It's impossible to have any insight whatsoever into what Denner is or isn't doing.
He ran his playbook so far -- bought a stake, threatened management and the Board, decided their response was unsatisfying, started a proxy battle. That's the playbook.
It's impossible to know anything about how he feels about the gamble he took here. What isn't impossible to know is that AMRN is hardly the top concern of Denner right now in the context of all of his activist investments.
It's a volume business. If he takes 10 positions and 6 of them are winners, he makes out like a bandit. He's perfectly capable of looking at 1 of them at some point and saying, "Ok, that was a loser. Get out and let's move on."