I just created a new React application by cloning the Relay starter kit:
git clone https://github.com/relayjs/relay-starter-kit.git
I then created a Idea project using File -> New -> Project from existing sources. The project was created successfully. But, imports from node_modules are not resolved; e.g., in:
import React from 'react';
'react' has a red squiggly line under it. The mouse-over message says "Cannot resolve file 'react'". I verified that react node_modules/react does in fact exist.