Summary of Significant Accounting Policies - Revenue by Geographic Areas (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenues	$ 50,884	$ 46,505	$ 138,969	$ 117,470
U.S. revenues
Disaggregation of Revenue [Line Items]
Total revenues	50,884	34,877	138,969	91,275
Foreign revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 11,628	$ 0	$ 26,195