Revenue - Summary of Deferred Revenue Activity (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)
Movement in Deferred Revenue [Roll Forward]
Balance as of December 31, 2019	$ 918
Additions to deferred revenue	0
Recognized as revenue	(76)
Balance as of March 31, 2020	842
NIDA Grant
Movement in Deferred Revenue [Roll Forward]
Balance as of December 31, 2019	918
Additions to deferred revenue	0
Recognized as revenue	(76)
Balance as of March 31, 2020	$ 842