Start Date and End Date--MDX Query

Hi guys,

 I have a date attribute from my OLAP cube. As per the requirement, I have to add a calendar "from date" to "to date"so I added a date parameter in data set designmode and selected range(inclusive) filter which gives me from date and to date. After that, I changed the parameter values as follows

="[SalesDetails].[Date].&[" + Format(Parameters!FromSalesDetailsDate.Value, "yyyy-MM-dd") + "]"

 but it is giving an error while executing the report.

 The 'xxxx' string cannot be converted to the date type.

 Any help would appreciated.

 Thanks

 Tarakq