When Lewis buys shares it signifies good insider information. He set up his buy program to allow him to purchase shares with full knowledge of "insider" information (ie. clinical/preclinical trial early indications). His purchase preceded the other insiders, who technically couldn't be told directly of any insider information. If he "didn't" buy it would be the opposite signal, letting insiders know to not purchase anything because preclinical and/or clinical trial wasn't going as planned. Genius!!!