Income Taxes - Summary of Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Income Tax Disclosure [Abstract]
Loss before income taxes	$ (8,213)	$ (5,950)	$ (24,258)	$ (15,108)
Provision for income taxes	$ 1,978	$ 927	$ 3,244	$ 1,775
Effective tax rate	(24.10%)	(15.60%)	(13.40%)	(11.70%)