I think its just making a correction for a biting it received from 8 Nov. to yesterday.
Unless there is something which has changed be careful bids are at 15.80 and below and only asks at 17.80 as at the time it traded such high. Get it at this level and don't scream when the gravity does its work in crashing you.
Note: This is just a personal opinion, dont quote me.
"The opportunity of a lifetime must be seized during the lifetime of the opportunity."