Revenue from Contracts with Customers - Contract Asset and Liability Balances (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Change in Contract Asset Balance
Beginning of period balance	$ 4,932	$ 3,083	$ 4,578	$ 2,881
Commission costs and upfront payments to a customer capitalized in period	657	1,389	1,822	2,105
Amortization of contract assets	(871)	(623)	(1,682)	(1,137)
End of period balance	4,718	3,849	4,718	3,849
Change In Contract With Customer, Liability [Roll Forward]
Beginning of period balance	12,102	11,536	10,498	11,176
Revenue deferred in period	2,173	916	5,693	2,471
Revenue recognized from amounts included in contract liabilities	(2,738)	(1,472)	(4,654)	(2,667)
End of period balance	$ 11,537	$ 10,980	$ 11,537	$ 10,980