The top after-market Nasdaq gainers Monday were IRobot Corporation, BioScrip Inc, Life Technologies Corp, XenoPort Inc and Stewart Enterprises Inc, while the top after-market Nasdaq losers were Lakeland Industries Inc, Perfect World Co, Diamond Foods Inc and Pacira Pharmaceuticals.

Gainers

IRobot Corporation (NASDAQ:IRBT) shares surged 10.37 percent to $25.11 in post-market trading. The company announced the appointment of Alison Dean as executive vice president and chief financial officer. She will take office effective Apr. 5, 2013 and will report to Colin Angle, chief executive officer.

BioScrip Inc (NASDAQ:BIOS) shares climbed 8.26 percent to $11.80 in post-market trading Monday. BioScrip reported adjusted EPS income of $0.04 per share beating the mean analyst estimate of $0.01. Its revenues stood at $180.7 million from the year earlier quarter, topping the average revenue estimate of $173.87 million.

Life Technologies Corp (NASDAQ:LIFE) shares advanced 6.37 percent to $65.00 in post-market trading. This follows news report published in the Wall Street Journal that KKR is considering teaming with other private-equity firms in an effort to bid for Life Technologies Corp, citing sources familiar with the deal.

XenoPort Inc (NASDAQ:XNPT) shares gained 6.05 percent to $9.11 in post-market trading. The company reported a fourth quarter profit of $0.07 per share compared to a loss of $0.48 per share reported in the same period a year ago.   

Stewart Enterprises Inc (NASDAQ:STEI) shares advanced 5.82 percent to $9.45 in post-market trading.  The company reported a profit and revenue for the first quarter of 2013 that beat Wall Street’s expectations. The company reported adjusted EPS income of $0.18 per share beating the mean analyst estimate of $0.13 and revenues of $135.7 million topping the average analysts’ estimate of $129.94 million on a year-on-year basis.

Losers

Lakeland Industries Inc (NASDAQ:LAKE) shares declined 11.24 percent to $4.40 in post-market trading. The company announced Monday that lower-than-expected sales in Brazil for the quarter ended Jan. 31, 2013 resulted in anticipated operating loss in Brazil, leading to a $11.5 million goodwill impairment charge in Brazil and potential default on bank line of credit with TD Bank, sending its shares plummeting down.

Perfect World Co. Ltd. (NASDAQ:PWRD) shares dropped 10.05 percent to $10.38 in post-market trading. The company reported a fourth quarter EPS of $2.90, $0.37 better than the analysts' estimate of $2.53. Revenue for the quarter came in at $679.9 million versus the consensus estimate of $680.22 million.

Diamond Foods Inc (NASDAQ:DMND) shares slumped 5.85 percent to $16.57 in post-market trading. The company reported second quarter net income of $10.1 million, or 43 cents per share versus a loss of $20.2 million, or 93 cents per share, same period a year ago. Excluding one-time item, Diamond earned 5 cents per share. Revenues fell 16 percent, to $220.8 million. Analysts expected a net income of 6 cents per share on $239.2 million in revenue, according to FactSet.

Pacira Pharmaceuticals Inc (NASDAQ:WCRX) shares fell 4.85 percent to $27.86 in post-market trading. The company stock has a 52-week average of $9.60-$30.11 and a market capitalization of $953.17 million.