Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Net sales	$ 214,623	$ 173,132	$ 653,415	$ 536,259
Cost of sales	145,610	118,957	446,109	369,254
Gross profit	69,013	54,175	207,306	167,005
Operating expenses:
Selling, general and administrative expenses	41,009	36,142	123,012	105,548
Research and development expenses	6,051	4,267	18,434	13,345
Restructuring costs	680	3,397	3,776	6,591
Total operating expenses	47,740	43,806	145,222	125,484
Income from operations	21,273	10,369	62,084	41,521
Other non-operating income and expense:
Interest expense, net	1,811	2,815	5,547	8,615
Other non-operating expense (income), net	696	45	30	(438)
Loss on extinguishment of convertible debt			1,797
Total other non-operating (income) expense, net	2,507	2,860	7,374	8,177
Income before income taxes	18,766	7,509	54,710	33,344
Provision for income taxes	5,489	2,196	15,723	9,872
Net income	$ 13,277	$ 5,313	$ 38,987	$ 23,472
Weighted average shares, basic	29,008	25,726	28,912	25,684
Weighted average shares, diluted	29,074	26,021	29,001	25,813
Net income per share:
Basic net income	$ 0.46	$ 0.21	$ 1.35	$ 0.91
Diluted net income	0.46	0.20	1.34	0.91
Cash dividend declared	$ 0.17	$ 0.15	$ 0.49	$ 0.45