Segment Information, Significant Customers and Geographic Information (Details)	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Customer A [Member]
Entity-Wide Revenue, Major Customer, Percentage	18.00%	24.00%	27.00%
Customer B [Member]
Entity-Wide Revenue, Major Customer, Percentage	12.00%	11.00%	11.00%
Customer C [Member]
Entity-Wide Revenue, Major Customer, Percentage			11.00%