function set( size ) {
	/* eslint-disable no-invalid-this */
	var err = isValid( size );
	if ( err ) {
		throw err;
	}
	debug( 'Current value: %d.', size );

	this._outerTickSize = size;
	debug( 'New Value: %s.', this._outerTickSize );

	this.emit( CHANGE_EVENT );
}
Sets the axis outer tick size.

@private
@param {NonNegativeInteger} size - size
@throws {TypeError} must be a nonnegative integer