[["unvested stock awards", "shares", "weighted-average grantdate fairvalue per share"], ["unvested at december 31 2017", "36931040", "$ 47.89"], ["granted ( 1 )", "12896599", "73.87"], ["canceled", "-1315456 ( 1315456 )", "54.50"], ["vested ( 2 )", "-16783587 ( 16783587 )", "49.54"], ["unvested at december 31 2018", "31728596", "$ 57.30"]]