Fair Value of Financial Instruments - Narrative (Detail) - USD ($)	3 Months Ended
	Aug. 02, 2015	May. 03, 2015		Aug. 03, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term investments	$ 2,893,000	$ 2,415,000	[1]	$ 1,749,000
Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments, maturity period	3 months
Short-term Investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term bond funds	$ 6,300,000	10,000,000		6,300,000
Unrealized loss on short-term bond funds	$ (184,000)	$ (95,000)		$ (70,000)

[1] Derived from audited financial statements.