Stock-Based Compensation and Employee Benefit Plan (Tables)

6 Months Ended

Jun. 30, 2020

Compensation Related Costs [Abstract]

Weighted-Average Valuation Assumptions

We used the following weighted-average assumptions in applying the Black-Scholes valuation model for determination of options:

	Three Months Ended June 30,		Six Months Ended June 30,
	2020	2019	2020	2019
Risk-free interest rate	0.6%	2.4%- 2.5%	0.6%	2.4% - 2.6%
Expected term (years)	6.6	6.4 - 6.7	6.6	6.4 - 6.7
Expected dividend yield	—	—	—	—
Expected volatility	71.0%	47.5%	71.0%	47.5% - 50.2%

Employee and Non-Employee Stock-Based Compensation Expense

The following table summarizes the components of stock-based compensation expense in the condensed consolidated statements of operations (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
			As Restated				As Restated
Cost of revenue	$	4,736	$	10,538	$	10,243	$	28,850
Research and development	4,714		12,218		10,810		26,448
Sales and marketing	2,234		8,935		6,124		20,447
General and administrative	6,947		19,673		14,473		43,441
	$	18,631	$	51,364	$	41,650	$	119,186

Stock Option and RSU Activity

The following table summarizes the stock option activity under our stock plans during the reporting period:

	Outstanding Options
	Number of Shares	Weighted Average Exercise Price		Remaining Contractual Life (Years)	Aggregate Intrinsic Value
					(in thousands)
December 31, 2019	17,837,316	$	20.76	6.94	$	14,964
Granted	200,000	7.30
Exercised	(170,873)	5.90
Cancelled	(694,838)	22.46
Balances at June 30, 2020	17,171,605	20.69		6.46	26,824
Vested and expected to vest at Current period end	16,555,245	21.08		6.37	24,325
Exercisable at Current period end	9,515,698	28.48		4.67	384

The following table presents the stock activity and the total number of RSUs available for grant under our stock plans as of June 30, 2020:

	Plan Shares Available for Grant
Balances at December 31, 2019	17,233,144
Added to plan	6,654,552
Granted	(1,414,942)
Cancelled	992,262
Expired	(675,276)
Balances at June 30, 2020	22,789,740

RSU Activity and Related Information

A summary of our RSUs activity and related information is as follows:

	Number of Awards Outstanding	Weighted Average Grant Date Fair Value
Unvested Balance at December 31, 2019	10,112,266	$	17.29
Granted	1,214,942	8.75
Vested	(3,320,153)	19.06
Forfeited	(298,951)	15.50
Balances at June 30, 2020	7,708,104	15.26