Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Consolidated Statements of Operations
Net sales	$ 108,954	$ 126,757	$ 306,147	$ 443,110
Cost of sales	66,731	80,372	192,924	284,651
Gross profit	42,223	46,385	113,223	158,459
Operating expenses, net:
Research and development	22,639	23,544	68,901	72,793
Selling, general, and administrative	20,962	20,186	60,620	70,842
Amortization of intangible assets	4,312	4,183	12,773	28,102
Restructuring	1,828	2,057	3,874	7,669
Acquisition costs		249		2,906
Asset impairment				252,343
Other, net	(153)	39	(232)	325
Total operating expenses, net	49,588	50,258	145,936	434,980
Operating income (loss)	(7,365)	(3,873)	(32,713)	(276,521)
Interest income	1,219	823	3,749	2,266
Interest expense	(5,549)	(5,602)	(16,491)	(16,113)
Income (loss) before income taxes	(11,695)	(8,652)	(45,455)	(290,368)
Income tax expense (benefit)	72	301	407	(27,954)
Net income (loss)	$ (11,767)	$ (8,953)	$ (45,862)	$ (262,414)
Income (loss) per common share:
Basic (in dollars per share)	$ (0.25)	$ (0.19)	$ (0.97)	$ (5.55)
Diluted (in dollars per share)	$ (0.25)	$ (0.19)	$ (0.97)	$ (5.55)
Weighted average number of shares:
Basic (in shares)	47,489	46,982	47,361	47,283
Diluted (in shares)	47,489	46,982	47,361	47,283