Employee benefit plans

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement [Abstract]

Employee benefit plans

Employee benefit plans

Equity incentive plans. The Company has outstanding equity grants from its three stock-based employee compensation plans: the 2014 Equity Incentive Plan (2014 Plan), the 2010 Equity Incentive Plan (2010 Plan) and the 2014 Employee Stock Purchase Plan (ESPP). No new options or awards have been granted under the 2010 Plan since June 2014. Outstanding options and awards under the 2010 Plan continue to be subject to the terms and conditions of the 2010 Plan. Options granted under the 2014 Plan generally expire within ten years from the date of grant and generally vest over one to four years. Restricted stock units (RSUs) granted under the 2014 Plan generally vest over two to four years based upon continued service and are settled at vesting in shares of the Company’s Class A common stock. Performance stock units (PSUs) granted under the 2014 Plan generally vest over three years based upon continued service and the Company achieving certain revenue targets, and are settled at vesting in shares of the Company’s Class A common stock. The Company accounts for forfeitures of stock-based payment awards in the period they occur. The ESPP allows eligible employees to purchase shares of the Company’s Class A common stock through payroll deductions at a price equal to 85% of the lesser of the fair market value of the stock as of the first date or the ending date of each six-month offering period. For additional information regarding the Company’s equity incentive plans, refer to the 2019 Annual Report.

Stock options

A summary of the Company’s stock option activity for the three months ended March 31, 2020 is as follows:

	Shares (in thousands)		Weighted-average exercise price		Weighted-average remaining contractual term (in years)	Aggregate intrinsic value (in thousands)
Outstanding at December 31, 2019	3,963		$	10.16	6.35	$	374
Granted	631		4.08
Exercised	(7	)	0.94
Forfeited/Cancelled	(320	)	10.46
Outstanding at March 31, 2020	4,267		$	9.25	6.48	$	157
Vested and expected to vest at March 31, 2020	4,267		$	9.25	6.48	$	157
Exercisable at March 31, 2020	2,934		$	11.01	5.25	$	157

The aggregate intrinsic value of the stock options outstanding as of March 31, 2020 represents the value of the Company’s closing stock price on March 31, 2020 in excess of the exercise price multiplied by the number of options outstanding.

Restricted stock units

A summary of the Company’s RSU activity for the three months ended March 31, 2020 is as follows:

	Shares (in thousands)		Weighted-average grant date fair value
Non-vested shares at December 31, 2019	8,225		$	6.11
Granted	4,231		4.08
Vested	(1,328	)	6.63
Forfeited	(377	)	6.32
Non-vested shares at March 31, 2020	10,751		$	5.24

Performance stock units

A summary of the Company’s PSU activity for the three months ended March 31, 2020 is as follows:

	Shares (in thousands)		Weighted-average grant date fair value
Non-vested shares at December 31, 2019	788		$	7.51
Granted	1,035		4.08
Vested	(144	)	7.51
Forfeited	(363	)	7.51
Non-vested shares at March 31, 2020	1,316		$	4.81

Employee stock purchase plan. For the three months ended March 31, 2020 and 2019, the Company issued 556,000 and 458,000 shares under its ESPP, respectively, at weighted-average prices of $3.38 and $4.96, respectively.

Stock-based compensation expense. The Company measures compensation expense for all stock-based payment awards based on the estimated fair values on the date of the grant. The fair value of stock options granted and ESPP issuance is estimated using the Black-Scholes option pricing model. The fair value of RSUs

and PSUs are determined using the Company’s closing stock price on the date of grant. There have been no significant changes in the Company’s valuation assumptions from those disclosed in its 2019 Annual Report.

The following table summarizes stock-based compensation expense included in the condensed consolidated statements of operations:

	Three months ended March 31,
(in thousands)	2020		2019
Cost of revenue	$	503	$	513
Research and development	3,022		4,677
Sales and marketing	1,717		2,213
General and administrative	2,395		2,382
Total stock-based compensation expense	$	7,637	$	9,785

The income tax benefit related to stock-based compensation expense was zero for the three months ended March 31, 2020 and 2019 due to a full valuation allowance on the Company’s United States net deferred tax assets (see Note 7 Income taxes).

At March 31, 2020, total unearned stock-based compensation of $53.2 million related to stock options, RSUs, PSUs and ESPP shares is expected to be recognized over a weighted-average period of 2.5 years.