v3.20.4
Subsequent events (Details) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
Feb. 26, 2021
Jan. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Performance-based restricted stock unit awards        
Subsequent events        
Granted (in shares)     36,000  
Vesting period     3 years 3 years
Subsequent events        
Subsequent events        
Merger price per share (USD per share) $ 14.00      
Go shop period 25 days      
Termination fee payable to enter into Superior proposal $ 13,100      
Termination fee payable in other circumstances $ 19,600      
Minimum percentage acquisition proposal not withdrawn prior to merger agreement termination (as a percent) 50.10%      
Period after termination of merger agreement within which receipt of acquisition proposal triggers termination fee 1 year      
Maximum expense payable to other party $ 2,500      
Parent termination fee payable $ 32,700      
Subsequent events | Executive members | Service based-restricted stock unit awards        
Subsequent events        
Granted (in shares)   295,000    
Vesting period   3 years    
Subsequent events | Executive members | Performance-based restricted stock unit awards        
Subsequent events        
Granted (in shares)   295,000    
Subsequent events | Non-executive personnel | Service based-restricted stock unit awards        
Subsequent events        
Granted (in shares)   336,000    
Vesting period   3 years