Cash and Cash Equivalents and Investments - Additional Information (Detail) - USD ($)	3 Months Ended
Apr. 30, 2016	May. 02, 2015
Investments Debt And Equity Securities [Abstract]
Sale or purchase of available-for-sale securities	$ 0	$ 0

Amount of cash outflow (inflow) through acquisition (sale) of short-term available-for-sale securities.

No definition available.

Name:	us-gaap_PaymentsForProceedsFromAvailableforsaleSecuritiesShortterm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration