Revenue Recognition Principal sources of revenue are (i) product sales from the product portfolio acquired with our acquisition of Tribute, and (ii) royalty revenues from sales of VIMOVO  by our commercialization partners. In all instances, revenue is recognized only when the price is fixed or determinable, persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, and collectibility of the resulting receivable is reasonably assured. Product Revenues, net All revenues from product sales are recorded net of applicable provisions for trade discounts, returns, and allowances in the same period the related sales are recorded. Estimates for gross-to-net provisions are analyzed quarterly. Other revenues Other revenues include revenue from licensing arrangements with other biopharmaceutical companies, including upfront payments, milestones payments, and royalties. Revenue from royalties is recognized when Aralez has fulfilled the terms in accordance with contractual agreements and has no material future obligation. Royalty revenue that is reasonably estimable and determinable is recognized based on those estimates which relies on information provided by our distribution partners. License revenues may include upfront fees or the amortization of upfront fees as well as ongoing milestones that we may receive under a license and collaboration agreement. At the inception of an agreement that includes milestone payments, we evaluate whether each milestone is substantive and at risk to both parties on the basis of the contingent nature of the milestone. If the milestones are deemed substantive and the milestone payments are nonrefundable, such milestone payments are recognized as revenue upon successful achievement of the milestones.