XML 21 R62.htm IDEA: XBRL DOCUMENT v3.20.1
Post-employment benefit obligations (Details) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Austria        
Post-employment benefit obligations        
Employer monthly contribution (as a percent)   1.53% 1.53% 1.53%
Contribution costs $ 68,000 $ 68,000 $ 58,000  
U.S.        
Post-employment benefit obligations        
Contribution costs $ 710,000 $ 448,000 $ 213,000  
Percent of match, first level   100.00% 100.00% 100.00%
Employee voluntary contribution, first level   3.00% 3.00% 3.00%
Percent match, second level   50.00% 50.00% 50.00%
Employee voluntary contribution, second level   2.00% 2.00% 2.00%