Normally information like this will be found in one of the following places in OS X:
/Users/username/Library/Preferences/AppName
/Users/username/Library/Preferences/com.appname.plist
/Users/username/Library/Application Support/AppName
/Library/Preferences/AppName
/Library/Preferences/com.appname.plist
/Library/Application Support/AppName
If the app adheres to the standard OS X conventions you weill find info in one or all of these places. If it doesnt store here you might check for a /Users/username/.intellij folder or something similar in your home directory