The company is one of two major players in the rapidly growing obesity drug market. Yet, the stock has lost half its value.Danish pharmaceutical giant Novo Nordisk (NVO -1.47%) has endured a significant decline in stock price, falling over 50% in the past year. The stock's miserable performance is particularly jarring, considering the pharmaceutical company is one of the leading players in the rapidly growing obesity drug market, which industry experts anticipate will explode to $150 billion in global sales ...