The rapid technological change and product obsolescence that characterize our industry require us to make continuous investments in research and development. Product development time frames vary but, in general, we incur research and development costs one to two years before generating sales from the associated new products. These expenses include personnel costs for members of our engineering workforce, cost of photomasks, silicon wafers and other
non-recurring
engineering charges related to product design. Additionally, we develop base line process technology through experimentation and through the design and use of characterization wafers that help achieve commercially feasible yields for new products. The majority of research and development expenses of our display business are material and design-related costs for OLED display driver IC product development involving
40-nanometer
or finer processes. The majority of research and development expenses of our power business are certain equipment, material and design-related costs for power discrete products and material and design-related costs for power IC products. Power IC uses standard BCD process technologies which can be sourced from multiple foundries, including Fab 4.
Our interest expense was incurred primarily under our 2021 Notes and 5.0% Exchangeable Senior Notes due March 1, 2021. We redeemed all outstanding 2021 Notes on October 2, 2020. Our Exchangeable Notes were exchanged for common stock prior to their maturity date of March 1, 2021. From and after October 2, 2020 and March 1, 2021, we have not and will not incur interest expense associated with the 2021 Notes and Exchangeable Notes, respectively.
Impact of Foreign Currency Exchange Rates on Reported Results of Operations.
Historically, a portion of our revenues and greater than the majority of our operating expenses and costs of sales have been denominated in
non-U.S.
currencies, principally the Korean won, and we expect that this will remain true in the future. Because we report our results of operations in U.S. dollars converted from our
non-U.S.
revenues and expenses based on monthly average exchange rates, changes in the exchange rate between the Korean won and the U.S. dollar could materially impact our reported results of operations and distort period to period comparisons. In particular, because of the difference in the amount of our consolidated revenues and expenses that are in U.S. dollars relative to Korean won, depreciation in the U.S. dollar relative to the Korean won could result in a material increase in reported costs relative to revenues, and therefore could cause our profit margins and operating income to appear to decline materially, particularly relative to prior periods. The converse is true if the U.S. dollar were to appreciate relative to the Korean won. Moreover, our foreign currency gain or loss would be affected by changes in the exchange rate between the Korean won and the U.S. dollar as a substantial portion of
non-cash
translation gain or loss is associated with the intercompany long-term loans to our Korean subsidiary, which is denominated in U.S. dollars. As of March 31, 2021, the outstanding intercompany loan balance including accrued interest between our Korean subsidiary and our Dutch subsidiary was $381.8 million. As a result of such foreign currency fluctuations, it could be more difficult to detect underlying trends in our business and results of operations. In addition, to the extent that fluctuations in currency exchange rates cause our results of operations to differ from our expectations or the expectations of our investors, the trading price of our stock could be adversely affected.
From time to time, we may engage in exchange rate hedging activities in an effort to mitigate the impact of exchange rate fluctuations. Our Korean subsidiary enters into foreign currency zero cost collar contracts in order to mitigate a portion of the impact of U.S. dollar-Korean won exchange rate fluctuations on our operating results. Obligations under these foreign currency zero cost collar contracts must be cash collateralized if our exposure exceeds certain specified thresholds. These zero cost collar contracts may be terminated by a counterparty in a number of circumstances, including if our credit rating falls below
B-/B3
or if our total cash and cash equivalents is less than $30.0 million at the end of a fiscal quarter unless a waiver is obtained from the counterparty. We cannot assure that any hedging technique we implement will be effective. If our hedging activities are not effective, changes in currency exchange rates may have a more significant impact on our results of operations.
Foreign Currency Gain or Loss.
Foreign currency translation gains or losses on transactions by us or our subsidiaries in a currency other than our or our subsidiaries’ functional currency are included in foreign currency gain (loss), net in our statements of operations. A substantial portion of this net foreign currency gain or loss relates to
non-cash
translation gain or loss related to the principal balance of intercompany balances at our Korean subsidiary that are denominated in U.S. dollars. This gain or loss results from fluctuations in the exchange rate between the Korean won and U.S. dollar.
We record our income taxes in each of the tax jurisdictions in which we operate. This process involves using an asset and liability approach whereby deferred tax assets and liabilities are recorded for differences in the financial reporting bases and tax basis of our assets and liabilities. We exercise significant management judgment in determining our provision for income taxes, deferred tax assets and liabilities. We assess whether it is more likely than not that the deferred tax assets existing at the
period-end
will be realized in future periods. In such assessment, we consider all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies and recent results of operations. In the event we were to determine that we would be able to realize the deferred income tax assets in the future in excess of their net recorded amount, we would adjust the valuation allowance, which would reduce the provision for income taxes.
We are subject to income- or
non-income-based
tax examinations by tax authorities of the U.S., Korea and multiple other foreign jurisdictions for all open tax years. Significant estimates and judgments are required in determining our worldwide provision for income- or
non-income
based taxes. Some of these estimates are based on interpretations of existing tax laws or regulations. The ultimate amount of tax liability may be uncertain as a result.