diff --git a/idea/idea-analysis/src/org/jetbrains/kotlin/idea/project/TargetPlatformDetector.java b/idea/idea-analysis/src/org/jetbrains/kotlin/idea/project/TargetPlatformDetector.java
index 5c2c1836124..2d4680c44d9 100644
--- a/idea/idea-analysis/src/org/jetbrains/kotlin/idea/project/TargetPlatformDetector.java
+++ b/idea/idea-analysis/src/org/jetbrains/kotlin/idea/project/TargetPlatformDetector.java
@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.idea.project;
 
+import com.intellij.openapi.application.ReadAction;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.module.Module;
 import com.intellij.openapi.project.Project;
@@ -60,11 +61,10 @@ public class TargetPlatformDetector {
             return contextFile instanceof KtFile ? getPlatform((KtFile) contextFile) : JvmPlatforms.INSTANCE.getUnspecifiedJvmPlatform();
         }
 
-        if (file.isScript()) {
-            ScriptDefinition scriptDefinition = DefinitionsKt.findScriptDefinition(file);
-            if (scriptDefinition != null) {
-                return getPlatform(file.getProject(), scriptDefinition);
-            }
+        final ScriptDefinition scriptDefinition =
+                ReadAction.compute(() -> file.isScript() ? DefinitionsKt.findScriptDefinition(file) : null);
+        if (scriptDefinition != null) {
+            return getPlatform(file.getProject(), scriptDefinition);
         }
 
         VirtualFile virtualFile = file.getOriginalFile().getVirtualFile();