Investors most probably won't invest in your company at all if they know you probably will have significant IP trouble. Law suits are money-dumps, which is why the small guy never seems to win. They drop out earlier or stop from the beginning because they just don't have the funds. No investor will invest in you if e.g. 50% of his funds are going to be used for law suits.

Also, if your employer has IP over your idea/process/whatever, he will sue your next company as well.