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 Mellanox Technologies (NASDAQ:MLNX) have lost 15% of their value today after the company reported disappointing first-quarter earnings following yesterday's closing bell.

So what: Mellanox's first-quarter revenue was up 19% year over year to $98.7 million, and its earnings came in at $0.10 per share, equal to last year's result. Both results were weaker than Wall Street had expected -- analysts were looking for $102.9 million in revenue and $0.12 in EPS. In GAAP terms, Mellanox lost $0.26 per share, worse than the year-ago quarter's $0.20 loss per share.

The company now expects second-quarter revenue to range from $100 million to $105 million, and for non-GAAP gross margins to range from 68% to 69%, with operating expenses to rise 4% to 6% from the first quarter. This projection implies that the company will arrive at roughly breakeven, or possibly report an adjusted loss per share, as this quarter's non-GAAP operating margin was only 5%. Both figures are substantially worse than Wall Street's expectations, which called for revenue of $109.6 million and for $0.18 in EPS.

Now what: Mellanox isn't cheap on any metric -- it's currently reporting a loss and its free cash flow is barely there at all, despite a billion-dollar-plus market cap. Investors have already suffered a huge loss over the past year, and the company doesn't appear poised for a surge on either top or bottom lines just yet. I'd watch from the sidelines until there's better evidence of improvement.