Revenue Recognition - Impacts of Adopting New Revenue Standard on Condensed Consolidated Statements of Cash Flows (Detail) - USD ($) $ in Thousands	9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017
Cash flows from operating activities:
Net loss	$ (25,904)	$ 17,591
Accounts payable	(8,681)	6,253
Accrued liabilities	(5,192)	(2,460)
Income taxes payable	(181)	1,879
Deferred revenue	140	(2,206)
Other long-term liabilities	843	$ 3,518
Topic 606 [Member] | Impact of Adoption [Member]
Cash flows from operating activities:
Net loss	(5,240)
Accounts payable	(142)
Accrued liabilities	(46)
Income taxes payable	194
Deferred revenue	5,233
Other long-term liabilities	1
Topic 606 [Member] | Amounts under ASC 605 [Member]
Cash flows from operating activities:
Net loss	(31,144)
Accounts payable	(8,823)
Accrued liabilities	(5,238)
Income taxes payable	13
Deferred revenue	5,373
Other long-term liabilities	$ 844