CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Cash Flows [Abstract]
Net (loss) income	$ (3,519)	$ 34,004	$ (21,067)
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Loss from discontinued operations, net of tax	10,370	2,291	43,094
Depreciation and amortization	58,863	46,434	31,013
Non-cash impairment charges	380	790	340
Deferred income tax provision (benefit)	(351)	(6,849)	(1,341)
Non-cash valuation allowance	37,210	0	0
Share-based compensation	15,450	14,554	9,842
Amortization of debt issuance costs	2,264	2,571	2,298
Non-cash interest expense	7,911	7,104	6,463
Payment of accreted interest	(384)	0	0
Loss on disposal of property and equipment	481	909	1,965
Excess tax benefits from stock-based compensation arrangements	(3,792)	(1,384)	(270)
Change in fair value of contingent consideration	(177)	(764)	0
Gain on bargain purchase	(1,111)	0	0
Changes in assets and liabilities, net of business acquisitions:
Accounts receivable	(16,231)	(17,145)	1,010
Inventories	(3,759)	(24,138)	(27,364)
Prepaid expenses and other current assets	(233)	16,526	1,996
Other non-current assets	610	(10,914)	1,872
Accounts payable, accrued expenses and other current liabilities	1,629	(1,907)	1,334
Deferred revenue	136	1,118	697
Other non-current liabilities	945	(4,357)	1,159
Net cash provided by operating activities of continuing operations	106,692	58,843	53,041
Net cash (used in) provided by operating activities of discontinued operations	(12,209)	20,620	227
Net cash provided by operating activities	94,483	79,463	53,268
INVESTING ACTIVITIES:
Change in restricted cash	(4,087)	0	0
Cash used in business acquisitions, net of cash acquired	(328,888)	(320,921)	(2,980)
Purchases of property and equipment	(33,413)	(38,340)	(42,301)
Sales of property and equipment	1,438	0	535
Other changes in intangible assets	0	(475)	0
Net cash used in investing activities of continuing operations	(364,950)	(359,736)	(44,746)
Net cash used in investing activities of discontinued operations	(7,060)	(3,581)	(5,550)
Net cash used in investing activities	(372,010)	(363,317)	(50,296)
FINANCING ACTIVITIES:
Borrowings under senior credit facility	545,000	425,000	30,000
Repayments under senior credit facility	(465,625)	(195,000)	(165,000)
Proceeds from the issuance of common stock, net of issuance costs	219,669	0	152,458
Distribution to SeaSpine	(47,013)	0	0
Payment of liability component of convertible notes	(2,519)	0	0
Payment of capital lease obligation	(709)	(605)	0
Debt issuance costs	(1,426)	(3,210)	(1,053)
Proceeds from exercised stock options	7,345	15,215	2,344
Excess tax benefits from stock-based compensation arrangements	3,791	1,384	270
Net cash provided by financing activities	258,513	242,784	19,019
Effect of exchange rate changes on cash and cash equivalents	(4,848)	(7,550)	1,685
Net (decrease) increase in cash and cash equivalents	(23,862)	(48,620)	23,676
Cash and cash equivalents at beginning of period	71,994	120,614	96,938
Cash and cash equivalents at end of period	$ 48,132	$ 71,994	$ 120,614