Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2021

Stockholders' Equity

Schedule of common stock reserved for future issuance

Stock options outstanding under 2019 Equity Incentive Plan	952,526
Restricted stock units outstanding under 2019 Equity Incentive Plan	168,195
Performance stock units outstanding under 2019 Equity Incentive Plan, at target	233,452
Shares authorized for future issuance under 2019 Equity Incentive Plan	2,259,725
Shares authorized for future issuance under 2019 Employee Stock Purchase Plan	681,840
Total	4,295,738

Schedule of stock-based compensation expense

	Three months ended September 30,				Nine months ended September 30,
	2021		2020		2021		2020
	(in thousands)				(in thousands)
Stock-Based Compensation	$	1,525	$	551	$	3,370	$	1,457

Schedule of stock option transactions

	Number of shares		Weighted-average exercise price	Weighted average remaining contractual term (in years)		Aggregate intrinsic value (in thousands)
Outstanding at January 1, 2021	1,008,648	$	23.92	8.43	$	66,028
Options granted	72,063		94.76
Options exercised	(112,819)		16.38
Options canceled	(15,366)		84.78
Outstanding at September 30, 2021	952,526	$	29.19	7.80	$	50,981
Vested and Exercisable at September 30, 2021	610,568	$	18.58	7.59	$	38,171

Schedule of fair value of each option granted was estimated on the grant date using the Black-Scholes option pricing model

Risk free rate of return (1)	0.57% - 1.15%
Expected share price volatility (2)	26.06% - 38.72%
Expected life in years (3)	5.89 years
Dividend yield (4)	0%

(1) Determined based on the U.S. Treasury yield in effect at the time of the grant for zero-coupon U.S. Treasury notes with remaining terms similar to the expected term of the options.

(2) Determined based on a blend of the Company’s historic stock price volatility and the historic volatility of a peer group of publicly traded companies.

(3) Determined using the “simplified method” for estimating the expected option life, which is the average of the weighted-average vesting period and contractual term of the option as the Company does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate expected term due to the limited period of time its common stock has been publicly traded.

(4) Determined to be zero as the Company has not historically issued dividends.

Schedule of RSU transactions

	Number of shares		Weighted-average grant date fair value
Outstanding at January 1, 2021	14,734	$	95.86
Granted	160,729		75.75
Released	(5,987)		91.35
Forfeited	(1,281)		96.90
Non vested outstanding at September 30, 2021	168,195	$	76.80

Schedule of Performance stock unit transactions

	Number of shares		Weighted-average grant date fair value
Outstanding at January 1, 2021	—	$	—
Granted	233,658		34.45
Vested	—		—
Forfeited	(206)		97.87
Non vested outstanding at September 30, 2021	233,452	$	34.40