Loss Per Share - Antidilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
“In the money” stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (shares)	19,233	46,869
“Out of the money” stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (shares)	247,897	171,057
“In the money” warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (shares)	0	0
“Out of the money” warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (shares)	7,392,966	4,969,702
Shares underlying convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (shares)	1,056,068	1,056,068
Shares underlying accrued interest on convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (shares)	101,937	56,752
Shares underlying convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (shares)	736,000	704,000