Same reasons Isrg. Went from 15 at to 800 then split. Every robot they sell is like a franchise. Every surgery needs at least one cartridge. They said they will sell at least 3 more robots in 2018. Cartridge sales are going up fast. That means more and more doctors are using the robot. It's starting to catch on. Just like the davinci robot. And they are looking for a partner. I believe a buyout is more likely. IMHO.