Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 210	$ 134
Marketable securities	5,083	6,025
Prepaid expenses and other assets	145	135
Total current assets	5,438	6,294
Property and equipment, net	5	6
Patent portfolios and patent rights, net	4,613	4,951
Deposit	26	26
Total assets	10,082	11,277
Current liabilities
Accounts payable and accrued expenses	175	123
Accrued salaries and benefits	339	446
Warrant liabilities	824	702
Short-term deferred revenue	1,145	1,216
Short-term lease liabilities	187	183
Total current liabilities	2,670	2,670
Long-term deferred revenue	3,009	3,245
Long-term lease liabilities		44
Total liabilities	5,679	5,959
Series I redeemable convertible preferred stock, $0.0001 par value; no shares issued and outstanding at March 31, 2017 and December 31, 2016; liquidation preference of $167 per share
Commitments and contingencies
Stockholders' equity
Preferred Stock
Common stock, $0.0001 par value, 100,000,000 shares authorized; 4,943,941 and 4,943,941 shares issued at March 31, 2017 and December 31, 2016, respectively; 4,943,929 and 4,943,929 shares outstanding at March 31, 2017 and December 31, 2016, respectively
Additional paid-in-capital	147,335	147,331
Treasury stock, at cost, 12 shares at December 31, 2016 and December 31, 2015	(264)	(264)
Accumulated deficit	(142,668)	(141,749)
Total stockholders' equity	4,403	5,318
Total liabilities and stockholders' equity	10,082	11,277
Series D-1 Convertible Preferred Stock [Member]
Stockholders' equity
Preferred Stock
Series H Convertible Preferred Stock [Member]
Stockholders' equity
Preferred Stock
Series F-1 Convertible Preferred Stock [Member]
Stockholders' equity
Preferred Stock
Series A Preferred Stock [Member]
Stockholders' equity
Preferred Stock
Series C Convertible Preferred Stock [Member]
Stockholders' equity
Preferred Stock
Series D Preferred Stock [Member]
Stockholders' equity
Preferred Stock
Series J Convertible Preferred Stock [Member]
Stockholders' equity
Preferred Stock
Series K Convertible Preferred Stock [Member]
Stockholders' equity
Preferred Stock

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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- Definition

Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders. Includes adjustments to additional paid in capital. Some examples of such adjustments include recording the issuance of debt with a beneficial conversion feature and certain tax consequences of equity instruments awarded to employees. Use this element for the aggregate amount of additional paid-in capital associated with common and preferred stock. For additional paid-in capital associated with only common stock, use the element additional paid in capital, common stock. For additional paid-in capital associated with only preferred stock, use the element additional paid in capital, preferred stock.