Idaho Code § 22-1206
Any handler, dealer or grower who fails to make collection or file return or to pay any tax within the time required by or pursuant to this act shall thereby forfeit to the state a penalty of ten per cent (10%) of the amount of tax determined to be due, as provided in this act, plus one and one-half percent (1 1/2%) of such amount of tax determined to be due for each month of delay or fraction thereof after the expiration of the first month after such return was required to be filed or such tax became due; but the commission, if satisfied that the delay was excusable, may remit all or any part of such penalty. Such penalty shall be paid to the Idaho potato commission and disposed of as provided with respect to moneys derived from the taxes levied and imposed by this act.
Idaho Code § 22-1206