Summary of Activity in Stock Option Plan (Detail) (USD $)	12 Months Ended
	Jan. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding as of February 1, 2014	5,166,566
Options granted	2,299,550
Options exercised	0
Options forfeited	(2,742,009)
Options expired	(557,708)
Outstanding as of January 31, 2015	4,166,399
Options vested and expected to vest as of January 31, 2015	3,831,450
Exercisable at end of period	1,927,152
Outstanding as of February 1, 2014	$ 10.00
Options granted, Weighted-Average Exercise Price	$ 10.00
Options exercised, Weighted-Average Exercise Price	$ 0
Options forfeited, Weighted-Average Exercise Price	$ 10.00
Options expired, Weighted-Average Exercise Price	$ 10.00
Outstanding as of January 31, 2015	$ 10.00
Options vested and expected to vest as of January 31, 2015, Weighted-Average Exercise Price	$ 10.00
Exercisable at end of period, Weighted-Average Exercise Price	$ 10.00
Outstanding as of January 31, 2015, Weighted Average Remaining Contractual Term	4 years 10 months 24 days
Options vested and expected to vest as of January 31, 2015, Weighted Average Remaining Contractual Term	4 years 9 months 18 days
Exercisable at end of period, Weighted Average Remaining Contractual Term	4 years 3 months 18 days