Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net loss	$ (13,116)	$ (5,655)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	22	35
Stock-based compensation	579	171
Loss on disposal of equipment	49	9
Fair value of debt in excess of proceeds		517
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(517)	65
Accounts payable and accrued expenses	(1,958)	(65)
Net cash used in operating activities	(14,941)	(4,923)
Investing activities
Cash received from merger transaction	23,250
Proceeds from sale of equipment	8	10
Purchase of property and equipment		(9)
Net cash provided by investing activities	23,258	1
Financing activities
Proceeds from issuance of common stock, net	4,750
Proceeds from exercise of warrants	3,119
Proceeds from convertible note		2,930
Net cash provided by financing activities	7,869	2,930
Net increase (decrease) in cash, cash equivalents and restricted cash	16,186	(1,992)
Cash, cash equivalents and restricted cash at beginning of period	1,117	3,109
Cash, cash equivalents and restricted cash at end of period	17,303	$ 1,117
Noncash activities:
Conversion of promissory note and interest to common stock	3,447
Conversion of contingently issuable shares to common stock	291
Issuance of common stock in merger	23,375
Conversion of preferred shares to common stock	27
Fair value of assets acquired, excluding cash and restricted cash	3,072
Fair value of liabilities assumed	(2,947)
Fair value of net assets acquired in the merger	$ 125