What: Shares of MannKind Corp. (NASDAQ:MNKD), the maker of the inhaled insulin product Afrezza, continued to fall today, dropping by as much as 23% on exceptionally high volume. The drugmaker's stock has been in free fall ever since its marketing partner Sanofi (NYSE:SNY) reported that Afrezza's sales failed to gain much traction in the third quarter. Specifically, Sanofi had Afrezza's net sales for the three month period coming in at $2.2. million, although MannKind did book $4.1 million in product shipments for the quarter.

Because of the unfavorable combination of Afrezza's painfully slow commercial uptake and MannKind's problematic balance sheet, the company's stock has now declined a whopping 63% so far this year, according to data from S&P Capital IQ.

So what: The big question swirling around MannKind right now is whether or not Sanofi will decide to terminate its marketing agreement for Afrezza early next year. As one would expect, a couple of the analysts covering this stock tried to get an answer to this burning question on the company's recent third quarter earnings call. However, management didn't reveal much beyond stating that their impression is that Sanofi plans on continuing the partnership for the foreseeable future.   

Now what: Based on how MannKind's shares have been plummeting this month, the market appears to be bracing for the worst case scenario, and perhaps for good reason. The fact is that MannKind may not have the resources to take on Afrezza's commercialization by itself if Sanofi bolts -- at least not on the scale required to turn Afrezza into a blockbuster product.

After all, MannKind exited the third quarter with a mere $32.9 million in cash and cash equivalents. So, even with some additional funds available through its loan agreement with the Mann Group and sales of its common stock, MannKind would probably be hard pressed to execute such a monumental undertaking on its own. As such, investors may want to avoid trying to catch this falling knife for the time being.  

George Budwell has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.