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.

Good Morning, fellow Fools! It's time to check out today's movers in the health care sector.

Insys in hot water over marketing practices
Insys Therapeutics (NASDAQ:INSY) is down nearly 20% pre-market this morning after word hit the Street late yesterday about the company being investigated for its marketing practices for Subsys.

Subsys was approved by the Food and Drug Administration in 2012 as a sublingual spray used for pain relief in opioid-tolerate cancer patients. Since coming on the market last year, sales have now risen nearly 1,000% , pushing Insys shares up an eye-popping 500% year to date. According to the company's statement on the matter, it's cooperating with the investigation.

Is this drop panic-worthy? My take is that the market is getting ready to overreact again to another investigation into marketing practices that may or may not result in anything. Similar allegations have been hanging over Questcor Pharmaceuticals for over a year now, and there are lessons from that case that can be applied to Insys today.

Firstly, these investigations typically take years to resolve. And in my experience, they generally result in a fine that isn't a major issue for drugs churning out hundreds of millions in sales. Although I'd like to see more details of the investigation before making a final call, Foolish investors should dig deeper into this legal matter to see if today's drop is creating a good buying opportunity. Buying fear is often a great long-term investing strategy.

XOMA raises cash
XOMA (NASDAQ:XOMA) could be in for a rare bad day after announcing an underwritten public offering after the bell yesterday. In after-hours trading, XOMA fell by more than 10%.

What seems to have investors spooked is that critical details of the offering, such as the size and price, have yet to be disclosed. Although I would like to see the requisite details, I don't think investors should hit the panic button over an offering. XOMA is shepherding its lead clinical candidate gevokizumab through a number of clinical trials for an impressive array of conditions, and it keeps producing good news for investors.

With the therapy set to read out late stage results in the so-called EYEGUARD trial soon and entering late-stage trials for multiple indications next year, I think an offering was inevitable. As such, I caution Foolish investors from reading too much into an offering, especially as a harbinger of bad things to come. Clinical trials are expensive, and they are almost always preceded by a public offering in developmental-stage biopharmas like XOMA.

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.