Making two form group in bootstrap's form vertical into inline

How to create form group inline in bootstrap vertical form nicely?

I can create those inline, but the padding is messy,

 <div class="form-group ">
                <div class="col-sm-6">
                    <label for="date">Date Invoice:</label>
                    <input class="form-control" placeholder="Tanggal Invoice (Harus diisi)" type="text">
                </div>
                <div class="col-sm-6" >
                    <label for="date">Date Invoice:</label>
                    <div class="input-group">
                        <input type="text" class="form-control" placeholder="Search for...">
                        <span class="input-group-btn">
                            <button class="btn btn-primary" type="button">Go!</button>
                        </span>
                    </div>
                </div>
            </div>

Here is the fiddle : JSFIDDLE, any help it so appreciated.