Had my eye on this one (CEPH) since November '09. Kept it in my watch list into February '10. Pulled the trigger on November 24, '10 at 64.10.
Today, CEPH received a hostile bid from Valeant for 73.00 per share. With a trading price of about 75.20, it is a good time to exit.
Sure, hostile takeovers may attract other suitors and higher bids... but then, the deal could fall apart.
Sudden spikes concern me and, with gains of 17.30% in four months, I would not hesitate to cash in.