Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (59,550)	$ (63,837)	$ (123,338)	$ (112,957)
Other comprehensive income, net of tax effect:
Change in unrealized net gain on available-for-sale securities	45	0	852	0
Comprehensive loss	$ (59,505)	$ (63,837)	$ (122,486)	$ (112,957)