Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 16,660	$ 12,910
Restricted cash	4	361
Prepaid expenses and other current assets	461	535
Total current assets	17,125	13,806
Property, equipment and leasehold improvements, net	100	157
Restricted cash	110
Other assets	1,042	82
Total assets	18,377	14,045
Current liabilities:
Accounts payable	815	988
Loan payable, current portion	100	452
Derivative warrant liability		4
Deferred rent, current portion		30
Accrued expenses	1,290	1,638
Total current liabilities	2,205	3,112
Loan payable, net of current portion		400
Deferred rent, net of current portion		367
Other liabilities	61	56
Total liabilities	2,266	3,935
Commitments and contingencies (Note 15)
Stockholders’ equity:
Common stock, $0.00001 par value, authorized 25,000,000 shares; 9,309,255 shares issued and outstanding at December 31, 2018; 1,370,992 shares issued and outstanding at December 31, 2017	1	1
Additional paid-in capital	223,440	194,016
Accumulated deficit	(207,330)	(183,907)
Total stockholders’ equity	16,111	10,110
Total liabilities and stockholders’ equity	$ 18,377	$ 14,045