I've had this problem most of this year on MacBook Pro - I'm on Version 7.2.3 (456888 App Store) / OS X El Capitain
I switched from the direct download to the App Store version which slightly improved this but the heavy resource gobbling is still there.
I have found no solution other than to completely quit and start the app again (like I used to have to do with Windows).
Over a GB and a half in resource for a note taking app? My video editing in FCP consumes less!
Literally the only app I have issues with on OS X.
