I think you will also need to keep track of the exchange rate between USD and the currency of the country in which you pay tax at the time of each purchase and sale.
Personally, I find helpful to group all Amazon lines together in one little diary in date order, all Netflix lines together, etc. When you sell part of your holding of Amazon you will need to calculate the average per share cost. This is more easily done if all the Amazon purchases are occurring in contiguous lines. Here is an example, showing purchases of GE. The first line is a summary of the 4 lines below.
Some key figures that are needed for figuring capital gains/loss when I sell are those in blue in the top line.