1st round phone interview w/ HR rep, mostly about getting to know candidate and company. 2nd round consists of a take-home exam, open book, open note, open world. You are allowed to discuss questions w/ other people, but not current employees. You've 1 week to complete as many questions as possible. They're engineering (including programming) and science questions in different fields. They're not intro questions, so a lot of background is needed to solve each question. The best approach might be to meet with friends who specialize in different backgrounds and solve all the questions, since they're judging solely on how many questions one can get correctly. There are about 30 questions on the exam (counting all parts of questions), and each can take ~3 hours to solve (if not working with others). As mentioned, you'll most likely have to either learn new or review material to correctly answer many of the questions. Probably the worst part of if all this is that you don't know what a "good score" is, since you're just trying to do as many questions as possible. When is a good enough score? I suppose it depends on who is also interviewing for the position. I was not offered a final round interview because they were getting "extremely competitive submissions" during my application cycle. My advice for future applicants: stay away from this company. Any company that thinks it's OK to give a test that could take 80+ hours to complete a test (if done mostly on your own) raises a lot of red flags. I understand that they might be checking to see if you're able to ask for help, but you don't need that long of an exam to test this. Save your and your friends' time and energy, and use it to apply to better companies. Good luck.

After learning a bit about the company, I was prompted to take challenge questions which were related to advanced topics in programing, chemistry, biology, statistics, etc. Scoring high enough will garner a typical 1 day interview with team members in the various teams.