Stock-based compensation expense is recorded in the consolidated statements of operations as follows (in thousands):


	Three months ended June 30,				Six months ended June 30,
	2026		2025		2026		2025
Cost of goods sold	$	37	$	39	$	62	$	112
Research and development		305		161		451		431
Sales and marketing		85		88		217		161
General and administrative		468		315		872		806
Total stock-based compensation expense	$	895	$	603	$	1,602	$	1,510

The following table summarizes the outstanding stock option activity during the period indicated (shares in thousands):


				Weighted average
	Number of stock options			Exercise price		Remaining contractual term (in years)		Aggregate intrinsic value (in thousands)
Balance at December 31, 2025		2,418		$	9.07		5.5	$	169
Granted		355		$	4.23
Exercised		(248	)	$	4.28
Expired/Forfeited		(151	)	$	6.43
Balance at June 30, 2026		2,374		$	9.02		5.2	$	1,502

Vested and exercisable at June 30, 2026		1,851		$	10.31		4.1	$	526
Vested and expected to vest at June 30, 2026		2,375		$	9.02		5.2	$	1,502

The weighted average grant-date fair value of options granted during the six months ended June 30, 2026 was $2.34. The grant-date fair value of each option award is estimated on the date of grant, using the Black-Scholes-Merton option-pricing model.

As of June 30, 2026, there was $1.2 million of unrecognized stock-based compensation costs related to unvested stock options granted under the Company’s equity plans. These costs are expected to be recognized over the next 2.3 years.

The following table summarizes the Company’s restricted stock unit (RSU) activity during the period indicated (shares in thousands):


	Restricted stock units			Weighted average grant date fair value
Balance at December 31, 2025		886		$	5.13
Grants		296		$	5.12
Vested and released		(371	)	$	5.03
Forfeited		(127	)	$	5.06
Balance at June 30, 2026		684		$	5.20

As of June 30, 2026, there was $2.2 million of unrecognized stock-based compensation costs related to non-vested RSUs, which are expected to be recognized over a remaining weighted-average vesting period of 2.3 years.

During the three months ended June 30, 2026, the Company did not issue shares under the ESPP. During the six months ended June 30, 2026, the Company received $0.1 million from the issuance of 19,785 shares under the ESPP.