plans include stock options, restricted stock units ("RSUs"), and performance share units ("PSUs"). The cost for such awards is measured at the grant date based on the fair value of the award. The value of the portion of the award that is expected to ultimately vest is generally recognized as expense on a straight-line basis, generally over the explicit service period and is included in Cost of goods sold, Research and development expenses, and Selling and administrative expenses in the Consolidated Statements of Earnings, depending on the functional area of the underlying employees. The cost related to PSUs is recognized based on the expected attainment of performance targets. Changes in estimates that impact the number of shares expected to vest are recognized prospectively through cumulative adjustments.

The Company uses the Black-Scholes valuation model to estimate the fair value of stock options granted to employees. The fair value of each RSU granted is equal to the share price at the date of the grant. The fair value of each PSU is determined using a binomial model simulation. At the time of grant, the Company estimates forfeitures, based on historical experience, in order to estimate the portion of the award that will ultimately vest. See Note 13. Equity Incentive Program for additional information related to the Company’s stock-based compensation.

Income Taxes - The Company records a provision for income taxes for the anticipated tax consequences of the reported results of operations using the asset and liability method. Under this method, the Company recognizes deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities, as well as for operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using the tax rates that are expected to apply to taxable income for the years in which those tax assets and liabilities are expected to be realized or settled. The Company offsets and presents deferred tax liabilities and assets, as well as any related valuation allowance, as a single non-current amount on the Consolidated Balance Sheets on a jurisdictional basis.

The Company establishes valuation allowances for its deferred tax assets if, based on all available positive and negative evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. In making such assessments, significant weight is given to evidence that can be objectively verified. The assessment of the need for a valuation allowance requires considerable judgment on the part of management with respect to the benefits that could be realized from future taxable income, as well as other positive and negative factors. Management considers the scheduled reversal of deferred tax liabilities, projected future taxable income, and tax-planning strategies in making this assessment.

The Company recognizes tax benefits from uncertain tax positions only if it believes that it is more likely than not that the tax position will be sustained on examination by the taxing authorities based on the technical merits of the position. Adjustments are made to these reserves when facts and circumstances change, such as the closing of a tax audit or the refinement of an estimate. To the extent that the final tax outcome of these matters is different than the amounts recorded, such differences will affect the provision for income taxes in the period in which such determination is made and could have a material impact on the Company's financial condition and operating results. The provision for income taxes includes the effects of any reserves that are believed to be appropriate, as well as the related net interest and penalties.

On December 22, 2017, the U.S. bill commonly referred to as the Tax Cuts and Jobs Act ("Tax Reform Act") was enacted, which significantly changed U.S. tax law by, among other things, lowering corporate income tax rates, implementing a territorial tax system, and imposing a repatriation tax on deemed repatriated earnings of foreign subsidiaries. The Tax Reform Act permanently reduces the U.S. corporate income tax rate from a maximum of 35% to a flat 21% rate, effective January 1, 2018. The Tax Reform Act also provided for a one-time deemed repatriation of post-1986 undistributed foreign subsidiary earnings and profits ("E&P") through the year ended December 31, 2017. The Global Intangible Low-Taxed Income ("GILTI") provisions of the Tax Reform Act also require the Company to include in its U.S. income tax return foreign subsidiary earnings in excess of an allowable return on the foreign subsidiary’s tangible assets. The Company was subject to the GILTI provisions beginning in 2018. The Company has elected to account for GILTI tax in the period in which it is incurred, and therefore has not provided any deferred tax impacts of GILTI in its Consolidated Financial Statements.

On December 22, 2017, the Securities and Exchange Commission ("SEC") staff issued Staff Accounting Bulletin No. 118 (“SAB 118”) to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Reform Act. The Company recognized provisional tax impacts related to deemed repatriated earnings, the change in beginning of year valuation allowance, and the benefit for the remeasurement of deferred tax assets and liabilities as of December 31, 2017. During the fourth quarter of 2018, the Company finalized its accounting for the effects of the Tax Reform Act under SAB 118. The Company recorded a $17.8 million reduction to the net transition tax liability due to the impact of an Internal Revenue Service ("IRS") approval for an entity classification received during the fourth quarter of 2018.

During the third quarter of 2018, the Company recorded an uncertain tax position of $36.0 million related to consequences of the Tax Reform Act. As a result of the IRS approval for an entity classification received during the fourth quarter of 2018, the Company recognized a $36.0 million benefit related to the release of the uncertain tax position.

Although the Company’s accounting for the effects of the Tax Reform Act is finalized under SAB 118, there may be future adjustments based on potential changes in the interpretation of the Tax Reform Act, its supporting regulations, and subsequent guidance that may be issued. The impact of any such adjustments, which could have a material impact on the Consolidated Financial Statements, will be recognized in the period the changes arise or the related regulations are enacted. The Company is in the process of evaluating the final regulations on Section 965, which were released by the IRS on January 15, 2019, and will recognize any related impact in the first quarter of 2019.

Non-cash Investing Activities - Purchases of property, plant, and equipment included in accounts payable at December 31, 2018, 2017, and 2016 were $7.1 million, $8.5 million, and $1.5 million, respectively. These non-cash amounts are not reflected as outflows to Additions to property, plant, and equipment within investing activities of the Consolidated Statements of Cash Flows for the respective periods.

In August 2018, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2018-14 to amend disclosure requirements related to defined benefit pension and other postretirement plans. The standard is effective for public business entities for fiscal years beginning after December 15, 2020. Early adoption is permitted and retrospective application of the guidance is required. The Company has not yet determined the impact of the standard on its disclosures or its adoption date.

In February 2018, the FASB issued ASU 2018-02, which allows the reclassification from accumulated other comprehensive income to retained earnings of stranded tax effects resulting from the Tax Reform Act. The standard also requires certain disclosures concerning stranded tax effects regardless of the election with respect to stranded tax effects resulting from the Tax Reform Act. The standard is effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. The standard should be applied either in the period of adoption or retrospectively to each period (or periods) in which the effects of the Tax Reform Act were recognized. The Company has elected to reclassify the stranded tax effects resulting from the Tax Reform Act upon adoption of the standard on January 1, 2019, the impact of which will not be significant.

In February 2016, the FASB issued ASU 2016-02 and issued subsequent amendments to the initial guidance within ASU 2018-01, ASU 2018-10, ASU 2018-11, and ASU 2018-20, which are collectively referred to as "ASC 842." This guidance requires a lessee to recognize a lease liability and right-of-use asset for all leases, including operating leases, with a term greater than 12 months. The guidance also provides clarification surrounding the presentation of the effects of leases in the statement of earnings. This standard is effective for public business entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Prior to the issuance of ASU 2018-11 in July 2018, the standard required a modified retrospective transition method under which the guidance would be applied at the beginning of the earliest comparative period presented in the financial statements. ASU 2018-11 allows entities to elect an additional transition method under which the guidance would be applied as of the adoption date. The Company will adopt the standard under this new transition method that will not require comparative period financial statements to be recast.

The standard includes a number of optional practical expedients that entities may elect to apply. The Company will elect the transition package of practical expedients for leases that commenced before the adoption date, which among other things, allows the Company to carry forward historical lease classifications. The Company will also elect the practical expedient to not separate nonlease components from lease components, which may increase lease liabilities and right-of-use assets through the inclusion of payments for nonlease components such as maintenance.

The Company is finalizing its evaluation of the impact of the standard on its Consolidated Financial Statements, accounting processes, internal controls, and disclosures. The impact of adoption will depend on the lease portfolio as of the transition date and the Company's accounting policy elections. The Company expects to recognize $40 million to $45 million of operating lease liabilities and $37 million to $42 million of operating lease right-of-use assets on its Consolidated Balance Sheets upon adoption of the standard. The standard is not expected to have any other material impacts on the Consolidated Financial Statements. The adoption date for the standard is January 1, 2019.

In August 2017, the FASB issued ASU 2017-12 with the objective of improving the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements and simplify the application of hedge accounting guidance. The standard is effective for public business entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. The standard requires adoption on a modified retrospective basis for hedging relationships existing as of the adoption date and on a prospective basis for the amended presentation and disclosure requirements. The Company elected to early adopt the standard as of January 1, 2018. Adoption of the standard did not result in a cumulative effect adjustment to retained earnings as of January 1, 2018 as the Company had no cumulative ineffectiveness recognized under its hedging relationships existing as of the adoption date. See Note 10. Hedging Transactions and Derivative Instruments for detail on the Company's prospective adoption of the amended presentation and disclosure requirements. The adoption of this standard had no other impact on the Consolidated Financial Statements.

In May 2017, the FASB issued ASU 2017-09 that provides guidance about when a change to the terms or conditions of a share based payment award must be accounted for as a modification. The new guidance requires modification accounting if the fair value, vesting condition, or classification of an award is not the same immediately before and after a change to the terms and conditions of the award. This standard is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company prospectively adopted this guidance on January 1, 2018, which had no impact on the Consolidated Financial Statements.

In March 2017, the FASB issued ASU 2017-07 primarily to improve the presentation of net periodic pension and post-retirement benefit cost. The new guidance requires that an employer report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be presented in the statement of earnings separately from the service cost component and outside of any subtotal of operating income. This standard is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company adopted this guidance on January 1, 2018 using a retrospective approach for the presentation of net benefit cost components. For the year ended December 31, 2017, net benefit income other than service cost of $0.3 million previously presented in both the Cost of goods sold and Selling and administrative expenses lines on the Consolidated Statements of Earnings has been reclassified to the Other expense (income), net line. For the year ended December 31, 2016, net benefit income other than service cost of $0.2 million previously presented in the Cost of goods sold line on the Consolidated Statements of Earnings has been reclassified to the Other expense (income), net line. The adoption of this standard had no other impact on the Consolidated Financial Statements. See Note 15. Employee Benefit Plans for additional information related to the Company’s pension and post-retirement plans.

In January 2017, the FASB issued ASU 2017-01, which requires a reporting entity to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or liabilities. This standard is effective for public business entities for annual periods beginning after December 15, 2017, including interim periods within those periods. The Company prospectively adopted this guidance on January 1, 2018, which had no impact on the Consolidated Financial Statements.

In August 2016, the FASB issued ASU 2016-15 with the objective of reducing the existing diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The new guidance requires evaluation of cash receipts and payments on the basis of the nature of the underlying cash flows and provides clarity for categorization for specific transactions. This standard is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company retrospectively adopted this guidance on January 1, 2018, which had no impact on the Consolidated Financial Statements.

In January 2016, the FASB issued ASU 2016-01, which requires a company to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk if the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. This standard is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company adopted this guidance on a modified retrospective basis as of January 1, 2018, which had no impact on the Consolidated Financial Statements.

In May 2014, the FASB issued ASU 2014-09 and issued subsequent amendments to the initial guidance within ASU 2015-14, ASU 2016-08, ASU 2016-10, ASU 2016-12, and ASU 2016-20, which are collectively referred to as "ASC 606." The core principal of the guidance is to provide a comprehensive revenue recognition model that requires a company to recognize revenue to depict the transfer of goods or services to a customer at an amount that reflects the consideration it expects to receive in exchange for those goods or services. The guidance also requires additional disclosure about the nature, amount, timing, and uncertainty of revenue and cash flows arising from customer contracts. The standard is effective for annual and interim periods beginning after December 15, 2017.

On January 1, 2018, the Company adopted ASC 606 using the modified retrospective (cumulative effect) transition method. Under this transition method, results for reporting periods beginning January 1, 2018 or later are presented under ASC 606, while prior period results continue to be reported in accordance with previous guidance. The Company did not recognize a cumulative effect adjustment to retained earnings as of January 1, 2018 as the impact of the standard on the Consolidated Financial Statements was not material. As described below, the analysis of contracts under ASC 606 supports the recognition of revenue at a point in time, resulting in revenue recognition timing that is materially consistent with our historical practice of recognizing revenue when title and risk of loss pass to the customer.

Revenue is recognized when control of the promised goods or services is transferred to the customer in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The majority of the Company’s revenue is generated through the manufacture and sale of a broad range of specialized products and components. For product and component sales, each good sold to a customer typically represents a distinct performance obligation. The Company’s performance obligation to provide goods to a customer is typically satisfied at a point in time upon completion of the shipping process as indicated by the terms of the contract, at which point control is transferred to the customer and revenue is recognized. The Company has no significant arrangements with multiple performance obligations. Remaining performance obligations consist of the aggregate amount of the total transaction price that is unsatisfied or partially satisfied. As of December 31, 2018, our total remaining performance obligations are immaterial. The Company recognizes sales-based royalty revenue under third-party license agreements as the related sales are made by licensees.

The terms of a contract or historical business practice can give rise to variable consideration, including customer discounts, rebates, and returns. The Company estimates variable consideration using either the expected value or most likely amount method. We include estimated amounts in the transaction price to the extent it is probable that a significant reversal of revenue will not occur in a subsequent reporting period. Our estimates of variable consideration are based on all reasonably available information (historical, current, and forecasted). Rebates are recognized over the contract period based on expected revenue levels. Sales discounts and rebates totaled $8.1 million, $9.1 million, and $8.7 million for the years ended December 31, 2018, 2017, and 2016, respectively. Returns and allowances totaled $7.7 million, $8.5 million, and $5.1 million for the years ended December 31, 2018, 2017, and 2016, respectively.

The Company elected to account for shipping and handling activities that occur after control of the related good transfers to the customer as fulfillment activities rather than evaluating such activities as performance obligations. As a result, all shipping and handling costs related to contracts with customers are recognized in the Cost of goods sold line on the Consolidated Statements of Earnings, which is consistent with our historical practice. Additionally, the Company elected to apply the practical expedient allowing incremental costs of obtaining a contract to be expensed as incurred if the amortization period of the resulting asset would have been less than one year. These costs primarily consist of sales commissions and the Company has no such significant costs exceeding the one year limit for applying the practical expedient.