I think it could easily reach to 20k$ in the January of 2018 for sure. Nothing can stop Bitcoin for now because most of them now are slowly accepting Bitcoin.
Most likely that 2018 could be the year that bitcoin reaches $20K. Many has speculated that it could hit and surpass at the end of the year, but its highly unlikely. It reaches $18K though, however the mental barriers that was by the trader is to book a sell order that's why we did see some minor corrections along the way. Its steady at $16K-$17K, which for me is good and its already a strong price.
Let's us continue to watch the march towards $20K though, I wouldn't be surprise if we did surpass it this year, from based from my opinion 2018 will be the time to get it there.