Common Stock

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Restricted Stock Units

The summary of restricted stock unit ("RSU") activity is as follows (in thousands, except per share data):


	Number of Shares	Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Nonvested units as of December 31, 2020	33,602	$	41.49	$	1,650,577
Granted	8,195	58.18
Vested	(5,218)	38.01
Canceled	(1,862)	44.79
Nonvested units as of March 31, 2021	34,717	$	45.84	$	2,168,444

Included in the grants for the three months ended March 31, 2021 are 150,000 performance based restricted stock units (“PSU”) that have a performance criteria tied to the Company’s stock performance. The Company valued these PSUs using a

Monte Carlo valuation model and took into consideration the likelihood of the market criteria being achieved. Compensation cost associated with these PSUs is recognized on an accelerated attribution model and ultimately based on whether or not satisfaction of the performance and market criteria is probable.

The fair value as of the respective vesting dates of RSUs that vested during the three months ended March 31, 2021 and 2020 was $307.5 million and $177.5 million, respectively. In connection with RSUs that vested in the three months ended March 31, 2021, the Company withheld 129,855 shares and remitted cash payments of $7.7 million on behalf of the RSU holders to the relevant tax authorities.

As of March 31, 2021, the total unrecognized compensation cost was $1.1 billion. The Company expects to recognize this expense over the remaining weighted-average period of 2.1 years. The Company recognizes compensation expense on the RSUs granted prior to the effectiveness of its IPO Registration Statement on March 28, 2019 using the accelerated attribution method. Generally, RSUs granted after March 28, 2019 vest on the satisfaction of a service-based condition only. The Company recognizes compensation expense for such RSUs upon a straight-line basis over their requisite service periods.

2019 Employee Stock Purchase Plan

In March 2019, the Company’s board of directors adopted, and the Company’s stockholders approved, the 2019 Employee Stock Purchase Plan (the “ESPP”). The ESPP went into effect on March 27, 2019. Subject to any limitations contained therein, the ESPP allows eligible employees to contribute, through payroll deductions, up to 15% of their eligible compensation to purchase the Company’s Class A common stock at a discounted price per share. The ESPP provides for consecutive, overlapping 12-month offering periods, subject to certain reset provisions as defined in the plan. The initial offering period ran from March 28, 2019 through June 30, 2020.

A total of 6,000,000 shares of Class A common stock were initially reserved for issuance under the ESPP. On January 1, 2020, an additional 3,025,957 shares of Class A common stock were reserved for issuance under the ESPP. On January 1, 2021, an additional 3,237,371 shares of Class A common stock were reserved for issuance under the ESPP. As of March 31, 2021, 1,296,206 shares of Class A common stock have been purchased under the 2019 ESPP. The number of shares reserved under the 2019 ESPP will automatically increase on the first day of each calendar year beginning on January 1, 2020 in a number of shares equal to the least of (i) 7,000,000 shares of Class A common stock, (ii) one percent of the outstanding shares of all classes of the Company’s common stock on the last day of the immediately preceding fiscal year, or (iii) an amount determined by the administrator of the 2019 ESPP.