Dreon Barlett led the Hornets with 18 points, Hornsby had 14 and 10 boards and Strings added 12 points with 11 rebounds.
Sacramento State (8-7, 1-3 Big Sky) claimed its first conference win after losing three straight on the road.
Trailing 33-29 at the half, Strings opened the second period with a jumper that started an 11-4 run to give Sacramento State a 40-37 lead at the 15:26 mark. The Hornets never trailed again.
Ethan Talfair had 23 points and Chivichyan added 21 for Idaho State (6-10, 1-3).