Revenue Recognition - Impacts of Adopting New Revenue Standard on Consolidated Statements of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue	$ 227,768	$ 295,402	$ 310,297
Cost of revenue	89,624	107,669	105,283
Gross profit	138,144	187,733	205,014
Loss from operations	(40,420)	24,431	60,363
Loss before income taxes	(34,552)	25,729	60,881
Provision (benefit) for income taxes	(4,105)	6,877	3,071
Net loss	$ (30,447)	$ 18,852	$ 57,810
Net loss per share:
Basic	$ (0.93)	$ 0.57	$ 1.77
Diluted	$ (0.93)	$ 0.55	$ 1.68
Topic 606 [Member] | Impact of Adoption [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue	$ (7,317)
Cost of revenue	(2,584)
Gross profit	(4,733)
Loss from operations	(4,733)
Loss before income taxes	(4,733)
Provision (benefit) for income taxes	(31)
Net loss	$ (4,702)
Net loss per share:
Basic	$ (0.14)
Diluted	$ (0.14)
Topic 606 [Member] | Amounts under ASC 605 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue	$ 220,451
Cost of revenue	87,040
Gross profit	133,411
Loss from operations	(45,153)
Loss before income taxes	(39,285)
Provision (benefit) for income taxes	(4,136)
Net loss	$ (35,149)
Net loss per share:
Basic	$ (1.07)
Diluted	$ (1.07)