The departure of the estimable Dr. Taylor was mentioned as well, but I'd be willing to bet that he wouldn't have retired if he'd been physically able to carry on. POET's key technology was his life's work, but unfortunately this happened:

POET also announced that Chief Scientist Dr. Geoff Taylor will be retiring from the Company, effective April 30, 2016.  Dr. Taylor noted that he made the decision to retire in order to focus on his recuperation from multiple surgeries. 

“Over the past several months I have been dealing with surgeries arising from complications with a knee replacement and therefore been unable to fulfill my duties as Chief Scientist at POET Technologies,” stated Dr. Taylor.