CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019		Mar. 31, 2018
Cash flows from operating activities
Net loss	$ (5,860)		$ (7,273)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	417		896
Depreciation and amortization	2		2
Amortization of debt discount and debt issuance costs	42		48
Changes in operating assets and liabilities:
Prepaids and other assets	(91)		988
Accounts payable	(532)		(659)
Accrued clinical expense	(80)		(197)
Accrued compensation	(266)		(578)
Other accrued liabilities	255		223
Net cash used in operating activities	(6,113)		(6,550)
Cash flows from investing activities
Proceeds from maturities of marketable securities			742
Net cash provided by investing activities			742
Cash flows from financing activities
Principal payments on notes payable	(1,406)
Proceeds from issuance of convertible preferred stock offering, net	7,944
Proceeds from issuance of common stock, net	10,690
Proceeds from issuance of common stock through controlled equity offering facilities, net			32
Proceeds from exercise of stock options and stock purchase rights			164
Net cash provided by financing activities	17,228		196
Net increase (decrease) in cash and cash equivalents	11,115		(5,612)
Cash and cash equivalents at beginning of period	13,696	[1]	26,977
Cash and cash equivalents at end of period	24,811		$ 21,365
Supplemental disclosure of non-cash activities
Conversion of preferred stock to common stock	3,228
Legal expenses accrued as cost of equity financing	$ 98

[1] The condensed consolidated balance sheet as of December 31, 2018, has been derived from the audited financial statements as of that date included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018.