Basis of Presentation (Details)n - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Basis of Presentation
Cash, cash equivalents and marketable securities	$ 164,000				$ 164,000
Net loss	(13,373)	$ (16,538)	$ (11,031)	$ (12,625)	(29,911)	$ (23,656)
Net cash used in operations					(30,014)	$ (23,332)
Indefinite-lived intangible assets	$ 30,700				$ 30,700		$ 30,700