In Development - An idea is in the early stages of development, which may include writing scripts, developing the look and feel of the world, figuring out where to shoot and how much the show would cost, or in rare cases even a preliminary casting search. Many of these series never make it to camera, as networks develop more series than they can air (and then choose the best).
Script - The network has ordered a script (or scripts), but not yet commissioned a pilot to be filmed. Some deals include "script-to-series" commitments, where if they like the script enough the network will skip the pilot stage and order several episodes to be produced.
Pilot - The network has put up the money to have a pilot episode filmed, including full casting, set-building, and more. Sometimes they will also ask to see additional scripts in order to make an informed decision. Many shot pilots do not make it to series, and the entire pilot process is becoming less common by the year.
Ordered to Series (or [Date]) - Shows marked above with a date (or season) have been picked up to series and will air on the network. (After they premiere they will be moved to SciFi Stream's "Now Airing" section.) Note that on rare occasions a show that receives a series order is cancelled during production.