Revenue (Tables)

9 Months Ended

Sep. 30, 2018

Revenue Recognition [Abstract]

Schedule of Disaggregation of Revenue

The following table presents the Company’s revenue disaggregated by revenue source:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
Systems	$	43,955	$	50,831	$	160,170	$	145,968
Software licensing, support and maintenance		6,877		6,053		21,879		20,447
Parts		7,141		7,101		20,884		20,779
Services		2,459		2,935		8,071		7,823
Total revenue	$	60,432	$	66,920	$	211,004	$	195,017

The following table represents a disaggregation of revenue by timing of revenue:

	Three Months Ended		Nine Months Ended
	September 30,		September 30,
	2018		2018
Point-in-time	$	56,185	$	198,864
Over-time		4,247		12,140
Total revenue	$	60,432	$	211,004

Schedule of Changes in Deferred Revenue

Changes in deferred revenue were as follows:

	Three Months Ended			Nine Months Ended
	September 30,			September 30,
	2018			2018
Balance, beginning of the period	$	8,799		$	7,206
Deferral of revenue		4,354			15,002
Recognition of deferred revenue		(4,449	)		(13,504	)
Balance, ending of the period	$	8,704		$	8,704