The Company grants options, RSUs and performance shares under the 2016 Incentive Plan (the "2016 Plan"), under which awards may be granted to all employees. Vesting periods under this plan are generally four years for options and RSUs and three years for performance shares. As of April 2, 2023, approximately 1.2 million shares were reserved for future grants under the 2016 Plan.

Additionally, the Company sponsors an Employee Stock Purchase Plan (the “ESPP”), pursuant to which eligible employees may contribute up to 10% of compensation, subject to certain income limits, to purchase shares of the Company's common stock. The terms of the plan include a look-back feature that enables employees to purchase stock semi-annually at a price equal to 85% of the lesser of the fair market value at the beginning of the offering period or the purchase date. The duration of each offering period is generally six-months. As of April 2, 2023, approximately 0.9 million shares were available for issuance under the ESPP.

Stock option activity was as follows:


(In thousands, except per share amounts)	Number of Shares			Weighted Average Exercise Price Per Share
	(In thousands)			(In dollars)
Outstanding as of December 31, 2022		872		$	30.64
Expired		(6	)	$	21.86
Outstanding as of April 2, 2023		866		$	30.70

RSU activity was as follows:


(In thousands, except per share amounts)	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Outstanding as of December 31, 2022		1,546		$	27.82
Granted		11		$	20.22
Vested		(16	)	$	28.98
Cancelled		(8	)	$	27.07
Outstanding as of April 2, 2023		1,533		$	27.75

In July 2020, July 2021 and April 2022, the Company's executive officers were granted performance shares with vesting occurring at the end of a three-year period if performance conditions are met. The number of performance shares earned and eligible to vest are determined based on achievement of the pre-determined performance conditions and the recipients’ continued service with the Company. The number of performance shares to vest could range from 0% to 150% of the target shares granted. At the end of each reporting period, the Company evaluates the probability of achieving the performance conditions and records the related stock-based compensation expense based on performance to date over the service period.

Performance shares activity was as follows:


(In thousands, except per share amounts)	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Outstanding as of December 31, 2022		430		$	29.38
Granted		—			—
Vested		—			—
Cancelled		(141	)	$	28.22
Outstanding as of April 2, 2023		289		$	29.94

Valuation and Expense Information

The following table sets forth the stock-based compensation expense resulting from stock options, RSUs, performance shares and the ESPP included in the Company's unaudited condensed consolidated statements of operations:


	Three Months Ended
(In thousands)	April 2, 2023		April 3, 2022
Cost of revenue	$	351	$	386
Research and development		1,065		1,087
Sales and marketing		1,431		1,456
General and administrative		1,818		1,768
Total	$	4,665	$	4,697

As of April 2, 2023, $0.2 million of unrecognized compensation cost related to stock options was expected to be recognized over a weighted-average period of 0.3 years and $28.7 million of unrecognized compensation cost related to unvested RSUs and performance shares was expected to be recognized over a weighted-average period of 2.0 years.