Stockholders' Equity (Tables)

12 Months Ended

Jan. 02, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Stock-Based Compensation Expense

Total stock-based compensation expense included in our Consolidated Statements of Operations was as follows: 

	Year Ended
(In thousands)	January 2, 2016		January 3, 2015		December 28, 2013
Line item:
Cost of products sold	$	1,416	$	819	$	627
Research and development	9,141		5,176		3,916
Selling, general, and administrative	6,793		6,807		4,979
Acquisition related charges	4,293		—		—
Total stock-based compensation	$	21,643	$	12,802	$	9,522

Schedule of Share-based Payment Award, Stock Options and Employee Stock Purchase Plan, Valuation Assumptions

The following table summarizes the assumptions used in the valuation of stock option and ESPP compensation for fiscal years 2015, 2014, and 2013:

	Year Ended
	January 2, 2016	January 3, 2015	December 28, 2013
Employee and Director Stock Options
Expected volatility	43.6% to 47.3%	45.4% to 50.4%	51.4% to 54.3%
Risk-free interest rate	1.4% to 1.7%	1.5% to1.7%	0.7% to 1.0%
Expected term (years)	4.08 to 4.75	4.1 to 4.7 years	4.1 to 4.5 years
Dividend yield	—%	—%	—%
Employee Stock Purchase Plan
Weighted average expected volatility	33.6%	38.7%	48.0%
Weighted average risk-free interest rate	0.12%	0.08%	0.11%
Expected term (years)	6 months	6 months	6 months
Dividend yield	—%	—%	—%

Schedule of Share-based Compensation, Stock Options, Activity

The following table summarizes our stock option activity and related information for the year ended January 2, 2016:

(Shares and aggregate intrinsic value in thousands)	Shares		Weighted average exercise price		Weighted average remaining contractual term (years)	Aggregate Intrinsic Value
Balance, January 3, 2015	9,369		$	5.45
Grants as a result of Acquisition	2,087		4.63
Granted	2,348		5.68
Exercised	(1,159	)	3.95
Forfeited or expired	(1,201	)	5.77
Balance, January 2, 2016	11,444		$	5.46
Vested and expected to vest at January 2, 2016	11,444		$	5.46	4.26	$	12,719
Exercisable, January 2, 2016	6,692		$	5.32	3.26	$	8,256

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The following table summarizes the assumptions used in the valuation of stock options and RSUs with a market condition for fiscal years 2015 and 2014. No stock options or RSUs with a market condition were granted in fiscal year 2013:

	Year Ended
	January 2, 2016	January 3, 2015
Executive stock options with a market condition
Expected volatility	44% to 46%	n/a
Risk-free interest rate	1.4%	n/a
Expected term (years)	4.5	n/a
Dividend yield	—%	n/a
Executive RSUs with a market condition
Expected volatility	36.9%	53.5%
Risk-free interest rate	0.6%	2.2%
Expected term (years)	2.0	0.24
Dividend yield	—%	—%

Schedule of Nonvested Restricted Stock Units Activity

The following table summarizes our RSU activity for the year ended January 2, 2016:

(Shares in thousands)	Shares		Weighted average grant date fair value
Balance at January 3, 2015	2,021		$	6.66
Grants as a result of Acquisition	2,025		5.37
Granted	3,203		5.92
Vested	(1,624	)	6.04
Forfeited	(868	)	6.02
Balance at January 2, 2016	4,757		$	5.95