Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 12,960	$ 19,145
Marketable securities	49,177	21,355
Prepaid expenses and other current assets	583	707
Total current assets	62,720	41,207
Property and equipment, net	111	3
Total assets	62,831	41,210
Current liabilities:
Accounts payable	1,400	762
Accrued expenses	7,123	4,038
Total current liabilities	8,523	4,800
Total liabilities	8,523	4,800
Stockholders' equity:
Preferred stock, par value $0.0001 per share authorized: 5,000,000 shares at September 30, 2017 and December 31, 2016; 1,969,797 and no shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively
Common stock, par value $0.0001 per share authorized: 200,000,000 at September 30, 2017 and December 31, 2016, respectively; 12,495,705 and 11,951,866 shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively	1	1
Additional paid-in-capital	152,276	111,691
Accumulated other comprehensive income	47	25
Accumulated deficit	(98,016)	(75,307)
Total stockholders' equity	54,308	36,410
Total liabilities and stockholders' equity	$ 62,831	$ 41,210