Summary of Business and Significant Accounting Policies - Accounts Receivable, Allowance for Credit Loss (Details) - USD ($) $ in Thousands	Apr. 30, 2020	Jan. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts receivable, gross	$ 269,502
Less: allowance for credit losses	(8,300)	$ (5,150)
Less: allowance for returns	(3,690)
Accounts receivable, net	$ 257,512