Stockholders' Equity (Warrants to Purchase Shares of Common Stock) (Details) - $ / shares		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of Common Stock Subject to Warrants	[1]	16,217,946	5,848,131
November 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 3,955.00
Expiration		2021-11
Shares of Common Stock Subject to Warrants	[1]		15
December 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 3,955.00
Expiration		2021-12
Shares of Common Stock Subject to Warrants	[1]		2
February 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 3,300.00
Expiration		2025-02
Shares of Common Stock Subject to Warrants	[1]	451	451
May 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 656.20
Expiration		2021-05
Shares of Common Stock Subject to Warrants	[1]		9,483
June 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 656.20
Expiration		2021-05
Shares of Common Stock Subject to Warrants	[1]		4,102
June 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 390.00
Expiration		2022-06
Shares of Common Stock Subject to Warrants	[1]	938	938
July 2017 [Member] | Warrants Exercise Price One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 345.00
Expiration		2022-07
Shares of Common Stock Subject to Warrants	[1]	318	318
July 2017 [Member] | Warrants Exercise Price Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 250.00
Expiration		2022-07
Shares of Common Stock Subject to Warrants	[1]	2,501	2,501
July 2017 [Member] | Warrants Exercise Price Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 212.60
Expiration		2022-07
Shares of Common Stock Subject to Warrants	[1]	50,006	50,006
February 2018 [Member] | Warrants Exercise Price Four [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 81.25
Expiration		2023-02
Shares of Common Stock Subject to Warrants	[1]	9,232	9,232
February 2018 [Member] | Warrants Exercise Price Five [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 65.00
Expiration		2023-02
Shares of Common Stock Subject to Warrants	[1]	92,338	92,338
October 2019 [Member] | Warrants Exercise Price Six [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 2.00
Expiration		2024-10
Shares of Common Stock Subject to Warrants	[1]	354,000	359,000
October 2019 [Member] | Warrants Exercise Price Seven [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 2.60
Expiration		2024-10
Shares of Common Stock Subject to Warrants	[1]	235,000	235,000
November 2020 [Member] | Warrants Exercise Price Eight [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 1.94
Expiration		2026-05
Shares of Common Stock Subject to Warrants	[1]		4,842,615
November 2020 [Member] | Warrants Exercise Price Nine [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 2.68
Expiration		2026-05
Shares of Common Stock Subject to Warrants	[1]	242,130	242,130
February 2021 [Member] | Warrants Exercise Price Ten [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 3.55
Expiration		2026-08
Shares of Common Stock Subject to Warrants		4,166,666		[1]
February 2021 [Member] | Warrants Exercise Price Eleven [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 3.90
Expiration		2026-08
Shares of Common Stock Subject to Warrants		416,666		[1]
March 2021 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 3.56
Expiration		2026-03
Shares of Common Stock Subject to Warrants		3,147,700		[1]
October 2021 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price		$ 2.05
Expiration		2027-04
Shares of Common Stock Subject to Warrants		7,500,000		[1]

[1] Warrants to purchase fractional shares of common stock resulting from the reverse stock split on August 22, 2019 were rounded up to the next whole share of common stock on a holder by holder basis.