Revenue Recognition Revenue Recognition - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Contract asset	$ 8,974				$ 17,790
Contract liability, gross	20,478				24,757
Net deferred revenue	11,504				6,967
Deferred revenue, current portion	4,428	$ 4,401	$ 4,401	$ 4,401	4,401	$ 2,595	$ 2,595	$ 2,638
Deferred revenue, net of current portion	$ 7,076	$ 3,725	$ 4,825	$ 5,926	$ 2,566	$ 4,000	$ 4,648	$ 5,294