Insightful damage is not working on thrown weapons, FYI.
It should work...and it shows up on the item description when you cast it.
After rolling several 1s for base damage I am convinced it is not.
(My str is 8 and my int is 21)
BTW, elemental damage infusion, and runearm damage bonus are working expected on thrown weapons.
Edit: Upon further testing I noticed this in the combat log
(Combat): This weapon can use your Intelligence modifier for damage rolls if it is a crossbow or a one handed melee weapon and is the only weapon (other than a Runearm) equipped. An item can have only one temporary item enchantment at a time.
This is the only place specified that it must be a one handed MELEE weapon.