LEASES - Components of lease expenses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
LEASES
Operating lease cost	$ 4,399	$ 3,380	$ 8,954	$ 6,777
Variable lease cost	1,236	1,578	2,216	2,288
Short-term lease cost	35	39	77	75
Total lease cost	5,670	4,997	11,247	9,140
Cash paid for amounts included in the measurement of lease liabilities included in operating cashflows	3,262	2,512	7,073	4,834
Tenant improvement allowance received for amounts included in the measurement of lease liabilities included in Operating cash flows	2,085		5,200
Right-of-use assets obtained from entering new leases	553		553
Increase / (decrease) in right-of-use assets from lease modifications	$ (180)	$ (215)	$ 7,493	$ 1,943
Weighted-average remaining lease terms (years)	14 years 3 days	17 years 11 months 19 days	14 years 3 days	17 years 11 months 19 days
Weighted-average discount rates	7.30%	7.50%	7.30%	7.50%