Unaudited Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Income Statement [Abstract]
Net revenue	$ 230,852	$ 255,276	$ 479,934	$ 500,477
Cost of revenue	165,407	174,996	332,481	343,878
Gross profit	65,445	80,280	147,453	156,599
Operating expenses:
Research and development	18,814	21,946	37,646	43,137
Sales and marketing	34,541	38,552	70,396	76,426
General and administrative	10,463	18,458	23,580	34,219
Separation expense	0	0	264	0
Restructuring and other charges	1,291	1,376	1,223	1,367
Litigation reserves, net	10	5	10	5
Total operating expenses	65,119	80,337	133,119	155,154
Income (loss) from operations	326	(57)	14,334	1,445
Interest income, net	782	1,073	1,483	1,821
Other income (expense), net	487	788	828	(530)
Income before income taxes	1,595	1,804	16,645	2,736
Provision for income taxes	756	1,271	2,963	1,185
Net income from continuing operations	839	533	13,682	1,551
Net loss from discontinued operations, net of tax	0	(5,763)	0	(1,191)
Net income (loss)	$ 839	$ (5,230)	$ 13,682	$ 360
Net income (loss) per share - basic:
Income per share - basic, continuing operations (in dollars per share)	$ 0.03	$ 0.02	$ 0.44	$ 0.05
Income per share - basic, discontinued operations (in dollars per share)	0	(0.19)	0	(0.04)
Net income per share - basic (in dollars per share)	0.03	(0.17)	0.44	0.01
Net income (loss) per share - diluted:
Income per share - diluted, continuing operations (in dollars per share)	0.03	0.02	0.42	0.05
Income per share - diluted, discontinued operations (in dollars per share)	0	(0.18)	0	(0.04)
Net income per share - diluted (in dollars per share)	$ 0.03	$ (0.16)	$ 0.42	$ 0.01
Weighted average shares used to compute net income (loss) per share:
Basic (in shares)	31,246	31,674	31,365	31,550
Diluted (in shares)	32,112	32,742	32,518	32,722