Equity Incentive Plans (Tables)

9 Months Ended

Sep. 30, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Changes in Shares Available for Grant

Changes in shares available for grant during the nine months ended September 30, 2023 were as follows:

	Shares Available for Grant
Shares available for grant at December 31, 2022		14,581,975
2019 Equity Incentive Plan reserve increase effective January 1, 2023		7,155,250
Stock options and restricted stock units granted and the maximum market-based restricted stock units granted eligible to be earned		(9,868,290	)
Stock options and restricted stock units forfeited or expired		2,921,613
Shares available for grant at September 30, 2023		14,790,548

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, 2023 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, 2022		13,520,997		$	16.88
Stock options granted		1,612,032			8.46
Stock options forfeited		(1,000,780	)		16.99
Stock options expired		(340,058	)		27.34
Stock options exercised		(367,405	)		5.87
Stock options outstanding at September 30, 2023		13,424,786		$	15.90	$	1,108
Stock options vested and exercisable at September 30, 2023		9,145,151		$	15.87	$	1,108

Summary of Restricted Stock Unit Activity

Restricted stock unit activity under the 2019 Plan during the nine months ended September 30, 2023 was as follows:

	Restricted Stock Units Outstanding			Weighted-Average Grant Date Fair Value per Share
Nonvested restricted stock units outstanding at December 31, 2022		5,981,755		$	14.11
Restricted stock units granted		6,837,818			8.36
Restricted stock units forfeited		(1,580,775	)		11.37
Restricted stock units vested		(1,300,344	)		14.80
Nonvested restricted stock units outstanding at September 30, 2023		9,938,454		$	10.49

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, 2023 and 2022 were estimated using the Black-Scholes option-pricing model with the following assumptions:

	Nine Months Ended September 30,
	2023		2022
Fair value of common stock	$8.46		$7.30 - $14.95
Expected term (in years)	5.27 - 6.08		5.27 - 6.08
Risk-free interest rate	4.2% - 4.3%		1.7% - 3.0%
Expected volatility	71.2% - 71.6%		68.2% - 71.0%
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, 2023 and 2022, 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,
	2023		2022		2023		2022
Cost of revenue	$	917	$	1,058	$	3,272	$	2,807
Research and development		5,187		4,382		15,267		13,370
Sales and marketing		3,241		3,357		11,111		10,170
General and administrative		5,991		5,345		17,702		14,836
Total share-based compensation expense	$	15,336	$	14,142	$	47,352	$	41,183

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

As of September 30, 2023, 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	$	40,916		2.08
Nonvested restricted stock units		85,893		2.90
Nonvested market-based restricted stock units		10,157		2.21