the reported amounts of assets, liabilities, revenue, cost of revenue, expenses and related disclosure of contingencies. On an on-going basis, we evaluate our estimates, including those related to revenue recognition, cash equivalents and marketable securities, accounts receivable, inventories, income taxes, goodwill, stock-based compensation, warranty liabilities, litigation, investigation and settlement costs and other contingencies. We base our estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities.

 

We believe the following critical accounting policies affect our significant judgments and estimates used in the preparation of our consolidated financial statements. Our management has discussed the development and selection of these critical accounting policies and estimates with the Audit Committee of our Board of Directors, or Board.  The Audit Committee has reviewed our disclosures relating to our critical accounting policies and estimates in this Annual Report on Form 10-K.  

  

Revenue Recognition

 

Product Revenue



We recognize revenue from product sales when persuasive evidence of an arrangement exists, the product has been delivered, the price is fixed or determinable, and collection is reasonably assured. For most sales, we use a binding purchase order and in certain cases we use a contractual agreement as evidence of an arrangement. We consider delivery to occur upon shipment provided title and risk of loss have passed to the customer based on the shipping terms. At the point of sale, we assess whether the arrangement fee is fixed or determinable and whether collection is reasonably assured. If we determine that collection of a fee is not reasonably assured, we defer the fee and recognize revenue at the time collection becomes reasonably assured, which is generally upon receipt of payment. Our policy on sales to certain distributors, with rights of return, is to defer recognition of revenue and related cost of revenue until the distributors resell the product.



Our customer programs primarily involve rebates, which are designed to serve as sales incentives to resellers of our products in various target markets. We accrue for 100% of the potential rebates and do not apply a breakage factor. We recognize a liability for these rebates at the later of the date at which we record the related revenue or the date at which we offer the rebate. Rebates typically expire six months from the date of the original sale, unless we reasonably believe that the customer intends to claim the rebate. Unclaimed rebates are reversed to revenue.



Our customer programs also include marketing development funds, or MDFs. We account for MDFs as either a reduction of revenue or an operating expense. MDFs represent monies paid to retailers, system builders, original equipment manufacturers, or OEMs, distributors and add-in card partners that are earmarked for market segment development and expansion and typically are designed to support our partners’ activities while