Cash, Cash Equivalents and Marketable Securities - Summary of Estimated Fair Value of Cash, Cash Equivalents and Marketable Securities (Detail) - USD ($) $ in Thousands	Apr. 29, 2017	Jan. 28, 2017	Apr. 30, 2016	Jan. 30, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Cash and cash equivalents	$ 22,320	$ 20,247	$ 16,890	$ 43,163
Estimated Fair Value, Cash and cash equivalents	22,320	20,247
Amortized Cost, Marketable securities	54,179	58,601
Gross Unrealized Holding Gains, Marketable securities	19	8
Gross Unrealized Holding Losses, Marketable securities	(23)	(30)
Estimated Fair Value, Marketable securities	54,175	58,579
Cash [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Cash and cash equivalents	21,594	19,190
Estimated Fair Value, Cash and cash equivalents	21,594	19,190
Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Cash and cash equivalents	726	657
Estimated Fair Value, Cash and cash equivalents	726	657
State and Local Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Cash and cash equivalents		400
Estimated Fair Value, Cash and cash equivalents		400
Amortized Cost, Marketable securities	33,139	19,151
Gross Unrealized Holding Gains, Marketable securities	19	8
Gross Unrealized Holding Losses, Marketable securities	(23)	(30)
Estimated Fair Value, Marketable securities	33,135	19,129
Variable-rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Marketable securities	21,040	39,450
Estimated Fair Value, Marketable securities	$ 21,040	$ 39,450