The top after-market Nasdaq gainers Monday were Netflix Inc, Veeco Instruments Inc., Illumina, Xoom Corporation. and Celldex Therapeutics, Inc., while the top after-market Nasdaq losers were Rent-A-Center Inc., Cardionet, RF Micro Devices Inc. and PCM Inc.

Gainers

Netflix Inc. (NASDAQ:NFLX) shares surged 24.68 percent to $217.40 in post-market trading. The company stock gained 6.73 percent in regular trading Monday after the leading online video subscription service, posted a better-than-expected gain in number of U.S. subscribers for the first quarter, adding more than 2 million new customers. The increase brought the domestic total for the period to 29.2 million subscribers against analysts’ estimate of 29 million online U.S. users in March.

Veeco Instruments Inc. (NASDAQ:VECO) shares climbed 7.82 percent to $34.75 in post-market trading. The company announced after the bell Monday that first quarter bookings were $70 million and that its unaudited cash balance as of Mar. 31, 2013 was $588 million, up from $579 million as of Dec. 31, 2012.

Illumina (NASDAQ:MAKO) shares advanced 7.26 percent to $59.12 in post-market trading. The company reported first quarter earnings per share of $0.46, $0.07 better than analysts' estimate of $0.39. Revenues for the quarter came in at $331 million versus a consensus estimate of $310.64 million.

Xoom Corporation (NASDAQ:XOOM) shares gained 4.13 percent to $20.40 in post-market trading. The company reported first quarter earnings per share of $0.02, $0.12 better than the analysts' estimate of a loss of $0.10. Revenues for the quarter came in at $24.3 million versus the consensus estimate of $22.82 million. The company expects to report loss in second quarter in the range of $0.07-$0.10 per share, versus a consensus estimate of loss of $0.07 per share. Xoom expects second quarter revenues in the range of $25 to $26 million, versus a consensus estimate of $25.06 million.

Celldex Therapeutics Inc. (NASDAQ:CLDX) shares advanced 2.54 percent to $13.3 in post-market trading. The company stock has a 52-week low of $3.88, a 52-week high of $13.27 and $1.05 billion in market capitalization.

Losers

Cardionet Inc (NASDAQ:BEAT) shares dropped 11.66 percent to $2.23 in post-market trading. The company on Monday reported first quarter earnings loss of $0.03 per share versus a loss of $0.10 per share reported for the same period last year. The shares gained 5.91 percent in regular trading Monday.

Rent-A-Center Inc. (NASDAQ:RCII) shares declined 6.55 percent to $33.55 in post-market trading. The company announced first quarter earnings per share of $0.80, $0.08 worse than the analysts' estimate of $0.88. Revenues for the quarter came in at $819.3 million versus a consensus estimate of $845.7 million. The company expects FY-2013 earnings per share in the range of $2.95-$3.10, versus a consensus estimate of $3.31 per share.

RF Micro Devices Inc. (NASDAQ:RFMD) shares slumped 4.52 percent to $5.00 in post-market trading. The company stock gained 4.74 percent in regular trading Monday.

PCM Inc. (NASDAQ:PCMI) shares fell 3.42 percent to $6.21 in post-market trading. The company stock gained 2.88 percent in regular trading Monday.

Netflix Investment