Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 59,754	$ 102,238
Restricted cash	1,069	1,592
Other current assets and prepaid expenses	1,786	986
Total current assets	62,609	104,816
Property and equipment, net	4,163	3,068
Other assets	171	198
Total assets	66,943	108,082
Current liabilities:
Accounts payable	549	1,153
Accrued expenses	7,380	8,875
Other current liabilities	190	250
Total current liabilities	8,119	10,278
Other long-term liabilities	$ 146	$ 241
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.0001 par value; 20,000,000 authorized and no shares issued or outstanding at September 30, 2015 and December 31, 2014	$ 0	$ 0
Common stock, $0.0001 par value; 130,000,000 shares authorized at September 30, 2015 and December 31, 2014; 24,145,680 and 23,982,786 shares issued and outstanding at September 30, 2015 and December 31, 2014, respectively	2	2
Additional paid-in capital	251,591	248,305
Accumulated other comprehensive income	81	89
Accumulated deficit	(192,996)	(150,833)
Total stockholders’ equity	58,678	97,563
Total liabilities and stockholders’ equity	$ 66,943	$ 108,082