Top Percentage Gainers and Losers as of 12pm 5/04/11 (VSEA, GMCR, BEAT, VCLK, SGI, GLUU, AXTI, KNDI, QSFT, SWSH, SONS, WWWW, MOTR, OPEN, AMAT)

Best

1) Varian Semiconductor Equipment Associates (NASDAQ: VSEA): Trading up 51.3% from yesterday's close to $61.37. Varian is being acquired by Applied Materials (NASDAQ: AMAT) for $63 per share in cash. The deal is valued at $4.9 billion.

2) Silicon Graphics International (NASDAQ: SGI): Trading up 20.86% from yesterday's close to $19.88. Silicon Graphics reported EPS of $0.07 per share versus -$0.12 estimates.

3) Green Mountain Coffee Roasters (NASDAQ: GMCR): Trading up 19.5% from yesterday's close to $76.56. Green Mountain reported EPS of $0.48 versus $0.38 estimates. Revenue came in at $647.66 million versus $629.35 million estimates. Shares set a new 52-week high of $78.45 earlier in the session.

4) ValueClick (NASDAQ: VCLK): Trading up 12.2% from yesterday's close to $18.48. ValueClick reported earnings of $0.26 per share versus $0.18 estimates. Revenue came in at $116.5 million versus $113.66 million estimates. The company was upgraded from Hold to Buy at Needham.

5) CardioNet (NASDAQ: BEAT): Trading up 11.8% from yesterday's close to $4.95. CardioNet stock was upgraded from Sell to Hold at Citigroup.

Other Notable Gainers

Glu Mobile (NASDAQ: GLUU): Trading up 9.4% from yesterday's close to $4.17. The company reported a narrower-than-expected loss for the first quarter. EPS came in at -$0.02 versus estimates of -$0.07.

AXT (NASDAQ: AXTI): Trading up 9.9% from yesterday's close to $7.90. Year-over-year sales grew 31.8% to $24.6 million.

Worst

1) Kandi Technologies (NASDAQ: KNDI): Trading down 27.5% from yesterday's close to $1.98. Shares put in a new 52-week low of $2.00 earlier in the session.

2) Swisher Hygiene (NASDAQ: SWSH): Trading down 16.7% from yesterday's close to $6.65. A negative article from Seeking Alpha was published today.

3) Web.com (NASDAQ: WWWW): Trading down 15.8% from yesterday's close to $12.62. Web.com was downgraded from Buy to Accumulate at Craig-Hallum.

4) Sonus Networks (NASDAQ: SONS): Trading down 15.5% from yesterday's close to $3.10. Sonus reported EPS of -$0.04 versus breakeven estimates. Revenue dropped 20 percent versus a year ago to $67.3 million.

5) Motricity (NASDAQ: MOTR): Trading down 14.8% from yesterday's close to $10.91. Motricity reported revenue of $32.2 million versus estimates of $32.6 million.

Other Notable Losers

Quest Software (NASDAQ: QSFT): Trading down 12.9% from yesterday's close to $21.98. Quest reported earnings of $0.20 per share versus estimates of $0.28 per share. Revenue came in at $188.2 million versus $197.9 million estimates.

OpenTable (NASDAQ: OPEN): Trading down 15% from yesterday's close to $89.06. OpenTable is replacing its current CEO, Jeffrey Jordan, with its current CFO, Matthew Roberts. The company was upgraded from Perform to Outperform by Oppenheimer.