Net gain on sale of vascular operations - Disc Ops - Schedule of Information Related to Sale of Vascular Operation (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2010
Assets Disposed of by Method Other than Sale, in Period of Disposition [Line Items]
Cash proceeds, net of litigation		$ 24,215
Net gain on sale of vascular operations		12,019
Gain on sale, net of taxes	1,345
Vascular operation [Member]
Assets Disposed of by Method Other than Sale, in Period of Disposition [Line Items]
Cash proceeds, net of litigation		24,215
Transaction related expenses		2,253
Inventory and property, plant and equipment		2,369
Goodwill and intangible assets		7,574
Net gain on sale of vascular operations		12,019
Income tax expense		(3,498)
Gain on sale, net of taxes		$ 8,521