Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Consolidated Statements of Operations
Net sales	$ 104,502	$ 99,371
Cost of sales	58,083	64,655
Gross profit	46,419	34,716
Operating expenses, net:
Research and development	19,195	23,340
Selling, general, and administrative	18,304	19,902
Amortization of intangible assets	3,837	4,218
Restructuring	625	1,430
Other operating expense (income), net	(109)	(34)
Total operating expenses, net	41,852	48,856
Operating income (loss)	4,567	(14,140)
Interest income	800	1,245
Interest expense	(5,666)	(5,445)
Income (loss) before income taxes	(299)	(18,340)
Income tax expense (benefit)	268	190
Net income (loss)	$ (567)	$ (18,530)
Income (loss) per common share:
Basic (in dollars per share)	$ (0.01)	$ (0.40)
Diluted (in dollars per share)	$ (0.01)	$ (0.40)
Weighted average number of shares:
Basic (in shares)	47,811	46,848
Diluted (in shares)	47,811	46,848