Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities:
Net loss	$ (21,961)	$ (22,262)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	81	144
Loss on disposal of property and equipment		39
Gain on lease termination	(227)
Noncash interest expense	46	164
Financing derivative		252
Reorganization items related to debtor-in-possession financing	1,627
Amortization of premium on marketable securities		130
Stock based compensation expense	317	913
Modification of stock options related to executive retirement		389
Modification of stock options related to restructuring activities		479
Issuance of warrants in connection with acquisition of licenses	272
Issuance of common stock to officer and directors	1,452
Changes in operating assets and liabilities:
Prepaid expenses and other assets	428	940
Accounts payable	3,537	(804)
Accrued expenses	(367)	(1,444)
Deferred rent		(9)
Liabilities subject to compromise	(3,153)
Net cash used in operating activities	(17,948)	(21,069)
Investing activities:
Purchase of marketable securities		(3,703)
Proceeds from maturities of marketable securities		33,371
Purchases of property and equipment		(136)
Proceeds from disposal of property and equipment		1
Changes in restricted cash	92	7
Net cash provided by investing activities	92	29,540
Financing activities:
Increase in restricted cash for notes payable		(8,291)
Net proceeds from issuance of common stock	10,132
Net proceeds from convertible notes payable	2,198
Principal payments under notes payable		(3,452)
Settlement of fractional shares upon reverse split		(1)
Net cash provided by (used in) financing activities	12,330	(11,744)
Net decrease in cash and cash equivalents	(5,526)	(3,273)
Cash and cash equivalents, beginning of period	8,431	10,923
Cash and cash equivalents, end of period	2,905	7,650
Supplemental cash flow disclosure:
Cash paid for interest		564
Supplemental disclosure of non-cash investing and financing activities:
Principal payments under notes payable from restricted cash		432
Conversion of notes payable and related accrued interest and fees to common stock	3,387
Issuance of warrants in connection with acquisition of licenses	272
Issuance of common stock to officer and directors	1,452
Issuance of notes payable to vendors	$ 1,212