UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Jan. 31, 2016	Jan. 31, 2015
Operating activities:
Net loss	$ (7,872)	$ (9,463)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	2,090	2,284
Depreciation expense	114	166
Provision for bad debts	33	0
Change in fair value of warrant liability	0	(1,401)
Changes in operating assets and liabilities:
Accounts receivable	(1,078)	233
Prepaid expenses and other current assets	(68)	125
Restricted cash	13	2
Accounts payable	101	381
Accrued liabilities	(116)	(167)
Other non-current liability	64	0
Deferred revenue	866	218
Net cash used in operating activities	(5,853)	(7,622)
Investing activities:
Purchase of property and equipment	(176)	(84)
Net cash used in investing activities	(176)	(84)
Financing activities:
Proceeds from executive note financing	0	2,000
Payment of issuance costs related to 2015 Private Placement	(18)	0
Capital lease payments	(17)	(5)
Proceeds from exercise of options	0	2
Net cash (used in)/provided by financing activities	(35)	1,997
Decrease in cash and cash equivalents	(6,064)	(5,709)
Cash and cash equivalents, beginning of period	9,357	5,891
Cash and cash equivalents, end of period	3,293	182
Non-cash investing and financing activities:
Purchased equipment under capital lease	$ 0	$ 124