Non-GAAP net income (loss) and non-GAAP net income (loss) per diluted share. Non-GAAP net income (loss) and non-GAAP net income (loss) per diluted share exclude the effects of share-based compensation expense, amortization of intangible assets, other non-cash expenses, restructuring and integration charges, certain items associated with acquisitions (such as inventory step-up, inventory revaluation and transaction costs), IPR litigation costs, (gain) loss on PP&E, start-up costs, loss on retirement of convertible subordinated notes, non-cash interest expense on convertible subordinated notes, loss (income) from equity investment and also reflect an adjustment of income taxes for cash basis. We believe that presentation of measures of net income (loss) and net income (loss) per diluted share that exclude these items is useful to both management and investors for the reasons described above with respect to non-GAAP gross profit and gross margin and non-GAAP operating income (loss) and operating margin. We believe disclosure of non-GAAP net income (loss) and non-GAAP net income (loss) per diluted share has economic substance because the excluded expenses are either unrelated to operations or do not represent current cash expenditures.
Non-GAAP research and development, marketing and selling and general and administrative expenses. Non-GAAP research and development, marketing and selling and general and administrative expenses exclude share-based compensation expense, amortization of intangible assets, other non-cash expenses, IPR litigation costs and restructuring and integration charges. We believe that presentation of measures of these operating expenses that exclude amortization of intangible assets and share-based compensation expense is useful to both management and investors for the same reasons as described above with respect to our use of non-GAAP gross profit and gross margin. We believe that other non-cash expenses, IPR litigation costs, and restructuring and integration charges do not constitute part of RFMD's ongoing operations and therefore, the exclusion of these costs provides management and investors with better visibility into the actual costs required to generate revenues over time and gives management and investors a more effective means of evaluating our historical and projected performance. We believe disclosure of these non-GAAP operating expenses has economic substance because the excluded expenses are either unrelated to operations or do not represent current cash expenditures.
Free cash flow. RFMD defines free cash flow as net cash provided by operating activities during the period minus property and equipment expenditures made during the period. We use free cash flow as a supplemental financial measure in our evaluation of liquidity and financial strength. Management believes that this measure is useful as an indicator of our ability to service our debt, meet other payment obligations and make strategic investments. Free cash flow should be considered in addition to, rather than as a substitute for, net income as a measure of our performance and net cash provided by operating activities as a measure of our liquidity. Additionally, our definition of free cash flow is limited, in that it does not represent residual cash flows available for discretionary expenditures due to the fact that the measure does not deduct the payments required for debt service and other contractual obligations. Therefore, we believe it is important to view free cash flow as a measure that provides supplemental information to our entire statement of cash flows.
EBITDA. RFMD defines EBITDA as earnings before interest expense and interest income, income tax expense (benefit), depreciation and intangible amortization. Management believes that this measure is useful to evaluate our ongoing operations and as a general indicator of our operating cash flow (in conjunction with a cash flow statement which also includes among other items, changes in working capital and the effect of non-cash charges). The amounts shown for EBITDA as presented herein differ from the amounts calculated under the definition of EBITDA used in our equipment term loan agreement. The definition of EBITDA as used in the loan agreement is further adjusted for certain cash and non-cash charges, including stock compensation expense, and is used to determine compliance with financial covenants.
Non-GAAP ROIC. Return on invested capital (ROIC) is a non-GAAP financial measure that management believes provides useful supplemental information for management and the investor by measuring the effectiveness of our operations' use of invested capital to generate profits. We use ROIC to track how much value we are creating for our shareholders. Non-GAAP ROIC is calculated by dividing annualized non-GAAP operating income, net of cash taxes, by average invested capital. Average invested capital is calculated by subtracting the average of the beginning balance and the ending balance of current liabilities (excluding the current portion of long-term debt and other short-term financings) from the average of the beginning balance and the ending balance of net accounts receivable, inventories, other current assets, net property and equipment and a cash amount equal to seven days of quarterly revenue.
Net debt or positive net cash. Net debt or positive net cash is defined as unrestricted cash, cash equivalents and short-term investments minus the principal amount of RFMD's convertible subordinated notes. Management believes that net debt or positive net cash provides useful information regarding the level of RFMD's indebtedness by reflecting cash and investments that could be used to repay debt.
Limitations of non-GAAP financial measures. The primary material limitations associated with the use of non-GAAP gross profit and gross margin, non-GAAP operating expenses, non-GAAP operating income (loss) and operating margin, non-GAAP net income (loss), non-GAAP net income (loss) per diluted share, free cash flow, EBITDA, non-GAAP ROIC and net debt or positive net cash, as compared to the most directly comparable GAAP financial measures of gross profit and gross margin, operating expenses, operating income (loss), net income (loss), net income (loss) per diluted share and net cash provided by operating activities are (i) they may not be comparable to similarly titled measures used by other companies in RFMD's industry, and (ii) they exclude financial information that some may consider important in evaluating our performance. We compensate for these limitations by providing full disclosure of the differences between these non-GAAP financial measures and the corresponding GAAP financial measures, including a reconciliation of the non-GAAP financial measures to the corresponding GAAP financial measures, to enable investors to perform their own analysis of our gross profit and gross margin, operating expenses, operating income (loss), net income (loss), net income (loss) per diluted share and net cash provided by operating activities.
RF Micro Devices will conduct a conference call at 5:00 p.m. EST today to discuss today's press release. The conference call will be broadcast live over the Internet and can be accessed by any interested party at http://www.rfmd.com (under Investors"). A telephone playback of the conference call will be available approximately one hour after the call's completion by dialing 303-590-3030 and entering pass code 4587278#.
RF Micro Devices, Inc. (Nasdaq: RFMD) is a global leader in the design and manufacture of high-performance radio frequency solutions. RFMD's products enable worldwide mobility, provide enhanced connectivity and support advanced functionality in the mobile device, wireless infrastructure, wireless local area network (WLAN or WiFi), cable television (CATV)/broadband, Smart Energy/advanced metering infrastructure (AMI), and aerospace and defense markets. RFMD is recognized for its diverse portfolio of semiconductor technologies and RF systems expertise and is a preferred supplier to the world's leading mobile device, customer premises and communications equipment providers.
Headquartered in Greensboro, N.C., RFMD is an ISO 9001-, ISO 14001-, and ISO/TS 16949-certified manufacturer with worldwide engineering, design, sales and service facilities. RFMD is traded on the NASDAQ Global Select Market under the symbol RFMD. For more information, please visit RFMD's web site at www.rfmd.com.
This press release includes "forward-looking statements" within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, statements about our plans, objectives, representations and contentions and are not historical facts and typically are identified by use of terms such as "may," "will," "should," "could," "expect," "plan," "anticipate," "believe," "estimate," "predict," "potential," "continue" and similar words, although some forward-looking statements are expressed differently. You should be aware that the forward-looking statements included herein represent management's current judgment and expectations, but our actual results, events and performance could differ materially from those expressed or implied by forward-looking statements. We do not intend to update any of these forward-looking statements or publicly announce the results of any revisions to these forward-looking statements, other than as is required under the federal securities laws. RF Micro Devices' business is subject to numerous risks and uncertainties, including variability in operating results, risks associated with the impact of global macroeconomic and credit conditions on our business and the business of our suppliers and customers, our reliance on a few large customers for a substantial portion of our revenue, the rate of growth and development of wireless markets, our ability to bring new products to market, our reliance on inclusion in third party reference designs for a portion of our revenue, our ability to manage channel partner and customer relationships, risks associated with the operation of our wafer fabrication, molecular beam epitaxy, assembly and test and tape and reel facilities, our ability to complete acquisitions and integrate acquired companies, including the risk that we may not realize expected synergies from our business combinations, our ability to attract and retain skilled personnel and develop leaders, variability in production yields, raw material costs and availability, our ability to reduce costs and improve margins in response to declining average selling prices, our ability to adjust production capacity in a timely fashion in response to changes in demand for our products, dependence on gallium arsenide (GaAs) for the majority of our products, dependence on third parties, and substantial reliance on international sales and operations. These and other risks and uncertainties, which are described in more detail in RF Micro Devices' most recent Annual Report on Form 10-K and other reports and statements filed with the Securities and Exchange Commission, could cause actual results and developments to be materially different from those expressed or implied by any of these forward-looking statements.