Revenue from Contracts with Customers - Schedule of Impact of Consolidated Statements of Cash Flows of Adopting ASC 606 (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Cash flows from operating activities:
Net loss	$ (9,080)	$ (1,529)	$ (14,551)	$ (6,900)
Unbilled receivables			(2,335)	2,558
Prepaid expenses and other assets			(1,584)	8
Deferred revenues			(5,729)	(870)
Other operating activities			2,430	230
Total cash used in operating activities			(19,416)	$ (2,317)
Under ASC 605 [Member] | ASU 2014-09 [Member]
Cash flows from operating activities:
Net loss	(10,470)		(18,334)
Unbilled receivables			(2,119)
Prepaid expenses and other assets			(949)
Deferred revenues			(478)
Other operating activities			111
Total cash used in operating activities			(19,416)
Adjustment [Member] | ASU 2014-09 [Member]
Cash flows from operating activities:
Net loss	$ 1,390		3,783
Unbilled receivables			(216)
Prepaid expenses and other assets			(635)
Deferred revenues			(5,251)
Other operating activities			$ 2,319