Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 49,778	$ 32,780
Available for sale securities	88,676	76,138
Prepaid expenses and other current assets	2,563	1,562
Total current assets	141,017	110,480
Property and equipment, net	540	210
Deferred offering costs	102
Other assets	1,281	305
Total assets	142,940	110,995
Current liabilities:
Accounts payable	2,313	2,021
Accrued expenses	9,555	4,864
Total current liabilities	11,868	6,885
Other liabilities	74	32
Total liabilities	$ 11,942	$ 6,917
Commitments and contingencies (Note 8)
Stockholders' equity:
Preferred stock $0.00001 par value, 25,000,000 shares authorized at December 31, 2015 and 2014; 0 shares issued and outstanding at December 31, 2015 and 2014
Common stock: $0.00001 par value; 175,000,000 shares authorized at December 31, 2015 and 2014; 30,662,218 and 20,370,624 shares issued and outstanding at December 31, 2015 and 2014, respectively	$ 0	$ 0
Additional paid-in capital	292,783	204,969
Treasury stock, at cost, 8,463 shares	(162)	(162)
Accumulated other comprehensive loss	(234)	(56)
Accumulated deficit	(161,389)	(100,673)
Total stockholders' equity	130,998	104,078
Total liabilities and stockholders' equity	$ 142,940	$ 110,995