I just installed IntelliJ IDEA Ultimate 2017.3 and I'm seeing prompts to run 'npm install' in a project after modifying package.json. I click to try that and the "Node.js Local Interpreter" dialog pops up. It seems to have found my node binary at ~/.nodenv/shims/node, since I'm using nodenv, but when I click '...' and enter the path to ~/.nodenev/shims/npm (or shims/yarn), it makes no difference to the dialog. The dialog still appears as if I have not selected an npm.
I have multiple node versions installed with nodenv. When I run 'npm config get prefix' (in the Intellij Content/bin dir or in the current project dir), it correctly emits the path to ~/.nodenv/versions/8.4.0, which is my nodenv global default. I'm running this on Mac OS X 10.11.6.