Revenue Recognition - Summary of the Post Adoption Impact of ASC 606 - Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue:
Total revenue	$ 227,458	$ 172,800	$ 459,283	$ 338,206
Operating expenses:
Cost of equipment revenue	64,350	14,649	116,643	26,297
Engineering, design and development	28,409	35,685	58,186	71,949
Net loss	(37,207)	(44,209)	(64,626)	(85,576)
Revenue	227,458	172,800	459,283	338,206
Cost of equipment revenue	64,350	14,649	116,643	26,297
Engineering, design and development	28,409	35,685	58,186	71,949
Net loss	(37,207)	(44,209)	(64,626)	(85,576)
Service [Member]
Revenue:
Total revenue	159,056	154,076	309,734	300,571
Operating expenses:
Revenue	159,056	154,076	309,734	300,571
Product [Member]
Revenue:
Total revenue	68,402	18,724	149,549	37,635
Operating expenses:
Revenue	68,402	$ 18,724	149,549	$ 37,635
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Operating expenses:
Cost of equipment revenue	(25,144)		(64,294)
Engineering, design and development	691		1,542
Net loss	(2,395)		(10,361)
Cost of equipment revenue	(25,144)		(64,294)
Engineering, design and development	691		1,542
Net loss	(2,395)		(10,361)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Service [Member]
Revenue:
Total revenue	4,514		8,906
Operating expenses:
Revenue	4,514		8,906
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Product [Member]
Revenue:
Total revenue	(31,362)		(82,019)
Operating expenses:
Revenue	(31,362)		(82,019)
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Operating expenses:
Cost of equipment revenue	39,206		52,349
Engineering, design and development	29,100		59,728
Net loss	(39,602)		(74,987)
Cost of equipment revenue	39,206		52,349
Engineering, design and development	29,100		59,728
Net loss	(39,602)		(74,987)
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Service [Member]
Revenue:
Total revenue	163,570		318,640
Operating expenses:
Revenue	163,570		318,640
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Product [Member]
Revenue:
Total revenue	37,040		67,530
Operating expenses:
Revenue	$ 37,040		$ 67,530