Revenues - Revenues By Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contract with customers	$ 130,837	$ 104,836	$ 359,009	$ 305,277
United States
Disaggregation of Revenue [Line Items]
Revenue from contract with customers	110,809	88,125	298,736	244,806
Other countries
Disaggregation of Revenue [Line Items]
Revenue from contract with customers	$ 20,028	$ 16,711	$ 60,273	$ 60,471
Revenue from Contract with Customer | Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%
Revenue from Contract with Customer | Geographic Concentration Risk | United States
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	85.00%	84.00%	83.00%	80.00%
Revenue from Contract with Customer | Geographic Concentration Risk | Other countries
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	15.00%	16.00%	17.00%	20.00%