It took a long time to get each interview, because it took the producer 2-3 weeks before responding to my emails. Sometimes I had to email him 4 times before getting a response.
Eventually though, I got a technical phone interview, and a month later, Riot flew me down to Santa Monica for an onsite interview.
The onsite consisted of a tour, lunch, and an extensive ( like 9 hours! ) series of interviews with various members of the team.