Acquisitions - Summary of Fair Value Consideration (Detail) - USD ($)			1 Months Ended	12 Months Ended
	Oct. 31, 2018	Sep. 21, 2015	Nov. 30, 2016	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Contingent consideration				$ 10,637,000	$ 12,418,000
Medical Surgery Technologies Ltd. [Member]
Business Acquisition [Line Items]
Stock consideration	$ 8,300,000
Cash consideration	5,800,000
Present value of deferred consideration	5,900,000
Other consideration	314,000
Total consideration	$ 20,314,000
Senhance Surgical Robotic System Acquisition [Member]
Business Acquisition [Line Items]
Common shares issued		15,543,413
Closing price per share		$ 2.81
Stock consideration		$ 43,677,000
Cash consideration		25,000,000
Contingent consideration		23,900,000		$ 10,600,000
Total consideration		$ 92,577,000	$ 400,000