Stockholders' Equity - Summary of Stock Options Activity (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Number of Options
Outstanding at January 1, 2019 (in shares)	3,257,875
Granted (in shares)	3,954,000
Canceled (in shares)	0
Exercised (in shares)	0
Expired/Forfeited (in shares)	(64,165)
Outstanding at March 31, 2019 and expected to vest (in shares)	7,147,710	3,257,875
Exercisable at March 31, 2019 (in shares)	2,672,710
Weighted Average Exercise Price
Outstanding at January 1, 2019 (in dollars per share)	$ 5.44
Granted (in dollars per share)	1.85
Canceled (in dollars per share)	0.00
Exercised (in dollars per share)	0.00
Expired/Forfeited (in dollars per share)	4.47
Outstanding at March 31, 2019. and expected to vest (in dollars per share)	3.46	$ 5.44
Exercisable at March 31, 2019 (in dollars per share)	$ 5.32
Outstanding Weighted Average Remaining Contractual Life (in Years)	8 years 4 months 10 days	3 years 2 months 9 days
Exercisable Weighted Average Remaining Contractual Life (in Years)	2 years 5 months 27 days
Aggregate Intrinsic Value, Outstanding	$ 0	$ 0
Aggregate Intrinsic Value, Exercisable	$ 0