I worked for a company and they wanted to do something similar, I think they went with something boilerplate or some suggestions from an attorney. I suggested a compromise and we use something akin to the [GitHub Balanced Employee Intellectual Property Agreement (BEIPA)](https://github.com/github/balanced-employee-ip-agreement/blo...).
I'm not sure if in your circumstance they would go for it, but it worked out for me. Here is the github blog post - https://github.blog/2017-03-21-work-life-balance-in-employee...