Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Company's Stock Option Activity and Related Information

A summary of the Company’s stock option activity and related information is as follows:

				Options Outstanding
	Shares Available for Grant			Number of Stock Options Outstanding			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
											(In thousands)
Balance at December 31, 2019		948,415			11,165,846		$	7.44		7.6	$	1,907
Additional options authorized		9,137,667
Options granted		(736,579	)		736,579			1.97
Options exercised		—			(20,579	)		0.72
Options cancelled		2,165,317			(2,165,317	)		6.27
Withheld shares to pay for taxes on released RSUs		45,913
RSUs granted		(5,962,979	)
RSUs forfeited		557,428
Balance at June 30, 2020		6,155,182			9,716,529		$	7.26		7.9	$	907
Vested and exercisable at June 30, 2020					4,870,115		$	7.04		7.3	$	626
Vested and expected to vest at June 30, 2020					9,297,531		$	7.28		7.8	$	871

Schedule of Weighted-Average Assumptions Used in Black-Scholes Option-Pricing Model to Estimate Fair Value of Employee Stock Options at Grant Date

The fair value of employee stock options is estimated at the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions:  

	Six Months Ended June 30,
	2020		2019
Expected term (in years)		6.0		6.0
Expected volatility	68.8%		60.1%
Risk-free interest rate	0.7%		2.5%
Expected dividend yield	0.0%		0.0%

Summary of RSU Activity

	RSUs
	Number of Shares			Weighted Average Grant Date Fair Value
Unvested at December 31, 2019		4,379,777		$	5.14
RSUs granted		5,962,979			2.78
RSUs vested		(393,772	)		6.20
RSUs forfeited		(557,428	)		3.16
Unvested at June 30, 2020		9,391,556		$	3.72
Vested and unreleased		142,336
Outstanding at June 30, 2020		9,533,892

Summary of Stock-Based Compensation Expense Recognized for Employee Stock Awards and Employee Stock Purchase Plan Shares

Total stock-based compensation expense recognized for employee stock awards and employee stock purchase plan shares in the Company’s condensed consolidated statements of operations and comprehensive loss is classified as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
Cost of revenue	$	270	$	628	$	508	$	1,210
Research and development		636		946		1,156		1,824
Selling and marketing		343		365		559		642
General and administrative		4,554		2,968		9,081		5,783
Total stock-based compensation expense	$	5,803	$	4,907	$	11,304	$	9,459