Net Sales | 3. Net Sales On January 1, 2018, we adopted Accounting Standard Codification 606 (ASC 606), "Revenue from Contracts with Customers" using the modified retrospective method and applying the standard only to uncompleted contracts at the date of adoption. The impact of adopting ASC 606 did not result in a change to income, and therefore we are not reflecting a cumulative effect to the opening balance of retained earnings due to the adoption of ASC 606. The comparative period has not been adjusted and continues to be reported under the accounting standards in effect for that period. Our revenues are primarily derived from the manufacture and sale of petroleum additives products. We sell petroleum additives products across the world including to customers located in the United States, Europe, Asia Pacific (including China), Latin America, Canada, India, and the Middle East. Our customers primarily consist of global, national, and independent oil companies. While some of our customers have payment terms beyond 30 days, we do not provide extended payment terms of a year or more, nor do our contracts include a financing component. Our allowance for doubtful accounts is immaterial, as are any bad debts we incur. In limited cases, we collect funds in advance of shipping product to our customers and recognizing the related revenue. These prepayments from customers are recorded as a contract liability to our customer until we recognize the revenue. Prepayments from our customers totaled $9.1 million at June 30, 2018 . Revenue recognized from funds collected in advance from customers in an earlier period was $3.2 million in 2018 . We recognize revenue when control of the product is transferred to our customer and for an amount that reflects the consideration that we expect to collect from the customer. Control is generally transferred to the customer when title transfers (which may include physical possession by the customer), we have a right to payment from the customer, the customer has accepted the product, and the customer has assumed the risks and rewards of ownership. We have supplier managed inventory arrangements with some of our customers to facilitate on-demand product availability. In some cases, the inventory resides at a customer site, although title has not transferred, we are not entitled to payment, and we have not invoiced for the product. We have evaluated the contract terms under these arrangements and have determined that control transfers when the customer uses the product, at which time revenue is recognized. Our contracts generally include one performance obligation, which is providing petroleum additives products. The performance obligation is satisfied at a point in time when products are shipped, delivered, or consumed by the customer, depending on the underlying contracts. Taxes assessed by a governmental authority which are concurrent with sales to our customers, including sales, use, value-added, and revenue-related excise taxes, are collected by us from the customer and are not included in net sales, but are reflected in accrued expenses until remitted to the appropriate governmental authority. When we are responsible for shipping and handling costs after title has transferred, we account for those as fulfillment costs and include them in cost of goods sold. Some of our contracts include variable consideration in the form of rebates or business development funds. We record rebates at the point of sale as contra-revenue when we can reasonably estimate the amount of the rebate. The estimates are based on our best judgment at the time of sale, which includes anticipated as well as historical performance. Depending upon the specific terms of a business development fund, amounts are accrued as contra-revenue at the point of sale or are expensed when costs are incurred by us. We regularly review both rebates and business development funds and make adjustments when necessary, recognizing the full amount of any adjustment in the period identified. We recognized an increase to net sales of $0.2 million for the second quarter of 2018 and an increase of $1.2 million for the first six months of 2018 related to adjustments to rebates or business development funds which were recognized in revenue in a prior period. At June 30, 2018 , accrued rebates were $15.7 million and accrued business development funds were $2.8 million . The following table provides information on our net sales by geographic area. Information on net sales by segment is in Note 4. Second Quarter Ended Six Months Ended (in thousands) 2018 2018 Net sales United States $ 185,225 $ 366,863 China 61,878 126,089 Europe, Middle East, Africa, India 208,738 407,398 Asia Pacific, except China 84,183 166,689 Other foreign 58,928 121,158 Net sales $ 598,952 $ 1,188,197 |