Revenue (Tables)

9 Months Ended

Sep. 30, 2019

Revenue

Revenues disaggregated by category

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Product revenue	$	92,582	$	79,388	$	273,716	$	211,595
Rental revenue		35,528		38,135		113,601		102,224
Field service and other revenue		32,698		33,135		100,859		90,492
Total revenue	$	160,808	$	150,658	$	488,176	$	404,311

Contracts with customers assets and liabilities

	September 30,		December 31,
	2019		2018
Unbilled revenue	$	22,027	$	26,804
Deferred revenue		1,492		1,110