Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (78,813)	$ (56,501)	$ (202,151)	$ (169,458)
Other comprehensive income, net of tax effect:
Change in unrealized net gain on available-for-sale securities	(554)	0	298	0
Comprehensive loss	$ (79,367)	$ (56,501)	$ (201,853)	$ (169,458)