BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 163,843	$ 42,803
Receivables	369	145
Prepaid expenses and other current assets	8,268	1,139
Total current assets	172,480	44,087
Property and equipment, net	262	531
Deposits	128	128
Other non-current assets	491	491
Total assets	173,361	45,237
Current liabilities:
Accounts payable	4,154	2,004
Accrued expenses	18,138	7,182
Deferred rent - current portion	402	280
Deferred revenue - current portion	6,933	1,360
Total current liabilities	29,627	10,826
Deferred rent	379	570
Deferred revenue	49,514
Total liabilities	$ 79,520	$ 11,396
Commitments and contingencies (Note 6)
Stockholders' equity:
Preferred stock, $0.001 par value; 30,000,000 shares authorized and no shares issued and outstanding
Common stock, $0.001 par value; 250,000,000 shares authorized; 130,887,901 and 104,452,105 shares issued and outstanding at September 30, 2015 and December 31, 2014, respectively	$ 131	$ 104
Additional paid-in capital - common stock	576,934	406,349
Accumulated deficit	(483,224)	(372,612)
Total stockholders' equity	93,841	33,841
Total liabilities and stockholders' equity	$ 173,361	$ 45,237