Do you clearly distinguish between technology development and product development? Technology development is science-facing, while product development is market-facing. Technology development turns money into knowledge, and product development turns knowledge back into money. Keep technology and product development separate if you want to avoid confusion and inefficiency. Milestones on a Gantt chart are great for product development, but good luck scheduling technical breakthroughs in your lab.
More in article, Timing is Everything (p6).