With the increasing availability of interactive tabletops, researchers and practitioners have the opportunity to expand the learning environment and provide further support for collaboration and reflective conversations around design problems. In this manuscript, we present IdeaSpace, a tabletop application designed to support collaborative design as a continuous and reflective process involving cycles of design and redesign. IdeaSpace allows users to work on a shared project, load digital images and sketches, annotate them using text and audio, record messages and take notes during their collaboration, keep step by step a record of the design process and share selected artefacts on Facebook. Outcomes from three pilot case studies provide evidence that IdeaSpace can support continuity in the interaction, revisit of information, and reflection across collaboration sessions. Concluding remarks and plans for future work are discussed.