XML 166 R151.htm IDEA: XBRL DOCUMENT v3.21.1
Segment, Product and Geographic Information - Revenue from contracts with customers (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Segment, Product and Geographic Information    
Contract liabilities $ 6,622 $ 1,902
Revenue that was included in contract liability balance at beginning of period $ 1,539