The sell decision is always hard.As easy way to address it is...

The sell decision is always hard.
As easy way to address it is the Crammer method, that is would you buy it now? If not then sell.

Some other criteria:
- a better investment opportunity
- consider it fairly or overvalued
- change in forward expectations.
- poor risk return profile, i.e. more downside risk than upside potential.

Bad reasons to hold:
- expect a takeover offer when the shares are already fairly to over-valued, significant blocking shareholder exists, founder holds large parcel and family controls the board.
- greed (it could go higher)

The reality is no-one consistently times tops or bottoms. So if you sell now, just accept that it is likely to go higher.

Cornish clearly see good returns from this point.

Perhaps ask yourself what will hurt more, selling to have the share price go higher or holding and have it fall to say $2?

Hope that is of some help - though I doubt it.