Share-based Compensation - Options (Details) - Stock options - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Summary of number of outstanding and exercisable options and the activity
Outstanding at beginning of year (in shares)	4,430,966
Exercisable at beginning of year (in shares)	1,518,972
Granted (in shares)	1,897,250	2,119,708
Exercised (in shares)	(833)
Expired, forfeited or cancelled (in shares)	(221,513)
Outstanding at end of period (in shares)	6,105,870	4,430,966
Exercisable at end of period (in shares)	2,131,328	1,518,972
Summary of weighted-average exercise price of outstanding and exercisable options and the activity
Outstanding at beginning of year (in dollars per share)	$ 5.551
Exercisable at beginning of year (in dollars per share)	8.735
Granted (in dollars per share)	1.141
Exercised (in dollars per share)	0.320
Expired, forfeited or cancelled (in dollars per share)	4.730
Outstanding at end of period (in dollars per share)	4.211	$ 5.551
Exercisable at end of period (in dollars per share)	$ 7.118	$ 8.735
Summary of intrinsic value of outstanding and exercisable options and other information
Intrinsic value, outstanding options	$ 54	$ 53
Intrinsic value, exercisable options	$ 4	$ 31
Weighted average remaining contractual life of options outstanding	8 years 7 months 6 days	8 years 2 months 12 days
Weighted-average remaining contractual life of options exercisable	7 years 3 months 18 days	6 years 10 months 24 days
Minimum
Summary of weighted-average exercise price of outstanding and exercisable options and the activity
Granted (in dollars per share)	$ 0.69	$ 1.36
Maximum
Summary of weighted-average exercise price of outstanding and exercisable options and the activity
Granted (in dollars per share)	$ 1.62	$ 3.14
Neos Therapeutics, Inc 2018 Inducement Plan
Summary of number of outstanding and exercisable options and the activity
Expired, forfeited or cancelled (in shares)	(100,000)