CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Total revenue, net	$ 1,472,441	$ 1,188,236	$ 992,075
Costs and Expenses:
Cost of goods sold	571,496	435,511	349,089
Research and development	78,041	63,455	58,155
Selling, general and administrative	690,746	624,096	455,629
Intangible asset amortization	21,160	20,370	13,862
Total costs and expenses	1,361,443	1,143,432	876,735
Operating income	110,998	44,804	115,340
Interest income	2,800	255	24
Interest expense	(64,683)	(35,019)	(25,803)
Other income, net	8,288	1,345	845
Income before income taxes	57,403	11,385	90,406
(Benefit from) provision for income taxes	(3,398)	(53,358)	15,842
Net income	$ 60,801	$ 64,743	$ 74,564
Basic net income per common share (in dollars per share)	$ 0.73	$ 0.84	$ 1.00
Diluted net income per common share (in dollars per share)	$ 0.72	$ 0.82	$ 0.94
Weighted average common shares outstanding (See Note 13):
Basic (in shares)	82,857	76,897	74,386
Diluted (in shares)	83,999	79,121	79,194