Use of Estimates The preparation of financial statements and related disclosures in conformity with accounting principles generally accepted in the United States of America requires management to make judgments, assumptions and estimates that affect the amounts reported in the consolidated financial statements and accompanying notes. The accounting estimates that require management’s most difficult and subjective judgments include, but are not limited to, those estimates related to bad debt expense, warranty obligations, inventory valuation, valuation and classification of auction rate securities, impairment of long-lived assets and investments, business combinations, goodwill, other intangible assets, sharebased compensation, income taxes and contingencies. We base our estimates on historical experience, current conditions and on various other assumptions that we believe are reasonable under the circumstances. However, future events are subject to change and estimates and judgments routinely require adjustment. Actual results may differ from these estimates under different assumptions or conditions. allowance for doubtful accounts was primarily related to $3,727 in bad debt expense recorded in the second quarter of fiscal 2012 for Elpida Memory, Inc. (Elpida), a significant customer in Japan that filed for bankruptcy protection in February 2012. Amounts charged to expense are recorded in general and administrative expenses. Elpida owed the Company $3,727 in accounts receivable for shipments made prior to its bankruptcy filing. To our understanding, Elpida’s bankruptcy plan has not been formally approved, and collection of any or all of this balance remains uncertain. Consequently, we have maintained a reserve for the entire balance. Elpida has been paying the Company on a current basis for all shipments made subsequent to its bankruptcy filing. The Elpida receivable is denominated in Japanese yen, so it is subject to foreign exchange fluctuations which are included in the table below under the deductions and adjustments. Our allowance for doubtful accounts changed during the fiscal year ended September 30, 2012 as follows: Balance as of September 30, 2011 Amounts charged to expense Deductions and adjustments Balance as of September 30, 2012 $ 1,090 3,771 (104) $4,757 Cash, Cash Equivalents and Short-Term Investments We consider investments in all highly liquid financial instruments with original maturities of three months or less to be cash equivalents. Short-term investments include securities generally having maturities of 90 days to one year. We did not own any securities that were considered short-term as of September 30, 2012 or 2011. See Note 3 for a more detailed discussion of other financial instruments. See Schedule II under Part IV, Item 15 of this Form 10-K for more information on our allowance for doubtful accounts. Concentration of Credit Risk Financial instruments that subject us to concentrations of credit risk consist principally of accounts receivable. We perform ongoing credit evaluations of our customers’ financial conditions and generally do not require collateral to secure accounts receivable. Our exposure to credit risk associated with nonpayment is affected principally by conditions or occurrences within the semiconductor industry and global economy. Prior to the one situation in fiscal 2012, we had not experienced significant losses relating to accounts receivable from individual customers or groups of customers. Customers who represented more than 10% of revenue are as follows: Year Ended September 30, 2012 Taiwan Semiconductor Manufacturing Co. (TSMC) Samsung United Microelectronics Corporation (UMC) *Denotes less than ten percent of total Accounts Receivable and Allowance for Doubtful Accounts Trade accounts receivable are recorded at the invoiced amount and do not bear interest. We maintain an allowance for doubtful accounts for estimated losses resulting from the potential inability of our customers to make required payments. Our allowance for doubtful accounts is based on historical collection experience, adjusted for any specific known conditions or circumstances such as customer bankruptcies and increased risk due to economic conditions. Uncollectible account balances are charged against the allowance when we believe that it is probable that the receivable will not be recovered. Accounts receivable, net of allowances for doubtful accounts, was $53,506 as of September 30, 2012 and $52,747 as of September 30, 2011. The increase was primarily due to the increase in revenue recorded in the fourth quarter of fiscal 2012 as compared to the fourth quarter of fiscal 2011, partially offset by an increase in the allowance for doubtful accounts. The increase in the 2011 17% 10% * 2010 18% * 11% 18% 13% * 40