applied through the website, got a phone interview and in-person interview, many technical questions from the senior engineers (they all have PhD)

One HR contact in first round, and then I was phone interviewed by a hiring manager. Finally, I was invited in the onsite interview in Portland, Oregon. They invited me to Oregon. They bought the flight, which depart at 6:00 a.m. and came back at 10 p.m. The onsite interview took 1 whole day, with 9 different people (45 min/each). It was exhausted. However, they tried not to challenge me. The interview process was easy ( not too much pressure because I am pretty I guess) However, they did not give me the offer because they think my technical background is not technical. They did not even ask a lot of technical questions, I guess my presentation was not good.