| Description of the transaction or nature of business giving rise to deferred revenue or unearned revenue, other than annual membership fees. Deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. | en-US | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |