Summary of Significant Accounting Policies - Summary of reconciliation of shares used to determine net loss per share (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Summary of Significant Accounting Policies
Net loss	$ (2,885)	$ (4,039)
Weighted average number of shares - basic	42,628,560	42,602,431
Weighted average number of shares outstanding - diluted	42,628,560	42,602,431