Segment Information and Geographic Information - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
Segment Reporting Information [Line Items]
Total revenues	$ 4,995	$ 18,812	$ 11,910	$ 27,297
United States Revenue [Member]
Segment Reporting Information [Line Items]
Total revenues	$ 1,662	$ 9,666	$ 4,005	$ 13,064
Total Revenue [Member] | Customer Concentration Risk [Member] | United States Revenue [Member]
Segment Reporting Information [Line Items]
% of total revenue	33.00%	51.00%	34.00%	48.00%