Revenue from Contracts with Customers (Schedule of New Accounting Standard Impact on Financial Statements) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Dec. 30, 2017
Consolidated Statement of Operations
Product revenue	$ 95,109	$ 92,669
Licensing and services revenue	3,514	11,918
Cost of product revenue	42,102	41,614
Net loss	$ (5,952)	$ (7,275)
Net loss per share, basic and diluted (in usd per share)	$ (0.05)	$ (0.06)
Consolidated Balance Sheets
Accounts receivable, net of allowance for doubtful accounts	$ 65,779		$ 55,104
Inventories	77,917		79,903
Prepaid expenses and other current assets	25,405		16,567
Total assets	644,833		635,961
Accounts payable and accrued expenses (includes restructuring)	55,274		54,405
Deferred income and allowances on sales to distributors	0		17,250
Accumulated deficit	(456,413)		(477,862)
Total liabilities and stockholders' equity	644,833		$ 635,961
Consolidated Statement of Cash Flows
Net loss	(5,952)	$ (7,275)
Accounts receivable, net	(8,867)	33,563
Inventories	2,356	1,393
Prepaid expenses and other assets	(3,253)	1,137
Accounts payable and accrued expenses (includes restructuring)	1,567	(35,029)
Deferred income and allowances on sales to distributors	0	$ (2,720)
Adjustments | Accounting Standards Update 2014-09
Consolidated Statement of Operations
Product revenue	(8,265)
Licensing and services revenue	(1,212)
Cost of product revenue	(3,819)
Net loss	$ (5,658)
Net loss per share, basic and diluted (in usd per share)	$ (0.04)
Consolidated Balance Sheets
Accounts receivable, net of allowance for doubtful accounts	$ 15,567
Inventories	(808)
Prepaid expenses and other current assets	(9,102)
Total assets	5,657
Accounts payable and accrued expenses (includes restructuring)	43
Deferred income and allowances on sales to distributors	38,673
Accumulated deficit	(33,059)
Total liabilities and stockholders' equity	5,657
Consolidated Statement of Cash Flows
Net loss	(5,658)
Accounts receivable, net	(17,375)
Inventories	438
Prepaid expenses and other assets	1,587
Accounts payable and accrued expenses (includes restructuring)	(415)
Deferred income and allowances on sales to distributors	21,423
Pro forma as if previous standard was in effect
Consolidated Statement of Operations
Product revenue	86,844
Licensing and services revenue	2,302
Cost of product revenue	38,283
Net loss	$ (11,610)
Net loss per share, basic and diluted (in usd per share)	$ (0.09)
Consolidated Balance Sheets
Accounts receivable, net of allowance for doubtful accounts	$ 81,346
Inventories	77,109
Prepaid expenses and other current assets	16,303
Total assets	650,490
Accounts payable and accrued expenses (includes restructuring)	55,317
Deferred income and allowances on sales to distributors	38,673
Accumulated deficit	(489,472)
Total liabilities and stockholders' equity	650,490
Consolidated Statement of Cash Flows
Net loss	(11,610)
Accounts receivable, net	(26,242)
Inventories	2,794
Prepaid expenses and other assets	(1,666)
Accounts payable and accrued expenses (includes restructuring)	1,152
Deferred income and allowances on sales to distributors	$ 21,423