Is the startup along the same lines as the work you're doing now? My last job I was a Software PM in an engineering studio and they had a clause in the handbook

Is the startup along the same lines as the work you're doing now? My last job I was a Software PM in an engineering studio and they had a clause in the handbook that any outside work done was owned by the company. One developer tried to put an app in the Android Store, he was making a business app and the company was a gambling company. And our employer said the app would be their property. So he just killed the effort. I'd check for clauses like that also.