Thank you for reaching out and expressing interest in the Telerik Platform!
You'll need to purchase a seat for each developer that will be working directly with the tool to create your mobile application. Your end-users do not need to purchase a license.
Please review our FAQ page for more information: http://www.telerik.com/purchase/faq/platform
If you have any questions, please don't hesitate to email me directly at Tim.Tognacci@telerik.com
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.