Jay Dudley added a 53-yard interception return for a touchdown for the Bulldogs (2-4, 1-1 Western Athletic Conference), who snapped a three-game losing streak. Isham hit David Gru for a 6-yard score in the third quarter, then got in himself from the 1 a few minutes later. He finished with 163 yards passing.
Justin Veltung scored on an 81-yard punt return with 3:35 remaining for the Vandals (1-5, 0-2). Veltung also led Idaho receivers with six catches for 94 yards.
Idaho's Brian Reader had 244 yards passing but completed just 19 of his 47 attempts, with three interceptions. The Vandals defense recorded a safety when Andre Ferguson tackled Lennon Creer in the end zone early in the first quarter.
GameDay 100: Ohio State wide receiver Braxton Miller's incredible spin move ends in a TD in the season opener against Virginia Tech.
GameDay 100: Buckeyes quarterback Cardale Jones wins the Sugar Bowl and national title for Ohio State.
GameDay 100: Auburn's Bo Jackson shows off his strength by running through the defense.
Pac-12 reporter Ted Miller says Washington State and Utah are the league's sleeper teams and explains his fourth-place ranking of the Cougars.
Clemson coach Dabo Swinney and FSU coach Jimbo Fisher know it's unlikely but wouldn't rule out two ACC teams making the College Football Playoff.
BYU athletic director Tom Holmoe said the school would be open to a football-only option to join the Big 12, though full membership with the conference would be its goal.