The top after-market Nasdaq gainers Thursday were Xyratex Ltd, Celldex Therapeutics Inc, Sequenom Inc, Fifth Street Finance Corp and Applied Micro Circuits Corporation.

The top after-market Nasdaq losers were: Informatica Corporation, Alexza Pharmaceuticals Inc, ValueVision Media Inc, Amtech Systems Inc and Alaska Communications Systems Group Inc.

Gainers

Xyratex Ltd (XRTX) shares climbed 7.51 percent to $12.60 in after-hours trading. The company reported Thursday a stronger growth rate and a better-than-expected forecast for the third quarter of the current fiscal year.

Shares of Celldex Therapeutics Inc (CLDX) rose 3.70 percent in post-market session to close at $5.61. The biopharmaceutical company's shares have a 52-week low of $2.05, a 52-week high of $5.72 and $317076 million in market capitalization.   

Sequenom Inc (SQNM) shares advanced 2.70 percent to $4.18 in post-market trading. The molecular diagnostic testing and genetics analysis company shares have a 52-week low of $3.45, a 52-week high of $8.01 and $466.18 million in market capitalization.   

Fifth Street Finance Corp (FSC) shares gained 2.34 percent and reached $10.50 in after-hours trading. The specialty finance company stocks have a 52-week low of $8.38, a 52-week high of $11.84 and $845.64 million in market capitalization.   

Applied Micro Circuits Corporation (AMCC) shares surged 1.79 percent to $ 6.25 in after-hours trading Thursday. The shares of the provider of semiconductor solutions have a 52-week low of $4.69, a 52-week high of $9.18 and $381.20 million in market capitalization.

Losers

Informatica Corporation (INFA) slumped 25.99 percent to $7.86 in the post-market session Thursday.  Informatica Corporation, the independent provider of data integration software, Thursday announced forecasts that were below analysts' expectations of preliminary financial results for the second quarter ending June 30, 2012.

The company expects total revenues to be in the range of $188 million to $190 million and earnings per share (EPS) to be in the range of $0.16 to $0.17 per diluted share and Non-GAAP earnings per share (EPS) to be in the range of $0.27 to $0.28 per diluted share. The analysts were expecting the company to report EPS of $0.37 on revenues of $217 million for the second quarter of 2012. 

Informatica announced that its Board of Directors has approved an additional $100 million to augment the existing authorization under its common stock repurchase program.

Alexza Pharmaceuticals Inc (ALXA) shares plunged 8.90 percent to $4.30 in post-market session. The company shares have a 52-week low of $2.55, a 52-week high of $18.80 and $55.97 million in market capitalization.   

ValueVision Media Inc (VVTV) shares lost 7.39 percent in after-hours trading to reach $2.13. The company shares have a 52-week low of $1.43, a 52-week high of $8.66 and 112.26 million in market capitalization.

Amtech Systems Inc. (ASYS) shares dropped 7.26 percent to $3.96 in after-hours trading.  Shares of the global provider of thermal processing systems surged 7.83 percent in regular session.

Alaska Communications Systems Group Inc (ALSK) shares declined 6.78 percent to $2.20 in after-hours trading. The company shares have a 52-week low of $1.73, a 52-week high of $8.83 and 107.35 million in market capitalization.