CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017
Cash flows from operating activities:
Net loss	$ (13,202)	$ (12,852)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,757	1,416
Expense related to modification of warrants		151
Depreciation expense	48	38
Change in fair value of warrant liability	1	(330)
Changes in assets and liabilities:
Accounts receivable	3	(4)
Inventories		23
Prepaid expenses and other assets	(160)	(289)
Accounts payable	11	(545)
Accrued expenses and other liabilities	49	528
Net cash used in operating activities	(11,493)	(11,864)
Cash flows from investing activities:
Purchases of property and equipment	(13)	(41)
Net cash used in investing activities	(13)	(41)
Cash flows from financing activities:
Proceeds from the issuance of common stock, preferred stock and warrants, net of issuance costs		6,355
Proceeds from exercises of common stock warrants	6,961	615
Proceeds from exercises of stock options	1	10
Payments on capital lease obligation	(14)
Net cash provided by financing activities	6,948	6,980
Net decrease in cash and cash equivalents	(4,558)	(4,925)
Cash and cash equivalents as of beginning of period	7,576	6,501
Cash and cash equivalents as of end of period	$ 3,018	$ 1,576