Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 21,713	$ 23,596
Available-for-sale securities		14,931
Prepaid expenses and other current assets	1,099	1,001
Total current assets	22,812	39,528
Property and equipment, net	388	568
Restricted cash	113	113
Total assets	23,313	40,209
Current liabilities:
Accounts payable	1,202	1,405
Accrued expenses	2,740	3,677
Current portion of notes payable, net of discount	3,296	3,243
Other liability	321
Total current liabilities	7,559	8,325
Deferred rent, net of current portion	97	53
Notes payable, net of current portion and discount		2,479
Other liability		266
Total liabilities	7,656	11,123
Commitments (Note 7)
Stockholders' equity:
Preferred stock, $0.001 par value per share, 5,000,000 shares authorized and no shares issued and outstanding
Common stock, $0.001 par value per share, 150,000,000 shares authorized; 22,895,033 and 18,817,572 shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively	23	19
Additional paid-in capital	181,571	173,141
Accumulated other comprehensive loss		(4)
Accumulated deficit	(165,937)	(144,070)
Total stockholders' equity	15,657	29,086
Total liabilities and stockholders' equity	$ 23,313	$ 40,209