10 Biggest Mid-Day Gainers For Tuesday

OpGen Inc OPGN shares jumped 61.9 percent to $1.70. OpGen shares have dropped 35.50 percent over the past 52 weeks, while the S&P 500 index has gained 11.62 percent in the same period.
GulfMark Offshore, Inc. GLF shares gained 17.7 percent to $2.00.
Achaogen Inc AKAO shares gained 13 percent to $14.72 as the company reported an offering of 5.7 million shares.
Organovo Holdings Inc ONVO shares rose 10.2 percent to $3.73. Organovo is presenting its first preclinical data on 3D bioprinted human liver tissues at the TERMIS-Americas Meeting in San Diego.
Atara Biotherapeutics Inc ATRA gained 9.7 percent to $18.60. Atara Biotherapeutics shares have dropped 19.29 percent over the past 52 weeks, while the S&P 500 index has gained 11.62 percent in the same period.
Neovasc Inc (US) NVCN shares climbed 9.1 percent to $2.47 after the company reported the close of its $75 million transaction with Boston Scientific Corporation BSX.
VeriFone Systems Inc PAY shares rose 8.5 percent to $17.83. VeriFone reported better-than-expected earnings for its fourth quarter, but issued a weak outlook for the first quarter.
U.S. Energy Corp. USEG shares climbed 8 percent to $1.57.
Monolithic Power Systems, Inc. MPWR shares gained 4.2 percent to $83.46. Monolithic Power Systems disclosed that it has filed a lawsuit against Intersil Corp ISIL for defamation, tortious interference, unfair competition, and misappropriation of trade secrets.
SeaWorld Entertainment Inc SEAS rose 3.5 percent to $19.22. Janney Capital upgraded SeaWorld from Neutral to Buy.