Revenue from Contracts with Customers - Contract Asset and Liability Balances (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Change in Contract Asset Balance
Beginning of period balance	$ 4,578	$ 2,881
Commission costs and upfront payments to a customer capitalized in period	1,165	716
Amortization of contract assets	(811)	(514)
End of period balance	4,932	3,083
Change In Contract With Customer, Liability [Roll Forward]
Beginning of period balance	10,498	11,176
Revenue deferred in period	3,520	1,555
Revenue recognized from amounts included in contract liabilities	(1,916)	(1,195)
End of period balance	$ 12,102	$ 11,536