Stock Option Activity under Two Thousand Six Plan (Detail) (Employee Stock Plan, 2006 Plan, USD $)	12 Months Ended
	Jan. 31, 2015
Employee Stock Plan, 2006 Plan
Number of Shares
Outstanding options at beginning of year	2,721,569
Options granted	170,596
Options canceled	(118,139)
Options exercised	(26,224)
Outstanding options at end of year	2,747,802
Options exercisable at end of year	607,628
Vested and expected to vest at end of year	1,585,755
Weighted-average exercise price per option
Outstanding options at beginning of year	$ 4.95
Options granted	$ 5.29
Options canceled	$ 4.32
Options exercised	$ 4.69
Outstanding options at end of year	$ 4.97
Options exercisable at end of year	$ 4.77
Vested and expected to vest at end of year	$ 4.91
Weighted-average remaining contractual term
Outstanding options at end of year	7 years 10 months 24 days
Options exercisable at end of year	6 years 4 months 24 days
Vested and expected to vest at end of year	7 years 7 months 6 days
Aggregate Intrinsic Value
Outstanding options at end of year	$ 457,575
Options exercisable at end of year	309,799
Vested and expected to vest at end of year	$ 411,863