Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current assets
Cash and cash equivalents	$ 4,503	$ 3,125
Prepaid expenses and other assets	107	151
Total current assets	4,610	3,276
Patent portfolios, net of accumulated amortization of $2,695 and $267	62,407	64,835
Goodwill	1,712	1,712
Deposit	30	30
Total assets	68,759	69,853
Current liabilities
Accounts payable and accrued expenses	1,039	270
Accrued salaries and benefits	77	233
Accrued patent cost		1,000
Warrant liability	8	48
Total liabilities	1,124	1,551
Series I redeemable preferred stock, $0.0001 par value; 119,760 shares issued and outstanding; liquidation preference of $167 per share	20,000	20,000
Commitments and contingencies
Stockholders' equity
Common stock, $0.0001 par value, 200,000,000 shares and 50,000,000 shares authorized at March 31, 2014 and December 31, 2013, respectively; 8,206,335 shares and 3,770,113 shares issued at at March 31, 2014 and December 31, 2013, respectively; 8,196,107 and 3,769,712 shares outstanding at March 31, 2014 and December 31, 2013, respectively	1
Additional paid-in-capital	109,137	102,043
Treasury stock, at cost, 228 shares at March 31, 2014 and 401 shares at December 31, 2013, respectively	(264)	(465)
Accumulated deficit	(61,239)	(53,276)
Total stockholders' equity	47,635	48,302
Total liabilities and stockholders' equity	68,759	69,853
Series A Preferred Stock [Member]
Stockholders' equity
Preferred stock
Series B 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 D-1 Preferred [Member]
Stockholders' equity
Preferred stock
Series E Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock
Series F Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock
Series F-1 Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock
Series H Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock