Antique Kidney shaped desks can date back to the 18th Century, but most we see today seldom predate the 1900 when mass production techniques brought down the price of what used to be custom made furniture. Based on the images this one is a 20th Century reproduction, many like this date from the second to third quarter of the 20th Century. Most furniture manufacturers had a line of desks like this in their catalogs and they have been mass produced since the 1920's. Values for them vary by the maker and quality of construction, without a maker's tag or label it's impossible to determine who made this one.
Most furniture made since the 1920's only requires regular dusting and polishing if in good condition. Refinishing desks like this in most cases will exceed the replacement cost of a comparable piece in undamaged condition. Currently at auction a comparable desk to this one in good condition would sell in the $275.00 - $500.00 range.