Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Consolidated Statements of Operations
Net sales	$ 542,082	$ 475,686	$ 331,702
Cost of sales	348,363	299,458	198,604
Gross profit	193,719	176,228	133,098
Operating expenses, net:
Research and development	97,755	81,987	81,016
Selling, general, and administrative	92,060	100,250	77,642
Amortization of intangible assets	32,351	35,475	19,219
Restructuring	8,556	11,851	5,640
Acquisition costs	2,959	17,786
Asset impairment	375,172	1,139	69,520
Other, net	368	(392)	223
Total operating expenses, net	609,221	248,096	253,260
Operating income (loss)	(415,502)	(71,868)	(120,162)
Interest income	3,186	2,335	1,180
Interest expense	(21,518)	(19,457)	(222)
Income (loss) before income taxes	(433,834)	(88,990)	(119,204)
Income tax expense (benefit)	(26,746)	(37,594)	2,823
Net income (loss)	$ (407,088)	$ (51,396)	$ (122,027)
Income (loss) per common share:
Basic (in dollars per share)	$ (8.63)	$ (1.16)	$ (3.10)
Diluted (in dollars per share)	$ (8.63)	$ (1.16)	$ (3.10)
Weighted average number of shares:
Basic (in shares)	47,151	44,174	39,340
Diluted (in shares)	47,151	44,174	39,340