Preferred Stock - Series B Convertible Preferred Stock (Details) - $ / shares				12 Months Ended
	Mar. 09, 2017	Feb. 10, 2017	Mar. 09, 2012	Dec. 31, 2018
Series B Convertible Preferred Stock
Shares issued upon conversion (in shares)	0
Series B voting convertible preferred stock
Series B Convertible Preferred Stock
Period of closing of offering after which shares are convertible				5 years
Conversion price per share (in dollars per share)				$ 3.25
Conversion ratio, the number of shares of common stock received per share of convertible preferred stock (in shares)				50
Series B-1 non-voting convertible preferred stock
Series B Convertible Preferred Stock
Number of common shares sold (in shares)			12,308
Offering price per share (in dollars per share)			$ 3,250
Preferred Class A and Class B
Series B Convertible Preferred Stock
Shares converted (in shares)		12,308
Accumulated shares but undeclared dividends (in shares)		9,570
Common Stock
Series B Convertible Preferred Stock
Shares issued upon conversion (in shares)		1,093,892