Obalon Therapeutics, a company focusing on commercializing medical devices designed to assist with weight loss, stood third among the flop IPOs of this year, with negative returns of 40.3 percent. Listed on the Nasdaq Global Market under the symbol “OBLN”, the Carlsbad, California-based company raised $75 million in October by offering 5 million shares at $15 per share, within the pricing range of $14 to $16 per share.