Stock-Based Compensation

6 Months Ended

Jun. 30, 2023

Stock-Based Compensation

Stock-Based Compensation

7. Stock-Based Compensation

Summary of Stock Option and Award Activity

The following table summarizes the stock option and award activity for the six months ended June 30, 2023:

		Options Outstanding
			Weighted-		Weighted-
	Options and		Average		Average	Aggregate
	Awards		Exercise		Remaining	Intrinsic
	Available for	Number of	Price Per		Contractual	Value
	Grant	Options	Share		Life (years)	(In thousands)
Balance—December 31, 2022	689,472	1,994,726	$	5.88	7.8	$	1,275
Authorized	611,228
RSUs granted	(693,518)
RSUs cancelled/forfeited	—
Options granted	(8,000)	8,000	$	6.47
Options exercised	—	(39,373)	$	4.09		$	146
Options cancelled/forfeited	3,210	(3,210)	$	7.05
Balance—June 30, 2023	602,392	1,960,143	$	5.92	7.3	$	6,488
Options exercisable—June 30, 2023		1,203,081	$	5.67	6.8	$	4,299

The total grant date fair value of options vested was $0.4 million and $0.9 million during the three months ended June 30, 2023 and 2022, respectively, and $1.3 million and $1.8 million during the six months ended June 30, 2023 and 2022, respectively.

The weighted-average grant date fair value of options granted was $4.43 and $4.40 per share during the three months ended June 30, 2023 and 2022, respectively, and $3.85 and $5.40 per share during the six months ended June 30, 2023 and 2022, respectively.

As of June 30, 2023, there was $3.0 million of total unrecognized stock-based compensation expense related to unvested options which is expected to be recognized over a weighted-average period of 2.0 years. Compensation cost capitalized within inventory at June 30, 2023 and 2022 was not material.

2016 Employee Stock Purchase Plan

In January 2023, there was an increase of 203,742 shares reserved for issuance under the Company’s Employee Stock Purchase Plan (ESPP) pursuant to the terms of the ESPP. The Company had 936,985 shares available for future issuance under the Company’s ESPP as of June 30, 2023. Employees purchased 40,894 shares for $181,000 during the three and six months ended June 30, 2023. Employees purchased 37,017 shares for $167,000 during the three and six months ended June 30 2022.

Restricted Stock Units

The following table summarizes restricted stock units (RSUs) activity for the six months ended June 30, 2023:

	RSUs Outstanding
		Weighted-
		Average
	Number of	Grant Date
	Restricted Stock	Fair Value Per
	Units	Share
Balance—December 31, 2022	656,646	$	6.45
Granted	693,518	$	6.43
Vested	(288,867)	$	6.18
Cancelled/forfeited	—	$	—
Balance—June 30, 2023	1,061,297	$	6.50

The fair value of RSUs is determined on the date of grant based on the market price of the Company’s common stock on that date.

As of June 30, 2023, there was $6.1 million of unrecognized stock-based compensation expense related to RSUs to be recognized over a weighted-average period of 2.1 years. Compensation cost capitalized within inventory at June 30, 2023 and 2022 was not material.