Ideas are not patentable. The embodiment of the idea - the invention - may be patentable. You have one year from the date of reduction to practice or from the date of non-confidential disclosure to file a patent application.

Depends on at least 3 issues:

First, is it new, useful and not obvious to someone of ordinary skill in the art to which it pertains from all that is known more than one year prior to the date by which you or your attorney can file a patent application covering it?

Second, are you able to describe it in a way that will enable someone of ordinary skill in the art to replicate your invention in workable form?(if not, you only have an "idea" not a patentable invention, as noted by Ms. Grosse in her answer above)

Third, Are you positive you haven't had your invention on sale more than a year, in non-experimental public use more than a year, or disclosed more than a year in a publicly available document, or finalized sufficiently in a workable concept that it could have been filed as a patent application more than a year ago?

If the answer to all 3 is yes, then the answer to your question is likely YES. If the answer to any of the three is no, then the answer to your question is probably NO.

However, a good patent attorney can usually find aspects of your idea that can be described in an enabling disclosure and validly claimed and patented, and the question usually becomes whether what can be patented is of sufficient commercial value to justify the expense of preparing and filing a patent application and prosecuting it to issuance, which will likely run $5,000-$10,000 for a typical invention, or more for a very complex invention. So the right initial question to ask is not whether you can get a patent but whether you should? It is an expensive and complex undertaking that takes several years, but which for the right invention of real commercial value might make an inventor rich.

So, bottom line, get yourself to a patent attorney and find out, and do it sooner rather than later. You need to see a patent attorney for a free initial consult and if it still is a GO after that, do an initial patentability search or preferably have one done for you and then, and only then, if it is still a GO, consider what can be patented and whether the commercial potential justifies the requisite expenses, time and effort involved. Time is of the essence and delay, even for a day, might cost you your rights or run your expenses through the roof.

Also, recognize a patent is only the right to STOP someone else not a license to sell or a guarantee of any profit, which is why you need to assess commercial value before actually filing for a patent.

Most patent attorneys will give you up to about a half-hour free consultation to get a feel for whether they want to work on a patent application for you, and will let you know if you are clearly barred due to lapse of time or if it clearly has no commercial value that could possibly justify a patent application.

There, you've had your free half-hour!! (Just kidding.)