The following extract from QV would answer your question.
There are four different types of CALs available: • Named CAL (an identified user on a server) - Access is based on user identity and valid for all documents on the server, that is any number of concurrent sessions from one user on one machine at a time is allowed. • Document CAL (an identified user within a given document) - Just as above, the access is based on user identity, but the CAL is valid only for one document. If the same user connects to two documents using this licensing method, he will hence consume two Document CALs. • Session CAL - Each Session CAL allows one user to access one QlikView document, that is to have one session at a time. Anonymous users are allowed, no identification of the client user is necessary. • Usage CAL - Each Usage CAL gives the right to initiate one session (single document) per running 28-day period. The session may last a maximum of one hour. Any activity after the first hour has expired will count as a new session (albeit without visible interruption). No identification of the client user is necessary.