WP_Query custom taxonomy by category ID

I have created a custom taxonomy, app_category, which works perfectly. I am working on a widget to get posts by the category they are in.

// widget form creation
  function form($instance) {
  	// Check values
  	$category = isset( $instance['category'] ) ? (int) $instance['category'] : '';
  	$terms = get_terms( 'app_category', 'parent=0&hide_empty=0' );
  	if ( !empty( $terms ) && !is_wp_error( $terms ) ) {
  ?>
      <!-- Category Select Menu -->
      <p>
        <label for="<?php echo $this->get_field_id( 'category' ); ?>"><?php _e( 'App Category: ', 'AppManager_plugin' ); ?></label>
        <h1><?php echo $category ?></h1>
        <select id="<?php echo $this->get_field_id( 'category' ); ?>" name="<?php echo $this->get_field_name( 'category' ); ?>" >
          <?php foreach ( $terms as $term ) { ?>
            <option <?php selected( $category, $term->term_id ); ?> value="<?php echo $term->term_id; ?>"><?php echo $term->name; ?></option>
          <?php } ?>
        </select>
      </p>
  <?php
  	}
  }

    // display widget
    function widget($args, $instance) {
       extract( $args );
       // these are the widget options
       $category = $instance['category'];
       echo $before_widget;

       // Query for data
        $args = array(
          'post_type'       => 'apps_post',
          /** Category slug, needs to be dynamic from widget selection **/
          'app_category'    => $category
        );
        $Apps = new WP_Query( $args );
        if( $Apps -> have_posts() ) {
          while( $Apps -> have_posts() ) {
            $Apps -> the_post();
            $postid = get_the_ID();
            ?>
              <h1><?php the_title() ?></h1>
              <div class='content'>
                <?php the_excerpt() ?>
                <?php
                  $value = get_post_meta( $postid, 'apps_post', true );
                  echo '<h3>Meta Data: ' . $value . '</h3>';
                ?>
              </div>
            <?php
          }
        }

I am able to output $category and it is the same ID that I am seeing when I print $category in the widget box. The problem is that I am not able to get any of the posts back. I just get the number. I know the issue is with my $args and using 'app_category' but I am not sure what to change it to so that I can get all the posts in a custom taxonomy using the category ID, can anyone help?