Stock Warrants - Warrant Activity (Details) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Warrants And Rights Note Disclosure [Abstract]
Outstanding, beginning (in shares)	7,556,323
Granted (in shares)	0
Outstanding, ending (in shares)	7,556,323	7,556,323
Exercisable (in shares)	7,556,323
Outstanding, beginning, weighted average exercise price (in dollars per share)	$ 4.45
Granted, weighted average exercise price (in dollars per share)	0
Outstanding, ending, weighted average exercise price (in dollars per share)	4.45	$ 4.45
Exercisable, weighted average exercise price (in dollars per share)	$ 4.45
Outstanding, weighted average remaining contractual life (Year)	3 years	3 years 9 months 18 days
Exercisable, weighted average remaining contractual life (Year)	3 years