Post-effective amendment to a registration statement that is not immediately effective upon filing

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Warranty Reserve (Details)

v3.21.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Warranty Reserve (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES      
Standard assurance warranty period 1 year 1 year  
Movement in Standard Product Warranty Accrual [Roll Forward]      
Warranty reserve, at the beginning of the year $ 1,553 $ 1,491 $ 116
Additions to warranty reserve 86 346 2,352
Claims fulfilled $ (152) (284) (977)
Warranty reserve, at the end of the period   $ 1,553 $ 1,491