I would take their employment contract to a lawyer and have them look at it.<p>In my experience, they either want everything, or they allow you a certain amount of autonomy. In the latter case, it often boils down to time and equipment. If you do things on your own time, using your own equipment, then you're probably OK, with various conditions. The most common condition (in my experience) is that what you're working on must not be something that could be construed as being related to the company's line of business, past, present, or future (which is intentionally broad).<p>Another thing they might have is a disclosure section, where you have the option of listing inventions or other IP that you want to claim as your own. This would be an attachment, like Appendix A. I'm not sure what the best approach is here. Again, something you should discuss with a lawyer.<p>Certain states have laws relating to this, which preclude overreaching on the part of the employer. For example, California Labor Code, section 2870. Here's a good link:<p><a href="http://answers.onstartups.com/questions/19422/if-im-working-at-a-company-do-they-have-intellectual-property-rights-to-the-st" rel="nofollow">http://answers.onstartups.com/questions/19422/if-im-working-...</a>