diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e6424df8..0459ec35 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -7,31 +7,30 @@ on: [push, pull_request]
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
     strategy:
       matrix:
         python-version: [3.6, 3.7, 3.8]
 
     steps:
-    - uses: actions/checkout@v2
-    - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v1
-      with:
-        python-version: ${{ matrix.python-version }}
-    - name: Install linting dependencies
-      run: |
-        python -m pip install --upgrade pip
-        pip install flake8 isort==4.3.21 yapf
-    - name: Lint with flake8
-      run: flake8 --max-complexity 20 .
-    - name: Lint with isort
-      run: isort -rc --check-only --diff pycocotools/ lvis/
-    - name: Format with yapf
-      run: yapf -r -d pycocotools/ lvis/
-    - name: Install python dependencies
-      run: pip install numpy
-    - name: Build and install pycocotools
-      run: cd pycocotools && rm -rf *.eggs-info && pip install .
-    - name: Build and install lvis
-      run: cd lvis && rm -rf *.eggs-info && pip install .
+      - uses: actions/checkout@v2
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v1
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install linting dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install flake8 isort==4.3.21 yapf
+      - name: Lint with flake8
+        run: flake8 --max-complexity 20 .
+      - name: Lint with isort
+        run: isort -rc --check-only --diff pycocotools/ lvis/
+      - name: Format with yapf
+        run: yapf -r -d pycocotools/ lvis/
+      - name: Install python dependencies
+        run: pip install numpy
+      - name: Build and install pycocotools
+        run: cd pycocotools && rm -rf *.eggs-info && pip install .
+      - name: Build and install lvis
+        run: cd lvis && rm -rf *.eggs-info && pip install .
diff --git a/pycocotools/setup.py b/pycocotools/setup.py
index 1a81fd95..e7cb07eb 100644
--- a/pycocotools/setup.py
+++ b/pycocotools/setup.py
@@ -1,4 +1,4 @@
-import numpy as np
+from setuptools import dist  # Install numpy and cython at start
 from setuptools import Extension, setup
 
 # To compile and install locally run "python setup.py build_ext --inplace"
@@ -8,6 +8,13 @@
 # the Visual C++ 2015 build tools.
 # They can safely be removed.
 
+dist.Distribution().fetch_build_eggs(['cython>=0.27.3', 'numpy'])
+
+try:
+    import numpy as np
+except ImportError:
+    exit('Please install numpy first.')
+
 ext_modules = [
     Extension(
         'pycocotools._mask',
@@ -24,5 +31,5 @@
       install_requires=[
           'setuptools>=18.0', 'cython>=0.27.3', 'matplotlib>=2.1.0'
       ],
-      version='12.0.3',
+      version='12.0.4',
       ext_modules=ext_modules)