Stock-Based Compensation

6 Months Ended

Jun. 30, 2024

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, 2024:

		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, 2023	598,397	1,829,428	$	5.96	6.9	$	5,676
Authorized	632,414
RSUs granted	(977,783)
RSUs cancelled/forfeited	10,007
Warrants exercised	—
Options granted	—	—		—
Options exercised	—	(106,741)	$	3.67		$	498
Options cancelled/forfeited	3,951	(4,565)	$	6.22
Balance—June 30, 2024	266,986	1,718,122	$	6.10	6.5	$	1,255
Options exercisable—June 30, 2024		1,369,585	$	5.86	6.2	$	1,197

The total grant date fair value of options vested was $0.3 million and $0.4 million during the three months ended June 30, 2024 and 2023, respectively, and $0.7 million and $1.3 million during the six months ended June 30, 2024 and 2023, respectively.

The weighted-average grant date fair value of options granted was $4.43 per share during the three months ended June 30, 2023 and $3.85 per share during the six months ended June 30, 2023. No shares were granted in the three and six months ended June 30, 2024.

As of June 30, 2024, there was $1.6 million of total unrecognized stock-based compensation expense related to unvested options which is expected to be recognized over a weighted-average period of 1.28 years. Stock-based compensation cost for options capitalized within inventory at June 30, 2024 and 2023 was not material.

2016 Employee Stock Purchase Plan

In January 2024, there was an increase of 210,804 shares reserved for issuance under the Company’s Employee Stock Purchase Plan (ESPP) pursuant to the terms of the ESPP. The Company had 1,063,270 shares available for future issuance under the Company’s ESPP as of June 30, 2024. Employees purchased 37,696 shares for $241,000 during the three and six months ended June 30, 2024. Employees purchased 40,894 shares for $181,000 during the three and six months ended June 30, 2023.

Restricted Stock Units

The following table summarizes restricted stock units (RSUs) activity for the six months ended June 30, 2024:

	RSUs Outstanding
		Weighted-
		Average
	Number of	Grant Date
	Restricted Stock	Fair Value Per
	Units	Share
Balance—December 31, 2023	905,781	$	6.59
Granted	977,783	$	8.62
Vested	(433,100)	$	6.69
Cancelled/forfeited	(10,007)	$	7.12
Balance—June 30, 2024	1,440,457	$	7.93

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, 2024, there was $10.1 million of unrecognized stock-based compensation expense related to RSUs to be recognized over a weighted-average period of 2.6 years. Stock-based compensation cost related to RSUs capitalized within inventory at June 30, 2024 and 2023 was not material.