Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 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)	December 31, 2016		January 2, 2016		January 3, 2015
Cost of products sold	$	888	$	1,416	$	819
Research and development	7,928		9,141		5,176
Selling, general, and administrative	7,397		6,793		6,807
Acquisition related charges	—		4,293		—
Total stock-based compensation	$	16,213	$	21,643	$	12,802

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 2016, 2015, and 2014:

	Year Ended
	December 31, 2016	January 2, 2016	January 3, 2015
Employee and Director Stock Options
Expected volatility	44.2% to 50.8%	43.6% to 47.3%	45.4% to 50.4%
Risk-free interest rate	.94% - 2.06%	1.4% to 1.7%	1.5% to 1.7%
Expected term (years)	4.06 - 4.78	4.08 to 4.75	4.1 to 4.7
Dividend yield	—%	—%	—%
Employee Stock Purchase Plan
Weighted average expected volatility	57.9%	33.6%	38.7%
Weighted average risk-free interest rate	0.43%	0.12%	0.08%
Expected term	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 December 31, 2016:

(Shares and aggregate intrinsic value in thousands)	Shares		Weighted average exercise price		Weighted average remaining contractual term (years)	Aggregate Intrinsic Value
Balance, January 2, 2016	11,444		$	5.46
Granted	3,907		5.65
Exercised	(1,466	)	3.91
Forfeited or expired	(1,319	)	5.47
Balance, December 31, 2016	12,566		$	5.70
Vested and expected to vest at December 31, 2016	12,566		$	5.70	4.39	$	20,966
Exercisable, December 31, 2016	6,876		$	5.65	3.15	$	11,851

Schedule of Nonvested Restricted Stock Units Activity

The following table summarizes our RSU activity for the year ended December 31, 2016:

(Shares in thousands)	Shares		Weighted average grant date fair value
Balance, January 2, 2016	4,757		$	5.95
Granted	1,376		5.64
Exercised	(1,742	)	5.97
Forfeited or expired	(1,144	)	5.68
Balance, December 31, 2016	3,247		$	5.90

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 2016, 2015 and 2014:

	Year Ended
	December 31, 2016	January 2, 2016	January 3, 2015
Executive stock options with a market condition
Expected volatility	46%	44% to 46%	n/a
Risk-free interest rate	1.1%	1.4%	n/a
Expected term (years)	4.5	4.5	n/a
Dividend yield	—%	—%	n/a
Executive RSUs with a market condition
Expected volatility	n/a	36.9%	53.5%
Risk-free interest rate	n/a	0.6%	2.2%
Expected term (years)	n/a	2.0	0.2
Dividend yield	n/a	—%	—%