They always have this position open, looking for talent. They reach out to those they find and want (that's what happened to me). You start with a phone screen with the Director of Engineering (it's a small company). If they you, then it is on-site with the team you will be working with (4-6 people). The interview is more of a conversation where I was comfortable asking more questions than I answered. You will also take a pen-and-paper coding test (yuck). Nothing too spectacular there, although you are left alone in a room with no monitoring, so it would be easy to 'cheat' finding answers on your phone. That is offset by 90% of the questions being specific to the industry (symbology, scanning, optics) and to the actual product. Some questions are seeking very-specific answers, other are more open-ended to peer into your thought process. It was novel to take the test with pen-and-paper, instead of electronically, and the overall test was more thought-out and effective than any other coding test I've ever taken. Easily more challenging, yet more enjoyable, than what the big-boys (Google, Apple, Microsoft, facebook, etc) like to put you through.