Net Loss Per Share Attributable to Common Stockholders- Excluded From Calculation (Details) - shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
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)	1,757,436	3,412,059
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)	39,481	38,638
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)	906	2,993
Warrants to purchase common 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)	1,237,871	38,582
Restricted stock units
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
Preferred Convertible 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	3,314,956
Convertible notes
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)		11,277