Shares of GoPro Inc. (NASDAQ: GPRO) jumped 19.5% in September, according to data from S&P Global Market Intelligence, after the action-camera and drone specialist offered strong preliminary results and introduced several new products.To start, GoPro stock rose than 12% on Sept. 7 alone, which was the first trading day after the company announced that third-quarter 2017 revenue and gross margin would both arrive near the high ends of its previous guidance ranges.