Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Consolidated Statements of Operations
Net sales	$ 98,637	$ 97,822	$ 203,139	$ 197,193
Cost of sales	56,743	61,537	114,826	126,192
Gross profit	41,894	36,285	88,313	71,001
Operating expenses, net:
Research and development	19,254	22,922	38,449	46,262
Selling, general, and administrative	17,818	19,757	36,123	39,660
Amortization of intangible assets	3,834	4,243	7,671	8,460
Restructuring	472	616	1,097	2,046
Asset impairment	281		281
Other operating expense (income), net	(174)	(44)	(283)	(80)
Total operating expenses, net	41,485	47,494	83,338	96,348
Operating income (loss)	409	(11,209)	4,975	(25,347)
Interest income	427	1,284	1,227	2,529
Interest expense	(6,041)	(5,495)	(11,706)	(10,941)
Loss on extinguishment of debt	(3,046)		(3,046)
Income (loss) before income taxes	(8,251)	(15,420)	(8,550)	(33,759)
Income tax expense (benefit)	51	145	319	336
Net income (loss)	$ (8,302)	$ (15,565)	$ (8,869)	$ (34,095)
Income (loss) per common share:
Basic (in dollars per share)	$ (0.17)	$ (0.33)	$ (0.18)	$ (0.72)
Diluted (in dollars per share)	$ (0.17)	$ (0.33)	$ (0.18)	$ (0.72)
Weighted average number of shares:
Basic (in shares)	48,109	47,112	48,147	47,145
Diluted (in shares)	48,109	47,112	48,147	47,145