Francisco Partners Management is buying Procera Networks for about $240 million.

The San Francisco private equity firm will pay $11.50 per share of Procera, a 21 percent premium to the technology company's Tuesday closing price of $9.51.

Shares of Procera surged more than 18 percent in premarket trading Wednesday.

Procera's board unanimously approved the deal, which is targeted to close in June. Once the transaction is complete, Procera will be a privately held company.

Procera, based in Fremont, California, also said that it anticipates first-quarter revenue in a range of $19.5 million to $20.5 million. That's above the $16.8 million projection from analysts that follow the company, according to a poll by FactSet.

Shares of Procera Networks Inc. added $1.76 to $11.27 before the market opened.