Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 25,114	$ 13,459
Restricted cash	361	422
Prepaid expenses and other current assets	397	1,072
Total current assets	25,872	14,953
Property, equipment and leasehold improvements, net	1,261	1,605
Other assets	124	135
Total assets	27,257	16,693
Current liabilities:
Accounts payable	953	569
Loan payable-current portion	259	320
Note payable-current portion		18
Derivative warrant liability	7,722	7,224
Accrued expenses	1,409	1,044
Total current liabilities	10,343	9,175
Loan payable	1,600	1,600
Total liabilities	$ 11,943	$ 10,775
Commitments and Contingencies
Stockholders' equity:
Common stock, $0.00001 par value, authorized 50,000,000 shares; issued and outstanding 26,011,852 and 23,453,000 shares at March 31, 2015 and December 31, 2014, respectively.	$ 1	$ 1
Additional paid-in capital	141,841	106,172
Accumulated deficit	(126,528)	(100,255)
Total stockholders' equity	15,314	5,918
Total liabilities and stockholders' equity	$ 27,257	$ 16,693

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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Data Type:	xbrli:monetaryItemType
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).