v3.19.3.a.u2

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Stock-Based Compensation

Schedule of stock-based compensation expense related to stock-based awards

Stock-based compensation expense related to stock-based awards, as well as the ESPP, is included in the following line items on the accompanying consolidated statements of operations and comprehensive loss:

	Year Ended December 31,
	2019				2018				2017
	(in thousands)
Curriculum and teaching	$	45			$	14			$	3
Servicing and support	8,915				4,764				4,036
Technology and content development	8,241				4,094				3,306
Marketing and sales	7,021				2,743				1,742
General and administrative	27,282				19,795				12,843
Total stock-based compensation expense	$	51,504			$	31,410			$	21,930

Stock options

Stock-Based Compensation

Schedule of assumptions used for estimating the fair value of the stock options granted

The following table summarizes the assumptions used for estimating the fair value of the stock options granted for the periods presented.

	Year Ended December 31,
	2019		2018		2017
Risk-free interest rate	1.6% - 2.6%		2.3% - 3.0%		2.0% - 2.1%
Expected term (years)	5.96 - 6.08		5.97 - 6.77		6.00 - 6.08
Expected volatility	45% - 64%		44% - 45%		46% - 49%
Dividend yield	0%		0%		0%

Schedule of stock option activity

The following is a summary of the stock option activity for the year ended December 31, 2019:

	Number of Options			Weighted-Average Exercise Price per Share				Weighted-Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding balance as of December 31, 2018	4,057,788			$	27.23			5.95		$	113,211
Granted	809,289			61.34				8.35
Exercised	(361,134	)		8.64				1.36
Forfeited	(116,435	)		56.00
Expired	(15,613	)		44.99
Outstanding balance as of December 31, 2019	4,373,895			34.24				5.88		28,736
Exercisable as of December 31, 2019	3,051,658			$	20.98			4.69		$	28,374

Restricted stock units

Stock-Based Compensation

Schedule of restricted stock unit activity

The following is a summary of RSU and PRSU activity for the year ended December 31, 2019:

	Number of Restricted Stock Units			Weighted-Average Grant Date Fair Value per Share
Outstanding balance as of December 31, 2018	1,139,045			$	52.47
Granted	3,388,919			32.50
Vested	(538,752	)		42.74
Forfeited	(294,297	)		50.15
Outstanding balance as of December 31, 2019	3,694,915			$	35.76

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