Shares of MannKind Corporation (NASDAQ: MNKD ) got crushed on Wednesday, ending the day down by 10.07%, on the back of a research note published by Piper Jaffray analyst Joshua E. Schimmer earlier in the day in which he downgraded the stock to 'Underweight' from 'Neutral'. Schimmer also reduced his price target on the stock to $1.50 from $4.00, which taking into account the fall yesterday, represents a remaining potential downside of 59% from the stock's current price. In his note, Schimmer cites the poor sales of the company's recently-launched and much-hyped diabetes drug, Afrezza, as the major reason for downgrading the stock, writing, "MNKD has vastly over-estimated the commercial potential for the drug".