Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Revenues	$ 88,837	$ 77,966	$ 170,196	$ 154,440
Cost of goods sold	42,890	42,215	84,487	84,988
Gross profit	45,947	35,751	85,709	69,452
Operating expenses
Sales and marketing	11,603	9,843	21,817	19,150
General and administrative	11,203	9,238	23,473	18,751
Research and development	5,244	2,608	10,595	5,644
Total operating expenses	28,050	21,689	55,885	43,545
Gain on sale of assets		(117)		(5,945)
Operating income	17,897	14,179	29,824	31,852
Interest expense	4,285	6,983	9,705	14,008
Loss on extinguishment of debt			2,161
Other income	(552)	(401)	(1,129)	(466)
Income before income taxes	14,164	7,597	19,087	18,310
Provision for income taxes	569	247	1,354	637
Net income	$ 13,595	$ 7,350	$ 17,733	$ 17,673
Net income per common share outstanding:
Basic	$ 0.37	$ 0.24	$ 0.48	$ 0.58
Diluted	$ 0.35	$ 0.24	$ 0.46	$ 0.58
Weighted-average common shares outstanding:
Basic	37,235	30,378	37,063	30,373
Diluted	38,900	30,543	38,726	30,454