Idaho Code § 34-1808
If the secretary of state shall refuse to accept and file any petition for the initiative or for the referendum with the requisite number of signatures of qualified electors thereto attached, any citizen may apply, within ten (10) days after such refusal to the district court for a writ of mandamus to compel him to do so. If it shall be decided by the court that such petition is legally sufficient, the secretary of state shall then file it, with a certified copy of the judgment attached thereto, as of the date on which it was originally offered for filing in his office. On a showing that any petition filed is not legally sufficient, the court may enjoin the secretary of state and all other officers from certifying or printing on the official ballot for the ensuing election the ballot title and numbers of such measure. All such suits shall be advanced on the court docket and heard and decided by the court as quickly as possible. Either party may appeal to the Supreme Court within ten (10) days after a decision is rendered. The district court of the fourth judicial district of the state of Idaho in and for Ada County shall have jurisdiction in all cases of measures to be submitted to the qualified electors of the state at large.
Idaho Code § 34-1808