Stock Option Activity and Restricted Share Activity (Detail) (Employee Stock Plan, 2006 Plan, USD $)	6 Months Ended
	Aug. 03, 2013
Employee Stock Plan, 2006 Plan
Number of Shares
Outstanding at beginning of year	376,374
Options granted	2,739,187
Options canceled	(3,987)
Options exercised
Outstanding at end of quarter	3,111,574
Options exercisable at end of quarter	305,510
Weighted-average Exercise price per Option
Outstanding at beginning of year	$ 4.31
Options granted	$ 5.04
Options canceled	$ 4.19
Options exercised
Outstanding at end of quarter	$ 4.95
Options exercisable at end of quarter	$ 4.50
Weighted-average Remaining Contractual Term
Outstanding options at end of quarter	9 years 4 months 24 days
Options exercisable at end of quarter	5 years 8 months 12 days
Aggregate Intrinsic Value
Outstanding options at end of quarter	$ 4,085,198
Options exercisable at end of quarter	$ 585,381