It was scheduled to begin on Monday, but has been continued until September.
Nicholas Smit and Steven Hansen face several felony charges. The two are accused of rigging booby traps to police cars and trying to fire a bazooka rocket into the station last year.
Prosecutors say Smit was trying to kill a detective to prevent him from testifying at his marijuana trial.
The Hemet Police Department invested thousands of dollars to step up security at its Latham Street station after the repeated attacks. The improvements include surrounding the building with wrought iron fencing and the installation of floodlights, surveillance cameras and windows with bullet-resistant coating.