The bitcoin price on Indodax.com is determined solely by the supply and demand from the trader in Indonesian market. If There are a lot of member in Indonesia buy bitcoins at the same time, the bitcoin price will rise drastically. on the other hand if there are a lot of member in Indonesisa sell their bitcoin at the same time, the bitcoin price will drastically fall.
And the Foreign market depend on the supply on demand of the international traders, or some country’s. but on the average The bitcoin price in the world is nearly equal.