Equity Method Investments - Summarized unaudited financial data (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Dec. 31, 2020
Summary financial information of equity method investments
Current assets	$ 132,914		$ 132,914			$ 188,968
Current liabilities	85,057		85,057			$ 42,657
Net revenues	50,460	$ 34,735	88,037		$ 67,144
Operating loss	7,178	8,964	12,244		13,030
Net loss	$ (6,341)	$ (6,605)	$ 27,040		$ (16,148)
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Summary financial information of equity method investments
Current assets				$ 14,021
Non-current assets				26,216
Current liabilities				64,151
Non-current liabilities				4,254
Net revenues				5,409
Operating loss				(6,638)
Net loss				$ (16,238)