Other Income (Expense), Net - Other Income (Expense), Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Other Income And Expenses [Abstract]
Foreign currency loss	$ (1,785)	$ (3,893)	$ (940)
Investment amortization	(2,804)	(2,424)	(366)
Interest income	4,617	3,537	502
Other income (expense), net	$ 28	$ (2,780)	$ (804)