Stock-Based Compensation (Tables)

3 Months Ended

Apr. 01, 2018

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

Schedule of stock based compensation expense

The stock-based compensation expense included in the Company's consolidated financial statements for the three months ended April 1, 2018 and April 2, 2017 was as follows (in thousands):

	Three Months Ended
	April 1, 2018		April 2, 2017
Cost of revenue	$	34	$	33
Research and development	183		139
Selling, general and administrative	215		146
Total costs and expenses	$	432	$	318

Summary of the activity in the shares available for grant under the 2009 plan

The following table summarizes the activity in the shares available for grant under the 2009 Plan during the three months ended April 1, 2018:

	Shares Available for Grant
	(in thousands)
Balance at December 31, 2017	3,899
Authorized	4,000
RSUs granted	(1,015	)
RSUs forfeited or expired	90
Performance RSUs forfeited or expired	8
Balance at April 1, 2018	6,982

Summary of stock options outstanding and stock option activity under the 1999 plan and the 2009 plan, and the related weighted average exercise price

The following table summarizes stock options outstanding and stock option activity under the 2009 Plan, and the related weighted average exercise price, for the first three months of 2018:

	Number of Shares	Weighted Average Exercise Price		Weighted Average Remaining Term	Aggregate Intrinsic Value
	(in thousands)			(in years)	(in thousands)
Balance outstanding at December 31, 2017	3,558	$	2.09
Forfeited or expired	—	—
Exercised	—	—
Balance outstanding at April 1, 2018	3,558	$	2.09	4.09	$	677
Exercisable at April 1, 2018	3,059	$	2.27	3.39	$	372
Vested and expected to vest at April 1, 2018	3,463	$	2.12	3.97	$	616

Summary of activity for RSUs and PRSUs

A summary of activity for the Company's RSUs for the three months ended April 1, 2018 and information regarding RSUs outstanding and expected to vest as of April 1, 2018 is as follows:

	RSUs & PRSUs Outstanding
	Number of Shares		Weighted Average Grant Date Fair Value
	(in thousands)
Nonvested at December 31, 2017	2,363		$	1.54
Granted	1,015		1.64
Vested	(115	)	1.79
Forfeited	(98	)	—
Nonvested at April 1, 2018	3,165		$	1.56

Summary of the fair value of rights issued pursuant to ESPP

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
	April 1, 2018		April 2, 2017
Expected term (months)	6		6
Risk-free interest rate	1.39	%	0.57	%
Volatility	54.87	%	48.69	%
Dividend yield	—		—