You may also want to check with your HR department to see how they interpret it. Your employer may even be willing to sign a statement clarifying they won't attempt to appropriate your other works. You could also consult a lawyer I suppose, though you've got to weigh the cost/benefit there.

I suppose the big question is how valuable you expect your side project to be. In most cases it probably isn't a big deal, though if you think it's gonna be the next Instagram or Uber, you might wanna make sure nobody comes after your money once you're popular.