BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 118,550	$ 42,803
Receivables	89	145
Prepaid expenses and other current assets	4,441	1,139
Total current assets	123,080	44,087
Property and equipment, net	321	531
Deposits	128	128
Other non-current assets	509	491
Total assets	124,038	45,237
Current liabilities:
Accounts payable	3,143	2,004
Accrued expenses	8,752	7,182
Deferred revenue	816	1,360
Deferred rent-current portion	399	280
Total current liabilities	13,110	10,826
Deferred rent	470	570
Other long- term liabilities	17
Total liabilities	$ 13,597	$ 11,396
Commitments and contingencies (Note 6)
Stockholders' equity:
Common stock, $0.001 par value; 250,000,000 shares authorized; 130,822,034 and 104,452,105 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively	$ 131	$ 104
Additional paid-in capital-common stock	575,364	406,349
Accumulated deficit	(465,054)	(372,612)
Total stockholders' equity	110,441	33,841
Total liabilities and stockholders' equity	$ 124,038	$ 45,237

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).