on the cutting edge of something —(also: at the cutting edge of something ) involved in the most advanced developments in a particular field:
- The Museum has remained on the cutting edge of science education by developing innovative and interactive programs.
on a razor’s edge of something —(also: on the knife-edge of something ) on the brink of smth. bad or dangerous:
- They could laugh themselves sick with the memory of it now, but at the time they had been on a razor’s edge of failure or success.