My guess would be from the boxes you brought in, or the potatoes. The ones in the link I had were from wood roaches, and they don't live in the house. But, they're similar in appearance to other cockroaches, and that was the best pic I could find. It's not unusual to bring them in from someplace else. I've heard of people opening bags of dog food, potatoes, etc and have the roaches just pour out of them. The ones you're seeing are the immature ones, or instar stage. That's why you're not seeing wings and are able to see the segments. The lack of wings and the segmented body are what made me suspect some type of roach.