FineUploader onComplete not firing with CoffeeScript

I'm creating my first project with FineUploader using Node.JS, Express, and CoffeeScript. Everything is working perfectly so far, with one exception. After the upload completes, I am returning a JSON object containing the success variable, as well as one other variable that is necessary to proceed. Unfortunately, I cannot successfully get the onComplete callback to fire. I believe all of my code is correct, and the Chrome console is not throwing any errors. I have also tried printing to the Chrome console in the onComplete method, but to no avail. Any assistance would be greatly appreciated.

    uploader = new $("#collaboration-fine-uploader").fineUploader
        autoUpload: false
        multiple: false
        validation: 
            allowedExtensions: ['pdf', 'doc', 'docx', 'ppt', 'pptx', 'xls', 'xlsx']
            sizeLimit: 1024*1024*1024*10 # 10MB
        text: 
            uploadButton: "<i class='icon-plus icon-white'></i> Select Files"
        request: 
            endpoint: "/files/discussions/collaborations/upload"
        callbacks:
            onComplete: (id, fileName, responseJSON)  ->
                if (responseJSON.success)
                    alert "response success"
                    discussionId = responseJSON.discussionId
                    $.ajax
                        type: "GET"
                        url: "/courses/"+serverData.course._id+"/discussions/"+discussionId
                        beforeSend: (xhr) ->
                            xhr.setRequestHeader 'x-pjax', 'true'
                        success: (html) ->
                            # Replace the old html
                            $(".discussions-tab").html html
                            $(".new-discussion").slideUp()
                            $("#new-discussion-modal").deactivateModal()

                            # History push
                            window.history.pushState window.history.state, "Discussions", "/courses/"+serverData.course._id+"/discussions/"+discussionId

                            # Scroll to top
                            $.scrollTo 0





    $(".trigger-upload-and-submit").on "click", (e) ->
        e.preventDefault()
        uploader.fineUploader "setParams",
            discussion: 
                title: $(".new-collaboration .discussion-title").val()
                body: $(".new-collaboration .discussion-body").val()
                groupId: serverData.course._id
                showProfessors: $(".new-collaboration .show-professor-checkbox").attr("checked")
                showStudents: $(".new-collaboration .show-students-checkbox").attr("checked")
                type: "Collaboration"

        uploader.fineUploader("uploadStoredFiles")