Computer network security company Sourcefire Inc. said Monday that its first-quarter net income dropped sharply because of higher operating expenses even though revenue grew.

The results came in above analysts' estimates and Sourcefire shares rose in after-hours trading.

The company earned $67,000, in the January-March period, which amounted to break-even on a per-share basis. That's down from $460,000, or 2 cents per share, in the same period a year ago.

Adjusted earnings were $3.4 million, or 11 cents per share in the latest quarter. That excludes stock-compensation expenses and other special items.

Revenue grew 50 percent to $46.3 million from $30.8 million.

Analysts, on average, expected earnings of 8 cents per share on revenue of $41.5 million, according to FactSet.

Total operating expenses rose 32 percent to $35.3 million from $26.8 million as research, marketing and other costs grew.

For the current quarter, Sourcefire expects adjusted earnings of 12 to 14 cents per share on revenue of $46.5 million to $48.5 million. Analysts forecast earnings of 13 cents per share on revenue of $46.3 million.

Sourcefire shares rose $3.21, or 6.3 percent, to $54.20 in after-hours trading. They closed down 58 cents in the regular session.