Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Apr. 30, 2016	Apr. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss		$ (63,459)	$ (49,120)
Other comprehensive income :
Change in net unrealized gains on available-for-sale securities	[1]	807	0
Comprehensive loss		$ (62,652)	$ (49,120)

[1] Tax effect was not material.