Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components Of Income Tax Expense Benefit [Line Items]
Corporate income tax rate			21.00%	21.00%	21.00%	35.00%
Additional income tax expense benefit		$ 8,300
Tax cuts and jobs act of 2017 change in tax rate deferred tax assets and liability expected to reserve in future						$ 8,600
Change of intention for foreign earnings						0
Tax cuts and jobs act of 2017 change in provisional income tax benefit						$ 300
Impact of the Tax Act	$ (600)				$ (560)
Deferred Tax Liabilities, Deferred Expense	8,600
Tax Cuts and Jobs Act, Transition Tax for Accumulated Foreign Earnings, Liability	$ 0
Cash paid related to taxes			$ 500	$ 8,100	15,600
Federal income tax refund recieved			3,500
Net increase in valuation allowance			11,800
Unremitted foreign earnings			$ 53,700	49,200
Minimum percentage of income tax benefit			50.00%
Gross unrecognized tax benefit			$ 4,600	16,900
Net interest and penalties on unrecognized tax benefits			(5,400)	(100)	1,400
Accrued interest and penalties related to unrecognized tax benefits			1,200	6,600
Income taxes			(2,885)	1,413	$ 9,074
Internal Revenue Service [Member]
Components Of Income Tax Expense Benefit [Line Items]
Income taxes				$ (1,800)
Minimum [Member]
Components Of Income Tax Expense Benefit [Line Items]
Decrease in unrecognized tax benefits, exclusive of interest and penalties			1,000
Maximum [Member]
Components Of Income Tax Expense Benefit [Line Items]
Decrease in unrecognized tax benefits, exclusive of interest and penalties			1,500
State and Foreign Jurisdiction [Member]
Components Of Income Tax Expense Benefit [Line Items]
Cash paid related to taxes			4,000
State [Member]
Components Of Income Tax Expense Benefit [Line Items]
Operating loss carry forwards, net of tax			$ 33,600
Operating loss carryforwards, expiration year			2027
State [Member] | Spinal Kinetics [Member]
Components Of Income Tax Expense Benefit [Line Items]
Operating loss carry forwards, net of tax			$ 21,400
Federal [Member]
Components Of Income Tax Expense Benefit [Line Items]
Operating loss carry forwards, net of tax			$ 21,400
Operating loss carryforwards, expiration year			2026
Research and development credits			$ 1,600
Foreign Tax Authority
Components Of Income Tax Expense Benefit [Line Items]
Operating loss carry forwards, net of tax			$ 140,200
Operating loss carryforwards, expiration year			2021