Summary of Significant Accounting Policies - Customers Accounted for Greater Than Ten Percent of Total Revenues or Ten Percent of Accounts Receivable (Detail)	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Customer A [Member]
Revenue, Major Customer [Line Items]
Percentage of total revenues	12.00%	11.00%	13.00%
Percentage of accounts receivable at fiscal year end	21.00%	24.00%
Customer B [Member]
Revenue, Major Customer [Line Items]
Percentage of accounts receivable at fiscal year end		15.00%	19.00%
Customer C [Member]
Revenue, Major Customer [Line Items]
Percentage of accounts receivable at fiscal year end	15.00%
Customer D [Member]
Revenue, Major Customer [Line Items]
Percentage of accounts receivable at fiscal year end	14.00%		15.00%
Customer E [Member]
Revenue, Major Customer [Line Items]
Percentage of accounts receivable at fiscal year end	10.00%	11.00%	13.00%