Acquisition of Senhance Surgical Robotic System - Schedule of Estimated Fair Values of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Sep. 21, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 68,697	$ 130,869		$ 93,842
Senhance Surgical Robotic System Acquisition [Member]
Business Acquisition [Line Items]
Accounts receivable			$ 78
Inventories			2,800
Current deferred tax asset			526
Other current assets			4,180
Property and equipment			1,384
Intellectual property			48,500
In-process research and development			17,100
Goodwill	$ 38,300		38,348
Total assets acquired			112,916
Accounts payable and other liabilities			1,915
Long-term deferred tax liabilities			18,424
Net assets acquired			$ 92,577