Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	[2]	Oct. 31, 2018	Oct. 31, 2017	[2]
Statement of Comprehensive Income [Abstract]
Net loss	$ (28,180)	$ (29,404)	[1]	$ (152,607)	$ (144,974)	[1],[3]
Other comprehensive loss:
Change in unrealized net loss on available-for-sale securities	(273)	(439)		(1,182)	(157)
Comprehensive loss	$ (28,453)	$ (29,843)		$ (153,789)	$ (145,131)

[1] * Prior period information has been adjusted to reflect the adoption impact of ASC 606, which we adopted on February 1, 2018.

[2] * Prior period information has been adjusted to reflect the adoption impact of ASC 606, which we adopted on February 1, 2018.

[3] * Prior period information has been adjusted to reflect the adoption impact of ASC 606 and Accounting Standards Update No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (ASU 2016-18), which we adopted on February 1, 2018