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 Ambarella (NASDAQ:AMBA) fell more than 13% during Wednesday's intra-day trading after an analyst at Needham downgraded the stock to hold from buy.

So what: While Needham analyst Quinn Bolton remained impressed by Ambarella's wearable offerings unveiled at this year's CES -- including a new pendant camera platform designed in a partnership with Google for use with its Helpouts service -- at the same time, he noted shares looked pricey following a nearly 45% run-up over the past month alone.

And that seems fair enough. Even after today's pullback, Ambarella stock is still trading around 27 times next year's estimated earnings, and nearly 7 times sales.

Now what: But that still doesn't mean Ambarella shareholders should be running for the hills. After all, in Q3, the company not only grew revenue by a solid 24% year over year to $35.7 million, but also managed to increase adjusted net income per share by almost 35% over the same period.

As a result, and despite today's downgrade, I'm still convinced we're talking about a healthy, fast-growing company poised to reward patient investors over the long term.