The top after-market NASDAQ Losers Wednesday were: Diamond Foods, iRobot Corp, Groupon, Array BioPharma, TripAdvisor, Celldex Therapeutics, TriQuint Semiconductor, Neurocrine Biosciences, Perceptron and Affymetrix.

Diamond Foods, Inc. (DMND) stock slumped 41.68 percent to $21.38 in post market trading session after announcing that its fiscal 2010 and 2011 results will need to be restated as an internal probe found that the company booked about $80 million worth of payments to walnut growers in the wrong periods.

iRobot Corp. (IRBT) stock slumped 20.63 percent to $30.40 in post market trading session as its first quarter and fiscal 2012 earnings guidance fell short of expectations.

For the first quarter, the company expects earnings to be in a range of loss of $0.08 per share to break even per share on revenue s of $90 to $100 million, while analysts’ expects the company to report first quarter earnings per share of $0.30 on revenue s of $120.63. The company also expects fiscal 2012 earnings to be in a range of $0.75 to $0.95 per share on revenues of $465 to $485 million, which fell short of analysts’ estimation of $1.45 per share on revenue s of $529.26 million.

Groupon, Inc. (GRPN) stock slumped 15.58 percent to $20.75 in post market trading session. The company reported quarterly earnings as a publicly traded company for the first time on Wednesday, posting a net loss of $42.7 million for the fourth quarter of 2011.

Groupon said the profit miss resulted from an unexpectedly high overseas tax rate prompted by the opening of an international headquarters in Switzerland. Revenue was $506.5 million, up 194 percent from the final quarter of 2010. A year earlier there was a loss of $378.6 million, or $1.08 a share.

Array BioPharma Inc. (ARRY) stock plunged 10.34 percent to $2.86 in aftermarket trading session. The company announced that it is offering to sell, subject to market and other conditions, shares of its common stock pursuant to an effective shelf registration statement in an underwritten public offering.

TripAdvisor, Inc. (TRIP) stock plunged 9.73 percent to $31.00 in post market trading session. The company reported fourth quarter net profit of $22.0 million or $0.16 per share compared to $0.14 per share in the same quarter a year-earlier.

Celldex Therapeutics, Inc. (CLDX) stock plunged 9.63 percent to $4.69 in post market trading session.

TriQuint Semiconductor, Inc. (TQNT) stock plunged 9.21 percent to $6.21 in post market trading session. Its fourth quarter net income declined to $4.31 million or $0.03 per share from $42.49 million or $0.25 per share in the same period a year-earlier.

Neurocrine Biosciences, Inc. (NBIX) stock plunged 8.75 percent to $8.55 in post market trading session. Its fourth quarter net income declined to $1.3 million or $0.02 per share from 2.5 million or $0.04 per share in the same period a year earlier.

Perceptron, Inc. (PRCP) stock plunged 8.09 percent to $5.00 in post market trading session. The company announced second quarter net profit of $1.7 million or $0.20 per share compared to $1.0 million or $0.11 per share in the same period a year earlier.

Affymetrix, Inc. (AFFX) stock plunged 5.95 percent to $4.90 in aftermarket trading session. The company swung to fourth quarter net loss of $14.7 million or $0.21 per share compared to net profit of $4.0 million or $0.06 per share in the same period last year, while analysts’ expected the company to report quarter net loss of $0.07 per share for the second quarter.