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

STOCK BASED COMPENSATION - Stock-based Compensation Expense (Details)

v3.21.1
STOCK BASED COMPENSATION - Stock-based Compensation Expense (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Sep. 28, 2020
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total stock based compensation expenses $ 1,800 $ 2,217 $ 1,259 $ 8,006 $ 5,215
Research and development          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total stock based compensation expenses   916 713 3,276 2,713
General and administrative expenses          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total stock based compensation expenses   839 237 3,464 941
Sales and marketing expense          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total stock based compensation expenses   345 209 894 1,373
Cost of sales          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total stock based compensation expenses   $ 117 $ 100 $ 372 $ 188