Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Stockholders' Equity Note [Abstract]

Assumptions Used to Determine Grant Date Fair Value of Stock Options Granted

The following table presents, on a weighted average basis, the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted to employees and directors:

	Year Ended December 31,
	2022			2021			2020
Risk-free interest rate		2.33	%		0.90	%		0.91	%
Expected term (in years)		6.03			6.03			5.97
Expected volatility		59	%		58	%		54	%
Expected dividend yield		0	%		0	%		0	%

Summary of Stock Option Activity

The following table summarizes the Company’s option activity since December 31, 2021:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Contractual Term		Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding as of December 31, 2021		2,797,550		$	20.64		7.54	$	14,625
Granted		1,195,910			19.48
Exercised		(507,795	)		9.19
Forfeited		(186,586	)		27.45
Expired		(10,288	)		31.89
Outstanding as of December 31, 2022		3,288,791		$	21.56		7.86	$	132,076
Vested and expected to vest as of December 31, 2022		3,288,791		$	21.56		7.86	$	132,076
Options exercisable as of December 31, 2022		1,603,499		$	17.86		6.92	$	70,331

Summary of Restricted Common Stock Activity

The following table summarizes the Company's restricted common stock activity since December 31, 2021:

	Shares			Weighted Average Grant Date Fair Value
Unvested restricted common stock as of December 31, 2021		—		$	—
Issued		26,093			28.74
Vested		—			—
Forfeited		(1,778	)		28.12
Unvested restricted common stock as of December 31, 2022		24,315		$	28.79

Schedule of Stock-Based Compensation Expense

The Company recorded stock-based compensation expense in the following expense categories of its consolidated statements of operations (in thousands):

	Year Ended December 31,
	2022		2021		2020
Cost of revenue	$	125	$	72	$	27
Research, development and clinical trials expenses		1,465		1,114		396
Selling, general and administrative expenses		8,731		5,692		1,991
	$	10,321	$	6,878	$	2,414