Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 1,538	$ 2,115
Escrow account for litigation settlement	1,750
Marketable securities	4,974	6,795
Inventory-work in process	1,326	1,326
Assets held for sale	764
Prepaid expenses and other current assets	378	335
Total current assets	10,730	10,571
Property and equipment, net	10,057	11,237
Patent and trademark rights, net	899	862
Other assets	232	134
Total assets	21,918	22,804
Current liabilities:
Accounts payable	1,391	1,213
Accrued expenses	3,038	1,219
Current portion of capital lease		1
Total current liabilities	4,429	2,433
Commitments and contingencies (Note 6)
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 248,829,720 and 247,559,487, respectively	249	247
Additional paid-in capital	313,619	313,220
Accumulated other comprehensive income (loss)	87	(97)
Accumulated deficit	(296,466)	(292,999)
Total stockholders' equity	17,489	20,371
Total liabilities and stockholders' equity	$ 21,918	$ 22,804

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).