Revenue - Composition of Contract Assets and Contract Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Contract assets, current
Unbilled accounts receivable	$ 3,830	$ 3,313
Contract assets, long-term
Unbilled accounts receivable	9,182	12,962
Total contract assets	13,012	16,275	$ 13,691	$ 11,253
Contract liabilities, current
Deferred revenue, current	5,452	6,209
Customer advance payment	204	139
Total	5,656	6,348
Contract liabilities, long-term
Deferred revenue, long-term	11,755	12,740
Total contract liabilities	$ 17,411	$ 19,088	$ 23,948	$ 22,055