Organization and Description of Business	3 Months Ended
Organization and Description of Business	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business Description of Business Castlight Health, Inc. (Castlight) is a pioneer in a new category of cloud-based software that enables enterprises to understand and manage health care spending as a strategic business investment, and help employees and their families make more informed medical decisions based on factors such as cost, quality and patient experience. Our Enterprise Healthcare Cloud allows our customers to conquer the complexity of the existing health care system by providing personalized, actionable information to their employees, implementing technology-enabled benefit designs and integrating disparate systems and applications. Our comprehensive technology offering aggregates complex, large-scale data and applies sophisticated analytics to make health care data transparent and useful. We were incorporated in the State of Delaware in January 2008. Our principal executive offices are located in San Francisco, California.

The entire disclosure for organization, consolidation and basis of presentation of financial statements disclosure.