Stock Warrants - Schedule of Liability of Warrants Subject to Re Measurement (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Apr. 30, 2021	Apr. 30, 2020	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Class of Warrant or Right [Line Items]
Change in fair value	$ (9,237)	$ (535)	$ 73,125	$ 875	$ 388
Warrant [Member] \| Level 3 [Member]
Class of Warrant or Right [Line Items]
Fair value at beginning of period	$ 75,843	$ 2,718	2,718	1,843	1,455
Change in fair value			73,125	875	388
Fair value at end of period			$ 75,843	$ 2,718	$ 1,843

Amount of expense (income) related to adjustment to fair value of warrant liability.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section 25
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=109262497&loc=d3e20148-110875

Name:	us-gaap_FairValueAdjustmentOfWarrants
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration