I have an array based on selected values from multiple select boxes:

> 
> Term 03 (-1000),1 (+1000),Price (+3000),1 (+1500),--,--,--,--,--,--,--,--,--,--,--,--,--,--,--,--,--,--
> 
> 
> 

Comma-separated. As you can see, some values have text in parentheses. I need to take these values in parentheses and sum them, therefore the `+` and `-` characters should remain. 

Values (+1000), (+3000), (-1000) represent changes of price: + indicates the product will be more expensive, - represents the product will be cheaper. The result of this should be a number that indicates change of the price - e.g. 1500 - the product will cost more than basic price, or e.g. -3000 - the product will be cheaper.
Thanks in advance.
Tom