Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities
Net loss	$ (51,465)	$ (30,532)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of patent portfolio	$ 6,317	9,831
Non-cash registration rights penalty		654
Change in fair value of warrant liabilities	$ (269)	(48)
Stock-based compensation	$ 371	12,676
Issuance of common stock - financial advisor		$ 225
Depreciation expenses	$ 1
Unrealized (gain) loss on marketable securities	(19)	$ 54
Impairment of goodwill and intangible assets	$ 40,600
Changes in assets and liabilities:
Marketable securities		$ (3,554)
Prepaid expenses and other assets	$ (223)	44
Accounts payable and accrued expenses	(344)	458
Accrued salaries and benefits	316	$ 96
Deferred revenue	268
Accrued lease liabilities	(173)	$ 580
Net cash used in operating activities	(4,620)	$ (9,516)
Cash flows from investing activities
Purchase of marketable securities	(7,994)
Purchase of property and equipment	$ (2)	$ (4)
Security deposits refund		$ 4
Sale of marketable securities	$ 8,121
Payment of accrued patent costs		$ (1,000)
Net provided by (cash used) in investing activities	$ 125	$ (1,000)
Cash flows from financing activities
Proceeds from issuance of common stock and warrants in July Financing, net	1,322
Proceeds from issuance of common stock and preferred stock in December Offering, net	$ 3,445
Proceeds from issuance of common stock and warrants in private placement, net		$ 3,874
Proceeds from issuance of Series J convertible preferred stock, net		18,387
Redemption of Series I redeemable convertible preferred stock	$ (935)	(14,065)
Net cash provided by financing activities	3,832	8,196
Net decrease in cash and cash equivalents	(663)	(2,320)
Cash and cash equivalents, beginning of period	805	3,125
Cash and cash equivalents, end of period	$ 142	$ 805
Cash paid for interest and taxes
Non-cash investing and financing activities
Retirement of treasury stock		$ 201
Conversion of preferred stock to common stock		$ 3
Extinguishment of Series I Convertible Preferred Stock in connection with license agreement	$ 5,000
Extinguishment of Series H Convertible Preferred Stock in connection with license agreement	4,766
Recognition of deferred revenue in connection with license agreement	$ 281