XML 36 R26.htm IDEA: XBRL DOCUMENT v3.10.0.1
Revenue Recognition (Details 1) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Contract liabilities:        
Deferred revenue, Balance at Beginning of Period $ 2,421 $ 2,291 $ 2,932 $ 2,933
Deferred revenue, Billings 1,991 1,527 4,176 3,430
Deferred revenue, Revenue Recognized (1,297) (1,089) (3,993) (3,634)
Deferred revenue, Balance at End of Period $ 3,115 $ 2,729 $ 3,115 $ 2,729