One of the really challenging aspects of innovation is that nothing stands still. Whilst you are developing new technologies, approaches and designs, so are your competitors. Whilst you are keeping it secret, others are talking, sharing and collaborating.
A great idea 12 months late is no longer a great idea even if it is technically superior, concept tested, validated and backed by deep experience.
The old adage of fail early / fail fast makes good sense - failure after several years of effort and investment is painful.
So get to know your competitors, those who have access to your market, those who may help, those with whom you could collaborate, those who can get you there faster - don't keep it to yourself, many heads are better than one. And a shared success is much better than a solo failure.
However, innovators often claim that they lack access to funding - I wonder if it is more a lack of willingness to share and collaborate, maybe a fear of what happens when a dream hits reality?