Stock Based Compensation (Tables)

3 Months Ended

Mar. 31, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation Expense

The following tables present the Company's stock-based compensation for stock-settled awards by type (i.e., stock options and restricted stock units (“RSUs”)) granted under the Company's incentive plans, and rights to purchase shares of common stock issued under the Company's Employee Stock Purchase Plan (“ESPP”) and financial statement lines included in the accompanying unaudited condensed consolidated statement of operations and comprehensive loss for the three months ended March 31:

	Three months ended March 31,
	2023		2022
	(in thousands)
Options	$	831	$	883
RSUs		1,066		511
ESPP	45			—
Total stock-based compensation expense	$	1,942	$	1,394
	Three months ended March 31,
	2023		2022
	(in thousands)
Cost of sales	$	148	$	101
Selling, general and administrative		1,562		978
Research and development		232		315
Total stock-based compensation expense	$	1,942	$	1,394

Schedule of Unamortized Compensation Cost and Weighted Average Service Period of Unvested Outstanding Awards

The following table presents the unamortized compensation cost and weighted average service period of all unvested outstanding awards as of March 31, 2023.

	Unamortized Compensation Costs		Weighted Average Service Period
	(in thousands)		(years)
Options	$	4,978	2.1
RSUs		13,456	3.2
Total unamortized compensation cost	$	18,434

Summary of Stock Option Activity under Incentive Plans

The following table summarizes stock option activity under the Company's incentive plans:

	Number of Shares			Weighted Average Exercise Price Per Share		Weighted- Average Remaining Contractual Life	Aggregate Intrinsic Value
						(in years)	(in thousands)
Options outstanding, December 31, 2022		2,756,368		$	2.83
Forfeited		(4,333	)	$	2.34
Expired		(3,541	)	$	2.34
Options outstanding, March 31, 2023		2,748,494		$	2.84	6.7	$	192
Options vested and exercisable, March 31, 2023		1,724,176		$	2.74	5.6	$	111
Vested and expected to vest after March 31, 2023		2,631,002		$	2.83	6.6	$	183

There were no options granted during the three months ended March 31, 2023.

Summary of Non Vested Stock Options

The following table summarizes the non-vested stock options that were outstanding as of March 31, 2023 and December 31, 2022:

	Number of Shares		Weighted Average Grant Date Fair Value
Non-vested Options, December 31, 2022		1,118,088	$	6.23
Non-vested Options, March 31, 2023		1,024,318	$	6.13

Summary of RSU Activity under Incentive Plans

The following table summarizes RSU activity under the Company's incentive plans:

	Number of Shares			Weighted Average Grant Date Fair Value
RSUs outstanding, December 31, 2022		2,858,649		$	4.49
Granted		2,988,302		$	1.65
Vested		(216,253	)	$	5.67
Forfeited		(32,169	)	$	5.28
RSUs outstanding, March 31, 2023		5,598,529		$	2.93