Stock-based compensation expense included in the Company's consolidated financial statements for the three months ended March 29, 2020 and March 31, 2019 was as follows (in thousands):

	Three Months Ended
	March 29, 2020			March 31, 2019
Cost of revenue	$	12		$	26
Research and development		(464	)		655
Selling, general and administrative		54			270
Total costs and expenses	$	(398	)	$	951

During the quarter ended March 29, 2020, the Company reversed certain stock-based compensation previously recorded due to the cancellation of certain performance based RSUs as established goals required for vesting were not achieved and due to the cancellation of RSUs due to restructuring related terminations.

No stock options were granted during the three-month periods ended March 29, 2020 and March 31, 2019.

The following table summarizes the activity in the shares available for grant under the 2019 Plan during the three months ended March 29, 2020 (in thousands):

	Shares Available for Grants
	2019 Plan
Balance at December 29, 2019		272
RSUs granted		(256	)
PRSU's granted		(129	)
RSUs forfeited or expired		123
PRSUs forfeited or expired		42
Balance at March 29, 2020		52

The following table summarizes stock options outstanding and stock option activity under the 2009 Plan and the 2019 Plan, and the related weighted average exercise price, for the three months ended March 29, 2020:

	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, 2019		186	$	32.09
Forfeited or expired	*			42.09
Exercised		-		-
Balance outstanding at March 29, 2020		186	$	32.08		3.06	$	—
Exercisable at March 29, 2020		179	$	32.80		2.93	$	—
Vested and expected to vest at March 29, 2020		186	$	32.11		3.05	$	—

* Shares expired were not material

There was no intrinsic value for the stock options based on the Company’s closing stock price of $3.04 per share as of March 29, 2020, which would have been received by the option holders had all option holders exercised their options as of that date.

The total intrinsic value of options exercised during the three months ended March 29, 2020 and March 31, 2019 was $0. Total cash received from employees as a result of employee stock option exercises during the three months ended March 29, 2020 and March 31, 2019 was $0 and $3,600, respectively. The Company settles employee stock option exercises with newly issued common shares. In connection with these exercises, there was no tax benefit realized by the Company due to the Company's current loss position.

Total stock-based compensation related to stock options was approximately $14,000 and $25,000 for the three months ended March 29, 2020 and March 31, 2019, respectively. As of March 29, 2020, the fair value of unvested stock options, net of forfeitures, was approximately $24,000. This unrecognized stock-based compensation expense is expected to be recorded over a weighted average period of 0.45 year.

The Company grants restricted stock units or RSUs, to employees and directors with various vesting terms. RSUs entitle the holder to receive, at no cost, one common share for each RSU as it vests. In general, the Company's policy is to withhold shares in settlement of employee tax withholding obligations upon the vesting of RSUs. The stock-based compensation related to RSUs was approximately $(418,000) and $877,000 for the three months ended March 29, 2020 and March 31, 2019, respectively. Due to the cancellation of certain performance based RSUs and cancellations relating to restructuring, which was implemented in January 2020, the Company reversed stock-based compensation previously recorded resulting in a credit to the stock based compensation during the quarter ended March 29, 2020. As of March 29, 2020 and March 31, 2019, there was approximately $2.4 million and $3.2 million, respectively, in unrecognized compensation expense related to RSUs. The remaining unrecognized stock-based compensation expense is expected to be recorded over a weighted average period of 1.24 years.

A summary of activity for the Company's RSUs for the three months ended March 29, 2020 is as follows:

	RSUs & PRSUs Outstanding
	Number of Shares			Weighted Average Grant Date Fair Value
	(in thousands)
Nonvested at December 29, 2019		377		$	12.55
Granted		385			4.52
Vested		(84	)		11.40
Forfeited		(165	)		—
Nonvested at March 29, 2020		513		$	8.13

As of March 29, 2020, 62,335 shares remained available for issuance under the 2009 ESPP. For the three months ended March 29, 2020 and March 31, 2019, the Company recorded stock-based compensation expense related to the 2009 ESPP of approximately $0 and $49,000, respectively. The weighted average estimated fair value, as defined by the amended authoritative guidance, of rights issued pursuant to the Company's 2009 ESPP during the first quarter ended March 29, 2020 and March 31, 2019, was $0 and $.0.31, respectively, per right, respectively.

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 29, 2020		March 31, 2019
Expected term (months)		—		6.00
Risk-free interest rate		—		2.37	%
Volatility		—		53.77	%
Dividend yield		—		—

As of March 29, 2020, there was no unrecognized stock-based compensation expense relating to the Company's 2009 ESPP. ESPP grants were suspended until the extension of the term of 2009 ESPP was ratified by the shareholders in the annual general meeting on April 22, 2020.