A chaotic market resulted in a rocky debut for Novocure Ltd. (St. Helier, Jersey Isle), a commercial stage oncology company developing a therapy for solid tumors. Shares (NASDAQ: NVCR) opened at $20.15 today, below its initial public offering price of $22, valuing the company at roughly $1.67 billion. The company set a price range of $26 to $29 but revised that price range to $23 to $24. Novacure's stock closed at $18.28 Friday, down 16.91%.