CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net loss	$ (3,055)	$ (3,398)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	48	47
Bad debt expense		24
Financing expense	250
Non-cash charges for stock-based compensation	393	406
Non-cash consideration for release of security interest	4
Change in warrant liabilities fair value	(765)
Changes in current assets and liabilities, net	(443)	(643)
Changes in non-current liabilities, net	(6)	4
Net cash used in operating activities	(3,574)	(3,560)
Cash flows from investing activities:
Purchases of property and equipment		(36)
Proceeds from maturities of investment securities	1,661	2,335
Net cash provided by investing activities	1,661	2,299
Cash flows from financing activities
Proceeds from issuance of common stock, net of issuance costs	4,528	(8)
Net cash provided by financing activities	4,528	(8)
Change in cash and cash equivalents	2,615	(1,269)
Beginning balance of cash and cash equivalents	7,015	7,968
Ending balance of cash and cash equivalents	9,630	$ 6,699
Non-cash financing activities:
Warrants issued	2,714
Shelf registration costs amortized against additional paid in capital	$ 10