Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Condensed Consolidated Statements of Income
Revenues	$ 198,723	$ 178,083	$ 567,849	$ 515,016
Cost of revenues	82,149	69,880	232,922	202,988
Gross margin	116,574	108,203	334,927	312,028
Operating expenses:
Research and development	52,000	48,437	156,756	149,118
Selling, general and administrative	39,606	38,034	119,587	116,716
Operating expenses	91,606	86,471	276,343	265,834
Operating income	24,968	21,732	58,584	46,194
Other income (expense):
Interest income and other, net	1,923	273	4,094	449
Interest expense	(4,764)	(643)	(9,265)	(1,939)
Income before income taxes	22,127	21,362	53,413	44,704
Provision for income taxes	2,178	1,344	1,469	3,319
Net income	$ 19,949	$ 20,018	$ 51,944	$ 41,385
Earnings per share:
Basic (in dollars per share)	$ 0.47	$ 0.48	$ 1.23	$ 0.99
Diluted (in dollars per share)	$ 0.46	$ 0.47	$ 1.20	$ 0.98
Weighted-average common shares outstanding:
Basic (in shares)	42,553	41,614	42,376	41,673
Diluted (in shares)	43,374	42,307	43,194	42,263