Deposit at Luxor Hotel in Las Vegas, NV?

Hi, I found a great rate at Luxor for 2 nights in Jan. 2014 but I am hesitant to book on their website because it states that a "deposit required" when booking. Now what I am curious to know is if the deposit goes towards the total room cost or is the deposit in addition to the total room cost? Please let me know. I must book by 12/28/13 to receive the deep discounted rate. Thank you.