Goodwill, In-Process Research and Development and Intellectual Property - Additional Information (Detail) - USD ($)		1 Months Ended	3 Months Ended			9 Months Ended
	Sep. 21, 2015	Nov. 30, 2016	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Goodwill And Intangible Assets [Line Items]
Goodwill			$ 71,038,000			$ 71,038,000		$ 68,697,000
Accumulated impairment of goodwill			61,800,000			61,800,000
Goodwill impairment			0	$ 0	$ 61,800,000		$ 61,784,000
In-Process Research and Development [Member]
Goodwill And Intangible Assets [Line Items]
Discount rate	45.00%
Intellectual Property [Member]
Goodwill And Intangible Assets [Line Items]
Discount rate	45.00%
Patents [Member] | SurgiBot System [Member]
Goodwill And Intangible Assets [Line Items]
Write-off of intellectual property			0			0	$ 1,600,000
Safe Stitch Medical Inc [Member]
Goodwill And Intangible Assets [Line Items]
Goodwill			93,800,000			93,800,000
Senhance Surgical Robotic System Acquisition [Member]
Goodwill And Intangible Assets [Line Items]
Goodwill			$ 38,300,000			$ 38,300,000
Intellectual property	$ 48,500,000
Acquisition price		$ 400,000
Senhance Surgical Robotic System Acquisition [Member] | In-Process Research and Development [Member]
Goodwill And Intangible Assets [Line Items]
In-process research and development	$ 17,100,000