Revenue from Contracts with Customers (Schedule of New Accounting Standard Impact on Financial Statements) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017	Dec. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 102,715	$ 94,137	$ 201,338	$ 198,724
Consolidated Statement of Operations
Net loss	$ (20,223)	$ (13,022)	$ (26,175)	$ (20,297)
Net (loss) income per share, basic and diluted (in usd per share)	$ (0.16)	$ (0.11)	$ (0.21)	$ (0.17)
Consolidated Balance Sheets
Accounts receivable, net of allowance for doubtful accounts	$ 76,566		$ 76,566		$ 55,104
Inventories	65,586		65,586		79,903
Prepaid expenses and other current assets	21,729		21,729		16,567
Total assets	623,204		623,204		635,961
Accounts payable and accrued expenses (includes restructuring)	53,500		53,500		54,405
Deferred income and allowances on sales to distributors	0		0		17,250
Accumulated deficit	(476,636)		(476,636)		(477,862)
Total liabilities and stockholders' equity	623,204		623,204		$ 635,961
Consolidated Statement of Cash Flows
Net loss	(20,223)	$ (13,022)	(26,175)	$ (20,297)
Accounts receivable, net			(19,654)	12,846
Inventories			14,687	689
Prepaid expenses and other assets			(7,891)	2,822
Accounts payable and accrued expenses (includes restructuring)			7,095	(13,554)
Deferred income and allowances on sales to distributors			0	(7,342)
Adjustments | Accounting Standards Update 2014-09
Consolidated Statement of Operations
Net loss	$ 2,040		$ (3,618)
Net (loss) income per share, basic and diluted (in usd per share)	$ 0.01		$ (0.03)
Consolidated Balance Sheets
Accounts receivable, net of allowance for doubtful accounts	$ 9,561		$ 9,561
Inventories	(615)		(615)
Prepaid expenses and other current assets	(4,472)		(4,472)
Total assets	4,474		4,474
Accounts payable and accrued expenses (includes restructuring)	(28)		(28)
Deferred income and allowances on sales to distributors	35,521		35,521
Accumulated deficit	(31,019)		(31,019)
Total liabilities and stockholders' equity	4,474		4,474
Consolidated Statement of Cash Flows
Net loss	2,040		(3,618)
Accounts receivable, net			(11,369)
Inventories			245
Prepaid expenses and other assets			(3,043)
Accounts payable and accrued expenses (includes restructuring)			(486)
Deferred income and allowances on sales to distributors			18,271
Pro forma as if previous standard was in effect
Consolidated Statement of Operations
Net loss	$ (18,183)		$ (29,793)
Net (loss) income per share, basic and diluted (in usd per share)	$ (0.15)		$ (0.24)
Consolidated Balance Sheets
Accounts receivable, net of allowance for doubtful accounts	$ 86,127		$ 86,127
Inventories	64,971		64,971
Prepaid expenses and other current assets	17,257		17,257
Total assets	627,678		627,678
Accounts payable and accrued expenses (includes restructuring)	53,472		53,472
Deferred income and allowances on sales to distributors	35,521		35,521
Accumulated deficit	(507,655)		(507,655)
Total liabilities and stockholders' equity	627,678		627,678
Consolidated Statement of Cash Flows
Net loss	(18,183)		(29,793)
Accounts receivable, net			(31,023)
Inventories			14,932
Prepaid expenses and other assets			(10,934)
Accounts payable and accrued expenses (includes restructuring)			6,609
Deferred income and allowances on sales to distributors			18,271
Product
Disaggregation of Revenue [Line Items]
Revenues	98,294	83,168	193,403	175,837
Consolidated Statement of Operations
Cost of revenue	52,208	40,749	94,310	82,363
Product | Adjustments | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Revenues	(4,084)		(12,349)
Consolidated Statement of Operations
Cost of revenue	(1,725)		(5,544)
Product | Pro forma as if previous standard was in effect
Disaggregation of Revenue [Line Items]
Revenues	94,210		181,054
Consolidated Statement of Operations
Cost of revenue	50,483		88,766
Licensing and services
Disaggregation of Revenue [Line Items]
Revenues	4,421	10,969	7,935	22,887
Consolidated Statement of Operations
Cost of revenue	259	$ 2,179	259	$ 4,320
Licensing and services | Adjustments | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Revenues	4,399		3,187
Licensing and services | Pro forma as if previous standard was in effect
Disaggregation of Revenue [Line Items]
Revenues	$ 8,820		$ 11,122