Currency formatting with AW.UI.Input

I'm missing something simple here. I'm trying to format a standard input for currency:

var dollars = new AW.Formats.Number;
dollars.setTextFormat("$ #,###.##");


var obj = new AW.UI.Input;
obj.setId("obj");
obj.setName("obj");
obj.setControlFormat(dollars);
obj.setControlValue("");

When I enter data into the field, it is not formatted. I know I'm missing something here.

Any assistance is appreciated. I've searched the forums and can find many examples for setCell for grids, but precious little for input objects.