Satan and/or his demons are in Heaven right now making accusation against saved people.  But, he is kicked out of Heaven for good at the midpoint of the Tribulation Period in Revelation 12, which is during a time the Jews are saved people (vs. 17).  Satan and his demons still have access to Heaven, as they are still accountable to God as it was in the Book of Job.  When they are finally kicked out, Heaven rejoices about it, but the earth will see the rule of Satan for a period of 1,260 day.  This episode helps a person understand these events better.