Convertible Debt at Fair Value (Narrative) (Details) - USD ($)					3 Months Ended								12 Months Ended
	Dec. 07, 2020	Mar. 01, 2017	Feb. 28, 2017	Mar. 16, 2016	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Nov. 19, 2020
Debt Instrument [Line Items]
Gain (loss) on derivatives and convertible debt					$ (5,722,000)	$ 131,000	$ 19,000	$ (759,000)	$ (155,000)	$ (223,000)	$ (456,000)	$ (237,000)	$ (6,331,000)	$ (1,071,000)	$ 317,000
Series D Preferred Stock [Member]
Debt Instrument [Line Items]
Preferred stock, annual dividend rate				6.25%
Series E Preferred Stock [Member]
Debt Instrument [Line Items]
Preferred stock, annual dividend rate		6.25%	6.25%										6.25%	6.25%	6.25%
Conversion price per share			$ 13.845
2016 Notes [Member]
Debt Instrument [Line Items]
Interest rate				6.25%
Principal amount				$ 1,012,000
Maximum ownership percentage of voting stock upon debt conversion				49.00%
Gain (loss) on derivatives and convertible debt													$ (5,795,000)	$ (80,000)	$ 69,000
2016 Notes [Member] | Series D Preferred Stock [Member]
Debt Instrument [Line Items]
Number of shares of common stock debt can convert into				97,269
2016 Notes [Member] | Series E Preferred Stock [Member]
Debt Instrument [Line Items]
Number of shares of common stock debt can convert into		97,269
Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Principal amount																$ 7,220,000
Loan Agreements [Member]
Debt Instrument [Line Items]
Principal amount																2,780,000
2020 Notes [Member]
Debt Instrument [Line Items]
Interest rate					10.00%								10.00%
Principal amount	$ 10,000,000															$ 10,000,000
Number of shares of common stock debt can convert into													4,000,000
Maturity date of debt													Jan. 02, 2023
Debt default interest rate													20.00%
Make Whole Fee interest rate													25.00%
Conversion price per share	$ 2.50				$ 2.50								$ 2.50
Trigger price	$ 2.50