Can't restart because OS X thinks an app is open

I was working with Xcode and it stopped responding so I force quit, reported the error, and tried reopening the app. When reopening the dock hung too so I ended up having to restart the dock with killall -KILL Dock. Unfortunately now OS X thinks Xcode is running but hung. Long pressing the icon in the dock or going to the force quit screen clearly show the app but selecting "Force Quit" does nothing and the app does not appear when I do ps -e.

Is there any way I can get OS X to realize the app isn't running so I can open it or safely restart the OS?