diff --git a/lib/do_wait_instance.js b/lib/do_wait_instance.js
index 3b8a45b..7cb63a4 100644
--- a/lib/do_wait_instance.js
+++ b/lib/do_wait_instance.js
@@ -4,25 +4,32 @@
  * `triton wait-instance ...`
  */
 
+var format = require('util').format;
+
 var common = require('./common');
+var errors = require('./errors');
+
+
 
 function do_wait_instance(subcmd, opts, args, cb) {
     var self = this;
     if (opts.help) {
-        this.do_help('help', {}, [subcmd], cb);
-        return;
-    } else if (args.length < 1 || args.length > 2) {
-        cb(new Error('invalid args: ' + args));
-        return;
+        return this.do_help('help', {}, [subcmd], cb);
+    } else if (args.length < 1) {
+        return cb(new errors.UsageError(format(
+            'incorrect number of args (%d): %s', args.length, args.join(' '))));
     }
+    var ids = args;
+    var states = [];
+    opts.states.forEach(function (s) {
+        states = states.concat(s.trim().split(/\s*,\s*/g));
+    });
 
     function log() {
         if (!opts.quiet)
             console.log.apply(console, arguments);
     }
 
-    var ids = args[0].split(',');
-    var states = (args[1] || 'failed,running').split(',');
     var done = 0;
 
     var machines = {};
@@ -90,7 +97,7 @@ do_wait_instance.help = [
     'Wait on instances moving to given states.',
     '',
     'Usage:',
-    '       {{name}} wait <name|id> [<states>]',
+    '       {{name}} wait [-s STATES] INSTANCE [INSTANCE ...]',
     '',
     '{{options}}',
     'Where "states" is a comma-separated list of target instance states,',
@@ -108,6 +115,14 @@ do_wait_instance.options = [
         type: 'bool',
         help: 'Disable all output.'
     },
+    {
+        names: ['states', 's'],
+        type: 'arrayOfString',
+        default: ['running', 'failed'],
+        helpArg: 'STATES',
+        help: 'Instance states on which to wait. Default is "running,failed".'
+            + 'Values can be comma-separated or multiple uses of the option.'
+    },
 ];
 
 module.exports = do_wait_instance;