What: Shares of cyber security solution company Imperva (NASDAQ:IMPV) were hit hard on Thursday following the company's first-quarter earnings release. Shares fell as much as 32%, but the stock's decline has improved to about 25% at the time of this writing.

Image source: Imperva.

So what: The stock's sell-off is likely related to the company's weaker-than-expected guidance. Its revenue of $59.8 million, which was up 34% compared to the year-ago quarter, was about in line with analysts' consensus expectations. And its non-GAAP loss per share of $0.25 was narrower than analysts' consensus forecast for a loss of $0.28. But its guidance for a second-quarter revenue in a range of $65.5 million to $66.5 million was worse than analysts' consensus estimate for revenue of $70.3 million.

Second-quarter revenue in the middle of Imperva's guidance range would imply a notable sequential deceleration in year-over-year growth compared to the company's 34% growth in Q1. This guidance represents 23% year-over-year growth in revenue.

Now what: Management was optimistic about the company's growth prospects in its first-quarter earnings press release, citing a growing need for cyber security, which is creating "a strong pipeline of opportunities globally."