Summary of Tax Returns Periods Subject to Examination by Federal, State and International Taxing Authorities (Detail)	12 Months Ended
	Dec. 31, 2017
United States | Earliest Tax Year
Income Tax Examination [Line Items]
Fiscal year subject to examination	2014
United States | Latest Tax Year
Income Tax Examination [Line Items]
Fiscal year subject to examination	2017
Sweden | Earliest Tax Year
Income Tax Examination [Line Items]
Fiscal year subject to examination	2011
Sweden | Latest Tax Year
Income Tax Examination [Line Items]
Fiscal year subject to examination	2017
Germany | Earliest Tax Year
Income Tax Examination [Line Items]
Fiscal year subject to examination	2016
Germany | Latest Tax Year
Income Tax Examination [Line Items]
Fiscal year subject to examination	2017
Netherlands | Earliest Tax Year
Income Tax Examination [Line Items]
Fiscal year subject to examination	2012
Netherlands | Latest Tax Year
Income Tax Examination [Line Items]
Fiscal year subject to examination	2017