This paper presents a grounded theory-analysis based on a qualitative study of professional interaction designers (n=20) with a focus on how they use tools to manage design ideas. Idea management can be understood as a subcategory of the field Personal Information Management, which includes the activities around the capture, organization, retrieval, and use of information. Idea management pertains then to the management and use of ideas as part of creative activities. The paper identifies tool-supported idea management strategies and needs of professional interaction designers, and discusses the context and consequences of these strategies. Based on our analysis, we identify a conceptual framework of ten strategies which are supported by tools: saving, externalizing, advancing, exploring, archiving, clustering, extracting, browsing, verifying, and collaborating. Finally, we discuss how this framework can be used to characterize and analyze existing and novel idea management tools.