Loss Per Share - Antidilutive Securities (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Shares underlying convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from EPS (shares)	0	720,000	0	720,000
“In the money” stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from EPS (shares)	0	36,000	0	36,000
“Out of the money” stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from EPS (shares)	286,327	263,467	286,327	263,467
“In the money” warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from EPS (shares)	0	1,528,668	0	1,528,668
“Out of the money” warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from EPS (shares)	7,392,966	4,903,736	7,392,966	4,903,736
Shares underlying convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from EPS (shares)	0	1,056,068	1,056,068	1,056,068
Shares underlying convertible accrued interest on convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from EPS (shares)	0	79,120	125,213	79,120