Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Share-Based Payment Arrangement, Cost by Plan

The following table summarizes stock-based compensation expense for the years ended December 31, 2023, 2022 and 2021, respectively:

	Year Ended December 31,
(in thousands)	2023		2022		2021
Stock options and other	$	14,550	$	16,103	$	17,553
Employee stock purchase plan	1,439		1,442		1,542
Total stock-based compensation expense	$	15,989	$	17,545	$	19,095
Cost of revenue	$	1,840	$	2,172	$	2,595
Operating expenses:
Marketing and sales	3,426		3,295		3,736
Research and development	2,556		2,189		2,833
General and administrative	8,167		9,889		9,931
Total stock-based compensation expense	$	15,989	$	17,545	$	19,095

Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions

The following table provides the assumptions used in the Black-Scholes option pricing model for the years ended December 31, 2023, 2022 and 2021:

	Year Ended December 31,
	2023	2022	2021
Risk-free interest rate	3.55 - 4.55%	1.94 - 3.40%	0.80 - 1.12%
Expected life (years)	2 - 6.25	6.25	6.25
Expected volatility	49.23 - 55.92%	45.95 - 46.03%	45.28 - 45.53%
Expected dividend yield	0%	0%	0%
Weighted average grant date fair value	$16.36	$23.11	$128.14

Share-Based Payment Arrangement, Option, Activity

The following table summarizes stock option activity and the weighted average exercise price for the years ended December 31, 2023, 2022 and 2021:

	Stock Options	Weighted- Average Exercise Price
Options outstanding at January 1, 2021	229,531	$	86.46
Granted	57,901	128.14
Exercised	(28,991)	58.78
Cancelled	(25,057)	109.31
Options outstanding at December 31, 2021	233,384	97.78
Granted	118,434	48.24
Exercised	(3,114)	30.58
Cancelled	(84,712)	89.32
Options outstanding at December 31, 2022	263,992	79.07
Granted	186,804	33.36
Exercised	—	—
Cancelled	(63,635)	62.44
Expired	(15,848)	55.67
Options outstanding at December 31, 2023	371,313	$	59.92
Exercisable at December 31, 2023	116,455	$	90.65

Share-Based Payment Arrangement, Option, Exercise Price Range

The following table summarizes information about stock options outstanding at December 31, 2023:

	Options Outstanding, Vested and Expected to Vest			Options Exercisable
Range of Exercise Prices	Number Outstanding	Weighted Average Remaining Contractual Life	Weighted Average Exercise Price ($)	Number Exercisable	Weighted Average Exercise Price ($)
$32.13 to $36.48	167,725	7.92	33.40	—	—
$36.49 to $64.92	100,391	7.45	50.60	37,242	52.90
$64.93 to $180.46	103,197	5.75	112.87	79,213	108.40

Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity

The following table summarizes restricted stock activity for the years ended December 31, 2023, 2022 and 2021:

	Restricted Stock Awards	Weighted- Average Grant Date Fair Value Per Share
Restricted stock at January 1, 2021	307,199	$	98.87
Granted	205,996	123.61
Restrictions lapsed	(115,908)	91.26
Forfeited	(53,505)	128.05
Restricted stock at December 31, 2021	343,782	111.79
Granted	315,432	42.03
Restrictions lapsed	(130,452)	101.32
Forfeited	(50,166)	96.48
Restricted stock at December 31, 2022	478,596	70.36
Granted	410,682	32.46
Restrictions lapsed	(137,053)	79.61
Forfeited	(98,760)	61.25
Restricted stock at December 31, 2023	653,465	$	45.89

Schedule of Nonvested Performance-Based Units Activity

The following table summarizes performance stock activity for the years ended December 31, 2023, 2022 and 2021:

	Performance Stock Awards	Weighted- Average Grant Date Fair Value Per Share
Performance stock at January 1, 2021	19,956	$	118.66
Granted	15,078	203.64
Restrictions lapsed	—	—
Performance change	(10,366)	192.95
Forfeited	(7,829)	113.91
Performance stock at December 31, 2021	16,839	115.56
Granted	35,697	96.71
Restrictions lapsed	—	—
Performance change	(13,156)	99.59
Forfeited	(3,578)	121.79
Performance stock at December 31, 2022	35,802	77.91
Granted	71,295	57.79
Restrictions lapsed	—	—
Performance change	—	—
Forfeited	—	—
Performance stock at December 31, 2023	107,097	$	74.08

Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions

The following table presents the assumptions used to estimate the fair value of the ESPP during the years ended December 31, 2023, 2022 and 2021:

	Year Ended December 31,
	2023	2022	2021
Risk-free interest rate	4.60 - 5.16%	0.17 - 4.60%	0.06 - 0.17%
Expected life (months)	6.00	6.00	6.00
Expected volatility	47.38 - 67.84%	47.05 - 67.84%	53.44 - 65.53%
Expected dividend yield	0%	0%	0%