Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 14,430	$ 17,417
Prepaid expenses and other current assets	105	485
Total current assets	14,535	17,902
Property and equipment, net of accumulated depreciation of $2,311 and $1,919, respectively	1,222	1,470
Other assets	1	39
Total assets	15,758	19,411
Current liabilities:
Accounts payable	452	862
Related party payable	100	2,303
Accrued expenses	1,470	1,260
Deferred rent, current	150	0
Total current liabilities	2,172	4,425
Convertible promissory notes, net of debt discount of $18,003 and $18,003, respectively (see Note 6)	0	0
Accrued interest payable	1,738	967
Warrant liability	152	1,073
Derivative liability	1,474	3,136
Deferred rent	665	803
Total liabilities	6,201	10,404
Commitments and contingencies (Note 14)
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; 8,000 shares issued and outstanding as of December 31, 2018; 5,000,000 shares authorized, 8,000 shares issued and outstanding as of December 31, 2017; aggregate liquidation preference of $8,600 at December 31, 2018 and $8,264 at December 31, 2017	0	0
Common stock, $0.001 par value; 150,000,000 shares authorized, 9,758,332 shares issued and outstanding as of December 31, 2018; 150,000,000 shares authorized, 5,189,755 shares issued and outstanding as of December 31, 2017	10	5
Additional paid-in capital	198,627	187,805
Accumulated deficit	(189,080)	(178,803)
Total stockholders’ equity	9,557	9,007
Total liabilities and stockholders’ equity	$ 15,758	$ 19,411