UPDATE 1-FireEye expects bigger loss as it spends more on new products

(Adds details, share movement)

May 6 (Reuters) - Cybersecurity company FireEye Inc reported higher-than-expected quarterly revenue but said it expects a bigger loss in 2014 as it spends more on developing new products.

The company uses cloud-based technologies to help businesses fight off sophisticated computer viruses that evade old-school anti-virus software made by companies such as Symantec Corp and Intel Corp's McAfee security division.

Shares of FireEye, which went public last September, fell as much as 8 percent in extended trading.

The company also said it would acquire privately held nPulse Technologies for about $70 million. NPulse handles ultra-fast search and analysis of network traffic and helps customers detect and prevent data loss.

FireEye said it expects full-year adjusted loss of $2.10-$2.30 per share on revenue of $405 million to $415 million. Research and development costs are expected to be as much as 40-43 percent of revenue.

It had previously forecast a loss of $2.00-$2.20 per share on revenue of $400 million to $410 million, with research and development expenses as 36-39 percent of revenue.

Analysts on average were expecting a loss of $2.04 per share on revenue of $406.9 million, according to Thomson Reuters I/B/E/S.

The net loss attributable to shareholders widened to $101.2 million, or 76 cents per share, in the first quarter ended March 31, from $26.9 million, or $1.78 per share, a year earlier before the company listed.

Excluding items, the company reported a loss of 53 cents per share.

Revenue nearly tripled to $73.9 million.

Analysts on average had expected a loss of 53 cents per share on revenue of $71.6 million, according to Thomson Reuters I/B/E/S.

Shares were down more than 7 percent at $34.35 after the bell on Tuesday.

The stock has lost about 40 percent of its value since April after a report by research firm NSS Labs that FireEye's breach-detection systems underperformed similar offerings by Cisco Systems, Trend Micro Inc and General Dynamics Corp. (http://link.reuters.com/myb29v)

(Reporting by Sruthi Ramakrishnan in Bangalore; Editing by Saumyadeb Chakrabarty)