Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 31,116	$ 56,901
Prepaid expenses and other current assets	1,529	1,220
Total current assets	32,645	58,121
Property and equipment, net	2,059	2,155
Other assets	97	108
Total assets	34,801	60,384
Current liabilities:
Accounts payable	1,075	1,049
Accrued expenses	7,185	9,141
Other current liabilities	39	91
Total current liabilities	8,299	10,281
Long-term liabilities	49	59
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.0001 par value; 20,000,000 authorized and no shares issued or outstanding at June 30, 2018 and December 31, 2017	0	0
Common stock, $0.0001 par value; 130,000,000 shares authorized at June 30, 2018 and December 31, 2017; 42,368,998 and 42,368,864 shares issued and outstanding at June 30, 2018 and December 31, 2017, respectively	4	4
Additional paid-in capital	349,392	345,915
Accumulated other comprehensive income	80	78
Accumulated deficit	(323,023)	(295,953)
Total stockholders’ equity	26,453	50,044
Total liabilities and stockholders’ equity	$ 34,801	$ 60,384