Got contacted by an employee of a headhunting agency through linkedIn. First call was with the person who contacted me on LinkedIn and was a quick 5-10 minute phone call to screen me. Then I had a 1 hour call with a senior member of the headhunting agency mostly about my experience and giving me context of the role. I was then put into contact with the hiring manager who I had another 30-ish minute call with, mostly theoretical and general questions about my experience. Last round was an onsite interview at the office in San Diego with the hiring manager, a senior developer, and a manager on the hardware side.