Revenue Recognition  Revenue is generally recognized when a product is shipped, provided that persuasive evidence of a sales arrangement exists, the price is fixed or determinable, title and risk has transferred, collection of resulting receivables is reasonably assured, there are no customer acceptance requirements and there are no remaining significant obligations. Customers typically provide a customer request date ( CRD ) which indicates the preferred date for receipt of the ordered products. Based on estimated transit time and other logistics, we may deliver products to the carrier in advance of the CRD and recognize revenue from the sale of such products at the time of shipment. Generally, we defer revenue recognition when the shipment occurs more than 10 days in advance of the CRD. Shipments to distributors are made under agreements which provide for certain pricing adjustments (referred to as  ship and debit ) and limited product return privileges, under a stock rotation provision. Many of our sales to distributors are invoiced at list price and the final price is set via ship and debit credits at the time of resale. The distributor may also receive additional price protection on a percentage of unsold inventories they hold. Accordingly, we make estimates of price adjustments based upon inventory reported by distributors as of the balance sheet date and record this as a distributor allowance. We rely on historical distributor allowances to estimate these adjustments. Distributors may also receive allowances for certain parts returned under a stock rotation provision of the distributor agreement. We estimate the stock rotation provision based on the percentage of sales made to distributors and historical returns. For certain distributors, we defer recognition until the distributors resell the products to their end customer ( sell-through distributor ). Revenue at published list price and cost of revenue to sell-through distributors are deferred until either the product is resold by the distributor or, in c