Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 20,560	$ 17,515
Prepaid expenses and other current assets	564	513
Total current assets	21,124	18,028
Property and equipment, net of accumulated depreciation of $1,636 and $1,561, respectively	1,468	1,489
Other assets	99	65
Total assets	22,691	19,582
Current liabilities:
Accounts payable	566	440
Related party payable	1,509	942
Accrued expenses	856	1,551
Warrant liability, current	29	54
Total current liabilities	2,960	2,987
Convertible promissory notes, net of debt discount of $18,088 (see Note 4)	0	0
Accrued interest payable	411	228
Warrant liability, long term	6,010	5,980
Derivative liability	2,047	1,735
Deferred rent	794	791
Total liabilities	12,222	11,721
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized: Series A nonredeemable convertible preferred stock; 8,000 shares designated, 8,000 shares issued and outstanding as of March 31, 2017; no shares designated, issued or outstanding as of December 31, 2016; aggregate liquidation preference of $8,020 at March 31, 2017	0	0
Common stock, $0.001 par value; 150,000,000 shares authorized, 14,695,076 and 14,688,135 shares issued and outstanding, respectively	15	15
Additional paid-in capital	178,024	170,409
Accumulated deficit	(167,570)	(162,563)
Total stockholders’ equity	10,469	7,861
Total liabilities and stockholders’ equity	$ 22,691	$ 19,582