Taking a new drug or therapy from idea to market is incredibly expensive, costing potentially billions of dollars, due to a lengthy and rigorous series of FDA-required tests to prove safety and efficacy. Companies will only risk such an investment if there is a realistic chance of success. Accordingly, publicly-funded scientists take the first investigative steps, which are relatively cheap. If they succeed, private enterprise may step in for the vastly more expensive testing and development stages, which may take decades.