Interactive Table with graph drilldown

The following is a very rough, very disguised view of what I'm really working on, so hopefully it will suffice as a visual example for the following conundrum:

I have an app with a large spreadsheet view, which potentially has hundreds of rows. The idea behind this view is that it includes some key data that exposes trends e.g. percentage changes year over year, etc. The goal for this data is to then allow the user to spot either a disturbing trend, something to watch out for, or perhaps to investigate further.

In the wireframe example, I've given the fictional metaphor of a sales account spreadsheet. You'll notice that each account has a checkbox, and multiple accounts can be selected. The idea behind this is that you can group accounts, and view their sales data in an aggregate graph.

Regardless of whether or not you select multiple accounts or a single account, the next step would be to view that data in a graph.

My question is - what's the best way, in terms of navigation/presentation/layout, to display the graph for either single or grouped accounts. The graph view contains various things like date ranges, pre-set intervals, and various visualization options (bar/line, etc.).

In a previous, much simpler, iteration of this, the page was divided into 2 columns, with the graph view being omnipresent, and taking up 2/3ds of the page, and the table of accounts taking up 1/3, but with an expand button that opened the table in a drawer that partially covered the graph. While this worked well for users switching back and forth - the table view is actually the primary view, and is more important for this set of users, in terms of getting the birds eye view of their accounts, and spotting trends/problem spots, while the graph is more of a secondary component. Additionally, because of the volume of accounts for some users, the sidebar was too difficult to navigate within (multiple scrollbars, etc.)

Here are some of the new options we've been discussing:

1) Lightbox/new screen with the graph view 2) Have a small graph above the table view, which can be resized at will 3) Drive to a separate graph view, each time the user wants to view a single or multiple account graph

None of these really feel like great solutions, and I'm kind of stumped. What would be some things I should take into consideration here?