I believe F1 engines have been using a similar spark controlled compression ignition system for a few years now, so maybe Mazda poached some engine designers from one of those engine manufacturers? Also I read that Toyota is a shareholder in Mazda now so maybe they are using Mazda to try some new tech without risking their reputation?
I really impressed that they are testing the system with a manual transmission as well, so there is hope for driver oriented cheap cars for a few more years!