Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 26,464	$ 62,780
Available-for-sale securities	20,803
Prepaid expenses and other current assets	1,032	772
Total current assets	48,299	63,552
Property and equipment, net	641	504
Restricted cash		113
Total assets	48,940	64,169
Current liabilities:
Accounts payable	1,721	1,328
Accrued expenses	3,595	3,278
Current portion of notes payable, net of discount	3,225	3,173
Total current liabilities	8,541	7,779
Deferred rent, net of current portion		26
Note payable, net of current portion and discount	3,296	5,720
Other liability	242	151
Total liabilities	12,079	13,676
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, 150,000,000 shares authorized; 18,639,285 and 15,313,297 shares issued and outstanding at September 30, 2016 and December 31, 2015, respectively	19	15
Additional paid-in capital	172,137	158,488
Accumulated other comprehensive loss	(3)
Accumulated deficit	(135,292)	(108,010)
Total stockholders' equity	36,861	50,493
Total liabilities and stockholders' equity	$ 48,940	$ 64,169