Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Consolidated Statements of Operations
Net sales	$ 99,371	$ 158,574
Cost of sales	64,655	101,894
Gross profit	34,716	56,680
Operating expenses, net:
Research and development	23,340	24,320
Selling, general, and administrative	19,902	26,383
Amortization of intangible assets	4,218	13,532
Restructuring	1,430	2,695
Acquisition costs		1,342
Other, net	(34)	(157)
Total operating expenses, net	48,856	68,115
Operating income (loss)	(14,140)	(11,435)
Interest income	1,245	624
Interest expense	(5,445)	(5,246)
Income (loss) before income taxes	(18,340)	(16,057)
Income tax expense (benefit)	190	(230)
Net income (loss)	$ (18,530)	$ (15,827)
Income (loss) per common share:
Basic (in dollars per share)	$ (0.40)	$ (0.34)
Diluted (in dollars per share)	$ (0.40)	$ (0.34)
Weighted average number of shares:
Basic (in shares)	46,848	46,963
Diluted (in shares)	46,848	46,963