CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
Revenues, net	$ 18	$ 33	$ 54	$ 85
Cost of goods sold	8	28	28	65
Gross margin	10	5	26	20
Operating expenses:
Research and development	2,111	2,487	7,465	7,633
Sales and marketing	546	529	1,929	2,531
General and administrative	1,088	1,154	3,671	3,516
Total operating expenses	3,745	4,170	13,065	13,680
Loss from operations	(3,735)	(4,165)	(13,039)	(13,660)
Change in fair value of warrant liability	169	334	330	334
Other expense, net	(148)	(47)	(142)	(45)
Loss before income taxes	(3,714)	(3,878)	(12,851)	(13,371)
Provision for income taxes			1	2
Net loss and comprehensive loss	$ (3,714)	$ (3,878)	$ (12,852)	$ (13,373)
Basic and diluted net loss per share	$ (0.05)	$ (0.12)	$ (0.17)	$ (0.47)
Shares used in computing basic and diluted net loss per share	79,659,000	31,253,000	73,977,000	28,737,000