String to Number Conversion

[sa0309]

I have a csv file that contains a source_field formatted as follows:

source_field string(19)

$193,249.54
$ 37,945.35

Note: $ is always in pos1

Target_Field NUMBER(12,2)

I need an expression to remove the $ and comma from the source_field so it will load as follows to the Target_Field
193249.54
37945.35

Any assistance would be appreicated.

Thank you.