Stock-Based Compensation (Summary of Stock Option Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock Incentive Plan Compensation [Abstract]
Shares, Beginning Balance	1,115,865	74,890
Shares, Granted	37,500	1,070,572
Shares, Forfeited	(3,300)	(29,597)
Shares, Ending Balance	1,150,065	1,115,865	74,890
Shares, Vested or expected to vest at December 31, 2018	864,952
Shares, Exercisable at December 31, 2018	402,642
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 3.17	$ 64.50
Weighted Average Exercise Price, Granted	1.18	1.22
Weighted Average Exercise Price, Forfeited	11.54	87.87
Weighted Average Exercise Price, Outstanding, Ending Balance	3.08	$ 3.17	$ 64.50
Weighted Average Exercise Price, Vested or expected to vest at December 31, 2018	3.79
Weighted Average Exercise Price, Exercisable at December 31, 2018	$ 5.86
Average Remaining Contractual Term (Years), Outstanding	8 years 11 days	8 years 11 months 23 days	8 years 7 months 24 days
Average Remaining Contractual Term (Years), Vested or expected to vest at December 31, 2018	7 years 9 months 11 days
Average Remaining Contractual Term (Years), Exercisable at December 31, 2017	6 years 8 months 23 days