Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 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		5,887,667
Options granted		(194,500	)		194,500			2.41
Options exercised		—			(2,870	)		0.75
Options cancelled		944,524			(944,524	)		7.13
Withheld shares to pay for taxes on released RSUs		45,913
RSUs granted		(4,178,620	)
RSUs forfeited		292,145
Balance at March 31, 2020		3,745,544			10,412,952		$	7.37		7.4	$	865
Vested and exercisable at March 31, 2020					5,437,954		$	6.52		6.4	$	799
Vested and expected to vest at March 31, 2020					10,011,820		$	7.31		7.4	$	857

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:  

	Three Months Ended March 31,
	2020		2019
Expected term (in years)		6.1		6.0
Expected volatility%	66.5%		60.4%
Risk-free interest rate%	1.4%		2.6%
Expected dividend yield%	0.0%		0.0%

Summary of RSU Activity (Detail)

	RSUs
	Number of Shares			Weighted Average Grant Date Fair Value
Unvested at December 31, 2019		4,379,777		$	5.14
RSUs granted		4,178,620			3.09
RSUs vested		(263,565	)		7.08
RSUs forfeited		(292,145	)		3.57
Unvested at March 31, 2020		8,002,687		$	4.06
Vested and unreleased		131,576
Outstanding at March 31, 2020		8,134,263

Summary of Stock-Based Compensation Expense

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

	Three Months Ended March 31,
	2020		2019
Cost of revenue	$	238	$	583
Research and development		520		878
Selling and marketing		216		277
General and administrative		4,527		2,814
Total stock-based compensation expense	$	5,501	$	4,552