BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 81,053	$ 140,717
Receivables	21	446
Prepaid expenses and other current assets	23,810	11,358
Total current assets	104,884	152,521
Property and equipment, net	843	581
Deposits	128	128
Other non current assets	493	494
Total assets	106,348	153,724
Current liabilities:
Accounts payable	156	2,008
Accrued expenses	9,109	8,906
Deferred revenue - current portion	6,389	6,861
Deferred rent - current portion	155	348
Total current liabilities	15,809	18,123
Deferred revenue, net of current portion	41,528	47,917
Deferred rent, net of current portion	126	313
Derivative liabilities	862
Total liabilities	58,325	66,353
Commitments and contingencies (note 7)
Stockholders' equity (deficit):
Common stock, $0.001 par value; 250,000,000 shares authorized; 132,376,670 and 131,718,579 shares issued and outstanding at December 31, 2016 and 2015, respectively	132	132
Additional paid-in capital - common stock	580,567	579,939
Accumulated Deficit	(657,997)	(492,700)
Total stockholders' equity (deficit)	(77,298)	87,371
Total liabilities and stockholders' equity (deficit)	106,348	$ 153,724
Series 1 Preferred Stock
Current liabilities:
Series 1 preferred stock, $1,200 stated value; 250,000 designated; 106,184 and 0 shares issued and outstanding at December 31, 2016, respectively; liquidation preference of $127.4 million and $0 at December 31, 2016 and December 31, 2015, respectively	$ 125,321