There could be several reasons for this, but the most likely cause is that you have VS Code installed but not the Flutter extension.
I get the same:
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel dev, v0.5.4, on Microsoft Windows [Version 10.0.17134.112], locale en-GB)
[√] Android toolchain - develop for Android devices (Android SDK 27.0.3)
[√] Android Studio (version 3.1)
[√] IntelliJ IDEA Community Edition (version 2017.2)
[√] IntelliJ IDEA Community Edition (version 2018.1)
[!] VS Code, 32-bit edition
[!] VS Code, 64-bit edition (version 1.22.2)
[!] Connected devices
! No devices available
! Doctor found issues in 3 categories.
Run flutter doctor -v for more details as it tells you to in the error message:
[√] Flutter (Channel dev, v0.5.4, on Microsoft Windows [Version 10.0.17134.112], locale en-GB)
• Flutter version 0.5.4 at C:\VirtualDrives\Programs\flutter
• Framework revision 3019ad976d (11 days ago), 2018-06-11 11:31:25 -0700
• Engine revision d33bbff470
• Dart version 2.0.0-dev.60.0.flutter-a5e41681e5
[√] Android toolchain - develop for Android devices (Android SDK 27.0.3)
• Android SDK at C:\VirtualDrives\Programs\Android\sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-27, build-tools 27.0.3
• ANDROID_HOME = C:\VirtualDrives\Programs\Android\sdk
• Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b02)
• All Android licenses accepted.
[√] Android Studio (version 3.1)
• Android Studio at C:\Program Files\Android\Android Studio
• Flutter plugin version 25.0.1
• Dart plugin version 173.4700
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b02)
[√] IntelliJ IDEA Community Edition (version 2017.2)
• IntelliJ at C:\Program Files (x86)\JetBrains\IntelliJ IDEA Community Edition 2017.1
• Flutter plugin version 19.1
• Dart plugin version 172.4343.25
[√] IntelliJ IDEA Community Edition (version 2018.1)
• IntelliJ at C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2018.1
• Flutter plugin version 25.0.2
• Dart plugin version 181.4892.1
[!] VS Code, 32-bit edition
• VS Code at C:\Program Files (x86)\Microsoft VS Code
• Flutter extension not installed; install from
https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter
[!] VS Code, 64-bit edition (version 1.22.2)
• VS Code at C:\Program Files\Microsoft VS Code
• Flutter extension not installed; install from
https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter
[!] Connected devices
! No devices available
! Doctor found issues in 3 categories.