Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (62,374)	$ (63,788)
Other comprehensive income:
Change in unrealized net gain on available-for-sale securities	117	807
Comprehensive loss	$ (62,257)	$ (62,981)