Applied on the website first. Email exchange with a recruiter. Then a phone screen. Phone screen went well so they flew me down to (outside) Philly for an in person.
The in-person session was intense. Full morning, tour of the facility, 15 min math flow problem (see earlier review that shows the problem laid out), followed by 4 separate 30-45 min sessions with different people.
It was basically entirely "tell me about a time" questions that applied to the leadership principles. I felt it went ok, but didn't receive an offer. I'm not sure I would have accepted anyway. Everyone there sounded like they worked 60-80 hrs a week, hardly had any personal life, etc...