Revenue from Contracts with Customers (Schedule of New Accounting Standard Impact on Financial Statements) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 101,484	$ 91,971	$ 302,822	$ 290,695
Consolidated Statement of Operations
Net loss	$ 6,974	(43,052)	$ (19,201)	(63,349)
Net (loss) income per share, basic and diluted (in usd per share)	$ 0.05		$ (0.15)
Consolidated Balance Sheets
Accounts receivable, net of allowance for doubtful accounts	$ 75,648		$ 75,648		$ 55,104
Inventories	66,381		66,381		79,903
Prepaid expenses and other current assets	24,143		24,143		16,567
Total assets	632,327		632,327		635,961
Accounts payable and accrued expenses (includes restructuring)	46,929		46,929		54,405
Deferred income and allowances on sales to distributors	0		0
Accumulated deficit	(469,662)		(469,662)		(477,862)
Total liabilities and stockholders' equity	632,327		632,327		635,961
Consolidated Statement of Cash Flows
Net loss	6,974	(43,052)	(19,201)	(63,349)
Accounts receivable, net			(18,736)	20,687
Inventories			13,892	1,519
Prepaid expenses and other assets			(11,729)	3,839
Accounts payable and accrued expenses (includes restructuring)			1,661	(17,901)
Deferred income and allowances on sales to distributors			0
Adjustments | Accounting Standards Update 2014-09
Consolidated Statement of Operations
Net loss	$ (2,971)		$ (6,589)
Net (loss) income per share, basic and diluted (in usd per share)	$ (0.02)		$ (0.06)
Consolidated Balance Sheets
Accounts receivable, net of allowance for doubtful accounts	$ 7,091		$ 7,091
Inventories	25		25
Prepaid expenses and other current assets	(6,568)		(6,568)
Total assets	548		548
Accounts payable and accrued expenses (includes restructuring)	(887)		(887)
Deferred income and allowances on sales to distributors	35,425		35,425
Accumulated deficit	(33,990)		(33,990)
Total liabilities and stockholders' equity	548		548
Consolidated Statement of Cash Flows
Net loss	(2,971)		(6,589)
Accounts receivable, net			(8,899)
Inventories			(395)
Prepaid expenses and other assets			(947)
Accounts payable and accrued expenses (includes restructuring)			(1,345)
Deferred income and allowances on sales to distributors			18,175
Pro forma as if previous standard was in effect
Consolidated Statement of Operations
Net loss	$ 4,003		$ (25,790)
Net (loss) income per share, basic and diluted (in usd per share)	$ 0.03		$ (0.21)
Consolidated Balance Sheets
Accounts receivable, net of allowance for doubtful accounts	$ 82,739		$ 82,739
Inventories	66,406		66,406
Prepaid expenses and other current assets	17,575		17,575
Total assets	632,875		632,875
Accounts payable and accrued expenses (includes restructuring)	46,042		46,042
Deferred income and allowances on sales to distributors	35,425		35,425
Accumulated deficit	(503,652)		(503,652)
Total liabilities and stockholders' equity	632,875		632,875
Consolidated Statement of Cash Flows
Net loss	4,003		(25,790)
Accounts receivable, net			(27,635)
Inventories			13,497
Prepaid expenses and other assets			(12,676)
Accounts payable and accrued expenses (includes restructuring)			316
Deferred income and allowances on sales to distributors			18,175
Product
Disaggregation of Revenue [Line Items]
Revenues	97,932	87,369	291,335	263,206
Consolidated Statement of Operations
Cost of revenue	43,120	38,032	137,430	120,395
Consolidated Balance Sheets
Deferred income and allowances on sales to distributors	0		0		17,250
Consolidated Statement of Cash Flows
Deferred income and allowances on sales to distributors			0	3,862
Product | Adjustments | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Revenues	(1,302)		(13,651)
Consolidated Statement of Operations
Cost of revenue	144		(5,400)
Product | Pro forma as if previous standard was in effect
Disaggregation of Revenue [Line Items]
Revenues	96,630		277,684
Consolidated Statement of Operations
Cost of revenue	43,264		132,030
Licensing and services
Disaggregation of Revenue [Line Items]
Revenues	3,552	4,602	11,487	27,489
Consolidated Statement of Operations
Cost of revenue	0	$ 617	259	4,937
Consolidated Balance Sheets
Deferred income and allowances on sales to distributors	0		0		$ 68
Consolidated Statement of Cash Flows
Deferred income and allowances on sales to distributors			(68)	$ (485)
Licensing and services | Adjustments | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Revenues	(1,525)		1,662
Licensing and services | Pro forma as if previous standard was in effect
Disaggregation of Revenue [Line Items]
Revenues	$ 2,027		$ 13,149