Equity Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Changes in Shares Available for Grant

Changes in shares available for grant during the year ended December 31, 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		(9,980,059	)
Stock options and restricted stock units forfeited or expired		3,542,597
Shares available for grant at December 31, 2023		15,299,763

Summary of Stock Option Activity Under 2009 Plan and 2019 Plan

Stock option activity under the 2009 Plan and 2019 Plan during the year ended December 31, 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		(1,030,388	)		17.07
Stock options expired		(757,191	)		22.92
Stock options exercised		(470,405	)		4.77
Stock options outstanding at December 31, 2023		12,875,045		$	15.90	$	506
Stock options vested and exercisable at December 31, 2023	9,071,627			$	16.20	$	506

Summary of Restricted Stock Unit Activity

Restricted stock unit activity under the 2019 Plan during the year ended December 31, 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	6,949,587				8.29
Restricted stock units forfeited		(1,755,018	)		11.24
Restricted stock units vested		(1,506,864	)		14.95
Nonvested restricted stock units outstanding at December 31, 2023		9,669,460		$	10.32

Summary of Estimated Grant Date Fair Values of Stock Options Granted

The estimated grant date fair values of stock options granted during the years ended December 31, 2023, 2022 and 2021 were estimated using the Black-Scholes option-pricing model with the following assumptions:

	Year Ended December 31,
	2023		2022		2021
Fair value of common stock	$8.46		$7.30 - $14.95		$30.86 - $66.50
Expected term (in years)	5.27 - 6.08		5.27 - 6.08		5.27 - 6.08
Risk-free interest rate	4.2% - 4.3%		1.7% - 3.9%		0.5% - 1.4%
Expected volatility	71.2% - 71.6%		68.2% - 71.0%		67.1% - 70.0%
Expected dividend yield		—		—		—

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

The compensation cost related to stock options, restricted stock units and market-based restricted stock units for the years ended December 31, 2023, 2022 and 2021 are included on the consolidated statements of operations as follows (in thousands):

	Year Ended December 31,
	2023		2022		2021
Cost of revenue	$	4,186	$	3,910	$	2,100
Research and development		20,465		17,689		14,061
Sales and marketing		14,553		13,597		12,312
General and administrative		23,704		20,281		14,778
Total share-based compensation expense	$	62,908	$	55,477	$	43,251

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

As of December 31, 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	$	33,892		1.94
Nonvested restricted stock units		76,944		2.67
Nonvested market-based restricted stock units		8,941		1.97