Changes in Stockholders' Equity and Accumulated Other Comprehensive Loss (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018	Dec. 29, 2018	Dec. 30, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	129,728
Beginning balance	$ 258,457	$ 217,693
Net income	7,408	(5,952)
Unrealized gain related to marketable securities, net of tax	42	(7)
Recognized gain on redemption of marketable securities, previously unrealized	(53)	(1)
Translation adjustments, net of tax	47	589
Common stock issued in connection with the exercise of stock options, ESPP and vested RSUs, net of tax	11,568	1,149
Stock-based compensation related to stock options, ESPP and RSUs	$ 3,686	4,800
Accounting method transition adjustment				$ 27,401
Ending balance (in shares)	131,905
Ending balance	$ 281,155	$ 245,672
Common stock, par value per share (in dollars per share)	$ 0.01000		$ 0.01000
Common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	129,728	123,895
Beginning balance	$ 1,297	$ 1,239
Common stock issued in connection with the exercise of stock options, ESPP and vested RSUs, net of tax (in shares)	2,177	416
Common stock issued in connection with the exercise of stock options, ESPP and vested RSUs, net of tax	$ 22	$ 4
Ending balance (in shares)	131,905	124,311
Ending balance	$ 1,319	$ 1,243
Additional Paid-in capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	736,274	695,768
Common stock issued in connection with the exercise of stock options, ESPP and vested RSUs, net of tax	11,546	1,145
Stock-based compensation related to stock options, ESPP and RSUs	3,686	4,800
Ending balance	751,506	701,713
Accumulated deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(476,783)	(477,862)
Net income	7,408	(5,952)
Accounting method transition adjustment				$ 27,401
Ending balance	(469,375)	(456,413)
Accumulated other comprehensive loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(2,331)	(1,452)
Unrealized gain related to marketable securities, net of tax	42	(7)
Recognized gain on redemption of marketable securities, previously unrealized	(53)	(1)
Translation adjustments, net of tax	47	589
Ending balance	$ (2,295)	$ (871)