Annual report pursuant to Section 13 and 15(d)

REVENUE - Contract with Customer Liability (Details)

v3.21.1
REVENUE - Contract with Customer Liability (Details) - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Jan. 01, 2019
Jan. 01, 2018
Revenue from Contract with Customer [Abstract]        
Contract liabilities, net (current) $ 1,494 $ 1,912 $ 1,800 $ 2,200