diff --git a/platform/features/plot/src/elements/PlotAxis.js b/platform/features/plot/src/elements/PlotAxis.js
index 29e67d1976..e2f7809c64 100644
--- a/platform/features/plot/src/elements/PlotAxis.js
+++ b/platform/features/plot/src/elements/PlotAxis.js
@@ -74,7 +74,8 @@ define(
 
         /**
          * Update axis options to reflect current metadata.
-         * @memberof platform/features/plot.PlotAxis
+         * @param {TelemetryMetadata[]} metadata objects describing
+         *        applicable telemetry
          */
         PlotAxis.prototype.updateMetadata = function (metadatas) {
             var axisType = this.axisType,
@@ -114,6 +115,12 @@ define(
             }
         };
 
+        /**
+         * Change the domain/range selection for this axis. If the
+         * provided `key` is not recognized as an option, no change
+         * will occur.
+         * @param {string} key the identifier for the domain/range
+         */
         PlotAxis.prototype.chooseOption = function (key) {
             var self = this;
             this.options.forEach(function (option) {
diff --git a/platform/features/plot/src/elements/PlotTelemetryFormatter.js b/platform/features/plot/src/elements/PlotTelemetryFormatter.js
index abe916e99d..de2a86c4a1 100644
--- a/platform/features/plot/src/elements/PlotTelemetryFormatter.js
+++ b/platform/features/plot/src/elements/PlotTelemetryFormatter.js
@@ -26,14 +26,33 @@ define(
     function () {
         'use strict';
 
+        /**
+         * Wraps a `TelemetryFormatter` to provide formats for domain and
+         * range values; provides a single place to track domain/range
+         * formats within a plot, allowing other plot elements to simply
+         * request that values be formatted.
+         * @constructor
+         * @memberof platform/features/plot
+         * @implements {platform/telemetry.TelemetryFormatter}
+         * @param {TelemetryFormatter} telemetryFormatter the formatter
+         *        to wrap.
+         */
         function PlotTelemetryFormatter(telemetryFormatter) {
             this.telemetryFormatter = telemetryFormatter;
         }
 
+        /**
+         * Specify the format to use for domain values.
+         * @param {string} key the format's identifier
+         */
         PlotTelemetryFormatter.prototype.setDomainFormat = function (key) {
             this.domainFormat = key;
         };
 
+        /**
+         * Specify the format to use for range values.
+         * @param {string} key the format's identifier
+         */
         PlotTelemetryFormatter.prototype.setRangeFormat = function (key) {
             this.rangeFormat = key;
         };