Stock-Based Compensation (Tables)

3 Months Ended

Mar. 30, 2014

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

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

The stock-based compensation expense included in the Company's consolidated financial statements for the three months ended March 30, 2014 and March 31, 2013 was as follows (in thousands):

	Three Months Ended
	March 30, 2014		March 31, 2013
Cost of revenue	$	42	$	30
Research and development	353		166
Selling, general and administrative	337		256
Total costs and expenses	$	732	$	452

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

The following weighted average assumptions are included in the estimated fair value calculations for stock option grants:

	Three Months Ended
	March 30, 2014		March 31, 2013
Expected term (years)	6.98		4.91
Risk-free interest rate	2.22	%	0.82	%
Expected volatility	53.11	%	65.22	%
Expected dividend yield	—		—

Schedule of Share-based Compensation, Activity

The following table summarizes the activity in the shares available for grant under the 2009 Plan during the first three months of 2014:

	Shares Available for Grant
	(in thousands)
Balance at December 29, 2013	2,253
Options granted	(38	)
Options forfeited or expired	8
RSUs granted	(275	)
PRSUs forfeited or expired	1
Balance at March 30, 2014	1,949

Schedule of Share-based Compensation, Stock Options, Activity

The following table summarizes stock options outstanding and stock option activity under the 1999 Plan and the 2009 Plan, and the related weighted average exercise price, for the first three months of 2014:

	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Term	Aggregate Intrinsic Value
	(in thousands)				(in years)	(in thousands)
Balance outstanding at December 29, 2013	7,242		$	2.62
Granted	38		5.28
Forfeited or expired	(8	)	3.28
Exercised	(1,167	)	2.53
Balance outstanding at March 30, 2014	6,105		$	2.65	5.90	$	15,464
Exercisable at March 30, 2014	4,670		$	2.54	5.03	$	12,349
Vested and expected to vest at March 30, 2014	5,908		$	2.64	5.79	$	15,061

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity

A summary of activity for the Company's RSUs and PRSUs for the three months ended March 30, 2014 and information regarding RSUs and PRSUs outstanding and expected to vest as of March 30, 2014 is as follows:

	RSUs & PRSUs Outstanding
	Number of Shares		Weighted Average Grant Date Fair Value
	(in thousands)
Nonvested at December 29, 2013	225		$	3.17
Granted	275		4.79
Vested	(242	)	4.82
Forfeited	(1	)	—
Nonvested at March 30, 2014	257		$	3.35

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumption

The fair value of rights issued pursuant to the Company's 2009 ESPP was estimated on the commencement date of each offering period using the following weighted average assumptions:

	Three Months Ended
	March 30, 2014		March 31, 2013
Expected term (months)	5.97		5.97
Risk-free interest rate	0.09	%	0.14	%
Volatility	39.62	%	50.28	%
Dividend yield	—		—