Equity Incentive Plans (Tables)

9 Months Ended

Sep. 30, 2022

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Changes in Shares Available for Grant

Changes in shares available for grant during the nine months ended September 30, 2022 were as follows:

	Shares Available for Grant
Shares available for grant at December 31, 2021		22,299,923
Stock options and restricted stock units granted and the maximum market-based restricted stock units granted eligible to be earned		(10,823,237	)
Stock options and restricted stock units forfeited, cancelled or expired		3,470,226
Shares available for grant at September 30, 2022		14,946,912

Summary of Stock Option Activity Under 2009 Plan and 2019 Plan

Stock option activity under the 2009 Plan and 2019 Plan during the nine months ended September 30, 2022 was as follows:

	Shares Subject to Outstanding Stock Options			Weighted-Average Exercise Price per Share		Aggregate Intrinsic Value (in thousands)
Stock options outstanding at December 31, 2021		12,778,984		$	19.72
Stock options granted	4,423,644				11.67
Stock options forfeited or cancelled		(1,554,973	)		28.64
Stock options expired		(496,457	)		33.05
Stock options exercised		(1,361,891	)		5.55
Stock options outstanding at September 30, 2022		13,789,307		$	17.05	$	4,183
Stock options vested and exercisable at September 30, 2022	7,226,163			$	14.42	$	4,178

Summary of Restricted Stock Unit Activity

Restricted stock unit activity under the 2019 Plan during the nine months ended September 30, 2022 was as follows:

	Restricted Stock Units Outstanding			Weighted-Average Grant Date Fair Value per Share
Nonvested restricted stock units outstanding at December 31, 2021		1,211,191		$	37.41
Restricted stock units granted		5,905,359			11.72
Restricted stock units forfeited or cancelled		(1,418,796	)		16.44
Restricted stock units vested		(231,371	)		39.40
Nonvested restricted stock units outstanding at September 30, 2022		5,466,383		$	15.01

Summary of Estimated Grant Date Fair Value of Stock Options Granted

The estimated grant date fair values of stock options granted during the nine months ended September 30, 2022 and 2021 were estimated using the Black-Scholes option-pricing model with the following assumptions:

	Nine Months Ended September 30,
	2022		2021
Fair value of common stock	$7.30 - $14.95		$30.86 - $66.50
Expected term (in years)	5.27 - 6.08		5.27 - 6.08
Risk-free interest rate	1.7% - 3.0%		0.5% - 1.1%
Expected volatility	68.2% - 71.0%		67.1% - 70.0%
Expected dividend yield		—		—

Summary of Compensation Costs Related to Stock Options and RSUs Included on Unaudited Condensed Consolidated Statements of Operations

The compensation cost related to stock options, restricted stock units and market-based restricted stock units for the three and nine months ended September 30, 2022 and 2021, respectively, are included on the unaudited condensed consolidated statements of operations as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
Cost of revenue	$	1,058	$	650	$	2,807	$	1,386
Research and development		4,382		3,637		13,370		10,311
Sales and marketing		3,357		3,369		10,170		9,166
General and administrative		5,345		3,987		14,836		10,513
Total share-based compensation expense	$	14,142	$	11,643	$	41,183	$	31,376

Schedule of Unrecognized Share-Based Compensation Expense and the Remaining Weighted-Average Recognition Period

As of September 30, 2022, unrecognized share-based compensation expense and the remaining weighted-average recognition period were as follows:

	Unrecognized Share-Based Compensation Expense (in thousands)		Remaining Weighted-Average Recognition Period (in years)
Nonvested stock options	$	74,954		2.65
Nonvested restricted stock units		69,624		3.22
Nonvested market-based restricted stock units		3,774		2.43