Revenue Recognition ? We adopted Accounting Standard Codification (ASC) Topic 606, Revenue from Contracts with Customers on July 1, 2018. We account for a contract with a customer when there is a legally enforceable contract, the rights of the parties are identified, the contract has commercial substance, and collectability of the contract consideration is probable. We have determined that we have two operating segments, which are the sleep and respiratory disorders sector of the medical device industry (Sleep and Respiratory Care) and the supply of business management software as a service to out-of-hospital health providers (SaaS). Our Sleep and Respiratory Care revenue relates primarily to the sale of our products that are therapy-based equipment. Some contracts include additional performance obligations such as the provision of extended warranties and data for patient monitoring. Our SaaS revenue relates to the provision of software access with ongoing support and maintenance services as well as professional services such as training and consulting. ? Disaggregation of revenue See note 15  Segment Information for our net revenue disaggregated by segment, product and region for the years ended June 30, 2019 , 2018 and 2017 . ? ? Performance obligations and contract balances Revenue is recognized when performance obligations under the terms of a contract with a customer are satisfied; generally, this occurs with the transfer of risk and/or control of our products are provided at a point in time. For products in our Sleep and Respiratory Care business, we transfer control and recognize a sale when products are shipped to the customer in accordance with the contractual shipping terms. For our SaaS business, revenue associated with professional services are recognized as they are provided. We defer the recognition of a portion of the consideration received when performance obligations are not yet satisfied. Consideration received from customers in advance of revenue recognition is classified as deferred revenue. Performance obligations resulting in deferred revenue in our Sleep and Respiratory Care business relate primarily to extended warranties on our devices and the provision of data for patient monitoring. Performance obligations resulting in deferred revenue in our SaaS business relate primarily to the provision of software access with maintenance and support over an agreed term and material rights associated with future discounts upon renewal of some SaaS contracts. Generally, deferred revenue will be recognized over a period of one to five years. The following table summarizes our contract balances at June 30, 2019 and June 30, 2018 (in thousands): ? ? ? 2019 2018 Balance sheet caption ? Contract assets ? Accounts receivable, net $ 528,484 $ 483,681 Accounts receivable, net ? Unbilled revenue, current 9,834 13,342 Prepaid expenses and other current assets ? Unbilled revenue, non-current 4,592 2,973 Prepaid taxes and other non-current assets ? ? Contract liabilities ? Deferred revenue, current (88,667) (60,828) Deferred revenue (current liabilities) ? Deferred revenue, non-current (81,143) (71,596) Deferred revenue (non-current liabilities) ? Transaction price determination Revenue is measured as the amount of consideration we expect to receive in exchange for transferring goods or providing services. In our Sleep and Respiratory Care segment, the amount of consideration received and revenue recognized varies with changes in marketing incentives (e.g., rebates, discounts, free goods) and returns offered to customers and their customers. When we give customers the right to return eligible products and receive credit, returns are estimated based on an analysis of historical experience. However, returns of products, excluding warranty-related returns, are infrequent and insignificant. We adjust the estimate of revenue at the earlier of when the most likely amount of consideration can be estimated, the amount expected to be received changes, or when the consideration becomes fixed. ? We offer our Sleep and Respiratory Care customers cash or product rebates based on volume or sales targets measured over quarterly or annual periods. We estimate rebates based on each customers expected achievement of its targets. In accounting for these rebate programs, we reduce revenue ratably as sales occur over the rebate period by the expected value of the rebates to be returned to the customer. Rebates measured over a quarterly period are updated based on actual sales results and, therefore, no estimation is required to determine the reduction to revenue. For rebates measured over annual periods, we update our estimates on a quarterly basis based on actual sales results and updated forecasts for the remaining rebate periods. We also offer discounts to both our Sleep and Respiratory Care as well as our SaaS customers as part of normal business practice and these are deducted from revenue when the sale occurs. ? Many of our Sleep and Respiratory Care contracts have a single performance obligation which is the shipment of our therapy-based equipment. However, when the Sleep and Respiratory Care or SaaS contract has multiple performance obligations, we generally use an observable price to determine the stand-alone selling price by reference to pricing and discounting practices for the specific product or service when sold separately to similar customers. Revenue is then allocated proportionately, based on the determined stand-alone selling price, to the performance obligation. ? Accounting and practical expedient elections We have elected to account for shipping and handling activities associated with our Sleep and Respiratory Care segment as a fulfillment cost within cost of sales, and record shipping and handling costs collected from customers in net revenue. We have also elected for all taxes assessed by government authorities that are imposed on and concurrent with revenue-producing transactions, such as sales and value added taxes, to be excluded from revenue. We have adopted two practical expedients including the right to invoice practical expedient, which allows us to recognize revenue in the amount of the invoice when it corresponds directly with the value of performance completed to date and which is relevant for some of our SaaS contracts. The second practical expedient adopted permits relief from considering a significant financing component when the payment for the good or service is expected to be one year or less. ?