Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Consolidated Statements of Operations
Net sales	$ 583,277	$ 454,163	$ 419,349
Cost of sales	341,003	259,863	261,155
Gross profit	242,274	194,300	158,194
Operating expenses, net:
Research and development	88,680	78,994	90,557
Selling, general, and administrative	84,536	76,251	79,749
Amortization of intangible assets	12,280	15,333	17,085
Restructuring		1,097	6,403
Asset impairment		281	4,020
Other operating expense (income), net	68	(221)	(42)
Total operating expenses, net	185,564	171,735	197,772
Operating income (loss)	56,710	22,565	(39,578)
Interest income	2,340	1,551	4,680
Interest expense	(28,360)	(24,739)	(22,085)
Other income (expense), net	(5,010)	(7,841)	(20,973)
Income (loss) before income taxes	25,680	(8,464)	(77,956)
Income tax expense (benefit)	(358)	(73)	777
Net income (loss)	$ 26,038	$ (8,391)	$ (78,733)
Income (loss) per common share:
Basic (in dollars per share)	$ 0.53	$ (0.17)	$ (1.66)
Diluted (in dollars per share)	$ 0.49	$ (0.17)	$ (1.66)
Weighted average number of shares:
Basic (in shares)	49,073	48,362	47,482
Diluted (in shares)	53,643	48,362	47,482