Securities Purchase Agreement (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair values of derivative liabilities
Derivative liabilities	$ 12,717	$ 15,270
Series D-1 Warrants [Member]
Fair values of derivative liabilities
Derivative liabilities	571	2,539
Series D-2 Warrants [Member]
Fair values of derivative liabilities
Derivative liabilities	5,464	5,266
Embedded Derivatives of Series C-1 Preferred (including dividends paid in Series C-12 Preferred) [Member]
Fair values of derivative liabilities
Derivative liabilities	3,707	3,628
Embedded Derivatives of accrued dividends payable in Series C-1 Preferred [Member]
Fair values of derivative liabilities
Derivative liabilities	193	52
Series C-2 Preferred [Member]
Fair values of derivative liabilities
Derivative liabilities	$ 2,782	$ 3,785