For a state legislative office, the petition must be signed by registered electors equaling at least 2 percent of the total number of votes cast for the office in that particular district in the last general election. (ballotpedia.org)
Idaho: A precinct which contains no more than 125 registered electors at the last general election may be designated by the board of county commissioners a mail ballot precinct no later than April 1 in an even - numbered year (Idaho Code § 34 - 308) (ncsl.org)
Registered electors with postal votes who have not yet sent them back can take them to a polling station. (bbc.com)