CONDENSED CONSOLIDATED STATEMENTS OF INCOME - UNAUDITED - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Revenue	$ 253,119	$ 245,617
Cost of revenue (exclusive of depreciation, shown separately below)	133,542	131,206
Other operating expenses:
Research and development	32,212	30,337
Selling, general and administrative	48,815	44,384
Depreciation	6,113	5,565
Restructuring and reorganization charges	1,060	966
Total operating expenses	221,742	212,458
Operating income	31,377	33,159
Other income (expense):
Interest expense	(3,592)	(4,213)
Amortization of original issue discount	(772)	(730)
Interest and investment income, net	124	529
Other, net	(555)	(69)
Total other	(4,795)	(4,483)
Income before income taxes	26,582	28,676
Income tax provision	(6,951)	(7,162)
Net income	$ 19,631	$ 21,514
Weighted-average shares outstanding:
Basic	31,844	31,994
Diluted	32,146	32,358
Earnings per common share:
Basic	$ 0.62	$ 0.67
Diluted	$ 0.61	$ 0.66