Thank you for the reply.  I went with a custom cell as follows:

export function ObjectiveDescriptionCell({ objectiveDescriptionEditField }) {
  return class extends GridCell {
    handleChange = (e) => {
      this.props.onChange({
          dataItem: this.props.dataItem,
          field: this.props.field,
          syntheticEvent: e.syntheticEvent,
          value: e.target.value
      });
    }
    public render() {
      const { dataItem } = this.props;
      const inEdit = dataItem[objectiveDescriptionEditField];
      const isNewItem = dataItem.ID === 0;
      return inEdit ? (
          <td>
            <input className="k-textbox" maxLength={ 255 } onChange={ this.handleChange } style={{ width: "100%" }} value={ dataItem.Description } />
          </td>
        ) : (
          <td className="k-command-cell">{ dataItem.Description }</td>
      );
    }
  };
}

Then I add it into the grid:

<GridColumn cell={ this.ObjectiveDescriptionCell } field="Description" title="Description"></GridColumn>