It all depends on the P/S the acquirer is willing to shell out.
The big unknown in the P/S ratio is the denominator. With time, the estimation of S will become more accurate and in the case of amrn, with Anchor potential mkt included, the potential for S can be big .
Take the case of Lipitor. You know the story right ? Pfe had the choice to acquire Lipitor for cheap early in the game but it decided not to. In the end it had to buy Lipitor at much higher price ( I actually don;t remember the price).
The same will happen here. The longer the acquirer waits, the clearer the trend for S is, the higher or lower the P/S will be.