on the edge
In a precarious position; also, in a state of keen excitement, as from danger or risk. For example, When the stock market crashed, their whole future was on the edge, or Skydivers obviously must enjoy living on the edge.
on the edge of. On the point of doing something, as in He was on the edge of winning the election when the sex scandal broke. [c. 1600] Both def. 1 and 2 allude to the danger of falling over the edge of a precipice.
Examples from the Web for on the edge
Nobody knew what to expect when he raced: an on-the-edge win, spectacular crash, or one of his amazing recoveries.The Can't-Miss Sochi Showdown: Bode Miller And Ted Ligety
February 9, 2014