ASC 606 Adoption Impact and Revenue from Contracts with Customers - Contract Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
Revenue from Contract with Customer [Abstract]
Accounts receivable, net	$ 37,655	$ 24,797	$ 24,797
Deferred contract acquisition costs, current	13,014	9,372	9,372
Deferred contract acquisition costs, non-current	30,655	21,514	21,514
Total deferred contract acquisition costs	43,669		30,886
Contract assets (included in prepaid expenses and other current assets)	825	330	330
Contract liabilities (deferred revenue)	24,681	$ 17,391	17,391
Net contract assets (liabilities)	$ (23,856)		$ (17,061)