v3.21.1
Stock incentive plans - Compensation expense (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Stock incentive plans    
Total stock-based compensation expense $ 2,277 $ 1,537
Out-of-period adjustments   481
Stock-based compensation expense capitalized $ 140 $ 149