Stephen asserts that Abraham departed Haran after the death of Terah. This understanding is in conflict with the biblical record. Genesis 11:26 mentions that Terah became the father of Abram after he lived 70 years. Genesis 11:32 says that Terah died in Haran after he lived 205 years. Genesis 12:4 states that Abram was 75 years old when he set out from Haran. Reading all these texts together, Terah should have been 150 years old when Abram set out from Haran. It appears as if Stephen followed a variant translation/tradition when it comes to the text of Genesis.1
4 Then he went out from the land of the Chaldeans and lived in Haran. And after his father died, God removed him from there into this land in which you are now living.