Revenue - Financial Statement Impact of ASC 606 (Balance Sheet) (Details) - USD ($) $ in Thousands		Oct. 31, 2018	Jan. 31, 2018
ASSETS
Accounts receivable	[1]	$ 105,714	$ 162,133
Deferred commissions		18,772	17,589
Deferred commissions, non-current		47,379	8,330	[2]
LIABILITIES AND STOCKHOLDERS’ EQUITY
Deferred revenue		281,289	291,902
Deferred revenue, non-current		19,952	29,021
Accumulated deficit		(1,114,204)	$ (1,039,088)
Balances without adoption of ASC Topic 606 | Accounting Standards Update 2014-09
ASSETS
Accounts receivable	[1]	105,498
Deferred commissions		14,912
Deferred commissions, non-current		6,658
LIABILITIES AND STOCKHOLDERS’ EQUITY
Deferred revenue		282,491
Deferred revenue, non-current		20,955
Accumulated deficit		(1,161,206)
Effect of Change | Accounting Standards Update 2014-09
ASSETS
Accounts receivable	[1]	216
Deferred commissions		3,860
Deferred commissions, non-current		40,721
LIABILITIES AND STOCKHOLDERS’ EQUITY
Deferred revenue		(1,202)
Deferred revenue, non-current		(1,003)
Accumulated deficit		$ 47,002

[1] Contract assets are reported as part of accounts receivable upon the adoption of ASC Topic 606.

[2] As of January 31, 2018, deferred commissions, non-current was reported as part of other long-term assets. The condensed consolidated balance sheet as of January 31, 2018 was reclassified to conform to the current period presentation.