I'm in negotiations for a position with a large corporation and I'm reading their employment terms. In their IP/copyright section they state that anything that I do outside of work that is "similar" to what I perform on the job is also theirs. I understand that it's intentionally very vague to protect them, but I'm also a little nervous that it could be abused. The way I read it, anything I produce outside of work could be claimed as well, because it would fall under "programming".

Is this relatively standard? Could I negotiate more specific terms (I have asked if I could get clarification)? Should I be worried that they could abuse this? I just don't want to be caught in a situation where come up with a (potentially) great idea outside of work and they swoop down and lay claim to it.