COMPENSATION ARRANGEMENTS (Tables)

12 Months Ended

Dec. 31, 2018

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

Schedule of Stock-Based Compensation Expense

The stock-based compensation expense related to stock awards issued under the Plans and acquisition-related awards are presented within the following line items of the consolidated statements of operations for the years ended December 31, 2018, 2017 and 2016 (in thousands):

	Year Ended December 31,
	2018		2017		2016
Cost of revenue	$	1,485	$	2,658	$	3,940
Marketing	6,948		7,949		8,929
Selling, general and administrative	56,288		70,343		96,654
Restructuring charges	—		849		4,749
Other income (expense), net	100		245		851
Total stock-based compensation expense	$	64,821	$	82,044	$	115,123

We recognized stock-based compensation from discontinued operations of $0.2 million and $3.1 million for the years ended December 31, 2017 and 2016. We also capitalized $7.4 million, $6.2 million, and $9.3 million of stock-based compensation for the years ended December 31, 2018, 2017 and 2016, in connection with internally-developed software. As of December 31, 2018, $95.2 million of unrecognized compensation costs related to unvested employee stock awards are expected to be recognized over a remaining weighted-average period of 1.35 years.

Schedule of Restricted Stock Unit Activity

The table below summarizes restricted stock unit activity under the Plans for the year ended December 31, 2018:

	Restricted Stock Units			Weighted- Average Grant Date Fair Value (per share)
Unvested at December 31, 2017	$	28,939,110		$	4.32
Granted	19,376,465			4.59
Vested	(15,226,639		)	4.46
Forfeited	(6,465,504		)	4.31
Unvested at December 31, 2018	$	26,623,432		$	4.47

Schedule of Stock Option Activity

The table below summarizes the stock option activity for the year ended December 31, 2018:

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands) (1)
Outstanding and exercisable at December 31, 2017	$	885,580		$	0.62	1.76	$	3,967
Exercised	(672,793		)	0.12
Forfeited	—			—
Outstanding and exercisable at December 31, 2018	$	212,787		1.80		1.37	$	298