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 [Abstract]
Revenue	$ 273,784	$ 255,098	$ 232,780
Cost of revenue	125,505	120,503	109,229
Gross profit	148,279	134,595	123,551
Operating expenses:
Research and development	49,053	46,986	44,964
Selling, general and administrative	46,608	39,381	38,562
Amortization	1,534	1,940	2,320
Patent litigation income	0	(13,000)	(14,643)
Total operating expenses	97,195	75,307	71,203
Operating income	51,084	59,288	52,348
Interest (income) expense, net	(2,206)	(971)	2,834
Other expense (income), net	(56)	457	(354)
Income before provision for income taxes	53,346	59,802	49,868
Provision for income taxes	8,250	26,893	12,916
Net income	$ 45,096	$ 32,909	$ 36,952
Earnings per share:
Basic	$ 1.42	$ 1.05	$ 1.19
Diluted	$ 1.40	$ 1.02	$ 1.16
Weighted average number of shares outstanding:
Basic	31,671	31,491	31,128
Diluted	32,200	32,162	31,790