FortiAP FortiGate-Managed & Licensing

Could someone clarify what the licensing options are for a FortiAP that is managed by a FortiGate? I'm aware there is an Advanced Management license when using Cloud-managed FortiAP but I want to confirm whether that is required for all FortiAP's or not. If you could point me to a document that explains this in detail, I would appreciate it. I've been searching documentation for a while & haven't found anything clear.