Stock-Based Compensation - Stock Option Activity under Two Thousand Six Plan (Details) - USD ($)		9 Months Ended
		Oct. 31, 2015	Nov. 01, 2014
Number of shares
Options granted		0	141,684
Employee Stock Plan, 2006 Plan
Number of shares
Outstanding options at beginning of year		2,747,802
Options canceled		(60,287)
Options exercised	[1]	(22,136)
Outstanding options at end of quarter		2,665,379
Options exercisable at end of quarter		588,692
Weighted-average exercise price per option
Outstanding options at beginning of year		$ 4.97
Options canceled		5.04
Options exercised	[1]	4.59
Outstanding options at end of quarter		4.98
Options exercisable at end of quarter		$ 4.74
Weighted-average remaining contractual term
Outstanding options at end of quarter		7 years 2 months 12 days
Options exercisable at end of quarter		5 years 7 months 6 days
Aggregate Intrinsic Value
Outstanding options at end of quarter		$ 2,376,745
Options exercisable at end of quarter		$ 719,276

[1] The intrinsic value of options exercised was immaterial.