Acquisitions - Additional Information (Detail) - USD ($) shares in Millions			3 Months Ended		9 Months Ended
	Jan. 31, 2019	Apr. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Feb. 06, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill			$ 71,177,000		$ 71,177,000			$ 72,401,000
Consideration for the assets acquired	$ 6,400,000
Options Medical Founder [Member]
Business Acquisition [Line Items]
Share based compensation, grant of restricted stock units	25,478
Share based compensation, grant fair value of restricted stock units	$ 1,400,000
Share based compensation, vesting rights of RSUs	33.33%
Spinal Kinetics [Member]
Business Acquisition [Line Items]
Business acquisition date		Apr. 30, 2018
Business acquisition conversion of shares into net cash subject to adjustments		$ 45,000,000.0
Fair value of the consideration transferred		76,600,000
Goodwill		17,612,000
Acquisition related costs			0	$ 300,000	0	$ 3,300,000
Net sales from acquisition			4,200,000	2,900,000	10,500,000	5,200,000
Net loss from Acquisition			$ 2,900,000	$ 2,100,000	$ 10,300,000	$ 3,500,000
Spinal Kinetics [Member] | Global Spine [Member]
Business Acquisition [Line Items]
Goodwill							$ 17,600,000
Spinal Kinetics [Member] | Maximum [Member]
Business Acquisition [Line Items]
Future milestone payments		$ 60,000,000.0