npm install ember-data just installs index.js file

When I do npm install ember-data --save, I get only the following files:

    ./node_modules/ember-data/
    ./node_modules/ember-data//lib
    ./node_modules/ember-data//lib/ember-addon
    ./node_modules/ember-data//lib/ember-addon/blueprints
    ./node_modules/ember-data//lib/ember-addon/blueprints/ember-data
    ./node_modules/ember-data//lib/ember-addon/blueprints/ember-data/index.js
    ./node_modules/ember-data//lib/ember-addon/index.js
    ./node_modules/ember-data//package.json
    ./node_modules/ember-data//README.md

I was expecting the same files bower installs, such as ember-data.min.js.

My hunch is I need to do npm install from within node_modules/ember-data? If so, why the extra step?