What: Shares of cybersecurity solutions company Imperva (NASDAQ:IMPV) sank as much as 15% on Thursday morning after it reported worse-than-expected guidance for the current quarter and the full year.

So what: Imperva's fourth-quarter results, which it reported after market close on Wednesday, were about in line or even better than analysts expected for the quarter. Analysts forecasted about $68.1 million in revenue and non-GAAP earnings per share of $0.15. Actual revenue and non-GAAP EPS were $72.7 million and $0.11, or a beat on revenue and slight miss on EPS.

But it's probably the company's weaker-than-expected guidance -- not its slight miss on its bottom line in Q4 -- that sent shares lower.

Now what: Imperva guided for a non-GAAP EPS loss in the range of $0.26 to $0.32 for the current quarter and a non-GAAP profit in the range of $0.17 to $0.23 per share for the full year.

CFO Terry Schmid is happy with the company's guidance, asserting that it is "a strong starting point for the year" during the earnings call following the release. He also noted that high growth rates in 2015 make year-over-year comparisons tough.