We also record a reduction to revenue by establishing a sales return allowance for estimated product returns at the time revenue is recognized, based primarily on historical return rates. However, if product returns for a particular fiscal period exceed historical return rates we may determine that additional sales return allowances are required to properly reflect our estimated exposure for product returns.



License and Development Revenue



For license arrangements that require significant customization of our intellectual property components, we generally recognize the related revenue over the period that services are performed. For most license and service arrangements, we determine progress to completion based on actual direct labor hours incurred to date as a percentage of the estimated total direct labor hours required to complete the project. We periodically evaluate the actual status of each project to ensure that the estimates to complete each contract remain accurate. Revenue recognized in any period is dependent on our progress toward completion of projects in progress. Significant management judgment and discretion are used to estimate total direct labor hours. Any changes in or deviations from these estimates could have a material effect on the amount of revenue we recognize in any period.



For license arrangements that do not require significant customization but where we are obligated to provide further deliverables over the term of the license agreement, we record revenue over the life of the license term, with consideration received in advance of the performance period classified as deferred revenue.



Please refer to Note 1 of the Notes to the Consolidated Financial Statements in Part IV, Item 15 of this Annual Report on Form 10-K for additional information.



Inventories



Inventory cost is computed on an adjusted standard basis, which approximates actual cost on an average or first-in, first-out basis. We charge cost of sales for inventory provisions to write down our inventory to the lower of cost or estimated market value or to completely write off obsolete or excess inventory. Most of our inventory provisions relate to the write-off of excess quantities of products, based on our inventory levels and future product purchase commitments compared to assumptions about future demand and market conditions.



Situations that may result in excess or obsolete inventory include changes in business and economic conditions, changes in consumer confidence caused by changes in market conditions, sudden and significant decreases in demand for our products, inventory obsolescence because of rapidly changing technology and customer requirements, failure to estimate customer demand properly for older products as newer products are introduced, or unexpected competitive pricing actions by our competition. In addition, cancellation or deferral of customer purchase orders could result in our holding excess inventory. Also, because we often sell a substantial portion of our products in the last month of each quarter, we may not be able to reduce our inventory purchase commitments in a timely manner in response to customer