Information about Options to Purchase Units (Detail) (USD $)	3 Months Ended
	May 03, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Number Outstanding	4,257,239
Options Exercisable Number Exercisable	886,460
Exercise Price $0.79 - $0.94
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Exercise price lower range	$ 0.79
Options, Exercise price upper range	$ 0.94
Options Outstanding, Number Outstanding	1,477,506
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	6 years 7 months 6 days
Options Exercisable Number Exercisable	533,857
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	5 years 2 months 12 days
Exercise Price $3.17
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Exercise price, average	$ 3.17
Options Outstanding, Number Outstanding	443,221
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	6 years 3 months 18 days
Options Exercisable Number Exercisable	198,382
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	4 years 10 months 24 days
Exercise Price $4.55 - $5.91
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Exercise price lower range	$ 4.55
Options, Exercise price upper range	$ 5.91
Options Outstanding, Number Outstanding	2,218,518
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	8 years 9 months 18 days
Options Exercisable Number Exercisable	154,221
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	6 years 4 months 24 days
Exercise Price $26.96
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Exercise price, average	$ 26.96
Options Outstanding, Number Outstanding	52,761
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	9 years 8 months 12 days
Exercise Prices $27. 40- $29.86
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Exercise price lower range	$ 27.40
Options, Exercise price upper range	$ 29.86
Options Outstanding, Number Outstanding	65,233
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	10 years