The characteristics of Wi-Fi networks and their ever-growing popularity make them an obvious target for attacks. While intrusion detection systems have been popular in wired networks for a long time, their wireless equivalents are very limited. Anomaly-based detection methods have received an increasing interest by the scientific community in the last years. They are able to fight attacks without the need of previous and thorough characterization. However, their application to wireless environments is more recent. In this paper we review some of the last proposals in this field. We also introduce a functional intrusion detection system that combines them in order to offer resilient detection of the most common attacks in 802.11 networks.