Significant Accounting Policies (Detail)	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 Source	Dec. 31, 2018 USD ($) Project Method	Dec. 31, 2017 USD ($) Project	Dec. 31, 2016 USD ($)
Accounting Policies [Line Items]
Inventory reserves	$ (108,567,000)		$ (108,567,000)	$ (83,566,000)
Restructuring and other charges			60,043,000	0	$ 0
Severance costs			7,324,000
Inventory write-down			32,070,000
Long-lived asset impairment	38,600,000		14,902,000
Restructuring costs			$ 5,700,000
Number of product revenue sources | Method			2
Unbilled receivables	57,000,000		$ 57,000,000	$ 41,000,000
Number of projects | Project			22	8
Percentage of total revenues			16.00%	13.00%
Percentage of product revenues			23.00%	16.00%
Number of service revenue sources | Source		2
Loss (gain) in foreign currency exchange transactions			$ (800,000)	$ 12,700,000	$ (25,600,000)
Inventories
Accounting Policies [Line Items]
Inventory reserves	$ (108,600,000)		$ (108,600,000)	$ (83,600,000)