How are championship rankings determined for riders with zero points?

I haven't been able to find an answer on how riders who don't score any points in a season are ranked in the championship standings at the end of the year. It's almost always going to be wild card riders who've only got one or two races on the season, but it still seems like they are ranked. This season might even have a more interesting example where Simeon or Luthi could potentially score no points. Where would he be ranked in the championship at the end if the year compared to a wild card rider who had two races but zero points?Are riders after 15th effectively given negative points so that someone who always finished in 16th would be the first rider ranked after the points scoring riders for the season? Obviously those negative points don't detract from any points scoring races and are never shown.Or do they do nothing other than list those riders in order of entry?
Submitted July 11, 2018 at 12:59PM by onedaylucky https://www.reddit.com/r/motogp/comments/8xyy50/how_are_championship_rankings_determined_for/?utm_source=ifttt