Warrants (Summary of Warrants Issued and Warrants Outstanding) (Details)	3 Months Ended
	Mar. 31, 2020 $ / shares shares
Class of Warrant or Right [Line Items]
Outstanding	19,295,773
2015 Warrant Issuance [Member]
Class of Warrant or Right [Line Items]
Issued	383,500
Outstanding	383,500
Exercise Price | $ / shares	$ 2.05
Expire	2021-06
2016 Warrant Issuance [Member]
Class of Warrant or Right [Line Items]
Issued	2,947,949
Outstanding	2,947,949
Exercise Price | $ / shares	$ 2.60
Expire	2022-02
2017 Warrant Issuance 1 [Member]
Class of Warrant or Right [Line Items]
Issued	100,000
Outstanding	100,000
Exercise Price | $ / shares	$ 2.25
Expire	2022-03
2017 Warrant Issuance 2 [Member]
Class of Warrant or Right [Line Items]
Issued	1,650,000
Outstanding	1,650,000
Exercise Price | $ / shares	$ 2.45
Expire	2022-11
2018 Warrant Issuance [Member]
Class of Warrant or Right [Line Items]
Issued	4,004,324
Outstanding	3,974,324
Exercise Price | $ / shares	$ 1.55
Expire	2023-07
2019 Warrant Issuance 1 [Member]
Class of Warrant or Right [Line Items]
Issued	240,000
Outstanding	240,000
Exercise Price | $ / shares	$ 0.55
Expire	2024-04
2019 Warrant Issuance 2 [Member]
Class of Warrant or Right [Line Items]
Issued	4,000,000
Outstanding	4,000,000
Exercise Price | $ / shares	$ 0.49
Expire	2024-10
2019 Warrant Issuance 2 [Member] | Immediately Exercisable Pre-Funded [Member]
Class of Warrant or Right [Line Items]
Exercise Price | $ / shares	$ 0.01
2019 Warrant Issuance 3 [Member]
Class of Warrant or Right [Line Items]
Issued	6,000,000
Outstanding	6,000,000
Exercise Price | $ / shares	$ 0.78
Expire	2024-10