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 Nuance Communications (NASDAQ:NUAN) plunged more than 18% Tuesday after the company reported solid quarterly results, but followed up with disappointing forward guidance.

So what: Adjusted quarterly sales rose to $490.4 million, which translated to adjusted net income of $95.2 million, or $0.30 per diluted share. Analysts, by contrast, were looking for adjusted earnings of just $0.29 per share on sales of $489.56 million.

However, Nuance also stated non-GAAP revenue for its fiscal first quarter 2014 to be between $477 million and $487 million, with non-GAAP earnings per share between $0.18 and $0.21. Analysts were modeling adjusted fiscal first-quarter earnings of $0.33 per share on sales of $494.74 million.

In addition, beginning with this report, Nuance is now including a bookings forecast to help investors more effectively track its transition away from perpetual license purchases and toward term-based and subscription pricing. In fiscal 2014, Nuance expects bookings to increase around 15% to between $2.15 billion and $2.25 billion.

Now what: It may serve as little consolation for shareholders who weathered today's plunge, but I agree with management's assertion this transition should serve to build for Nuance a more predictable, recurring revenue stream over the long-term. As it stands, though, the fickle market certainly doesn't appreciate the resulting near-term weakness.

That said, given today's drop, it looks like much of that pessimism is priced in. With shares now trading under 9 times next year's estimated earnings, I think shares of Nuance could turn out to be a bargain for patient long-term investors.