diff --git a/README.md b/README.md
index f455c86..5ed2cfd 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 # IDE-TypeScript package
 [![macOS Build Status](https://travis-ci.org/atom/ide-typescript.svg?branch=master)](https://travis-ci.org/atom/ide-typescript) [![Windows Build Status](https://ci.appveyor.com/api/projects/status/o1csvdbqau6m7awm?svg=true)](https://ci.appveyor.com/project/Atom/ide-typescript/branch/master) [![Dependency Status](https://david-dm.org/atom/ide-typescript.svg)](https://david-dm.org/atom/ide-typescript)
 
-TypeScript and JavaScript language support for Atom-IDE, powered by the [Sourcegraph TypeScript Language Server](https://github.com/sourcegraph/javascript-typescript-langserver).
+TypeScript and JavaScript language support for Atom-IDE, powered by the [Theia TypeScript Language Server](https://github.com/theia-ide/typescript-language-server).
 
 ![Screen shot of IDE-TypeScript](https://user-images.githubusercontent.com/118951/30306800-37e3c506-972f-11e7-805c-ba5a45a6bc3c.png)
 
@@ -18,6 +18,7 @@ This package is currently an early access release.  You should also install the
 * Go to definition
 * Hover
 * Signature help
+* Format code
 
 ## Contributing
 Always feel free to help out!  Whether it's [filing bugs and feature requests](https://github.com/atom/languageserver-typescript/issues/new) or working on some of the [open issues](https://github.com/atom/languageserver-typescript/issues), Atom's [contributing guide](https://github.com/atom/atom/blob/master/CONTRIBUTING.md) will help get you started while the [guide for contributing to packages](https://github.com/atom/atom/blob/master/docs/contributing-to-packages.md) has some extra information.
diff --git a/lib/main.js b/lib/main.js
index 389de78..4fbbaca 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -14,16 +14,15 @@ class TypeScriptLanguageClient extends AutoLanguageClient {
     return atom.config.get('ide-typescript.javascriptSupport') ? allScopes : tsScopes
   }
   getLanguageName () { return 'TypeScript' }
-  getServerName () { return 'SourceGraph' }
+  getServerName () { return 'Theia' }
 
   startServerProcess () {
     this.supportedExtensions = atom.config.get('ide-typescript.javascriptSupport') ? allExtensions : tsExtensions
-    const args = [ 'node_modules/javascript-typescript-langserver/lib/language-server-stdio' ]
-    return super.spawnChildNode(args, { cwd: path.join(__dirname, '..') })
-  }
-
-  preInitialization (connection) {
-    connection.onCustom('$/partialResult', () => {}) // Suppress partialResult until the language server honors 'streaming' detection
+    return super.spawnChildNode([
+      'node_modules/typescript-language-server/lib/cli',
+      '--stdio',
+      '--tsserver-path', atom.config.get('ide-typescript.typeScriptServer.path')
+    ] , { cwd: path.join(__dirname, '..') })
   }
 
   consumeLinterV2() {
@@ -45,12 +44,36 @@ class TypeScriptLanguageClient extends AutoLanguageClient {
 
   shouldStartForEditor(editor) {
     if (atom.config.get('ide-typescript.ignoreFlow') === true) {
-      const flowConfigPath = path.join(this.getProjectPath(editor.getURI() || ''), '.flowconfig');
-      if (fs.existsSync(flowConfigPath)) return false;
+      const flowConfigPath = path.join(this.getProjectPath(editor.getURI() || ''), '.flowconfig')
+      if (fs.existsSync(flowConfigPath)) return false
     }
+
+    if (!this.validateTypeScriptServerPath()) return false
+
     return super.shouldStartForEditor(editor);
   }
 
+  validateTypeScriptServerPath() {
+    const tsSpecifiedPath = atom.config.get('ide-typescript.typeScriptServer.path')
+    const isAbsolutelySpecified = path.isAbsolute(tsSpecifiedPath)
+    const tsAbsolutePath = isAbsolutelySpecified ? tsSpecifiedPath : path.join(__dirname, '..', tsSpecifiedPath)
+
+    if (fs.existsSync(tsAbsolutePath)) return true
+
+    atom.notifications.addError('ide-typescript could not locate the TypeScript server', {
+      dismissable: true,
+      buttons: [
+        { text: 'Set TypeScript server path', onDidClick: () => this.openPackageSettings() },
+      ],
+      description:
+        `No TypeScript server could be found at <b>${tsAbsolutePath}</b>`
+    })
+  }
+
+  openPackageSettings() {
+    atom.workspace.open('atom://config/packages/ide-typescript')
+  }
+
   getProjectPath(filePath) {
     const projectPath = atom.project.getDirectories().find(d => filePath.startsWith(d.path))
     return projectPath != null ? projectPath.path : ''
@@ -62,7 +85,7 @@ class TypeScriptLanguageClient extends AutoLanguageClient {
       cancel = true;
     })
 
-    return new Promise((resolve, reject) => {
+    return new Promise((resolve, _reject) => {
       let timeout = setTimeout(() => {
         clearTimeout(timeout)
 
@@ -83,9 +106,17 @@ class TypeScriptLanguageClient extends AutoLanguageClient {
     return provided
   }
 
-  onDidConvertAutocomplete(completionItem, suggestion, request) {
-    if (suggestion.rightLabel == null || suggestion.displayText == null) return
+  onDidConvertAutocomplete(_completionItem, suggestion, _request) {
+    TypeScriptLanguageClient.setLeftAndRightLabels(suggestion)
+
+    // Theia language server sets snippets to '' leading to ambiguity between using that and text
+    if (suggestion.snippet === '' && suggestion.text != null && suggestion.text !== '') {
+      suggestion.snippet = undefined
+    }
+  }
 
+  static setLeftAndRightLabels(suggestion) {
+    if (suggestion.rightLabel == null || suggestion.displayText == null) return
     const nameIndex = suggestion.rightLabel.indexOf(suggestion.displayText)
     if (nameIndex >= 0) {
       const signature = suggestion.rightLabel.substr(nameIndex + suggestion.displayText.length).trim()
@@ -93,8 +124,8 @@ class TypeScriptLanguageClient extends AutoLanguageClient {
       let paramsEnd = -1
       let returnStart = -1
       let bracesDepth = 0
-      for(let i = 0; i < signature.length; i++) {
-        switch(signature[i]) {
+      for (let i = 0; i < signature.length; i++) {
+        switch (signature[i]) {
           case '(': {
             if (bracesDepth++ === 0 && paramsStart === -1) {
               paramsStart = i;
@@ -115,6 +146,7 @@ class TypeScriptLanguageClient extends AutoLanguageClient {
           }
         }
       }
+
       if (atom.config.get('ide-typescript.returnTypeInAutocomplete') === 'left') {
         if (paramsStart > -1) {
           suggestion.rightLabel = signature.substring(paramsStart, paramsEnd + 1).trim()
diff --git a/package.json b/package.json
index 2241a58..7028a3a 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,18 @@
       "default": true,
       "description": "Use the TypeScript language server to provide diagnostics and warnings."
     },
+    "typeScriptServer": {
+      "title": "TypeScript server",
+      "type": "object",
+      "properties": {
+        "path": {
+          "title": "TypeScript server path",
+          "type": "string",
+          "default": "node_modules/typescript/lib/tsserver.js",
+          "description": "Path to a TypeScript `tsserver.js` the language server will use to process TypeScript. Defaults to the bundled version."
+        }
+      }
+    },
     "javascriptSupport": {
       "type": "boolean",
       "title": "JavaScript support",
@@ -49,8 +61,9 @@
     }
   },
   "dependencies": {
-    "atom-languageclient": "0.9.7",
-    "javascript-typescript-langserver": "^2.7.0"
+    "atom-languageclient": "0.9.8",
+    "typescript": "~3.1.6",
+    "typescript-language-server": "0.3.7"
   },
   "enhancedScopes": [
     "source.ts",