Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Company's Stock Award Activity and Related Information

A summary of the Company’s stock award 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 shares authorized		9,137,667
Options granted		(736,579	)		736,579			1.97
Options exercised		—			(20,579	)		0.72
Options cancelled or forfeited		3,496,601			(3,496,601	)		6.99
Withheld shares to pay for taxes on released RSUs		299,898
RSUs granted		(5,981,966	)
RSUs cancelled or forfeited		599,623
Balance at September 30, 2020		7,763,659			8,385,245		$	7.12		7.6	$	2,273
Vested and exercisable at September 30, 2020					5,180,433		$	7.11		7.1	$	1,199
Vested and expected to vest at September 30, 2020					8,095,506		$	7.15		7.5	$	2,134

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:  

	Nine Months Ended September 30,
	2020		2019
Expected term (in years)		6.0		6.0
Expected volatility	68.8%		60.7%
Risk-free interest rate	0.7%		2.4%
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		5,981,966			2.78
RSUs vested		(996,529	)		8.14
RSUs forfeited		(599,623	)		3.13
Unvested at September 30, 2020		8,765,591		$	3.33
Vested and unreleased		153,055
Outstanding at September 30, 2020		8,918,646

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 September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Cost of revenue	$	217	$	757	$	725	$	1,967
Research and development		549		1,076		1,705		2,900
Selling and marketing		258		385		817		1,027
General and administrative		4,735		2,692		13,816		8,475
Total stock-based compensation expense	$	5,759	$	4,910	$	17,063	$	14,369