I think like a trader rather than an investor, so I often sell too soon. But I hate losing hard fought gains, so I usually I sell a chunk of my holdings on anything that looks like a spike - and this looks like a spike, although it's still a bit modest.

I really hate giving specific advice on any one position because anything can happen, but this one fits a common pattern - spike and possible pullback to the breakout point. I don't own this - only because I didn't have room in my portfolio when it broke out. But if I owned it, I would watch it closely tomorrow, and sell a quarter of my holdings if it fails to make a new high. I would sell another quarter when it breaks the accelerated trend line of the last few days. This trend line is too steep, so it's almost certain to break in a matter of days. I'd hold the other half as a core position until there was either a super-spike or a technical breakdown.

As far as buying back, I would put in a limit order at the breakout point. There's a 50/50 chance it will pull back to the 1.16-1.21 area. I'd also look to buy back if it puts in a bull flag - and breaks out of the flag formation. By that time, I may even have room in my portfolio.....