Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of performance-based awards

Period Granted	Options Granted	RSUs Granted	Options Vested	RSUs Vested	Milestone	Valuation Method
(in thousands)
Q1 2019	200	300	200	300	(1)	Monte-Carlo Simulation
Q2 2019	—	188	—	140	(2)	Grant Date Stock Price
Q3 2019	—	50	—	50	(1)	Monte-Carlo Simulation
Q1 2020	150	300	150	300	(1)	Monte-Carlo Simulation
Q1 2020	—	436	—	408	(3)	Grant Date Stock Price
Q1 2020	129	—	129	—	(3)	Black-Scholes-Merton
Q2 2020	—	21	—	21	(3)	Grant Date Stock Price
Q3 2020	10	—	10	—	(4)	Black-Scholes-Merton
Q3 2020	—	27	—	17	(3)	Grant Date Stock Price
Q4 2020	—	32	—	19	(1)	Monte-Carlo Simulation
Q4 2020	—	22	—	2	(5)	Grant Date Stock Price
Q1 2021	150	125	—	—	(1)	Monte-Carlo Simulation
Q1 2021	—	279	—	15	(3)	Grant Date Stock Price
Q2 2021	163	—	—	—	(1)	Monte-Carlo Simulation
Q2 2021	29	—	—	—	(3)	Black-Scholes-Merton
Q2 2021	—	7	—	—	(3)	Grant Date Stock Price
Q4 2021	—	20	—	—	(1)	Monte-Carlo Simulation
Q4 2021	—	205	—	—	(3)	Grant Date Stock Price
Q1 2022	110	—	—	—	(3)	Black-Scholes-Merton
Q1 2022	—	849	—	—	(3)	Grant Date Stock Price

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(1) The awards will vest based on the achievement of certain values of the Company’s common stock at multiple thresholds within certain periods and are contingent upon the completion of requisite service through the date of such vesting.

(2) The vesting of the awards will be triggered after the end of the achievement milestone, as measured by the Company.

(3) The awards vest based on achievement of certain revenue targets, units, and system implementation, contingent upon the completion of requisite service through the date of such vesting.

(4) The awards have vested based on a change of coverage.

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(5) The awards will vest based on achievement of certain revenue and recruiting targets.

Summary of stock option activity

	Outstanding Options
					Weighted-
			Weighted-		Average
	Shares		Average		Remaining	Aggregate
	Available for	Number of	Exercise		Contractual	Intrinsic
(in thousands, except for contractual life and exercise price)	Grant	Shares	Price		Life	Value
					(in years)
Balance at December 31, 2021	4,319	5,900	$	17.54	5.40	$	451,505
Additional shares authorized	3,500	—
Options granted	(221)	221	$	65.48
Options exercised	—	(631)	$	6.59
Options forfeited/cancelled	9	(9)	$	19.56
RSUs granted	(4,105)	—
RSUs forfeited/cancelled	115	—
Balance at March 31, 2022	3,617	5,481	$	20.73	5.53	$	139,798
Exercisable at March 31, 2022		4,528	$	11.58	4.92	$	132,665
Vested and expected to vest at March 31, 2022		5,424	$	20.29	5.50	$	139,391

Restricted stock units

		Weighted-
		Average
		Grant Date
(in thousands, except for grant date fair value)	Shares	Fair Value
Balance at December 31, 2021	3,988	$	74.33
Granted	4,105	$	44.25
Vested	(488)	$	56.24
Cancelled/forfeited	(115)	$	62.30
Balance at March 31, 2022	7,490	$	59.50

Summary of stock-based compensation expenses

	Three months ended March 31,
	2022						2021
	Employee		Non-Employee		Total		Employee		Non-Employee		Total
	(in thousands)
Cost of revenues	$	1,716	$	—	$	1,716	$	708	$	—	$	708
Research and development		9,006		415		9,421		3,650		224		3,874
Selling, general and administrative		23,875		75		23,950		18,604		46		18,650
Total	$	34,597	$	490	$	35,087	$	22,962	$	270	$	23,232

Employee stock options

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of assumptions used in valuation of fair value

	Three months ended March 31,
	2022				2021
Expected term (years)	5.12	—	10.00			10.00
Expected volatility	55.91	—	62.30	%		55.33	%
Expected dividend rate			0.00	%		0.00	%
Risk-free interest rate	1.62	—	1.78	%		1.13	%