Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Condensed Consolidated Statements of Income
Revenues	$ 190,098	$ 174,908	$ 369,126	$ 336,933
Cost of revenues	76,906	66,614	150,773	133,108
Gross margin	113,192	108,294	218,353	203,825
Operating expenses:
Research and development	52,432	51,635	104,756	100,681
Selling, general and administrative	39,826	39,045	79,981	78,682
Operating expenses	92,258	90,680	184,737	179,363
Operating income	20,934	17,614	33,616	24,462
Other income (expense):
Interest income and other, net	1,595	296	2,171	176
Interest expense	(4,699)	(641)	(4,501)	(1,296)
Income before income taxes	17,830	17,269	31,286	23,342
Provision (benefit) for income taxes	1,261	1,710	(709)	1,975
Net income	$ 16,569	$ 15,559	$ 31,995	$ 21,367
Earnings per share:
Basic (in dollars per share)	$ 0.39	$ 0.37	$ 0.76	$ 0.51
Diluted (in dollars per share)	$ 0.38	$ 0.37	$ 0.74	$ 0.51
Weighted-average common shares outstanding:
Basic (in shares)	42,478	41,775	42,287	41,702
Diluted (in shares)	43,178	42,284	43,104	42,242