Thomas,
Given that you are probably sitting on a triple (I got a nice triple in about 9 months or so) it is rational to consider, okay, take profits or risk a TEVA approval (we discount the lawsuit as nothing, although it is not quite nothing, but I'll assume that it is nothing for now).
All this said, M356 is what convinced me to keep it here. M356 alone appears to be worth more than M-Lovenox (when/if it is finally approved - even if approved before patents expire if their is a loss in the patent suit as the market will start discounting its large value as the clock ticks down), and it means we are not sitting on a one time, take your money and run asset. There is real and legitimate follow-up here. I can therefore, as long as I have patience, not shoot myself if it does crash back down to $15 because TEVA does somehow garner approval. Now if it crashes to $5 if the lawsuit pans out for Sanofi, well, that is a risk I'm discounting to practically zero at present.
Given that I don't diversify very well, one has to keep these things in mind. So trying to value the downside is as important as valuing the upside. Which is why I've been feverishly trying to do so over the last few days. Risk/reward is the nature of any investment, and I only invest in very few.
It is why I bought in the single digits, and not at $20 or $15 a share, with biotechs, there is so much volatility, you have to ascertain the risk/reward and in the single digits it was undeniable, and if the downside is 20%, then still undeniable. Although, like another poster suggested, it will fall (at least temporarily) to less than $18 if Teva were to garner approval I would guesstimate, probably to $15, so a 31% downside, but with M356 still ahead of it as another upside. Without M356 as a back-up then it is rational to reevaluated the risk/reward at this level and adjust.
August 17 will be another important day.
Tinker