The top after-market NASDAQ gainers Friday were Obagi Medical Products Inc, SLM Corporation, Microvision Inc, Canadian Solar Inc and Exide Technologies.

The top after-market NASDAQ losers were: Santarus Inc, United Therapeutics Corporation, ATP Oil & Gas Corporation, 21Vianet Group, Inc and American Superconductor Corporation.

Gainers

Obagi Medical Products, Inc. (OMPI) shares climbed 3.38 percent to $ 14.98 in after-hours trading.  The specialty pharmaceutical company that develops markets and sells skin care systems and related products climbed 5 percent in regular trading session.

Shares of SLM Corporation (SLM) rose 2.80 percent in post-market session to close at $15.43.  

Microvision, Inc. (MVIS) shares surged 2.64 percent to 2.33 in after-hours trading Friday. The company shares lost 24.08 percent in regular trading session Friday. The company announced that it had priced an underwritten public offering of 4.2 million units at $2.50 per unit for gross proceeds of approximately $10.5 million Friday. The company said it expected to receive net proceeds of approximately $9.9 million from the offering.

Canadian Solar Inc (CSIQ) shares advanced 2.64 percent to $ 2.33 in post-market trading after the company Friday announced that its photovoltaic (PV) modules continued to rank among the top for PVUSA Test Conditions (PTC) Ratings.  

Exide Technologies (XIDE) shares gained 1.72 percent and reached $2.96 in after-hours trading.

Losers

Santarus, Inc. (SNTS) traded 6.20 percent lower at $ 6.51 in post-market session Friday. The stock has a 52-week low of $2.40, a 52-week high of $7.11 and $ 434.52 million in market capitalization.

United Therapeutics Corporation (UTHR) shares plunged 4.40 percent to $45.68 in post-market session.  The biotechnology company stocks have a 52-week low of $ 36.55, a 52-week high of $ 59.40 and $ 2.57 billion in market capitalization.

ATP Oil & Gas Corporation (ATPG) stocks dropped 4.02 percent to $5.02 in after-hours trading. The company shares surged 29.78 percent in regular hours trading.

21Vianet Group, Inc. (VNET) shares declined 3.56 percent to $10.56 in after-hours trading after gaining 10.61 percent in regular trading session.  The carrier-neutral internet data center services provider has a 52-week low of $ 8.31, a 52-week high of $ 14.82.

American Superconductor Corporation (AMSC) shares lost 3.35 percent in after-hours trading to reach $3.75. The company's shares gained 3.74 percent in regular market trading.