Net Loss Per Share - Excluded From Calculation (Details) - shares	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Outstanding common stock equivalents have been excluded from diluted net loss per common share
Outstanding common stock equivalents have been excluded from diluted net loss per common share (in shares)	23,360,526	1,757,436
Options issued and outstanding
Outstanding common stock equivalents have been excluded from diluted net loss per common share
Outstanding common stock equivalents have been excluded from diluted net loss per common share (in shares)	4,455,101	39,481
Inducement options issued and outstanding
Outstanding common stock equivalents have been excluded from diluted net loss per common share
Outstanding common stock equivalents have been excluded from diluted net loss per common share (in shares)	3,392	906
Restricted stock units issued and outstanding
Outstanding common stock equivalents have been excluded from diluted net loss per common share
Outstanding common stock equivalents have been excluded from diluted net loss per common share (in shares)	5,613	5,613
Warrants issued and outstanding
Outstanding common stock equivalents have been excluded from diluted net loss per common share
Outstanding common stock equivalents have been excluded from diluted net loss per common share (in shares)	16,991,395	1,237,871
Series A convertible preferred stock
Outstanding common stock equivalents have been excluded from diluted net loss per common share
Outstanding common stock equivalents have been excluded from diluted net loss per common share (in shares)	473,565	473,565
Series B-2 convertible preferred stock
Outstanding common stock equivalents have been excluded from diluted net loss per common share
Outstanding common stock equivalents have been excluded from diluted net loss per common share (in shares)	1,431,460