Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Total revenues	$ 108,252	$ 103,155	$ 256,220	$ 272,298
Cost of sales	49,073	45,487	106,114	108,359
Gross profit	59,179	57,668	150,106	163,939
Research and development	11,723	13,284	25,653	25,905
Sales and marketing	26,926	27,545	56,515	56,103
General and administrative	12,876	11,500	26,307	22,032
Acquisition and integration costs	1,836	4,935	4,660	8,402
Total operating expenses	53,361	57,264	113,135	112,442
Operating income	5,818	404	36,971	51,497
Interest expense, net	(4,505)	(6,839)	(9,087)	(14,689)
Loss on extinguishment of debt	(748)	(2,398)	(748)	(6,965)
Total other expense, net	(5,253)	(9,237)	(9,835)	(21,654)
Income (loss) before income taxes	565	(8,833)	27,136	29,843
(Benefit) provision for income taxes	(705)	(5,757)	1,022	(1,039)
Net income (loss)	$ 1,270	$ (3,076)	$ 26,114	$ 30,882
Basic (loss) earnings per share (in USD per share)	$ 0.03	$ (0.08)	$ 0.65	$ 0.84
Diluted (loss) earnings per share (in USD per share)	$ 0.03	$ (0.08)	$ 0.65	$ 0.81
Shares used in basic per share calculation (in shares)	40,209	37,925	39,957	36,586
Shares used in diluted per share calculation (in shares)	41,429	37,925	42,315	42,255