v3.10.0.1

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of stock-based compensation expense included in the consolidated statements of operations and comprehensive loss

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

	Three Months Ended September 30,								Nine Months Ended September 30,
	2018				2017				2018				2017
	(in thousands)
Curriculum and teaching	$	3			$	2			$	10			$	2
Servicing and support	1,346				1,100				3,538				2,956
Technology and content development	1,089				904				2,875				2,447
Marketing and sales	839				463				2,046				1,235
General and administrative	4,656				3,678				15,595				8,897
Total stock-based compensation expense	$	7,933			$	6,147			$	24,064			$	15,537

Schedule of stock option activity

The following is a summary of the stock option activity for the nine months ended September 30, 2018:

	Number of Options			Weighted-Average Exercise Price per Share
Outstanding balance at December 31, 2017	4,559,176			$	15.10
Granted	663,615			84.13
Exercised	(1,000,574	)		7.03
Forfeited	(124,737	)		41.20
Expired	—			—
Outstanding balance at September 30, 2018	4,097,480			27.45
Exercisable at September 30, 2018*	2,814,863			13.34

* As of September 30, 2018, the aggregate intrinsic value of options exercisable was $174.2 million and such shares had a weighted-average remaining contractual term of 5.08 years.

Schedule of restricted stock unit activity

The following is a summary of restricted stock unit activity for the nine months ended September 30, 2018:

	Number of Restricted Stock Units			Weighted- Average Grant Date Fair Value
Outstanding balance at December 31, 2017	1,413,423			$	29.95
Granted	523,281			81.74
Vested	(585,799	)		25.54
Forfeited	(133,744	)		43.98
Outstanding balance at September 30, 2018	1,217,161			52.80

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- References

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Tabular disclosure of the allocation of equity-based compensation costs to a given line item on the balance sheet and income statement for the period. This may include the reporting line for the costs and the amount capitalized and expensed.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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Tabular disclosure of the number and weighted-average grant date fair value for restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock units that were granted, vested, or forfeited during the year.

+ References

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- Definition

Tabular disclosure for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (d)
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