Collaborative ideation is a key aspect of many innovation processes. However, a lack of proper support can hinder the process and limit the ability of participants to generate innovative ideas. Thus, we introduce AI-deation, a digital environment for collaborative ideation. At the heart of the system is an AI collaborator powered by Generative Artificial Intelligence that participates in the ideation process by automatically suggesting new ideas. Moreover, the submitted ideas are processed by a Large Language Model, acting as an idea editor. It strengthens the anonymity of the contributions to alleviate fears of judgment. We studied this system in a randomized experiment where groups solved complex problems in two conditions: humans only and humans supported by an AI collaborator. Results show that the idea editor effectively strengthened the participants' anonymity. Despite being more innovative, the AI collaborator did not significantly influence the participants' innovativeness.