Plugin installation doesn't seem to work

[jasonhornsby]

After installing the plugin in the way described in the docs typedoc failes to build any documentation. It just throws this error:

> typedoc --out ./doc ./src --module commonjs --mode modules

Error: The plugin typedoc-plugin-external-module-name could not be loaded.

Error: Cannot find module 'typedoc-plugin-external-module-name'
    at Function.Module._resolveFilename (module.js:469:15)
    at Function.Module._load (module.js:417:25)
    at Module.require (module.js:497:17)
    at require (internal/module.js:20:19)
    at PluginHost.load (/usr/lib/node_modules/typedoc/dist/lib/utils/plugins.js:46:32)
    at CliApplication.Application.bootstrap (/usr/lib/node_modules/typedoc/dist/lib/application.js:51:22)
    at CliApplication.bootstrap (/usr/lib/node_modules/typedoc/dist/lib/cli.js:38:49)
    at CliApplication.Application (/usr/lib/node_modules/typedoc/dist/lib/application.js:39:15)
    at new CliApplication (/usr/lib/node_modules/typedoc/dist/lib/cli.js:35:42)
    at Object.<anonymous> (/usr/lib/node_modules/typedoc/bin/typedoc:4:1)

The only way I can figure out how to get it working again is by deinstalling the plugin.