Stock-Based Compensation (Tables)

9 Months Ended

Sep. 28, 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 and nine months ended September 28, 2014 and September 29, 2013 was as follows (in thousands):

	Three Months Ended				Nine Months Ended
	September 28, 2014		September 29, 2013		September 28, 2014		September 29, 2013
Cost of revenue	$	32	$	24	$	110	$	76
Research and development	176		74		750		286
Selling, general and administrative	244		232		890		705
Total costs and expenses	$	452	$	330	$	1,750	$	1,067

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				Nine Months Ended
	September 28, 2014		September 29, 2013		September 28, 2014		September 29, 2013
Expected term (years)	6.2		4.9		6.2		6.1
Risk-free interest rate	1.98	%	1.51	%	1.98	%	1.19	%
Expected volatility	55.10	%	62.62	%	55.10	%	60.53	%
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 nine months of 2014:

	Shares Available for Grant
	(in thousands)
Balance at December 29, 2013	2,253
Options granted	(208	)
Options forfeited or expired	154
RSUs granted	(416	)
PRSUs forfeited or expired	24
Balance at September 28, 2014	1,807

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 nine 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	208		3.84
Forfeited or expired	(154	)	3.55
Exercised	(1,687	)	2.56
Balance outstanding at September 28, 2014	5,609		$	2.66	5.42	$	3,237
Exercisable at September 28, 2014	4,461		$	2.55	4.60	$	2,992
Vested and expected to vest at September 28, 2014	5,404		$	2.64	5.29	$	3,199

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 nine months ended September 28, 2014 and information regarding RSUs and PRSUs outstanding and expected to vest as of September 28, 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	416		4.47
Vested	(300	)	4.76
Forfeited	(24	)	—
Nonvested at September 28, 2014	317		$	3.36

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				Nine Months Ended
	September 28, 2014		September 29, 2013		September 28, 2014		September 29, 2013
Expected term (months)	6.09		6.08		6.09		6.08
Risk-free interest rate	0.05	%	0.09	%	0.05	%	0.09	%
Volatility	49.17	%	39.03	%	49.17	%	39.03	%
Dividend yield	—		—		—		—