CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
Revenues, net	$ 10	$ 18	$ 52	$ 54
Cost of goods sold	60	8	80	28
Gross margin	(50)	10	(28)	26
Operating expenses:
Research and development	2,228	2,111	7,285	7,465
Sales and marketing	550	546	1,717	1,929
General and administrative	1,624	1,088	4,252	3,671
Total operating expenses	4,402	3,745	13,254	13,065
Loss from operations	(4,452)	(3,735)	(13,282)	(13,039)
Change in fair value of warrant liability	42	169	(1)	330
Other income and expense, net	20	(148)	83	(142)
Loss before provision for income taxes	(4,390)	(3,714)	(13,200)	(12,851)
Provision for income taxes			2	1
Net loss and comprehensive loss	$ (4,390)	$ (3,714)	$ (13,202)	$ (12,852)
Basic and diluted net loss per share	$ (0.02)	$ (0.05)	$ (0.07)	$ (0.17)
Shares used in computing basic and diluted net loss per share	191,360,000	79,659,000	187,551,000	73,977,000