BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 84,406	$ 81,053
Receivables	13	21
Prepaid expenses and other current assets	30,469	23,810
Total current assets	114,888	104,884
Property and equipment, net	1,047	843
Deposits	128	128
Other non-current assets	496	493
Total assets	116,559	106,348
Current liabilities:
Accounts payable	1,524	156
Accrued expenses	10,110	9,109
Deferred revenue - current portion	6,389	6,389
Deferred rent - current portion	166	155
Total current liabilities	18,189	15,809
Deferred revenue, net of current portion	36,736	41,528
Deferred rent, net of current portion	14	126
Derivative liabilities	2,350	862
Total liabilities	57,289	58,325
Commitments and contingencies (Note 6)
Preferred stock, $0.001 par value, 30,000,000 shares authorized
Stockholders' deficit:
Common stock, $0.001 par value; 250,000,000 shares authorized; 141,962,789 and 132,376,670 shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively	142	132
Additional paid-in capital - common stock	619,232	580,567
Accumulated deficit	(699,169)	(657,997)
Total stockholders' deficit	(79,795)	(77,298)
Total liabilities and stockholders' deficit	116,559	106,348
Series 1 Preferred Stock
Current liabilities:
Series 1 preferred stock, $1,200 stated value; 250,000 designated; 116,127 and 106,184 shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively; liquidation value of $139.4 million and $127.4 million at September 30, 2017 and December 31, 2016, respectively	$ 139,065	$ 125,321