Revenue Recognition - Deferred Revenues (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Revenue recognized during the period that was included in deferred revenues at the beginning of the period	$ 4,943
Deferred revenue, current portion	52,392	$ 56,016
Deferred revenue, Long-term	22,533	23,808
Total deferred revenues	74,925	$ 79,824
BGI
Deferred revenue, current portion	$ 500