Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 2,115	$ 2,156
Marketable securities- unrestricted	6,795	13,952
Work in process inventory	1,326	0
Prepaid expenses and other current assets	335	399
Total current assets	10,571	16,507
Property and equipment, net	11,237	4,601
Patent and trademark rights, net	862	861
Construction in progress	0	7,337
Other assets	134	134
Total assets	22,804	29,440
Current liabilities:
Accounts payable	1,213	2,081
Accrued expenses	1,219	2,333
Current portion of capital lease	1	22
Total current liabilities	$ 2,433	$ 4,436
Commitments and contingencies (Notes 9,11,12,14 and 15)
Stockholders' equity:
Preferred stock, par value $0.01 per share, authorized 5,000,000; issued and outstanding; none
Common stock, par value $0.001 per share, authorized 350,000,000 shares; issued and outstanding 247,559,487 and 204,004,818, respectively	$ 247	$ 204
Additional paid-in capital	313,220	302,729
Unrealized loss	(97)	(160)
Accumulated deficit	(292,999)	(277,769)
Total stockholders' equity	20,371	25,004
Total liabilities and stockholders' equity	$ 22,804	$ 29,440

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).