diff --git a/readme_renderer/markdown.py b/readme_renderer/markdown.py
index cfdec80..0a82476 100644
--- a/readme_renderer/markdown.py
+++ b/readme_renderer/markdown.py
@@ -13,25 +13,15 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
-from CommonMark import commonmark
+import cmarkgfm
 
 from .clean import clean
 
 
-try:
-    import cmarkgfm
-except ImportError:
-    cmarkgfm = None
-
-
-variants = {}
-
-if cmarkgfm is not None:
-    variants["gfm"] = cmarkgfm.github_flavored_markdown_to_html
-    # Preferentially use cmarkgfm for CommonMark.
-    variants["CommonMark"] = cmarkgfm.markdown_to_html
-else:
-    variants["CommonMark"] = commonmark
+variants = {
+    "gfm": cmarkgfm.github_flavored_markdown_to_html,
+    "CommonMark": cmarkgfm.markdown_to_html,
+}
 
 
 def render(raw, variant="CommonMark", **kwargs):
diff --git a/readme_renderer/txt.py b/readme_renderer/txt.py
index 4edb60e..0c0c533 100644
--- a/readme_renderer/txt.py
+++ b/readme_renderer/txt.py
@@ -13,14 +13,7 @@
 # limitations under the License.
 from __future__ import absolute_import, division, print_function
 
-try:
-    from html import escape as html_escape
-except ImportError:
-    from cgi import escape as _html_escape
-
-    def html_escape(s, quote=True):
-        return _html_escape(s, quote=quote)
-
+from html import escape as html_escape
 
 from .clean import clean
 
diff --git a/setup.py b/setup.py
index 08ff708..5f2b64a 100644
--- a/setup.py
+++ b/setup.py
@@ -60,17 +60,14 @@
     ],
 
     install_requires=[
-        "commonmark>=0.7.4",
         "bleach>=2.1.0",
+        "cmarkgfm>=0.2.0",
         "docutils>=0.13.1",
+        "future",
         "Pygments",
         "six",
     ],
 
-    extras_require={
-        "gfm": "cmarkgfm>=0.1.0"
-    },
-
     entry_points={
         "distutils.commands": [
             "check = readme_renderer.integration.distutils:Check",
diff --git a/tests/test_markdown.py b/tests/test_markdown.py
index cc92236..c0087b1 100755
--- a/tests/test_markdown.py
+++ b/tests/test_markdown.py
@@ -2,7 +2,6 @@
 import glob
 import os
 
-import cmarkgfm
 import pytest
 
 from readme_renderer.markdown import render, variants
@@ -39,7 +38,3 @@ def test_md_fixtures(md_filename, html_filename, variant):
 
 def test_missing_variant():
     assert render('Hello', variant="InvalidVariant") is None
-
-
-def test_cmarkgfm_is_preferred():
-    assert variants['CommonMark'] is cmarkgfm.markdown_to_html
diff --git a/tox.ini b/tox.ini
index 5ee1df4..8719bb3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,7 +2,6 @@
 envlist = py27,pypy,py34,py35,py36,pep8,py2pep8,packaging
 
 [testenv]
-extras = gfm
 deps =
     pytest
     mock