Interest income and expense. The Company receives interest income on investments and incurs interest expense on loans, capital leases and other financing arrangements. These amounts may vary from period to period due to changes in cash and debt balances and interest rates driven by general market conditions or other circumstances outside of the normal course of Mercury's operations.
. The Company's GAAP tax expense can fluctuate materially from period to period due to tax adjustments that are not directly related to underlying operating performance or to the current period of operations.
. The Company incurs depreciation expense related to capital assets purchased to support the ongoing operations of the business. These assets are recorded at cost or fair value and are depreciated using the straight-line method over the useful life of the asset. Purchases of such assets may vary significantly from period to period and without any direct correlation to underlying operating performance.
Amortization of acquired intangible assets
. The Company incurs amortization of intangibles related to various acquisitions it has made and license agreements. These intangible assets are valued at the time of acquisition, are amortized over a period of several years after acquisition and generally cannot be changed or influenced by management after acquisition.
. The Company incurs restructuring charges in connection with management's decisions to undertake certain actions to realign operating expenses through workforce reductions and the closure of certain Company facilities, businesses and product lines. Management believes this item is outside the normal operations of the Company's business and is not indicative of ongoing operating results.
Impairment of long-lived assets
. The Company incurs impairment charges of long-lived assets based on events that may or may not be within the control of management. Management believes these items are outside the normal operations of the Company's business and are not indicative of ongoing operating results.
Acquisition costs and other related expenses
. The Company incurs costs associated with third-party professional services related to acquisition and potential acquisition opportunities, such as legal and accounting fees. Although we may incur such costs and other related charges and adjustments, it is not indicative that any transaction will be consummated. Management believes the exclusion of these items eliminates fluctuations in our selling, general, and administrative expenses related to acquisition activities which are unrelated to ongoing operations.
Fair value adjustments from purchase accounting
. As a result of applying purchase accounting rules to acquired assets and liabilities, certain fair value adjustments are recorded in the opening balance sheet of acquired companies. These adjustments are then reflected in the Company's income statements in periods subsequent to the acquisition. In addition, the impact of any changes to originally recorded contingent consideration amounts are reflected in the income statements in the period of the change. Management believes these items are outside the normal operations of the Company and are not indicative of ongoing operating results.
Stock-based compensation expense
. The Company incurs expense related to stock-based compensation included in its GAAP presentation of cost of revenues, selling, general and administrative expense and research and development expense. Although stock-based compensation is an expense of the Company and viewed as a form of compensation, these expenses vary in amount from period to period, and are affected by market forces that are difficult to predict and are not within the control of management, such as the market price and volatility of the Company's shares, risk-free interest rates and the expected term and forfeiture rates of the awards. Management believes that exclusion of these expenses allows comparisons of operating results to those of other companies, both public, private or foreign, that disclose non-GAAP financial measures that exclude stock-based compensation.
Mercury uses adjusted EBITDA as an important indicator of the operating performance of its business. Management excludes the above-described items from its internal forecasts and models when establishing internal operating budgets, supplementing the financial results and forecasts reported to the Company's board of directors, determining the portion of bonus compensation for executive officers and other key employees based on operating performance, evaluating short-term and long-term operating trends in the Company's operations, and allocating resources to various initiatives and operational requirements. The Company believes that adjusted EBITDA permits a comparative assessment of its operating performance, relative to its performance based on its GAAP results, while isolating the effects of charges that may vary from period to period without any correlation to underlying operating performance. The Company believes that these non-GAAP financial adjustments are useful to investors because they allow investors to evaluate the effectiveness of the methodology and information used by management in its financial and operational decision-making. The Company believes that trends in its adjusted EBITDA are valuable indicators of its operating performance.