Capital Structure - Warrants (Details) - $ / shares	Jun. 30, 2019	Dec. 27, 2018
Common Stock Warrants
Number of shares available under warrant (in shares)		4,000,000
Exercise price per share (in dollars per share)		$ 12.50
Common stock warrants, expiration date of October 2018 \| Common Stock
Common Stock Warrants
Number of shares available under warrant (in shares)	22,328
Exercise price per share (in dollars per share)	$ 8.40
Common stock warrants, expiration date of October 2018 \| Common Stock
Common Stock Warrants
Number of shares available under warrant (in shares)	2,380
Exercise price per share (in dollars per share)	$ 8.68
Common stock warrants, expiration date of December 2018 \| Common Stock
Common Stock Warrants
Number of shares available under warrant (in shares)	4,000,000
Exercise price per share (in dollars per share)	$ 12.50
Warrants on common stock \| Common Stock
Common Stock Warrants
Number of shares available under warrant (in shares)	4,024,708