Nature of the Business (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit	$ 266,169						$ 266,169		$ 249,655
Net loss	$ 8,855	$ 175	$ 7,484	$ 8,871	$ 10,007	$ 11,341	$ 16,514	$ 30,219