Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Income Statement [Abstract]
Revenue	$ 347,200	$ 393,575	$ 932,646	$ 940,784
Cost of revenue	239,248	240,061	627,027	554,132
Gross profit	107,952	153,514	305,619	386,652
Operating expenses:
Research and development	65,693	79,840	213,651	256,223
Sales and marketing	71,296	66,676	222,972	239,573
General and administrative	23,083	24,812	74,640	91,111
Total operating expenses	160,072	171,328	511,263	586,907
Operating loss	(52,120)	(17,814)	(205,644)	(200,255)
Interest income, net	2,388	2,072	8,476	5,599
Other income (expense), net	(492)	(5,141)	1,242	(2,366)
Loss before income taxes	(50,224)	(20,883)	(195,926)	(197,022)
Income tax expense (benefit)	1,669	(18,827)	3,950	4,179
Net loss	$ (51,893)	$ (2,056)	$ (199,876)	$ (201,201)
Net loss per share:
Basic (in dollars per share)	$ (0.20)	$ (0.01)	$ (0.78)	$ (0.83)
Diluted (in dollars per share)	$ (0.20)	$ (0.01)	$ (0.78)	$ (0.83)
Shares used to compute net loss per share:
Basic (in shares)	258,753	245,838	256,046	242,746
Diluted (in shares)	258,753	245,838	256,046	242,746