Net Loss per Common Share (Basic and Diluted Income (Loss) Per Share) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Basic and diluted net loss per common share calculation:
Net loss, basic	$ (3,050,000)	$ (6,461,000)	$ (6,184,000)	$ (9,707,000)
Net loss, diluted	$ (3,050,000)	$ (8,041,000)	$ (6,184,000)	$ (11,287,000)
Weighted average number of shares outstanding, basic	16,464,675	5,350,930	14,890,164	3,514,181
Net loss per share of common stock - basic	$ (0.19)	$ (1.21)	$ (0.42)	$ (2.76)
Weighted average number of shares outstanding, diluted	16,464,675	5,519,895	14,890,164	3,652,501
Net loss per share, diluted	$ (0.19)	$ (1.46)	$ (0.42)	$ (3.09)
November 2016 Warrants [Member]
Basic and diluted net loss per common share calculation:
Changes in estimated fair value of warrants		$ (1,580,000)		$ (1,580,000)