CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue	$ 990,533	$ 996,810	$ 875,059
Cost of revenue (exclusive of depreciation, shown separately below)	535,597	525,122	449,820
Other operating expenses:
Research and development	122,847	127,994	124,034
Selling, general and administrative	198,279	191,329	169,308
Depreciation	22,926	21,422	18,304
Restructuring and reorganization charges	5,328	4,834	8,661
Total operating expenses	884,977	870,701	770,127
Operating income	105,556	126,109	104,932
Other income (expense):
Interest expense	(15,500)	(17,748)	(17,667)
Amortization of original issue discount	(2,983)	(2,819)	(2,664)
Interest and investment income, net	1,244	1,785	2,646
Loss on extinguishment of debt			(810)
Other, net	(2,961)	(1,604)	550
Total other	(20,200)	(20,386)	(17,945)
Income before income taxes	85,356	105,723	86,987
Income tax provision	(26,645)	(22,953)	(20,857)
Net income	$ 58,711	$ 82,770	$ 66,130
Weighted-average shares outstanding:
Basic	32,010	32,051	32,488
Diluted	32,278	32,465	32,855
Earnings per common share:
Basic	$ 1.83	$ 2.58	$ 2.04
Diluted	$ 1.82	$ 2.55	$ 2.01