Although we don’t believe in timing the market or panicking over market movements, we do like to keep an eye on big changes—just in case they’re material to our investing thesis.

What: Shares of Mannkind Corp. (Nasdaq: MNKD) popped 10.5% in intraday trading today, but no significant news indicated why investors were feeling so optimistic.

So what: Maybe some investors feel like things can't get any worse for Mannkind. A quick glance at the company's stock chart and the recent steep drop in price gives a little "tell" that something went wrong. Maybe some folks are feeling slightly more bullish because CEO Alfred Mann has been purchasing shares, showing he's willing to put some personal skin in the game.

Now what: Mannkind shares recently traded near 52-week lows, but there's a reason for that: It's got some major challenges at the moment. Its inhaled insulin product was recently rejected by the FDA, and the company also faces several shareholder lawsuits that allege it failed to disclose important facts about the drug's risks. Despite today's pop, Mannkind looks like a "buyer, beware" kind of stock.

Interested in more info on Mannkind? Add it to your watchlist here by clicking here.

Alyce Lomax does not own shares of Mannkind. 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.